Let me start with something I tell every candidate who attends our UT Level II training in Bangalore.

Knowing how to perform an ultrasonic test — how to set up the instrument, calibrate the DAC curve, scan the weld, and find an indication — is half the job. The other half, equally important and far more frequently misunderstood, is knowing what to do with what you find. How long is too long? How strong an echo is too strong? When do you call a weld rejected — and when do you leave it in service?

Those questions are answered by acceptance standards. And for ultrasonic testing of welds in the ISO world, the primary acceptance standard is ISO 11666:2018 — Non-Destructive Testing of Welds — Ultrasonic Testing — Acceptance Levels.

In nearly three decades of doing and teaching UT in Indian industry, I have found ISO 11666 to be one of the most misquoted, misapplied, and misunderstood standards in the NDT practitioner’s toolkit. Engineers mix it up with ISO 17640 (the testing technique standard). They confuse its acceptance levels with those in ASME Section VIII. They apply AL2 where AL3 was specified — or vice versa — without understanding what the practical consequence is.

This article is my attempt to fix that. We will go through ISO 11666:2018 from beginning to end — the scope, the logic, the numbers, the practical application, and the relationship to every other standard in the ISO weld inspection family. By the end, you will be able to look at a UT test report referencing this standard and know exactly what it means.

What ISO 11666 Is — And What It Is Not

Before we go any further, let us establish clearly what ISO 11666 does and does not cover.

ISO 11666 tells you: Given an ultrasonic indication found during UT of a weld, what amplitude and length criteria determine whether it is acceptable or rejectable?

ISO 11666 does not tell you: How to perform the UT test. Which probes to use. How to calibrate the instrument. What scanning patterns to follow. All of those are covered by ISO 17640 — Non-Destructive Testing of Welds — Ultrasonic Testing — Techniques, Testing Levels and Assessment — which is the technique standard that ISO 11666 depends upon.

Think of it this way: ISO 17640 tells you how to look. ISO 11666 tells you what you are allowed to find. They work together — and you cannot apply one without the other. Every UT of a weld to ISO standards is a two-standard exercise: technique per ISO 17640, acceptance per ISO 11666.

Scope and Application — What This Standard Covers

ISO 11666:2018 was published in 2018 as the second edition, replacing ISO 11666:2010. As of 2025, a new committee draft (ISO/CD 11666) is under development — so a third edition is on the horizon. However, the 2018 edition remains the active international standard and is the version cited in the vast majority of current contracts and codes.

The standard applies to:

Full penetration welded joints in ferritic steels with thicknesses from 8 mm to 100 mm. This is the primary scope — the application that covers the overwhelming majority of welded pressure vessels, structural steel, pipelines, and process piping in Indian and international fabrication.

It can also be used for other types of welds, materials and thicknesses, provided the tests have been performed with necessary consideration of the geometry and acoustic properties of the component, and an adequate sensitivity can be employed to enable the acceptance levels of this document to be applied.

This second paragraph is more important in practice than the first. It is the clause that experienced practitioners use to apply ISO 11666 to austenitic stainless steel welds, aluminium alloy welds, and nickel alloy welds — always with the caveat that the UT technique must be appropriate for the material, and that adequate sensitivity to the relevant indication sizes must be demonstrably achievable.

What the standard does NOT apply to:

• Partial penetration welds — fillet welds, tee joints with partial penetration, overlay welds
• Welds in materials below 8 mm thickness (for thin section, other standards apply)
• Welds in materials above 100 mm thickness (special thick-section procedures are required)
• Austenitic stainless steel welds where specific acoustic problems preclude adequate sensitivity without specific additional provisions

The ISO Weld Inspection Standard Family — Understanding Where ISO 11666 Fits

To understand ISO 11666 properly, you need to understand the ecosystem of ISO standards it belongs to. These standards are not independent — they form a structured hierarchy.

ISO 5817:2014 — Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) — Quality Levels for Imperfections

This is the foundational document that defines what imperfection sizes and types are acceptable for different applications of welded joints. ISO 5817 defines three weld quality levels:

• Quality Level B — the highest quality; strictest limits on imperfection sizes
• Quality Level C — intermediate quality; moderate limits
• Quality Level D — the lowest quality; most permissive limits

These three quality levels are the starting point for everything in the ISO weld acceptance world. When a contract specifies “ISO 5817 Quality Level B welds”, it is saying: every weld in this project must meet the strictest permissible imperfection limits.

ISO 17640:2018 — Non-Destructive Testing of Welds — Ultrasonic Testing — Techniques, Testing Levels and Assessment

This is the testing technique standard. It defines how UT of welds shall be performed — probe selection, frequency, scanning technique, calibration, recording level, and how to determine the length of an indication. It defines four testing levels (A, B, C, and D) of increasing thoroughness, corresponding to the criticality of the application.

ISO 11666:2018 — Non-Destructive Testing of Welds — Ultrasonic Testing — Acceptance Levels

This is what we are discussing today. It takes the findings produced by a UT test performed per ISO 17640 and tells you whether those findings are acceptable or rejectable, at one of two acceptance levels that correspond to ISO 5817 quality levels.

The relationship is beautifully systematic: the quality of the weld (ISO 5817) drives the strictness of the testing (ISO 17640 testing level) which drives the strictness of the acceptance criteria (ISO 11666 acceptance level). Everything ties together.

The Two Acceptance Levels — AL2 and AL3

ISO 11666:2018 specifies two ultrasonic acceptance levels known as acceptance level 2 (AL 2) and acceptance level 3 (AL 3) for full penetration welded joints in ferritic steels, which correspond to ISO 5817:2014, quality levels B and C.

Let me be very specific about what these numbers mean and which is stricter — because this is where confusion consistently occurs.

Acceptance Level 2 (AL2) = ISO 5817 Quality Level B = The STRICTER level

Acceptance Level 3 (AL3) = ISO 5817 Quality Level C = The LESS STRICT level

The counterintuitive thing for newcomers is that a lower number (2) is the stricter acceptance level. This follows the ISO 5817 convention where Quality Level B (the best) is stricter than Quality Level C, which is in turn stricter than Quality Level D. The numbering reflects the ISO 5817 quality level letters: B = 2, C = 3.

An acceptance level corresponding to ISO 5817:2014, quality level D is not included in this document, as ultrasonic testing is generally not requested for this weld quality.

This is a logical and practical decision. ISO 5817 Quality Level D represents the most lenient weld quality — welds where relatively large imperfections are acceptable. For such welds, UT is typically not a contractual requirement because the quality level is low enough that the effort and cost of ultrasonic testing is disproportionate to the application’s criticality.

The Three Levels You Must Understand — Recording, Evaluation, and Acceptance

One of the most common sources of confusion in applying ISO 11666 is the distinction between three different amplitude thresholds that appear in the standard. These are not the same thing, and mixing them up leads to incorrect reporting.

The Recording Level (also called the Detection Level)

This is the amplitude threshold above which the technician must write the indication into the test record. Every indication that exceeds the Recording Level must be documented — its location, depth, length, and amplitude relative to the reference level. The recording level does NOT determine acceptance or rejection — it only determines what gets written down.

Per ISO 17640 and ISO 11666, the evaluation levels are expressed in dB relative to the reference DAC (Distance-Amplitude Correction) curve established from a reference reflector (typically a 3 mm side-drilled hole in the calibration block of the same material and nominal thickness as the test object).

Evaluation and Acceptance Levels

The Evaluation Level

This is the amplitude above which the technician must measure the indication’s length (using the 6 dB drop method or the specified echo-amplitude method) and assess it against the acceptance criteria. Indications above the recording level but below the evaluation level are recorded in full but their length does not need to be measured and they are not evaluated against the acceptance criteria tables.

In ISO 11666:2018, the evaluation levels for techniques 1 to 4 are given in ISO 11666:2018, Table A.1. These are expressed as dB values below the reference DAC level — typically in the range of DAC -10 dB or DAC -6 dB depending on the technique and thickness range.

The Acceptance Level

This is the maximum amplitude and maximum length that an indication may have while still being classified as acceptable. An indication that exceeds either the amplitude acceptance criterion OR the length acceptance criterion (or both) at its given evaluation level must be classified as rejectable.

Understanding the hierarchy — Recording → Evaluation → Acceptance — is the key to reading ISO 11666 correctly.

How the Acceptance Criteria Work — The Practical Application

The core of ISO 11666 is a set of tables that relate:

1. Wall thickness of the weld joint (which affects the amplitude reference level and the length acceptance criteria)
2. Amplitude of the indication (expressed in dB relative to the H0 reference level — the point on the DAC curve at the depth of the indication)
3. Measured length of the indication (determined by the 6 dB drop method or echo-amplitude method)

These three variables together determine whether an indication is accepted or rejected.

Let me work through this in practical terms.

Setting Up the Reference — What H0 Means

H0 is the amplitude reference point in ISO 11666 — it is the amplitude of the echo from the reference reflector (a 3 mm diameter flat-bottom hole or side-drilled hole, depending on the technique) at the same metal path distance as the indication being evaluated, as read from the DAC curve.

This is critical: H0 is not a fixed point on the instrument. It changes with depth. When you evaluate an indication at 20 mm depth, H0 is the DAC curve amplitude at 20 mm. When you evaluate an indication at 50 mm depth, H0 is the DAC curve amplitude at 50 mm. The DAC curve automatically accounts for sound attenuation with distance, so H0 always represents the same equivalent flaw size regardless of depth.

What the Acceptance Tables Tell You

For each combination of acceptance level (AL2 or AL3) and weld thickness range, the acceptance table gives you pairs of conditions. An indication must be evaluated against both conditions — amplitude and length — and must satisfy BOTH to be accepted.

In simplified practical terms, for a typical structural steel weld at Acceptance Level 2:

An indication is accepted if BOTH of the following apply:

• Its amplitude does not exceed H0 (the DAC curve amplitude at that depth), and Its measured length does not exceed a specified fraction of the wall thickness (typically t/4 for certain thickness ranges)

An indication is rejected if EITHER:

• Its amplitude exceeds H0 at any depth, OR
• Its length exceeds the maximum permitted regardless of amplitude, OR
• Its amplitude and length combination falls above the acceptance line in the table

The elegance of this system is that it mirrors real-world defect behaviour: large but shallow and short indications may be acceptable, while long continuous linear indications are rejectable even at relatively low amplitudes, because a long linear discontinuity (which could be a crack, a linear slag line, or a lengthy area of lack of fusion) is always more dangerous than an isolated point reflector.

The Amplitude-Length Relationship — The Key Insight

There is a principle embedded in the ISO 11666 tables that every practising UT inspector should internalise:

As an indication’s length increases, the maximum acceptable amplitude decreases.

Or stated another way: the longer the indication, the stricter the amplitude criterion. A short indication (length less than half the wall thickness, for example) may be accepted at full H0 amplitude. But a long indication — one whose length approaches or exceeds the wall thickness — must have an amplitude significantly below H0 to be accepted.

Why? Because length is a proxy for defect type and severity. A point-like porosity pore gives a short indication. A slag inclusion can give a moderate-length indication. But lack of fusion — particularly if it extends over a long run of the weld — gives a long indication. And lack of fusion, being a planar defect with potential stress-concentration effect, is far more dangerous in service than an equivalent-length chain of porosity. The amplitude-length relationship in the acceptance tables reflects this physical reality.

AL2 vs AL3 — When to Apply Which, and Why It Matters

The choice of acceptance level for a given weld is one of the most important decisions in a UT inspection contract. It is not a decision that should be made by the NDT inspector on site — it should be specified in the inspection contract, the design documentation, or the applicable product standard.

Here is the practical guidance:

Apply AL2 (the stricter level) when:

• The weld carries high stress or is in a fatigue-critical location
• The weld is in a pressure-retaining system (pressure vessels, boilers, pipelines) where failure could cause catastrophic release
• The applicable product standard or contract specifies ISO 5817 Quality Level B
• The weld joins safety-critical structural members — primary load-bearing joints in bridges, offshore platforms, or building frames
• Failure of the weld would have significant consequences for life safety or environmental integrity
• The design has been based on weld quality Level B assumptions

Apply AL3 (the less strict level) when:

• The weld is in a lower-criticality structural application
• The applicable product standard or contract specifies ISO 5817 Quality Level C
• The weld carries static (non-cyclic) loading and the design tolerates a larger imperfection
• The fabrication is categorised as standard quality rather than special quality

The critically important point: The contract or product standard determines the acceptance level. The inspector applies it — but does not choose it. If you receive a UT contract with no acceptance level specified, this must be resolved before testing begins. Applying AL3 where AL2 was required, or vice versa, is a significant quality failure — not just an administrative one. It can result in unsafe welds being accepted into service, or acceptable welds being unnecessarily rejected.

The Length Measurement Question — 6 dB Drop vs Echo-Amplitude Method

One area where ISO 11666 gives inspectors a choice — but a choice that must be consistently documented — is in the method for measuring indication length.

The 6 dB Drop Method

The probe is scanned along the weld axis until the echo from the indication drops to half its maximum amplitude (a 6 dB reduction). The distance between the two 6 dB drop positions along the scan axis is reported as the indication length. This method is straightforward, well-understood, and appropriate when the indication is reasonably distinct and not near the weld root or cap.

The Echo-Amplitude Method (DAC-based)

The inspector scans the probe along the weld until the indication amplitude falls below a specified threshold relative to H0, then reports the distance between those threshold-crossing positions as the indication length. This method tends to give shorter reported lengths than the 6 dB drop method for the same indication — which means that choosing this method rather than 6 dB drop for the same indication may be the difference between acceptance and rejection.

This is not a trick — it is a legitimate technical approach, and ISO 11666 permits both methods. But the method must be specified in the written procedure and consistently applied. An inspector who switches between methods depending on which gives a more convenient result for a marginal indication is not practising good NDT — and any competent reviewer of the test records would spot this immediately.

The Relationship with ISO 17640 Testing Levels — A Table Worth Understanding

In addition to possessing general knowledge of ultrasonic weld testing, personnel must also understand the testing challenges specifically associated with the type of welded joints under examination.

ISO 17640 defines four testing levels — A, B, C, and D — of increasing thoroughness and coverage. The choice of ISO 17640 testing level determines the scanning coverage, the probe angles used, and the number of probe positions. ISO 11666 acceptance levels are linked to ISO 17640 testing levels:

The important implication is that a contract specifying AL2 will almost certainly require ISO 17640 Testing Level B or C, because only the more comprehensive scanning coverage provided by those testing levels can reliably detect the smaller indications that AL2 is intended to control.

Conversely, a contract that specifies ISO 17640 Testing Level B but AL3 is a contract for moderately thorough scanning with moderately lenient acceptance — appropriate for secondary structural members in non-critical applications.

Transfer Correction — The Most Frequently Missed Step

Transfer differences, between test object and reference block, at a representative number of locations. ISO 16811 describes suitable techniques for this evaluation. When the differences are less than or equal to 2 dB, inspectors do not need to apply correction. The differences exceed 2 dB but remain less than or equal to 12 dB, inspectors must compensate for them. Transfer losses exceed 12 dB, inspectors must investigate the cause and carry out further preparation of the scanning surface.

This is one of the most practically significant provisions in the standard — and one of the most consistently overlooked in routine inspection work.

The calibration block has a smooth, flat surface. The inspected weld may have a rough surface due to the as-welded condition, scale, or minor corrosion. This surface roughness introduces additional sound attenuation, reducing the sound entering the weld compared with the amount that entered the calibration block. If inspectors do not measure and compensate for this transfer difference, the actual sensitivity becomes lower than assumed, causing the system to miss small indications that should have appeared above the recording level.

The correct procedure: after calibrating on the reference block, measure the DAC amplitude using the same probe on the actual weld surface at several representative locations. The difference between this reading and the calibration block reading is the transfer correction. If the difference exceeds 2 dB, inspectors must increase the instrument gain by the correction value before the test begins.

In my experience training UT Level II candidates, transfer correction is the step that separates the technician who follows a procedure from the technician who understands what the procedure is trying to achieve.

What the 2018 Revision Changed From the 2010 Edition

For those who have worked with ISO 11666:2010 and are updating their knowledge, the 2018 revision introduced several important clarifications and updates:

Clearer correlation with ISO 5817:2014: The 2018 edition more explicitly links AL2 to ISO 5817 Quality Level B and AL3 to ISO 5817 Quality Level C, making it easier to use the standard in conjunction with quality requirements specified per ISO 5817.

The revised Table A.1 aligns the evaluation level table with the updated ISO 17640:2018 technique definitions, particularly for the four standard techniques.

Expanded guidance on non-ferritic materials: The 2018 edition provides slightly more guidance on applying the acceptance criteria to non-ferritic materials where specific acoustic properties affect the validity of the reference calibration.

The 2018 edition clarifies that inspectors must establish the recording threshold before scanning begins and cannot retrospectively adjust it to change the documented results.

As of late 2024, the committee registered a new draft standard (ISO/CD 11666) to replace ISO 11666:2018 and initiated committee drafting in December 2025. The comment period closed in February 2026. This indicates that the committee is likely to publish a new edition within the next two to three years. NDT professionals working to this standard should monitor ISO’s publications for the DIS (Draft International Standard) — which will give advance notice of any significant changes to the acceptance criteria.

Applying ISO 11666 with PAUT — A Growing Practical Question

One of the questions that advanced UT practitioners ask me most frequently is whether they can apply ISO 11666 acceptance criteria to Phased Array Ultrasonic Testing (PAUT) results.

The short answer is: yes, with important conditions.

There is a document that specifies the application of the phased array technology for the semi- or fully automated ultrasonic testing of fusion-welded joints in metallic materials of minimum thickness 6 mm. It applies to full penetration welded joints of simple geometry in plates, pipes, and vessels, where both the weld and the parent material are low-alloy and/or fine grained steel.

The relevant companion standard for PAUT of welds is ISO 13588 — which covers the PAUT technique for weld inspection and references ISO 11666 acceptance levels. When inspectors use PAUT to perform weld UT in accordance with ISO 17640 technique requirements and express the results in equivalent amplitude terms relative to the same reference reflector (3 mm SDH or FBH), they can apply the ISO 11666 acceptance tables directly.

The critical condition requires the PAUT technique to demonstrate, through validation, that it achieves at least equivalent detection capability to the manual UT technique it replaces. The amplitude reference calibration must use the same reference reflector as specified for the manual technique. When PAUT produces results in S-scan or E-scan format, inspectors must properly extract the maximum amplitude at any point in the weld cross-section and compare it with the acceptance criteria.

PAUT done properly to ISO standards is a powerful tool — faster, more reproducible, and often more sensitive than manual UT for complex weld geometries. PAUT done without proper calibration and without attention to the acceptance standard requirements is just impressive-looking data that may not mean what the client thinks it means.

A Worked Example — From DAC Calibration to Accept/Reject Decision

Let me take you through a realistic scenario — the kind of situation that comes up on the shop floor regularly.

The Setup:

• Butt weld in carbon steel pressure vessel
• Wall thickness: 30 mm
• Acceptance level specified: AL2 (ISO 5817 Quality Level B)
• Testing per ISO 17640, Testing Level B
• Technique: Angle beam, 60° probe, 4 MHz, single angle
• Calibration: DAC curve from 3 mm SDH in reference block, 30 mm thickness, same material

The Calibration: You establish the DAC curve. At the 30 mm metal path depth, your DAC amplitude corresponds to the response from the 3 mm SDH. You set this as H0 at that depth. You adjust sensitivity to bring this point to 80% full screen height (FSH) — a standard reference point.

The Scan: You scan the weld. You find an indication at approximately 22 mm depth (metal path). The maximum echo amplitude from this indication is 72% FSH. You note that it exceeds the recording level, which you set below DAC—perhaps at DAC -10 dB, equivalent to about 25% FSH. You stop and evaluate.

Reading H0 at 22 mm depth: From your DAC curve, at 22 mm metal path, the DAC is — let’s say — 78% FSH. So your indication amplitude of 72% FSH is below H0. In dB terms, it is approximately 0.7 dB below H0. This means the indication is below the maximum amplitude acceptance criterion of H0.

Length Measurement: You measure the indication length using the 6 dB drop method. The amplitude drops from 72% FSH to 36% FSH (half) at two positions along the weld axis. The distance between these positions: 18 mm.

Applying the Acceptance Table

For AL2 with a 30 mm wall thickness and an indication amplitude below H0, what maximum length does the standard permit?

The ISO 11666:2018 Table gives maximum indication lengths that depend on the amplitude relative to H0 and the wall thickness. For an indication at or below H0 in a 30 mm wall, the standard typically expresses the maximum permitted length as a fraction of the wall thickness.Approximately t/2 for the amplitude level under discussion—which corresponds to 15 mm.

Our indication is 18 mm long. The acceptance criterion is 15 mm. AL2 rejects this indication.

Evaluators would need to reassess the same indication against the AL3 acceptance criteria to determine whether the less stringent level would accept it. Although that assessment remains academic from a contractual standpoint if the contract specifies AL2. It belongs in a fitness-for-service assessment, not the inspection report.

The Most Common Mistakes I See in ISO 11666 Application

After reviewing test reports and conducting audits for fabricators and inspection companies across India, these are the recurring errors:

Mistake 1 — Applying AL3 instead of AL2 because it is “easier to pass” The acceptance level is specified in the contract. Applying the wrong level — intentionally or through carelessness — is a quality system failure. Any reputable inspection company that discovers this has happened must issue a corrected report and notify the client.

Mistake 2 — Not performing transfer correction The calibration block surface is different from the weld surface. If the difference is more than 2 dB, correction is mandatory. Many inspectors on site skip this step because it adds time. It compromises the sensitivity of the inspection.

Mistake 3 — Measuring length by eye rather than by the 6 dB drop method “It looks about 15 mm long” is not a length measurement. Inspectors must use and document the 6 dB drop method or the echo-amplitude method.

other Common Mistakes That Needs Consideration

Mistake 4 — Confusing the evaluation level with the acceptance level. Inspectors must assess an indication that exceeds the evaluation level; they cannot automatically reject it. Many technicians incorrectly treat exceeding the evaluation level as a rejection. It is a threshold that triggers length measurement and acceptance assessment.

Mistake 5 — Using calibration blocks of the wrong material ISO 17640 and ISO 11666 require that the calibration block be of the same material group. As the test object.

Using a carbon steel calibration block for a 316L stainless steel weld inspection will give incorrect sensitivity because the acoustic properties differ.

Mistake 6 — Failing to specify the acceptance level in the test report. Every UT weld test report should clearly state the applied acceptance level (AL2 or AL3). The evaluation level in dB, the recording level in dB, and the reference reflector used. Reports that omit this information are incomplete and non-compliant with ISO 17640 reporting requirements.

How ISO 11666 Relates to Other Major UT Acceptance Standards

For practitioners who work across multiple code environments, here is the orientation table that I share in our UT Level II training:

The important thing to note: ASME and ISO acceptance systems are fundamentally different in their approach. ASME uses a simpler reject/accept binary based primarily on whether the indication exceeds the DAC curve. A DAC-crossing indication is typically rejectable (with some additional evaluation criteria). ISO 11666 uses a more nuanced system in which amplitude and length together determine acceptance. Thus allowing inspectors to accept certain above-DAC indications if their length remains within permissible limits.

This means you cannot substitute one for the other without understanding which is more conservative for a given indication. ASME might reject a short but high-amplitude indication that ISO 11666 AL3 would accept.While certain ASME interpretations might accept a long but moderate-amplitude indication that ISO 11666 AL2 would reject. Know your code, and apply it correctly.

Writing the ISO 11666 UT Test Report

The ISO 17640 reporting requirements (which govern the test report for UT of welds using ISO 11666 acceptance criteria) specify that every compliant test report must include:

• Name of the testing organisation and name of the inspector
• Inspector’s qualification level and certification scheme
• Name of the client and identification of the tested object
• Material specification, dimensions, and condition of the weld
• Testing standard: ISO 17640, testing level specified
• Acceptance standard: ISO 11666:2018, acceptance level applied (AL2 or AL3)
• Reference reflector: type (SDH or FBH), diameter, location in calibration block
• Probe details: type, frequency, angle, size, manufacturer, serial number
• Instrument type and serial number
• Calibration date and reference (instrument must be in calibration)
• Recording level, evaluation level, and acceptance level in dB relative to H0
• Transfer correction applied (value in dB, or statement that correction was less than 2 dB)
• Scanning pattern and coverage achieved
• For each recorded indication: location, depth, measured length, maximum amplitude (relative to H0), assessment (Accepted/Rejected)
• Overall conclusion: Accepted or Rejected
• Date of testing
• Authorised signature — minimum UT Level II per applicable certification scheme

A report that is missing any of these elements is incomplete by the standard’s requirements. For NABL-accredited reports (as issued by Trinity NDT WeldSolutions), additional requirements per ISO/IEC 17025 — including measurement uncertainty statement, NABL logo and accreditation number, unique report reference, and non-modification statement — also apply.

The Bigger Picture — Why Acceptance Standards Matter More Than Many Realise

Let me close with something that goes beyond the technical detail.

I started in NDT in the late 1990s, and early on, a conversation with a senior inspector who had worked on refinery piping for two decades struck me deeply. He said something that stayed with me: “The acceptance criterion is not just a number. It is a statement about what humanity has collectively agreed is safe enough.”

That sounds philosophical for an NDT standard. But think about what is behind ISO 11666:2018. The acceptance levels are not guesses or conservative rule-of-thumb estimates. They are the product of decades of fracture mechanics research — understanding how cracks and other weld discontinuities behave under load, how they grow under cyclic stress, at what size they become critical under the design loading conditions of real structures. Research grounds the ISO 5817 quality levels, which in turn drive the ISO 11666 acceptance levels.

When you apply AL2 and reject a weld with an indication that slightly exceeds the acceptance criteria, you are making a decision that the research says that particular combination of amplitude and length represents a risk that the design did not account for and cannot reliably tolerate. When you accept a weld with a 14 mm indication where the limit is 15 mm, you are making a decision that the research says this particular size, in this material, at this depth, is below the threshold at which fracture mechanics predicts failure at the design stress.

This is why the acceptance criterion matters. It is not negotiable based on convenience or client pressure. Every UT inspector who applies ISO 11666 should understand — not just memorise — the principles behind the numbers.

Our UT Testing and Training Services at Trinity NDT

At Trinity NDT WeldSolutions, we provide NABL ISO/IEC 17025:2017 accredited Ultrasonic Testing services for welds in pressure vessels. Also, piping, structural steel, and aerospace components — to ISO 17640 and ISO 11666, as well as ASME Section V, AWS D1.1, API 1104, and other applicable codes. Trinity NDT issues all UT test reports with NABL accreditation. Wherever they fall within scope, giving your quality system independently verified confidence in the results.

Trinity NDT also conducts UT Level I and Level II certification training—both online (live virtual via Zoom) and offline (in-person at its Peenya, Bangalore facility)—covering ISO 11666, ISO 17640, and ASME Section V acceptance criteria in detail using real production radiographs and UT test records.

If you have a specific question about ISO 11666 application — which acceptance level is appropriate for your application. How to handle a borderline indication, or how to write a compliant UT procedure referencing this standard. I am happy to discuss it. That is exactly the kind of technical consultation that we provide as part of our ASNT Level III NDT consulting service.

WhatsApp: +91 98441 29439 | Email: info@trinityndt.com

About the Author: Ravi Kumar Thammana is the CEO and Co-Founder of Trinity NDT WeldSolutions Pvt. Ltd., Bangalore. He holds ASNT Level III certification in all six NDT methods (UT, RT, MT, PT, VT, ET), International Welding Engineer (IWE) from IIW India, NAS 410 Level III (Aerospace NDT), and Radiological Safety Officer (RSO) from AERB/BARC. Trinity NDT holds NABL ISO/IEC 17025:2017 accreditation (TC-5934) and NADCAP Aerospace Merit accreditation. He blogs at materials-testing.blogspot.com.

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The post Guide for Industrial Radiography Artifacts appeared first on Trinity NDT WeldSolutions Private Limited.

Guide for Industrial Radiography Artifacts

All indications appearing in a radiograph are to be interpreted. Interpretation requires analysing the indication as to whether it is a true indication due to discontinuities or a false indication due to problems with film manufacturing, mishandling of film or poor storage. The interpreter should be able to distinguish a relevant discontinuity from a false indication.

No image in the area of interest must obscure the true indication. All false indications appearing in the area must be re-radiographed for interpretation. All true indications are interpreted and characterized.

In Industrial radiography, false indications are also called artifacts, which may form due to improper handling of film, lead screens or cassettes during any stage of the radiographic process. Common artifacts include: 

Static marks

Branchlike, jagged dark lines or irregular dark spots originating from rapid loading or unloading of film.

Pressure marks

produced by extreme pressure on an area of film.• Chemical stain – streaks on the film caused by inadequate removal of chemicals between processing stages or insufficient agitation of the film hanger.

Crimp marks

Caused by abrupt bending of film; typically crescent shaped. • Water mark – circular pattern caused by water droplets drying on the film surface. 

Reticulation

Formation of a network of wrinkles or cracks in a photographic emulsion. 

Dichoric fog

A stain visible under reflected or transmitted light due to improper development. 

Frilling of emulsion

Loosening of the emulsion from the film base due to warm or exhausted fixer solution, high temperature of processing solutions or prolonged washing in warm water. 

Scratches

Caused by abrasive materials or rough handling, including fingernails.

Damaged lead screens – Includes scratches on lead foil screens

Damaged or reused cassette – may cause a false indication to reappear after processing if the same cassette is used. However, the indication will probably move slightly because cassette placement is usually not exact.

Conclusion

The above guide may not be complete and exhaustive. Radiography Film Artifacts are common while processing the films. As long as they do not interfere with interpretation they can be ignored. If the artifacts are masking the relevant flaw indications it is better to re-shoot the same spot radiography.

Artifacts are not only appear in manual processing. There are artifacts in automatic processing such as PI Lines due to scratched on the rollers.

Proper precautions can minimize the artifacts in Industrial Radiography service and may not be completely avoidable. Visit us to know more about NDT testing services.

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Types of Weld Repairs

Weld repairs can be divided into two specific areas:
1 Production
2 In-service

Reasons For Weld Repair

The reasons for making a repair are many and varied, from the removal of weld defects induced during manufacture to a quick and temporary running repair to an item of production plant. In these terms, the subject of welding repairs is also wide and varied and often confused with maintenance and refurbishment where the work can be scheduled.

Repair Welding is Unplanned

With planned maintenance and refurbishment, sufficient time can be allowed to enable the tasks to be completed without production pressures being applied. In contrast, repairs are usually unplanned and may result in shortcuts being taken to allow the production programme to continue. It is, therefore, advisable for a fabricator to have an established policy on repairs and to have repair methods and procedures in place.

Welding Processes for Repairs

The manually controlled welding processes are the easiest to use, particularly if it is a local repair or one to be carried out on site. Probably the most frequently used of these processes is MMA as this is versatile,
portable and readily applicable to many alloys because of the wide range of off-the-shelf consumables. Repairs almost always result in higher residual stresses and increased distortion compared with first time welds. With C-Mn and low/medium alloy steels, the application of pre and post weld heat treatments may be required.

Key Factors to be Considered Before Weld Repairs

There are a number of key factors that need to be considered before undertaking any repair. The most important being a judgement as to whether it is financially worthwhile. Before this judgement can be made, the
fabricator needs to answer the following questions:
• Can structural integrity be achieved if the item is repaired?
• Are there any alternatives to welding?
• What caused the defect and is it likely to happen again?
• How is the defect to be removed and what welding process is to be used?
• Which NDT method is required to ensure complete removal of the defect?
• Will the welding procedures require approval/re-approval?
• What will be the effect of welding distortion and residual stress?
• Will heat treatment be required?
• What NDT is required and how can acceptability of the repair be demonstrated?
• Will approval of the repair be required – if yes, how and by whom?

How difficult to carryout weld repairs?

Although a weld repair may be a relatively straightforward activity, in many instances it can be quite complex and various engineering disciplines may need to be involved to ensure a successful outcome.
It is recommended that ongoing analysis of the types of defect is carried out by the QC department to discover the likely reason for their occurrence (material/process or skill related).

Things to be considered before carrying out weld repairs

In general terms, a welding repair involves:
• A detailed assessment to find out the extremity of the defect. This may involve the use of a surface or sub-surface NDT methods.
• Cleaning the repair area, (removal of paint grease etc).
• Once established the excavation site must be clearly identified and marked out.
• An excavation procedure may be required (method used ie grinding, arc/air gouging, preheat requirements etc).
• NDT testing to locate the defect and confirm its removal.
• A welding repair procedure/method statement with the appropriate* welding process, consumable, technique, controlled heat input and interpass temperatures, etc will need to be approved.
• Use of approved welders.
• Dressing the weld and final visual inspection.
• NDT procedure/technique prepared and carried out to ensure that the defect has been successfully removed and repaired.
• Any post repair heat treatment requirements.
• Final NDT procedure/technique prepared and carried out after heat treatment requirements.
• Applying protective treatments (painting etc as required).
*Appropriate means suitable for the alloys being repaired and may not apply in specific situations.

Production Weld repairs

Repairs are usually identified during production inspection. Evaluation of the reports is carried out by the Welding Inspector, or NDT operator. Discontinuities in the welds are only classed as defects when they are
outside the range permitted by the applied code or standard. Before the repair can commence, a number of elements need to be fulfilled.

Analysis before commencement of Weld Repair

As this defect is surface-breaking and has occurred at the fusion face the problem could be cracking or lack of sidewall fusion. If the defect is found to be cracking the cause may be associated with the material or the welding procedure, however if the defect is lack of sidewall fusion this can be apportioned to the lack of skill of the welder.

Assessment

In this particular case as the defect is open to the surface, magnetic particle inspection (MPI) or dye penetrant inspection (DPI) may be used to gauge the length of the defect and ultrasonic testing (UT) used to gauge the depth. In addition for volumetric type flaws such as blow holes and slag it is good opt for X-ray radiography testing.

A typical defect is shown below:

Excavation – Removal of Defective area prior to weld repair

If a thermal method of excavation is being used ie arc/air gouging it may be a requirement to qualify a procedure as the heat generated may have an effect on the metallurgical structure, resulting in the risk of cracking in the weld or parent material.

Is Preheat Necessary?

To prevent cracking it may be necessary to apply a preheat based on carbon content of the base material and filler materials. High carbon and high alloy steels needs preheat to avoid cracking at later stages of repair.
The depth to width ratio shall not be less than 1 (depth) to 1 (width), ideally 1 (depth) to 1.5 (width) would be recommended (ratio: depth 1 to width 1.5).

Cleaning of the excavation

At this stage grinding of the repair area is important, due to the risk of carbon becoming impregnated into the weld metal/parent material. It should be ground back typically 3 to 4mm to bright metal.

Confirmation of Removal of Defective area

At this stage NDT should be used to confirm that the defect has been completely excavated from the area.

Re-welding of the excavation

Prior to re-welding of the excavation a detailed repair welding procedure/method statement shall be approved.

NDT confirmation of successful repair

After the excavation has been filled the weldment should then undergo a complete retest using the same NDT inspection techniques as previously used to establish the original repair.

This is carried out to ensure no further defects have been introduced by the repair welding process. NDT may also need to be further applied after any additional postweld heat treatment has been carried out.

In-service Weld Repairs

Most in-service repairs can be of a very complex nature as the component is very likely to be in a different welding position and condition than it was during production.

It may also have been in contact with toxic or combustible fluids hence a permit to work will need to be sought prior to any work being carried out. The repair welding procedure may look very different to the original production procedure due to changes in these elements.

Other factors may also be taken into consideration, such as the effect of heat on any surrounding areas of the component, ie electrical components, or materials that may become damaged by the repair procedure. This may also include difficulty in carrying out any required pre- or post-welding heat treatments and a possible restriction of access to the area to be repaired.

For large fabrications it is likely that the repair must also take place on site without a shutdown of operations, which may bring other elements that need to be considered. Repair of in-service defects may require consideration of these and many other factors, and as such are generally considered more complicated than production repairs.

Joining technologies often play a vital role in the repair and maintenance of structures. Parts can be replaced, worn or corroded parts can be built up, and cracks can be repaired.

When a repair is required it is important to determine two things: Firstly, the reason for failure and, secondly, can the component be repaired? The latter point infers that the material type is known.

For metals, particularly those to be welded, the chemical composition is vitally important. Failure modes
often indicate the approach required to make a sound repair. When the cause-effect analysis, however simple, is not followed through it is often the case that the repair is unsafe –- sometimes disastrously so.

In many instances, the Standard or Code used to design the structure will define the type of repair that can be carried out and will also give guidance on the methods to be followed. Standards imply that when designing or
manufacturing a new product it is important to consider a maintenance regime and repair procedures. Repairs may be required during manufacture and this situation should also be considered.

Normally there is more than one way of making a repair. For example, cracks in cast iron might be held together or repaired by pinning, bolting, riveting, welding, or brazing. The method chosen will depend on factors such as the reason for failure, material composition and cleanliness, environment and the size and shape of the component.

It is very important that repair and maintenance welding are not regarded as activities, which are simple or straightforward. In many instances a repair may seem undemanding but the consequences of getting it wrong can be catastrophic failure with disastrous consequences.

Is welding the best method of repair?

If repair is called for because a component has a local irregularity or a shallow defect, grinding out any defects and blending to a smooth contour might be acceptable.

It will certainly be preferable if the steel has poor weldability or if fatigue loading is severe. It is often better to reduce the so called factor of safety slightly, than to risk putting defects, stress concentrations and residual stresses into a brittle material.

In fact brittle materials – which can include some steels (particularly in thick sections) as well as cast irons – may not be able to withstand the residual stresses imposed by heavy weld repairs, particularly if defects are not all
removed, leaving stress concentrations to initiate cracking.

Is the repair like earlier repairs?

Repairs of one sort may have been routine for years, but it is important to check that the next one is not subtly different.

For example, the section thickness may be greater; the steel to be repaired may be different and less weldable, or the restraint higher. If there is any doubt, answer the remaining questions.

What is the composition and weldability of the base metal?

The original drawings will usually give some idea of the steel involved, although the specification limits may then have been less stringent, and the specification may not give enough compositional details to be helpful.

If sulphur-bearing free-machining steel is involved, it could give hot cracking problems during welding.

If there is any doubt about the composition, a chemical analysis should be carried out. It is important to analyse for all elements, which may affect weldability (Ni, Cr, Mo, Cu, V, Nb and B) as well as those usually, specified
(C, S, P, Si and Mn).

A small cost spent on analysis could prevent a valuable component being ruined by ill-prepared repairs or, save money by reducing or avoiding the need for preheat if the composition were leaner than expected. Once the
composition is known, a welding procedure can be devised.

What strength is required from the repair?

The higher the yield strength of the repair weld metal, the greater the residual stress level on completion of welding, risk of cracking, clamping needed to avoid distortion and more difficulty in formulating the welding
procedure. In any case, the practical limit for the yield strength of conventional steel weld metals is about 1000N/mm2.

Can preheat be tolerated?

Not only does a high level of preheat make conditions more difficult for the welder; the parent steel can be damaged if it has been tempered at a low temperature. In other cases the steel being repaired may contain items which are damaged by excessive heating.

Preheat levels can be reduced by using consumables of ultra-low hydrogen content or by non-ferritic weld metals. Of these, austenitic electrodes may need some preheat, but the more expensive nickel alloys usually do not. However, the latter may be sensitive to high sulphur and phosphorus contents in the parent steel if diluted into the weld metal.

Can softening or hardening of the HAZ be tolerated?

Softening of the HAZ is likely in very high strength steels, particularly if they have been tempered at low temperatures. Such softening cannot be avoided, but its extent can be minimised. Hard HAZs are particularly
vulnerable where service conditions can lead to stress corrosion. Solutions containing H2S (hydrogen sulphide) may demand hardness below 248HV (22HRC) although fresh aerated seawater appears to tolerate up to about
450HV. Excessively hard HAZs may, therefore, require PWHT to soften them but provided cracking has been avoided.

Is Post Weld Heat Teatment (PWHT) practicable?

Although it may be desirable, PWHT may not be possible for the same reasons that preheating is not. For large structures, local PWHT may be possible, but care should be taken to abide by the relevant codes, because
it is too easy to introduce new residual stresses by improperly executed PWHT.

Is PWHT necessary?

PWHT may be needed for one of several reasons, and the reason must be known before considering whether it can be avoided.

Will the fatigue resistance of the repair be adequate?

If the repair is in an area which is highly stressed by fatigue and particularly if the attempted repair is of a fatigue crack, inferior fatigue life can be expected unless the weld surface is ground smooth and no surface defects are left.

Fillet welds, in which the root cannot be ground smooth, are not tolerable in areas of high fatigue stress.

Will the repair resist its environment?

Besides corrosion, it is important to consider the possibility of stress corrosion, corrosion fatigue, thermal fatigue and oxidation in-service.

Corrosion and oxidation resistance usually require the composition of the filler metal is at least as noble or oxidation resistant as the parent metal. For corrosion fatigue resistance, the repair weld profile may need to be
smoothed.To resist stress corrosion, PWHT may be necessary to restore the correct micro-structure, reduce hardness and the residual stress left by the repair.

Can the repair be inspected and tested?

For onerous service, radiography and/or ultrasonic examination are often desirable, but problems are likely if stainless steel or nickel alloy filler is used; moreover, such repairs cannot be assessed by Magnetic particle Inspection. In such cases, it is particularly important to carry out the procedural tests for repairs very critically, to ensure there are no risks of cracking and no likelihood of serious welder-induced defects.

Indeed, for all repair welds, it is vital to ensure that the welders are properly motivated and carefully supervised.

As-welded repairs

Repair without PWHT is, of course, normal where the original weld was not heat treated, but some alloy steels and many thick-sectioned components require PWHT to maintain a reasonable level of toughness, corrosion
resistance, etc. However, PWHT of components in-service is not always easy or even possible, and local PWHT may give rise to more problems than it solves except in simple structures.

The post Weld Repairs during Production and In-service Maintenance appeared first on Trinity NDT WeldSolutions Private Limited.

Basic Standard for QMS

   ISO 9001 -2000

Manufacturing

   ISO 3834, EN 1011, ISO 5817

Personnel

   ISO 9606, EN 287, ISO 14731, ISO 14732

Procedures

   ISO 15607 – 15614

Testing and Inspection Personnel

   ISO 9712, EN 1289

Basis for ISO 3834  series of welding standards

As is well known, weld quality is achieved by sound welding, not by inspection. Inspection, however, provides a check of the reliability of the product, but cannot improve poor quality. Therefore, welding requires continuous control and/or to follow documented procedures. Certifications such as ISO3834 can build a robust quality management systems thus attracting more customers.

Genesis of ISO-3834

A member of the International Union of Technical Associations and Organisations (UTAO), IIW is a part of the International Council for Engineering and Technology (ICET), one of the twelve key formal umbrella organisations associated with UNESCO.

The experts of International Institute of Welding (IIW) have supplied the technical basis of the great majority of welding standards issued by the International Standards Organisation – ISO.

Since 1989, IIW has been recognised by ISO as an International Standardisation Body to prepare the final texts of international welding standards.

Criteria of selection of part of  the standard

• Financial loss
• Loss to human life
• Repair cost
• Loads- static and dynamic

Application of ISO 3834

• Certification of companies in accordance with ISO – 3834 Parts 2, 3 or 4
• Certification of personnel in accordance with ISO 14731

What is ISO 3834?

ISO3834 is an international standard created by welding professionals. ISO 9001 provides the requirements for a quality management system; it does not establish requirements for products. The standard on the other hand, does provide the quality requirements for a welded product.

It specifies requirements relating only to the quality of the welded product. Encourages a proactive process orientated approach to managing and controlling welding   product quality in a workshop or on site. Also, gives a Factory Control System to control activities for the manufacture of the product.

Why adopt ISO 3834 when we have ISO 9001?

ISO 9001 is a comprehensive standard that lays down quality management system requirements for any organisation. However, the standard does not prescribe specific details for “special processes”. Welding is regarded as a ‘special process’. ISO 3834 was developed to identify all factors that could affect the quality of welded product and which need to be controlled at all stages, before, during and after welding.

What are the benefits of specifying the ISO 3834 Standard for the purchaser & supplier?

• More assurance of contract delivery dates
• Greater assurance of the quality of welded products
• Greater reliability and performance of plant
• Reduction in maintenance costs
• Reduction or elimination of third party inspection costs
• More competent suppliers of welded products

What are the benefits of using the ISO 3834 Standard for the manufacturer?

• Less rework
• Jobs completed on time
• Local and international recognition as a competent organisation
• Meet the welding-related requirements of ISO 9001
• More efficient coordination of welding activities
• More pro-active and responsible workforce
• Increased opportunities and capability to bid on jobs
• Cost savings – more efficient technology
• Reduced surveillance audits and inspections by purchasers with significant savings

What are the benefits of using the ISO 3834 Standard for the individual employees?

• Helps to do the job more satisfactorily
• Greater job security
• Higher regard by other people
• Professional recognition
• Satisfied employer and customer
• More rewarding job position
• Develops team spirit

How important are welding personnel?

A key feature of ISO 3834 is the requirement to ensure that people with welding responsibilities are competent to discharge those responsibilities. This is achieved by incorporation of another standard, namely, ISO 14731 “Welding coordination – Tasks and responsibilities”. The specifying of minimum requirements for personnel dealing with welding coordination and welding inspection personnel.

What is the definition of a manufacturer as per standard?

ISO 3834 defines a manufacturer as a ‘person or organization responsible for the welding production’.

The Standard uses this term to describe any such organisation, including manufacturing organisations supplying welding services, either for new products or for repair and maintenance, as well as others where the application of the requirements of ISO 3834 are relevant.

A manufacturer may be involved in manufacture, fabrication, construction, repair or maintenance.

What are the types of manufacturing organisation that ISO 3834 can be applied to?

Fabrication companies

• Construction companies – on-site work

• Repair and maintenance contractors

• Manufacturers of products

• Welding workshops on sites under the same technical and quality management

• Owners of plant with their own workshop(s)

What are the types of other organisation that ISO 3834 can be applied to?

Asset owners without own workshops, both private and government

• Project management companies

• Design companies

• Consultants

• Government agencies

Those which, though not creating welded product themselves, are specifying or requiring such work from others and are thus involved in weld design, contract development, and review of technical requirements and competencies of subcontractors

How many parts does ISO 3834 have?

• ISO 3834: 2005 “Quality requirements for fusion welding of metallic materials” consists of 6 parts:
• ISO 3834-1:2005, Criteria for the selection of the appropriate level of quality requirements
• ISO 3834-2:2005, Comprehensive quality requirements
• ISO 3834-3:2005, Standard quality requirements
• ISO 3834-4:2005, Elementary quality requirements
• ISO 3834-5:2005, Applicable documentation (not full title)
• ISO/TR 3834-6:2007, Guidelines on implementing ISO 3834

How does ISO 3834 link in with ISO 9001?

ISO 3834 does not replace ISO 9001 as a quality management system. However, it contains many attributes that will be important for a welding manufacturer, in both workshops and at field installation sites, seeking ISO 9001 certification. Elements of ISO 9001 should be considered when implementing ISO 3834 quality requirements and seeking ISO 3834 certification. The specific complementary elements of ISO 9001 are detailed in ISO 3834.

What are the main welding requirements covered in ISO 3834 ?

Review of requirements

• Technical review

• Subcontracting

• Welding personnel

– Welders and welding operators, Welding coordination personnel

• Inspection & testing personnel

– Welding Inspection personnel; Non-destructive testing personnel

• Equipment

– Production and testing equipment; Description of equipment; Suitability of equipment; New

equipment; Equipment maintenance

Welding and related activities

– Production planning; Welding procedure specifications (WPS); Qualification of the welding

procedures; Work instructions; Procedures for preparation and control of documents

• Welding Consumables

– Batch testing; Storage and handling

• Storage of parent materials

• Post-weld heat treatment

Inspection and testing

– Inspection & testing before welding; Inspection & testing during welding; Inspection & testing after

welding; Inspection & test status

• Non-conformance and corrective actions

• Calibration and validation of measuring, inspection and testing equipment

• Identification & traceability

• Quality records

Selection of Welding Quality Requirement as per ISO:3834

Comparison of Welding quality requirements with regard to ISO 3834-2, 3834-3  & 3834-4

How do Manufacturers select the Appropriate Part of ISO 3834?

A balanced decision needs to be taken based on the following, related to products & processes:

• The extent and significance of safety-critical products
• The complexity of manufacture
• The range of products manufactured
• The range of different materials used
• The extent to which metallurgical problems may occur
• The extent to which manufacturing imperfections e.g. misalignment, distortion or weld imperfection, affect product performance
• Service condition (Dynamic loading, fatigue, low/high Temperature, corrosion)
• The welding processes adopted, their level of sophistication and automation

Suggested Steps for Implementation of ISO 3834 by an Organisation

• Gap Analysis to identify action areas for  System, training and resources
• Upgradation of System based on above
• Personnel Training for competence
• Assessment of additional Resources if any
• Internal Audit to close NCR’s
• Management Review
• Trial operation to stabilise system
• Application for Certification to Certification Body

Gap Analysis internally by the Organisation against requirements of ISO 3834 & ISO 14731

• ISO 9001 systems if existing or desired and compare with the present system.
• System requirements for applicable part of 3834 (2, 3 or 4) as determined previously and detailed in next three slides.
• Identify each area as per check list for gaps between required/desired level and actual status recorded.
• May take assistance from Consultants or Certifying bodies for this step
• Management corrective action to close the non conformities

To check for Gaps –

Requirements in ISO 3834 & Essential Tasks of  Welding Coordination Personnel in ISO 14731

1.Review of requirements & Technical review to understand parent material specification and welded joint properties, quality and acceptance requirements, etc.

2.Subcontracting Supplier to be treated as extension of manufacturers facility

3.Welding personnel Welders and welding operators, Welding coordination personnel

4.Inspection & testing personnel Welding Inspection personnel; Non-destructive testing personnel

5.Equipment: Production and testing equipment; Description of equipment; Suitability of equipment; New equipment; Equipment maintenance

6.Welding and related activities: Production planning; Welding procedure specifications (WPS); Process Qualification of the welding (WPQR); Work instructions;

7.Welding Consumables: Batch testing; Storage and handling

8.Storage of parent materials

9.Post-weld heat treatment

10. Inspection and NDT testing: Inspection & testing before welding; Inspection & testing during welding; Inspection & testing after welding; Inspection & test status

11.Non-conformance and corrective actions ¬ Learning from experience

12.Calibration and validation of measuring, inspection and testing equipment

13.Identification & traceability

14.Quality records

How important are welding personnel?

A key feature of ISO 3834 is the requirement to ensure that people with welding responsibilities are competent to discharge those responsibilities.

This is achieved by incorporation of another standard, namely, ISO 14731 ‘Welding coordination – Tasks and responsibilities’

The specifying of minimum requirements for personnel dealing with welding coordination and welding inspection personnel

The Human Resource

­Without an appropriate specific technical competence (intended as a combination of knowledge, experience and attitude) no management system can be successful in the manufacturing of any product. ­

A great importance has been entrusted to the Welding Coordinator, who has become the real “key element” around whom all the welding production process works.

ISO 14731 Requirements for Welding Co-ordination Personnel

Welding Co-ordination :

   – Manufacturing operations for all welding and welding related activities

  – The sole responsibility of the manufacturer

  – May be sub-contracted

  – May be carried out by more than one person

Welding Co-ordinator

– Responsible and competent person

– Specified tasks and responsibilities

– Qualified for each task

Welding Inspection

– Is part of welding co-ordination

Role of the Responsible Welding Co-ordinator

The company shall nominate at least one Responsible Welding Co-ordinator ( RWC ). He must be competent to make decisions and sign on behalf of the manufacturer.

The RWC must be authorised with the overall responsibility for monitoring welding activities as well as taking action when welding has not been correctly performed. May also be responsible for the work of other welding co-ordinators in the in the same department / site.

RWC may be to an individuals normal job title eg, Technical Manager, QC Manager, Production Manager etc.

IIW International Diploma Qualifications for Welding Co-ordination Personnel

International Welding Engineer ( IWE )

International Welding Technologist ( IWT )

International Welding Specialist ( IWS )

International Welding Practitioner ( IWP )

International Welding Inspection Personnel (IWIP)

International Welded Structure Designer ( IWSD )

International Welder ( IW ) – Diploma awarded for Specific process and material & at 3 levels

In India, ANB-India of IIW India is authorised to award the above diplomas. Contact IIW India.

ISO 14731 Gradation of Responsible Welding Coordinators

Three different levels of RWC are given. The selection of RWC depends mainly on the variability and technical complexity of the welding procedures required.

How can Trinity NDT Can Help you in ISO3834 certifications?

Center of Welding – Trinity NDT provides comprehensive consulting services for ISO3834 certifications. Being an associate of The Indian Institute of Welding – IIW India, can hand hold organizations in the process of certification.

This includes, quality manual preparation, establishing wps, documentation, QMS implementation, Gap analysis from ISO9001 to ISO3834, NDT Level II personnel certification. Also provide welding coordinator services by our IWE experts. Also an IBR approved Welding & NDT Lab in Bangalore.

Let us know your requirement. Contact Trinity NDT today.

The post ISO3834 Quality Management in Welding Companies appeared first on Trinity NDT WeldSolutions Private Limited.

Detailed Online NDT Level II Schedule for ‘April’ and ‘May’ is

Spell ‘1’

• 03 – 04 April 2023 Radiography Film Interpretation (RTFI Level II)
• 05 – 06 April 2023 Visual Testing
• 05 – 07 April 2023 Welding Inspector Course
• 07 – 10 April 2023 Eddy Current testing

Spell ‘2’

• 03 – 06 May 2023 Ultrasonic Testing
• 07 – 08 May 2023 Magnetic Particle testing
• 09 – 10 May 2023 Liquid Penetrant testing

Online NDT examinations dates will be announced for each method. Training Coordinator will inform the registered candidates.

Online Course Timings: 06am to 08am & 06:30pm to 08:30pm every day.

Mode of sessions: Through Microsoft Teams

Prerequisites: A lap top or computer with internet connection. We recommend to have a standby system or a mobile phone for any exigencies.

Eligibility for Level II online NDT

• 10+2 with maths or science
• B.E or B.Tech in Engineering
• B.Sc with Science or Maths

Check more details and requirements about Eligibility for NDT Level II certifications.

Fee Structure* for Online NDT Courses and Duration. Check more details about each course at below links.

• Ultrasonic testing Course (5Days) – Rs. 7399/-
• Magnetic particle testing Course (3Days) – Rs.6399/-
• Liquid penetrant testing (3Days) Rs.6399/-
• Radiography Film Interpretation Course (3Days) – Rs.6999/-
• Visual Testing Course (3 Days)- Rs.6999/-
• Welding Inspector Course (3days) – Rs.9500/-
• Eddy Current Testing Course (5days) – Rs 12499/-

gst will be charged extra as per Government of India policy. Training cost specified is for Indian Nationals. Other nationals can contact ‘Training Coordinator’ for Foreigner Fee Details in USD. Duration is inclusive of practical duration to be held at NDT Service Labs.

For information contact:

Training Coordinator,

Trinity Institute of NDT Technology ( A Unit of Trinity NDT),

#491, Site No.12, 14th Cross, 4th Phase, Peenya Industrial Area, Bengaluru 560 058, India

Phone: +91 9844129439, 9141339994 | E-mail: training@trinityndt.com | Website: www.trinityndt.com

The post Online NDT Training Schedule April & May 2023 appeared first on Trinity NDT WeldSolutions Private Limited.

Detailed Online NDT Level II Schedule for ‘April’ and ‘May’ is

Spell ‘1’

• 03 – 04 April 2023 Radiography Film Interpretation (RTFI Level II)
• 05 – 06 April 2023 Visual Testing
• 05 – 07 April 2023 Welding Inspector Course
• 07 – 10 April 2023 Eddy Current testing

Spell ‘2’

• 03 – 06 May 2023 Ultrasonic Testing
• 07 – 08 May 2023 Magnetic Particle testing
• 09 – 10 May 2023 Liquid Penetrant testing

Online NDT examinations dates will be announced for each method. Training Coordinator will inform the registered candidates.

Online Course Timings: 06am to 08am & 06:30pm to 08:30pm every day.

Mode of sessions: Through Microsoft Teams

Prerequisites: A lap top or computer with internet connection. We recommend to have a standby system or a mobile phone for any exigencies.

Eligibility for Level II online NDT

• 10+2 with maths or science
• B.E or B.Tech in Engineering
• B.Sc with Science or Maths

Check more details and requirements about Eligibility for NDT Level II certifications.

Fee Structure* for Online NDT Courses and Duration. Check more details about each course at below links.

• Ultrasonic testing Course (5Days) – Rs. 7399/-
• Magnetic particle testing Course (3Days) – Rs.6399/-
• Liquid penetrant testing (3Days) Rs.6399/-
• Radiography Film Interpretation Course (3Days) – Rs.6999/-
• Visual Testing Course (3 Days)- Rs.6999/-
• Welding Inspector Course (3days) – Rs.9500/-
• Eddy Current Testing Course (5days) – Rs 12499/-

gst will be charged extra as per Government of India policy. Training cost specified is for Indian Nationals. Other nationals can contact ‘Training Coordinator’ for Foreigner Fee Details in USD. Duration is inclusive of practical duration to be held at NDT Service Labs.

For information contact:

Training Coordinator,

Trinity Institute of NDT Technology ( A Unit of Trinity NDT),

#491, Site No.12, 14th Cross, 4th Phase, Peenya Industrial Area, Bengaluru 560 058, India

Phone: +91 9844129439, 9141339994 | E-mail: training@trinityndt.com | Website: www.trinityndt.com

The post Online NDT Training Schedule April & May 2023 appeared first on Trinity NDT WeldSolutions Private Limited.

Magnetic Particle testing is also known as MPI or MPT is a well accepted NDT method to reveal surface and below surface flaws. Applied for ferro-magnetic metals such as Iron, Nickel and Cobalt alloys. Due to its effectiveness in detecting flaws, industries such as Automobile, Oil and Gas, Processing and Aerospace accepted as a means of verifying quality of components and structures.

How to Start Magnetic particle testing?

Before start of any NDT method a detailed procedure shall be prepared. MPI testing also needs a procedure that outlines, essential and non essential parameters. The MPI procedure shall address all key elements of testing. For instance, MPI techniques, powders, light requirements, medium, current calculations, sequence of testing, equipment to be used, personnel qualification etc.,

Therefore, an MPI testing procedure shall be prepared considering the parameters on site. Procedure shall be prepared by a certified NDT Level II and shall be approved by a NDT Level III in Magnetic Particle testing.

Here are key elements and procedure for MPI testing as per ASTM E709/ASTM E1444

What is the difference between ASTM E709 and ASTM E1444

Both the international standards are issued by The American Society for Testing Materials (ASTM). Both the standards are widely used in every industry involving MPI. ASTM E 709 is a mother standards for many of the worlds country specific standards being used today.

ASTM E709 – A Standard Guide for Magnetic Particle testing, covers in detail about every requirement, recommendation pertaining magnetic particle testing.

ASTM E1444 – A standard practice for Magnetic Particle Testing is specifically applicable for Aerospace NDT applications. This is a replacement for US military standard – MIL-STD-1949. Covers minimum requirements for performing MPI testing. Also recommended to use in conjunction with ASTM E709.

Though both the standards are widely accepted in industry, where stringent requirements are to be followed ASTM E1444 is a better choice. Because it has close acceptance limits, this standard is especially used in Aerospace sector for MPI testing. More specifically this standard covers requirement for aerospace industry.

Scope

It covers the techniques for both dry and wet magnetic particle inspection. Applicable for raw materials and semi-processed materials such as blooms, billets, castings, rolled products, forgings and weld joints. It is also can be used in in-service maintenance inspection of plants and structures.

ASTM E709 is a guide that helps you in preparing MPI procedures, establishing techniques. This can also be used for evaluating and reviewing customer specifications. This standard can be applied for parts of any size, material(ferro) and any shape for any application. Therefore, users of this standard are required to exercise to evaluate specific requirements pertaining to their job and conditions.

Does This Standard Specify Acceptance Criteria?

No. ASTM E709 does not specify any acceptance or rejection criteria. This only covers the procedure for magnetic particle inspection. As this standard is used for variety of applications such as automotive, structural, oil and gas and even for aerospace, it is left to the user to specify the criteria for acceptance or rejection.

Therefore, the contracting parties shall specify acceptance or rejection criteria in the MPI procedure. It may also be cross referenced in place of specifying in procedure. An ASNT Level III or an expert in design shall be consulted for deciding on the criteria. This shall be based on criticality of application, risk associated with failure of the part.

What MPI techniques are used?

1. Dry Powder Technique
2. Wet powder technique

and other techniques which are not much use in industries.

What is the personnel qualification requirement to do MPT testing?

MPI testing inspector should be performed by qualified and certified as per ASNT recommended practice SNT TC 1A or ANSI, CP189 or NAS410(aerospace). The document also gives freedom to specify certification scheme based on agreement between contacting parties such as ISO9712 certifications.

Reference Documents

A number of specifications and standards are listed for the benefit of users. It is good if you can buy there standards from ASTM website for additional knowledge. Also, a standard ASTM E1316 gives definitions related to terminology applicable for Nondestructive testing.

Summary of Magnetic particle Testing

In MPT testing, initially magnetic flux is introduced by a suitable means. This could be using directly passing current techniques such as Head Shot, Prod or Indirect techniques that passes only magnetic field, such as Yoke, Central conductor etc.,

By applying Fleming’s right hand rule we can find the direction of magnetic field if we know the direction of electric current. Once magnetic field is introduced into any ferro magnetic metals, flux lines will be travelling through the materials. If there are any flaws, flux will be distorted and leakage field is created. As we cannot sense leakage flux, a finely powdered ferro-magnetic powder is uniformly sprinkled on the surfaces.

Leakage flux attracts the ferro-magnetic powder thereby bridging the space between the crack/flaw faces. The powder is added with a pigment for suitable viewing. Fluorescent powders are to be used only in darkened room. These powders emits yellowish green light when impinged by Ultraviolet (UV) light in the wavelength range of 320-365nm.

Fluorescent powder absorbs UV light and emit visible light at around 555nm. As Yellowish green light is highly sensitive to human eye, the MPI inspector will be able to locate the indication easily. Non-fluorescent powders are colored with black, red, grey to give contrast with respect to surface.

How to select fluorescent or Non-fluorescent techniques in Magnetic particle testing?

Fluorescent powder technique is suitable for high speed sensitive applications. Non-fluorescent techniques are good for field/site testing conditions where components cannot be moved to a darked area to maintain darkness. Later technique is economical and a cost effective solution at the cost of less sensitivity.

Magnetization Techniques

• Permanent Magnet
• Electromagnetic Yoke
• Head Shot
• Central Conductor
• Cable wrap
• Solenoid
• Coil Shot
• Prod Technique
• What kind flaws can MPI testing detect?

Magnetic particle testing detect flaws located perpendicular to magnetic flux. Flaws located up to 45 degree may also be detected.

How many directions do we need to magnetize?

For effective testing, magnetic field shall be introduced in two mutually perpendicular directions. Inspector shall ensure this while establishing the technique for all surfaces, wherever practicable. The procedure must address techniques to generate the field in various directions.

What is multi-directional magnetization?

Equipment with multi directional magnetization are available. These equipment generate vector field so that the magnetic field rotates almost 360 degree in each shot. Therefore, whatever may be the flaw orientation at one point of time the vector will be perpendicular to the flaw. However, equipment that generate multi directional fields are expensive thus can be used only in critical applications such as aerospace.

Magnetic Field Strength

Magnetic field strength should be sufficient enough to generate leakage flux to detect flaws. Under magnetized components cannot generate the flux enough to detect the defects. Over magnetization causes the field to cause excess in whole of the materials leading to excessive field leakage and heavy accumulation of particles. This leads to shadowing of relevant indications. Because, the contrast is lost flaw identification becomes a challenge.

Therefore, while establishing magnetic field strength it is required to generate just sufficient to detect minimum size of flaw and should not over magnetize to mask indications.

Check how to use ASTM field indicator (Pie Gauge)

Types of Magnetic Particles

Magnetic particles both Dry or Wet based can be used. Fluorescent and non-fluorescent dry or wet particles to be selected based on end user need. Powder concentrates also are specified. Wet particles can be dispersed in water(water based) or carrier oil based (petroleum distillate) that confirms to ASTM E709.

What is meant by indication?

Clustering of powder at a specific area under MPI testing is called Indication. Each indication shall be evaluated for relevance, acceptance or rejection.

How does surface indications looks like?

MPI Indications from surface flaws will be sharp, distinct pattern and tightly held to the surface.

How does subsurface indications looks like?

In MPI testing, subsurface(near surface) indications produce less distinct, fuzzy patterns and powder is loosely held. Indications will be broader than sharp. Just with a small puff of air from mouth can fully or partially eliminate from the surface.

Magnetic Particle testing Equipment Selection

A big challenge for inspectors in MPI testing is selecting right equipment. Numerous equipment and types are available today to choose for testing components and structures.

With the exception of permanent magnetic yoke, all other equipment needs electricity to generate magnetic field.

When do you choose permanent magnetic yoke?

If you want to perform the testing at fire hazard area or where spark can ignite the surrounding or getting electricity at a high altitude is a challenge, such as chimney, permanent magnet is preferred. This equipment does not need electricity. In almost all petroleum refineries, for testing weld joints and parts, permanent magnet is the best option. When all other equipment are prohibited to use, this equipment is the last option.

Before using permanent magnetic yoke, check for calibration and evaluate the strength. It is covered in this post else where.

The post How to Do Magnetic Particle Testing as per ASTM E709 & E1444 appeared first on Trinity NDT WeldSolutions Private Limited.

Magnetic Particle testing is also known as MPI or MPT is a well accepted NDT method to reveal surface and below surface flaws. Applied for ferro-magnetic metals such as Iron, Nickel and Cobalt alloys. Due to its effectiveness in detecting flaws, industries such as Automobile, Oil and Gas, Processing and Aerospace accepted as a means of verifying quality of components and structures.

How to Start Magnetic particle testing?

Before start of any NDT method a detailed procedure shall be prepared. MPI testing also needs a procedure that outlines, essential and non essential parameters. The MPI procedure shall address all key elements of testing. For instance, MPI techniques, powders, light requirements, medium, current calculations, sequence of testing, equipment to be used, personnel qualification etc.,

Therefore, an MPI testing procedure shall be prepared considering the parameters on site. Procedure shall be prepared by a certified NDT Level II and shall be approved by a NDT Level III in Magnetic Particle testing.

Here are key elements and procedure for MPI testing as per ASTM E709/ASTM E1444

What is the difference between ASTM E709 and ASTM E1444

Both the international standards are issued by The American Society for Testing Materials (ASTM). Both the standards are widely used in every industry involving MPI. ASTM E 709 is a mother standards for many of the worlds country specific standards being used today.

ASTM E709 – A Standard Guide for Magnetic Particle testing, covers in detail about every requirement, recommendation pertaining magnetic particle testing.

ASTM E1444 – A standard practice for Magnetic Particle Testing is specifically applicable for Aerospace NDT applications. This is a replacement for US military standard – MIL-STD-1949. Covers minimum requirements for performing MPI testing. Also recommended to use in conjunction with ASTM E709.

Though both the standards are widely accepted in industry, where stringent requirements are to be followed ASTM E1444 is a better choice. Because it has close acceptance limits, this standard is especially used in Aerospace sector for MPI testing. More specifically this standard covers requirement for aerospace industry.

Scope

It covers the techniques for both dry and wet magnetic particle inspection. Applicable for raw materials and semi-processed materials such as blooms, billets, castings, rolled products, forgings and weld joints. It is also can be used in in-service maintenance inspection of plants and structures.

ASTM E709 is a guide that helps you in preparing MPI procedures, establishing techniques. This can also be used for evaluating and reviewing customer specifications. This standard can be applied for parts of any size, material(ferro) and any shape for any application. Therefore, users of this standard are required to exercise to evaluate specific requirements pertaining to their job and conditions.

Does This Standard Specify Acceptance Criteria?

No. ASTM E709 does not specify any acceptance or rejection criteria. This only covers the procedure for magnetic particle inspection. As this standard is used for variety of applications such as automotive, structural, oil and gas and even for aerospace, it is left to the user to specify the criteria for acceptance or rejection.

Therefore, the contracting parties shall specify acceptance or rejection criteria in the MPI procedure. It may also be cross referenced in place of specifying in procedure. An ASNT Level III or an expert in design shall be consulted for deciding on the criteria. This shall be based on criticality of application, risk associated with failure of the part.

What MPI techniques are used?

1. Dry Powder Technique
2. Wet powder technique

and other techniques which are not much use in industries.

What is the personnel qualification requirement to do MPT testing?

MPI testing inspector should be performed by qualified and certified as per ASNT recommended practice SNT TC 1A or ANSI, CP189 or NAS410(aerospace). The document also gives freedom to specify certification scheme based on agreement between contacting parties such as ISO9712 certifications.

Reference Documents

A number of specifications and standards are listed for the benefit of users. It is good if you can buy there standards from ASTM website for additional knowledge. Also, a standard ASTM E1316 gives definitions related to terminology applicable for Nondestructive testing.

Summary of Magnetic particle Testing

In MPT testing, initially magnetic flux is introduced by a suitable means. This could be using directly passing current techniques such as Head Shot, Prod or Indirect techniques that passes only magnetic field, such as Yoke, Central conductor etc.,

By applying Fleming’s right hand rule we can find the direction of magnetic field if we know the direction of electric current. Once magnetic field is introduced into any ferro magnetic metals, flux lines will be travelling through the materials. If there are any flaws, flux will be distorted and leakage field is created. As we cannot sense leakage flux, a finely powdered ferro-magnetic powder is uniformly sprinkled on the surfaces.

Leakage flux attracts the ferro-magnetic powder thereby bridging the space between the crack/flaw faces. The powder is added with a pigment for suitable viewing. Fluorescent powders are to be used only in darkened room. These powders emits yellowish green light when impinged by Ultraviolet (UV) light in the wavelength range of 320-365nm.

Fluorescent powder absorbs UV light and emit visible light at around 555nm. As Yellowish green light is highly sensitive to human eye, the MPI inspector will be able to locate the indication easily. Non-fluorescent powders are colored with black, red, grey to give contrast with respect to surface.

How to select fluorescent or Non-fluorescent techniques in Magnetic particle testing?

Fluorescent powder technique is suitable for high speed sensitive applications. Non-fluorescent techniques are good for field/site testing conditions where components cannot be moved to a darked area to maintain darkness. Later technique is economical and a cost effective solution at the cost of less sensitivity.

Magnetization Techniques

• Permanent Magnet
• Electromagnetic Yoke
• Head Shot
• Central Conductor
• Cable wrap
• Solenoid
• Coil Shot
• Prod Technique
• What kind flaws can MPI testing detect?

Magnetic particle testing detect flaws located perpendicular to magnetic flux. Flaws located up to 45 degree may also be detected.

How many directions do we need to magnetize?

For effective testing, magnetic field shall be introduced in two mutually perpendicular directions. Inspector shall ensure this while establishing the technique for all surfaces, wherever practicable. The procedure must address techniques to generate the field in various directions.

What is multi-directional magnetization?

Equipment with multi directional magnetization are available. These equipment generate vector field so that the magnetic field rotates almost 360 degree in each shot. Therefore, whatever may be the flaw orientation at one point of time the vector will be perpendicular to the flaw. However, equipment that generate multi directional fields are expensive thus can be used only in critical applications such as aerospace.

Magnetic Field Strength

Magnetic field strength should be sufficient enough to generate leakage flux to detect flaws. Under magnetized components cannot generate the flux enough to detect the defects. Over magnetization causes the field to cause excess in whole of the materials leading to excessive field leakage and heavy accumulation of particles. This leads to shadowing of relevant indications. Because, the contrast is lost flaw identification becomes a challenge.

Therefore, while establishing magnetic field strength it is required to generate just sufficient to detect minimum size of flaw and should not over magnetize to mask indications.

Check how to use ASTM field indicator (Pie Gauge)

Types of Magnetic Particles

Magnetic particles both Dry or Wet based can be used. Fluorescent and non-fluorescent dry or wet particles to be selected based on end user need. Powder concentrates also are specified. Wet particles can be dispersed in water(water based) or carrier oil based (petroleum distillate) that confirms to ASTM E709.

What is meant by indication?

Clustering of powder at a specific area under MPI testing is called Indication. Each indication shall be evaluated for relevance, acceptance or rejection.

How does surface indications looks like?

MPI Indications from surface flaws will be sharp, distinct pattern and tightly held to the surface.

How does subsurface indications looks like?

In MPI testing, subsurface(near surface) indications produce less distinct, fuzzy patterns and powder is loosely held. Indications will be broader than sharp. Just with a small puff of air from mouth can fully or partially eliminate from the surface.

Magnetic Particle testing Equipment Selection

A big challenge for inspectors in MPI testing is selecting right equipment. Numerous equipment and types are available today to choose for testing components and structures.

With the exception of permanent magnetic yoke, all other equipment needs electricity to generate magnetic field.

When do you choose permanent magnetic yoke?

If you want to perform the testing at fire hazard area or where spark can ignite the surrounding or getting electricity at a high altitude is a challenge, such as chimney, permanent magnet is preferred. This equipment does not need electricity. In almost all petroleum refineries, for testing weld joints and parts, permanent magnet is the best option. When all other equipment are prohibited to use, this equipment is the last option.

Before using permanent magnetic yoke, check for calibration and evaluate the strength. It is covered in this post else where.

The post How to Do Magnetic Particle Testing as per ASTM E709 & E1444 appeared first on Trinity NDT WeldSolutions Private Limited.

A process of confirming an individual the person certified is having required knowledge and skills (proficiency) to perform the NDT task such as Ultrasonic testing of casting or radiography testing of weld joint.

NDT is to be performed as per as per Level III approved procedure. Each procedure shall address techniques, parameters and settings to be used while doing the test.

Performing the test, accurately evaluating the flaws is the purpose of NDT certification. Inspector with educational qualification and experience is eligible for certification.

The aim of NDT certification is to get the results of inspection accurate and reliable.

There are accreditation bodies such as British Institute of NDT(BINDT), The American Society for Nondestructive testing(ASNT), Australian Institute for Nondestructive testing(AINDT), Canadian Society for Nondestructive testing(CNDT), Canadian General Standards Board(CGSB). These bodies issues certifications for NDT personnel.

Before granting certification the inspector shall take class room training and practical training. Each individual is assessed for skills and sit for examinations. An NDT Level III evaluate the examination Results. Declared the inspector is passed or failed.

Important Certifications

PCN certification from BINDT: The British Institute of Non-Destructive Testing (BINDT) issues Level I, Level II and Level III NDT certifications, well recognized in industry as PCN (Personnel Certification in NDT) certification.

CGSB Certified NDT Technician: Canadian General Standards Board(CGSB) issues certification for NDT technicians in Canada. This certification is recognized in Canada and is based on Canadian standards.

ASNT Certifications: The American Society for Nondestructive testing(ASNT) issues certification. Classified as Level I, Level II and Level III these certifications are well recognized in Middle East(Dubai, Saudi Arabia, UAE, Oman, Kuwait), African continent (Nigeria, Cameroon, Kenya, Angola and other oil producing and exporting countries). The certification has wider acceptance in Indian subcontinent ( India, Bangladesh, Srilanka, Bhutan and Nepal).

ASNT Certifications are significantly useful for ASME code, API code and AWS certified companies. These codes mandates to employ only SNT TC 1A certified inspectors during nondestructive testing of components.

How to Get Certified to NDT Level I

Here is the procedure to get your NDT Level I certification. There could be variation in procedure based on the certification scheme. contact the certification issuing authority for additional details.

To be eligible for NDT Level I, you shall have a minimum of high school (SSLC in India) pass. Shall also have 3-9 months of experience based on the method. He/she shall take training for about minimum 16 hours to maximum of 40 Hours. It is based on NDT method in which the candidates intend to take certification.

How to Get Certified to NDT Level II

Procedure for NDT Level II certification is similar to the one for Level I. Eligibility for Level II is either Diploma in Engineering or Degree in Science. SNT TC 1A specifies minimum experience before attending training.

Examinations

After completion, NDT trainee shall take theory and practical examinations. Theory examination consists of method and specification examinations. Method exam is a closed book examination. Multiple choice questions with 4 options. Whereas, specification exam is an open book exam. A specification or NDT procedure is given in exam based on which multiple choice questions are required to be answered.

NDT trainee shall secure 80% in each category for passing. Failed trainees should take reexamination after an interval of 30days as per ASNT SNT TC 1A.

Validity of NDT Certification

5 years is the validity of NDT Level I, Level II and Level III

However, some fabrication codes mandates 3 years for NDT Level I, Level II and 5 years for Level III.

How to get certification Renewal (Re-validation)

All NDT certifications shall be renewed once in every 5 years(3 years for some codes) Level I and II and 5 Years for Level II. Renewal is based on providing adequate evidence of continuing experience. ASME Section V mandates renewal based on re-examination.

Greatest NDT Courses

For the employment, there are total 6 NDT courses. Out of this, Ultrasonic testing is the best course that significantly increase chances of employment. Other five methods are:

Duration of NDT training

Duration of NDT training is,

Ultrasonic testing – 05 Days

Radiography Testing – 05 Days

Magnetic particle testing – 02 Days

Penetrant testing – 02 days

Visual testing – 03 Days

Eddy Current Testing – 05 Days

Radiographic Interpretation – 03 Days

Note: Number of days for Level II training from Level I. For direct Level II the time period required consist of of days required for both levels.

Pay Scales for employment

Pay scales for Fresh NDT Level II inspector starts at Rs.15000 per month

Salaries vary based on organization, work profile and responsibility of inspector.

Check our blog post on Exploring the Salary of NDT Technicians in India: Factors That Influence Pay and Average Earnings

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