Nickel Alloy NDT Acceptance Criteria: Buyer Guide

By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012

Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360

Quick Answer: Nickel Alloy NDT Acceptance Criteria

Specify NDT by method, standard and acceptance level before ordering nickel alloy bar, plate, tube or forgings. ASTM A388, A578, E213 and E309 cover the common volumetric and surface methods, but note MT, eddy-current calibration and personnel certification. Demand records, not just a pass or fail statement.

Key Takeaways

• NDT verifies the absence of discontinuities under a stated technique, not a material property. The method, scan coverage, sensitivity and acceptance level are all agreement clauses, and the purchase order that omits them hands the choice to the supplier.
• Every product form has a different governing standard. Bar and billet ultrasonic testing commonly cites ASTM A388 or AMS 2631, plate cites ASTM A578 or AMS 2632, and seamless tube cites ASTM E213 for ultrasonic and ASTM E309 for eddy current examination.
• Austenitic nickel alloys are paramagnetic, so magnetic particle testing normally does not apply. Inconel, Incoloy, Hastelloy, Monel and Nimonic grades must be examined by penetrant testing instead, and a specification that calls for MT on these grades is a specification error.
• Acceptance level and recording level are two different numbers. Confusing them is the single most common source of receiving disputes, because a report can be fully compliant with the recording level while the material still fails the acceptance level.
• Personnel qualification must be named. ASNT SNT-TC-1A, ISO 9712 and NAS 410 are not interchangeable, and a Level II or Level III certificate to the wrong scheme invalidates the report for the buyer's quality system.
• A certificate that states a conclusion without records is not evidence. Demand the scan plan, the calibration block data, the indication log, the acceptance level applied and the identity of the examiner.

Why NDT Acceptance Criteria Decide Whether a Nickel Alloy Order Is Accepted

Nickel alloy components fail acceptance far more often for documentary reasons than for metallurgical ones. A heat of Inconel 625 bar can meet every chemistry and tensile requirement on the purchase order and still be rejected at the buyer's receiving inspection, because the ultrasonic report states a conclusion rather than a record, because the acceptance level was never written down, or because the penetrant examination was performed by an operator whose qualification cannot be traced to a recognised scheme. These are not exotic failures. They are the routine disputes that fill the correspondence of every nickel alloy supplier and every fabricator working to a nuclear, oil and gas, aerospace or pressure vessel specification.

The reason is structural. Non-destructive testing does not verify a material property; it verifies the absence of a defined class of discontinuities, under a stated technique, at a stated sensitivity, over a stated volume. Every one of those variables is a decision that has to be made before the material is examined, and if the order does not fix them, the supplier will choose the least expensive defensible set and the buyer will discover the mismatch only when the certificate arrives. Chemistry and mechanical properties are defined by the product standard; the rejection thresholds for internal and surface discontinuities are, in most cases, defined by agreement.

This article is written from the buyer's side. It sets out which NDT methods apply to each nickel alloy product form — bar, plate, tube, pipe, forging and finished machined part — which standard governs each method, how acceptance level differs from record level, what the purchase order must state so that a dispute cannot arise, and what the common traps cost. The focus is on the austenitic nickel alloys: Inconel, Incoloy, Hastelloy, Monel and Nimonic grades, whose physical behaviour changes which methods are even applicable. It complements the material-selection material in our news section and our knowledge base, and it assumes the reader already knows which grade is required and now has to buy it correctly.

The commercial argument for getting this right is straightforward. NDT is a small fraction of the value of a nickel alloy order, but it is a large fraction of the risk. A rejected heat of 100 mm Inconel 718 bar can carry a four-figure loss in testing, freight and schedule, and a missed internal defect that reaches a pressure boundary carries a cost that no certificate can repair. Writing four extra lines on the purchase order is the cheapest insurance available to a buyer.

Which NDT Method Applies to Which Product Form

The first decision is method. Ultrasonic testing is the workhorse for internal discontinuities in wrought product; eddy current dominates for tube and bar surface and wall condition in continuous inspection; penetrant testing covers surface-breaking defects on any form; radiographic testing covers welds and castings; and magnetic particle testing applies only to ferromagnetic material, which excludes the austenitic nickel alloys. The table below maps the methods to the standards that are normally cited and to the forms they serve.

NDT method	Standard (primary reference)	Applicable forms	Detects	Notes
Ultrasonic, straight beam, bar and billet	ASTM A388 / AMS 2631 (verify current title)	bar, billet, rod	internal inclusions, porosity, pipe, segregation	contact or immersion; requires calibration block
Ultrasonic, straight beam, plate	ASTM A578 / AMS 2632 (verify current title)	plate, sheet above about 6 mm	laminations, delamination, inclusions	acceptance classes AA/A/B/C by agreement
Ultrasonic, pipe and tube	ASTM E213	seamless and welded tube, pipe	longitudinal and transverse defects, wall loss	two-directional scan normally required
Eddy current, tubular and bar	ASTM E309	tube, pipe, bar, wire	surface and near-surface discontinuities	reference notch or drilled hole per order
Liquid penetrant (PT)	ASTM E165 / ASTM E1417 / ASME BPVC Section V, Article 6	all forms, welds, machined parts	surface-breaking discontinuities	applicable to austenitic nickel alloys
Magnetic particle (MT)	ASTM E709 / ASTM E1444 / ASME BPVC Section V, Article 7	ferromagnetic materials only	surface and near-surface	not applicable to austenitic nickel alloys
Radiographic (RT)	ASTM E94 / E1032 / E1742 / ASME BPVC Section V, Article 2	welds, castings, forgings	volumetric internal discontinuities	IQI and density limits required
Visual and dimensional	ASME BPVC Section V, Article 9	all forms	surface condition, profile	normally the first examination step
Positive material identification (PMI)	ASTM E1476	all forms	elemental identity, not defects	not an NDT method for defects

Table note: Standard numbers are given as commonly cited on nickel alloy purchase orders; where a title is marked for verification the current edition should be confirmed against the ASTM, SAE or ASME catalogue before it is written into a contract. Methods listed under ASME BPVC Section V are the article-level references used when the component is designed and stamped to Section VIII Division 1; the equivalent ASTM method standards are used for material-supply examination. PMI is included for completeness because it is frequently confused with NDT, but it verifies identity and not the absence of discontinuities.

The second decision is which of those methods the order actually requires, form by form, because a single grade can be bought as bar, plate, tube, forging or finished part and the applicable examination changes with the form. There is no single "NDT requirement" that covers a nickel alloy order.

Product form	Normally required	Agreed or optional	Governing standard	Acceptance level basis	Document
Bar and rod	UT straight beam (where specified)	ET, PT	ASTM A388 / ASTM E213 / AMS 2631 (verify)	free of internal discontinuities to an agreed class	EN 10204 3.1 + NDT report
Plate and sheet	UT straight beam	PT on cut edges	ASTM A578 / AMS 2632 (verify)	acceptance class AA/A/B/C by agreement	EN 10204 3.1 + NDT report
Seamless tube and pipe	UT and/or ET, hydrostatic	PT on welds	ASTM E213 / ASTM E309	wall and seam criteria, calibration hole by agreement	EN 10204 3.1 + NDT report
Welded pipe	ET on weld seam	RT, PT	ASTM E309 / ASTM E213 / ASME V	seam acceptance level by agreement	EN 10204 3.1 + NDT report
Forgings	UT and PT	RT, dimensional	ASTM A388 / ASTM E165 / E1417	agreed class and coverage	EN 10204 3.1 or 3.2
Wire and strip	ET (where specified)	PT	ASTM E309	agreed reference standard	EN 10204 3.1
Fittings and flanges	PT, dimensional, PMI	UT, RT	ASME BPVC Section V / Section VIII Div.1 appendix (verify)	code or order acceptance level	EN 10204 3.1
Finished machined part	PT or ET final examination	UT, dimensional	customer drawing and ASME V	drawing or order acceptance level	full test and NDT dossier

Table note: The "normally required" column reflects common practice for material-supply orders and is not a standard requirement in itself; the binding requirement is always the standard, code or customer specification named on the order. Where the component is a pressure part designed to ASME BPVC Section VIII Division 1, the examination requirements of the code and its mandated appendices take precedence over mill-supply practice, and the applicable appendix for the joint type should be confirmed for the current edition. Documents are normally supplied to EN 10204 type 3.1 for mill product and type 3.2 where an independent inspector is named.

Three points follow from these two tables. First, ultrasonic testing of bar and of plate are governed by different standards with different acceptance classes, so a blanket "UT to ASTM" clause on a mixed order is meaningless. Second, eddy current examination of tube is only as good as the reference standard agreed for it, a subject covered below. Third, the austenitic nickel alloys change one row of the first table completely: magnetic particle testing is not applicable, and the buyer who copies an MT clause from a carbon steel or martensitic specification onto an Inconel, Monel or Hastelloy order has written a clause that cannot be executed. Our Monel range and nickel range orders are reviewed against exactly this matrix before an NDT scope is quoted.

Acceptance Level, Record Level and the Reporting Requirement

The second and more dangerous gap in a typical purchase order is not the method but the number at which the method accepts and rejects. NDT reports use two different thresholds, and the difference between them is the difference between a usable report and a useless one.

Term	Meaning	Typical expression	Who sets it	Consequence if omitted
Recording level	Amplitude, size or count above which an indication is written down	a percentage of the reference echo, or a size in mm	ASTM method standard, then the order	indications are not documented; no audit trail
Acceptance level	Amplitude, size or count above which the material is rejected	a lower amplitude or larger size than the recording level	purchase order or drawing, by agreement	no rejection criterion; disputes on delivery
Reference standard	Artificial reflector that calibrates the method and sets sensitivity	flat-bottom hole, side-drilled hole, notch, drilled hole	method standard plus order	sensitivity is undefined; results not comparable
Scan coverage	Fraction of the volume or surface examined, and the scan pattern	100 %, 25 % grid, two-directional	purchase order, by agreement	partial examination reported as complete
Report content	The information the report must carry	technique, calibration, indications, level applied, examiner	method standard plus EN 10204	conclusion without evidence

Table note: The definitions follow the structure used in the ASTM ultrasonic, eddy current and radiographic method standards and in ASME BPVC Section V; the specific numeric recording and acceptance levels are deliberately not quoted here because they depend on the method, the form and the agreed class, and the controlling values are those named on the purchase order. The safe drafting rule is to state the method standard, the acceptance class or level, the recording level where the standard permits a choice, and the scan coverage as separate clauses.

The practical consequence is that "the material shall pass UT" is not a requirement, it is a hope. A report can be entirely truthful and entirely compliant with the recording level that the laboratory chose, and still describe material that the buyer will reject, because the two parties never agreed where acceptance sat. In one common pattern the supplier examines bar with an ultrasonic reference sensitivity that records only large indications, reports "no recordable indications", and the buyer's own incoming eddy current or ultrasonic check finds smaller discontinuities above the drawing limit. Both parties are acting in good faith; the order simply failed to fix the acceptance level.

The removal of the trap is drafting, not negotiation. State the method and its edition, the acceptance class or level in the language of that standard, the recording level where a choice exists, the scan coverage and pattern, the reference reflector and its dimensions, the report contents and the personnel qualification scheme. Where a standard offers quality classes, name the class rather than describing it in prose. Where the buyer cannot yet fix a numeric level, state that the level must be agreed and recorded in writing before examination begins, so that the laboratory's default is not adopted silently. Our purchase specification guide sets out the clause list we recommend for nickel alloy orders and explains how the NDT clauses interlock with the EN 10204 certificate type.

Penetrant, Magnetic Particle and Radiographic Testing on Nickel Alloys

Surface and volumetric methods behave differently on the austenitic nickel alloys than on steel, and the differences are the source of several specification errors. The first and most important is magnetic particle testing. Inconel, Incoloy, Hastelloy, Monel and Nimonic grades are austenitic and therefore paramagnetic or very weakly magnetic; they cannot be magnetised to the level MT requires, and the method is not applicable to them. A specification that calls for MT on any of these grades is asking for an examination that cannot produce a meaningful result, and a supplier who "performs" it is producing a document with no technical content. Where a surface examination is needed on these alloys, the correct method is liquid penetrant testing, performed to ASTM E165, to ASTM E1417 for aerospace and critical applications, or to ASME BPVC Section V, Article 6 where the component is code-stamped. The only nickel-base materials where MT legitimately applies are the ferromagnetic grades, which are the exception rather than the rule in this family, and the applicable standards there are ASTM E709 and ASTM E1444.

Penetrant testing itself has two traps. The first is the removal method and the sensitivity level: solvent-removable, water-washable and post-emulsifiable processes have different sensitivities, and a Level 3 requirement in one process is not equivalent to Level 3 in another. The second is the dwell and development discipline, which must be recorded, because a penetrant examination performed with an inadequate dwell is not a valid examination even if the operator is qualified. For nickel alloys the examination is otherwise routine and the process is normally colour-contrast penetrant for field work and fluorescent penetrant for the shop.

Radiographic testing applies mainly to welds, castings and certain forgings, and it is governed by ASTM E94 for the general technique, ASTM E1032 for the radiographic examination of castings, and ASTM E1742 for the radiographic examination of metallic materials for aerospace applications, or by ASME BPVC Section V, Article 2 for code work. The clauses that matter to a buyer are the image quality indicator type and placement, the density limits, the acceptance level for the indication type being sought and the film or digital image retention requirement. A radiograph without an IQI placed and recorded to the standard is not evidence of anything, and a report that gives a density outside the permitted band describes an image the buyer cannot rely on. Radiography is also a candidate for the classic confusion with PMI, because both are sometimes loosely called "X-ray": radiographic testing finds volumetric defects using ionising radiation, while PMI measures chemistry and is not an NDT method for defects at all.

Surface and volumetric method	Applies to austenitic nickel alloys?	Governing standard	Key order clause	Common error
Liquid penetrant (PT)	Yes	ASTM E165 / E1417 / ASME V Art.6	process, sensitivity level, dwell time, acceptance level	sensitivity level not stated
Magnetic particle (MT)	No (paramagnetic)	ASTM E709 / E1444 (ferromagnetic grades only)	field direction, method, acceptance level	MT specified on austenitic grades
Radiographic (RT)	Yes	ASTM E94 / E1032 / E1742 / ASME V Art.2	IQI type, density limits, acceptance level, retention	no IQI or density record
Ultrasonic (UT)	Yes	ASTM A388 / A578 / E213 / AMS 2631, 2632 (verify)	scan coverage, reference reflector, acceptance class	coverage and reflector not agreed
Eddy current (ET)	Yes	ASTM E309	reference notch or drilled hole, frequency, acceptance level	calibration hole type not specified

Table note: The applicability column reflects the metallurgical behaviour of the austenitic nickel alloys and the scope of the named standards; it is not a substitute for reading the standard. Where a customer specification derived from a ferritic or martensitic steel specification is copied onto a nickel alloy order, the MT row is the clause most often carried over in error. AMS standard titles should be confirmed against the SAE catalogue for the current edition.

Standards Compared: ASTM and ASME Against GB, JIS, DIN/EN and GOST

Nickel alloy orders travel across several standard systems, and a buyer who receives mill product from a Chinese, Japanese, European or Russian mill may be offered examination to a different national standard that is nominally equivalent but not identical. The table below sets the principal methods side by side so that the equivalence question can be asked before the order is placed rather than after delivery.

Examination	ASTM / ASME	GB (China)	JIS (Japan)	DIN / EN (Europe)	GOST (Russia / CIS)
UT of forgings	ASTM A388; ASME V Art.4 / 5	GB/T 6402	JIS G 0587	EN 10228-3 (steel forgings)	GOST 7512 (RT), UT per GOST
UT of bar and plate	ASTM A388, ASTM A578	GB/T 4162	JIS G 0587	EN 10228 (verify part)	GOST 7512
UT of tube	ASTM E213	GB/T 5777	JIS G 0582	EN 10228 (verify part)	GOST 7512
Eddy current of tube	ASTM E309	GB/T 5777 (related)	JIS G 0582	DIN EN 571 area (verify)	GOST 7512
Liquid penetrant	ASTM E165, E1417; ASME V Art.6	GB/T (verify number)	JIS Z 2343 (verify)	DIN EN 571-1	GOST 7512
Magnetic particle	ASTM E709, E1444; ASME V Art.7	GB/T (verify number)	JIS G 0565 (verify)	EN ISO 9934 area	GOST 7512
Radiography	ASTM E94, E1032, E1742; ASME V Art.2	GB/T 3323 (verify)	JIS G 0581 (verify)	EN ISO 17636 area	GOST 7512
Personnel qualification	ASNT SNT-TC-1A; NAS 410	GB/T (verify)	JIS (verify)	ISO 9712	GOST 7512 (verify)
Inspection documents	EN 10204 2.2 / 3.1 / 3.2	GB/T (verify)	JIS (verify)	EN 10204	GOST (verify)

Table note: Where a cell carries "verify", the exact number or part should be confirmed against the current national catalogue before it is written into a contract; the table is a map of the systems, not a certified equivalence register. GB/T 6402 is the Chinese practice for ultrasonic testing of forgings, GB/T 4162 and GB/T 5777 are the Chinese practices for ultrasonic testing of wrought metal and of seamless steel tube respectively, JIS G 0582 covers eddy current examination of steel tube and JIS G 0587 covers ultrasonic examination of steel forgings, EN 10228 covers NDT of steel forgings, DIN EN 571 covers penetrant testing, and GOST 7512 is the Russian standard for radiographic examination of welded joints. Standards from different systems are not automatically interchangeable, and the acceptance levels they define differ, so the safe clause names the standard and the edition and states that the acceptance level is the one in that edition.

Two practical rules follow. The first is that a nickel alloy is not a steel, so a forged or tubular nickel alloy component examined to a steel standard is being examined to a scope that may not have been written with its alloy behaviour in mind; where the buyer's quality system requires a national standard, the clause should say so explicitly and, where possible, name the nickel-alloy-specific product standard for the form as well. The second is that equivalence claims should never be accepted on a certificate without the supporting level and coverage data, because "to GB/T 6402" and "to ASTM A388" do not specify the same acceptance class. Where a project spans a Chinese mill and a European engineering contractor, the cleanest solution is to specify the ASTM or ASME method standard, which is internationally recognised, and to add the national standard only where a local code requires it. Our Inconel range and our other product pages are supplied with the method standard, the acceptance level and the personnel scheme stated on the certificate for exactly this reason.

Risk-Based Selection: Choosing the NDT Combination for the Application

Not every nickel alloy component needs the same examination. The correct combination follows from what happens if the component fails, and the money spent on examination should track the consequence of failure rather than the value of the material. The table below is a selection guide, not a code requirement.

Service risk	Consequence of failure	Recommended NDT combination	Acceptance level basis
General structural, non-wetted	low	dimensional and visual only	drawing tolerance
Machined part, no pressure	low to moderate	PT final examination, dimensional	agreed surface acceptance level
Low-pressure process piping	moderate	PT on welds, ET or UT on tube where specified	order acceptance level
Pressure-retaining, non-critical	high	UT or ET on product, PT on welds, EN 10204 3.1	standard class plus order level
Critical pressure or high temperature	very high	100 % UT with two-directional scan, PT 100 %, RT on welds, 3.2 with third-party witness	agreed class, tightest applicable
Aerospace or rotating part	very high	UT immersion with tight class, PT fluorescent, dimensional, process certification	AMS or customer class; NADCAP route
Nuclear or safety-related	extreme	full volumetric and surface regime to code, personnel to a formal scheme, full records retained	ASME Section III / Section V code level

Table note: The combinations are guidance drawn from common practice in petrochemical, power, aerospace and general engineering supply chains and are not requirements of any single standard; the binding examination regime for a given component is set by the applicable code, the customer specification and the classification society, and it should be recorded on the drawing or the purchase order. Where the risk category is high or above, the personnel qualification scheme and the record retention period should be specified as well, because a technically valid examination whose report cannot be produced five years later does not serve a critical application.

The reading of this table is that examination depth should escalate with consequence, and that the escalation is mainly in coverage, class tightness and documentation rather than in the number of different methods. A 100 % two-directional ultrasonic scan with a tight acceptance class is a far stronger requirement than a 25 % single-directional scan with a loose class, even though both are "UT". Buyers who are constrained on cost can often obtain more real assurance by tightening coverage and class on one method than by adding a second method at low sensitivity. Where the application is wetted, the selection of the grade itself dominates the risk and should be settled first, which is why our Hastelloy range and our corrosion-selection material are quoted together with the examination scope rather than separately.

Purchase Order Clauses, Personnel Certification and NDT Cost (2026, EXW Shanghai)

The clauses below are the ones that most often go missing from a nickel alloy purchase order, and each of them has been the subject of a rejected consignment at some point. They should be read as a checklist rather than as a preference.

First, name the method and the standard with its edition, for example "ultrasonic examination of bar to ASTM A388" or "eddy current examination of seamless tube to ASTM E309". Second, name the acceptance level or class in the language of that standard, and the recording level where the standard allows a choice. Third, state the scan coverage and pattern, for example 100 % with two-directional scanning, or a 25 % grid. Fourth, specify the reference reflector or calibration block and its dimensions: for ultrasonic work a flat-bottom hole or side-drilled hole, for eddy current either a drilled through-hole or a reference notch, with the choice stated rather than left to the laboratory. Fifth, state the report contents, which must include the technique, the calibration data, the indication log, the acceptance level applied and the examiner's identity and qualification. Sixth, name the inspection document type to EN 10204, since the NDT report is normally attached to a type 3.1 certificate and, where an independent inspector is named, to a type 3.2 certificate. Seventh, and most often forgotten, name the personnel qualification scheme and the minimum level: ASNT SNT-TC-1A, ISO 9712 or NAS 410, with Level II for the examination and Level III for the procedure and the final interpretation where the specification requires it.

NDT activity	Basis	Reference range, 2026, EXW Shanghai	Note
UT, bar or billet, straight beam	per batch	USD 60–180 per batch	small quantities at the upper end
UT, plate, straight beam	per piece or per plate	USD 25–70 per plate	larger plate scans scale with area
UT, seamless tube	per metre or per batch	USD 1.5–4.0 per metre	100 % two-directional at the top
ET, tube or bar	per metre	USD 0.8–2.5 per metre	depends on frequency and reference standard
PT, batch of parts or welds	per part or per batch	USD 8–35 per part	fluorescent penetrant at the upper end
RT, weld or casting	per film or per part	USD 15–60 per exposure	IQI and density records included
Third-party witness (SGS, BV, TUV)	per inspection visit	USD 350–900 per visit	scope, location and notice period drive cost
NDT as an uplift on material price	percentage	1.5–6 % of order value	full regimes to a tight code class at the top

Table note: Reference range only, 2026, EXW Shanghai, in USD, subject to the scope actually agreed, the quantity, the accessibility of the material, the notice period for third-party attendance and the code class required; these figures are indicative and are not a quotation. Costs are quoted per batch, per piece or per metre because the laboratory charges on the setup and the machine time rather than on the mass of the material, which is why the same examination is proportionally more expensive on a small order. Actual charges depend on the standard, the acceptance level, the coverage, the reporting requirement and the personnel scheme named on the order, and are quoted against the specific NDT scope after it is agreed.

Three commercial observations close this section. First, NDT cost is driven by coverage and documentation rather than by method, so the difference between a light and a heavy regime on the same order is usually a few per cent of order value, which is small against the cost of a rejected consignment. Second, the decision that saves the most money is not a cheaper examination but an agreed one, because a dispute costs far more than the examination that would have prevented it. Third, the personnel scheme deserves as much attention as the method, because ASNT SNT-TC-1A, ISO 9712 and NAS 410 are distinct qualifications and a certificate to the wrong scheme is not a minor paperwork defect: it means the examination was not performed by personnel the buyer's quality system recognises. Our news section carries the related buying and verification material, and our contact page is the route for confirming an NDT scope against a specific code before an order is placed.

Standard Index

Standard	Title / scope	Covers	Form
ASTM A388	Ultrasonic examination of steel forgings	UT method and acceptance	forging, billet
ASTM A578	Straight-beam ultrasonic examination of rolled steel plates	UT method and acceptance classes	plate
ASTM E213	Ultrasonic examination of metal pipe and tubing	UT method	tube, pipe
ASTM E309	Eddy-current examination of steel tubular products	ET method	tube, pipe
ASTM E165	Liquid penetrant examination, general practice	PT method	all forms
ASTM E1417	Liquid penetrant testing, aerospace	PT method	all forms
ASTM E709	Magnetic particle testing, guide	MT method	ferromagnetic only
ASTM E1444	Magnetic particle testing, aerospace	MT method	ferromagnetic only
ASTM E94	Radiographic examination, guide	RT method	welds, castings, forgings
ASTM E1032	Radiographic examination of castings	RT method	castings
ASTM E1742	Radiographic examination for aerospace	RT method	aerospace parts
ASTM E1476	Metals identification by PMI	identity verification	all forms
AMS 2631	Ultrasonic inspection of wrought metal (verify title)	UT method and class	bar, billet
AMS 2632	Ultrasonic inspection of wrought metal (verify title)	UT method and class	plate
AMS 2647	Fluorescent penetrant inspection (verify number)	PT method	all forms
ASME BPVC Section V	NDT — Articles 2, 4, 5, 6, 7, 8, 9	RT, UT, PT, MT, ET, VT	code components
ASME BPVC Section VIII Div.1	Rules for construction of pressure vessels; mandated appendices (verify)	examination of welded joints	pressure vessel
ASNT SNT-TC-1A	Personnel qualification and certification in NDT	Level I, II, III	personnel scheme
ISO 9712	Non-destructive testing — qualification and certification of personnel	Level 1, 2, 3	personnel scheme
NAS 410	Certification and qualification of NDT personnel (aerospace)	Level 1, 2, 3	personnel scheme
EN 10204	Metallic products — types of inspection documents	2.2 / 3.1 / 3.2	all forms
EN 10228	NDT of steel forgings (parts 1–5)	UT, PT, MT, RT	forging
DIN EN 571	Penetrant testing — general principles	PT method	all forms
GB/T 6402	Chinese practice, ultrasonic testing of forgings	UT method	forging
GB/T 4162	Chinese practice, UT of wrought metal	UT method	bar, plate
GB/T 5777	Chinese practice, UT of seamless steel tube	UT method	tube
JIS G 0582	Eddy current examination of steel tube	ET method	tube
JIS G 0587	Ultrasonic examination of steel forgings	UT method	forging
GOST 7512	Radiographic examination of welded joints	RT method	welds

Table note: Standards are listed by number and scope; where an edition year is not quoted the latest edition applies, and the controlling edition is the one named on the purchase order. Entries marked "verify" should be confirmed against the current catalogue of the issuing body, because AMS and some national numbers are revised and titles change; no standard number in this table should be written into a contract without that confirmation. The ASTM method standards govern the technique and default acceptance levels, the ASME BPVC Section V articles govern examination of code-stamped components, the personnel schemes govern who may perform and interpret the examination, and EN 10204 governs the document that carries the result.

FAQ

Q1: Which NDT methods apply to nickel alloy bar, plate and tube?

Nickel alloy bar and billet are normally examined by straight-beam ultrasonic testing to ASTM A388 or to AMS 2631 for wrought product, with eddy current testing to ASTM E309 as an alternative or additional surface method. Plate is examined by straight-beam ultrasonic testing to ASTM A578, which defines acceptance classes that the buyer must name rather than leave to the laboratory. Seamless tube and pipe are examined by ultrasonic testing to ASTM E213 and by eddy current to ASTM E309, and where a welded seam exists the seam is examined by eddy current or by radiographic testing. Forgings are examined by ultrasonic testing to ASTM A388 and by liquid penetrant testing to ASTM E165 or E1417. In every case the standard fixes the technique, but the acceptance level, the scan coverage and the reference reflector are set by the purchase order, so a method name alone is not a sufficient requirement. Our product range is quoted with a form-specific NDT scope stated explicitly.

Q2: Why is magnetic particle testing not used on Inconel and Monel?

Inconel, Incoloy, Hastelloy, Monel and Nimonic grades are austenitic, which makes them paramagnetic or, at most, very weakly magnetic. Magnetic particle testing depends on magnetising the material strongly enough to produce a leakage field at a surface discontinuity, and these alloys cannot be magnetised to that level, so the method produces no meaningful indication of defects. The correct substitute is liquid penetrant testing to ASTM E165, to ASTM E1417 for aerospace work, or to ASME BPVC Section V, Article 6 for code-stamped components. A purchase order that specifies MT on an austenitic nickel alloy is not a stricter requirement, it is an inapplicable one, and any report issued against it has no technical value. Magnetic particle testing is reserved for the genuinely ferromagnetic nickel-base exceptions and for steels, where the applicable standards are ASTM E709 and E1444 and ASME BPVC Section V, Article 7.

Q3: What is the difference between acceptance level and recording level?

Recording level and acceptance level are two different thresholds, and confusing them is the most common cause of receiving disputes. The recording level is the amplitude, size or count above which an indication must be written down in the report; the acceptance level is the amplitude, size or count above which the material must be rejected. The acceptance level is normally more stringent than the recording level, so a report can be entirely truthful and fully compliant with the recording level the laboratory selected, and still describe material that the buyer will reject. The recording level is generally set by the method standard and the acceptance level by the purchase order or drawing, which is why both must be stated. Where the buyer cannot yet fix the band, the order should require the level to be agreed and recorded in writing before examination begins, so the laboratory's default is not adopted silently. Our knowledge base lists the clauses we recommend for this purpose.

Q4: What must a purchase order state for ultrasonic testing of bar?

A sufficient ultrasonic clause for nickel alloy bar names six things. First, the method standard and edition, normally ASTM A388 or AMS 2631. Second, the acceptance level or class in the language of that standard. Third, the recording level where the standard permits a choice. Fourth, the scan coverage and pattern, for example 100 % with two-directional scanning or a stated grid. Fifth, the reference reflector and its dimensions, such as a flat-bottom hole or a side-drilled hole of a stated diameter. Sixth, the report contents, which must include the technique, the calibration data, the indication log, the acceptance level applied and the examiner's identity and qualification. Where the material is a forging rather than bar, ASTM A388 remains the natural reference; where it is wrought bar supplied to an aerospace specification, the AMS route applies. State all six and the ambiguity that causes most bar rejections disappears.

Q5: How is eddy current testing of nickel alloy tube calibrated?

Eddy current examination of nickel alloy tube to ASTM E309 is only as good as the reference standard agreed for it, and this is where orders most often go wrong. The method can be calibrated against a drilled through-hole, a flat-bottom hole or a machined notch, and these reflectors produce different signals and therefore different effective sensitivities. A tube that passes against a notch of a given depth may show indications against a drilled hole of an equivalent nominal size, and neither result is wrong; they are results against different references. The purchase order must therefore state the reference standard type and its dimensions, the examination frequency, the fill factor where a coil is used, and the acceptance level expressed against that reference. For welded tube the seam is normally examined and the reference is normally a longitudinal notch in the weld, but the buyer should state this rather than assume it. Our Monel tube range confirms the reference type before examination.

Q6: What personnel qualification should I require for NDT reports?

The purchase order should name the personnel qualification scheme and the minimum level, because ASNT SNT-TC-1A, ISO 9712 and NAS 410 are distinct schemes and a certificate to the wrong one is not recognised by the buyer's quality system. As a default, examinations should be performed by Level II personnel, with the procedure and the final interpretation under Level III responsibility. SNT-TC-1A is the widely used employer-based scheme in North America, ISO 9712 is the internationally recognised certification scheme common in Europe and Asia, and NAS 410 is the aerospace scheme. The report should identify each examiner, state the qualification scheme and level, and give the certificate number and expiry date. Where the component is safety-related, the buyer may also require the examination to be performed under an accredited laboratory system. Naming the scheme is a one-line clause that removes an entire class of post-delivery argument.

Q7: Is PMI the same as NDT?

No, and the confusion is common because both are sometimes loosely described as X-ray work. Positive material identification measures the elemental composition of the material and confirms that the grade delivered matches the grade ordered; it is performed by X-ray fluorescence or optical emission spectrometry to ASTM E1476 and it verifies identity. Non-destructive testing for defects establishes the absence of a defined class of internal or surface discontinuities under a stated technique, coverage and acceptance level. PMI cannot find a crack, a lamination or porosity, and ultrasonic or radiographic testing cannot tell you whether the bar is Inconel 625 or 316L stainless steel. A complete verification package for a critical nickel alloy order therefore contains both: PMI, or the mill certificate chemistry, for identity, and NDT reports for integrity. Treating one as a substitute for the other leaves one of the two risks entirely uncovered.

Q8: Which inspection documents should accompany an NDT examination?

The NDT report itself must carry the technique and standard, the equipment and its calibration, the reference reflector data, the indication log with positions and sizes, the acceptance level applied, the result, the examination date and the examiner's identity and qualification. This report is normally attached to a mill certificate issued to EN 10204 type 3.1, which is the standard inspection document for mill product with a specific heat analysis and test results. Where an independent inspector is named and the buyer requires third-party verification, the certificate is issued to EN 10204 type 3.2, and the NDT scope is usually witnessed as part of that. A type 2.2 document, which is a non-specific declaration, is not adequate where NDT results are the basis of acceptance. State the certificate type in the order, because the NDT report and the certificate type must be consistent for the buyer's quality system to accept the consignment.

Q9: How much does NDT add to the cost of a nickel alloy order?

NDT is normally a small fraction of the value of a nickel alloy order, with the cost driven by scan coverage and documentation rather than by the method itself. As a 2026, EXW Shanghai reference, straight-beam ultrasonic testing of bar runs at roughly USD 60–180 per batch, plate at about USD 25–70 per plate, seamless tube at about USD 1.5–4.0 per metre for a full two-directional scan, eddy current of tube or bar at about USD 0.8–2.5 per metre, penetrant testing at about USD 8–35 per part, and radiographic testing at about USD 15–60 per exposure. A third-party witness visit by SGS, BV or TUV is typically USD 350–900. Taken together, a full examination regime usually adds about 1.5–6 % to order value. These figures are indicative only and depend on the standard, class, coverage and personnel scheme named, so they should be confirmed against a specific scope.

Q10: Can I use GB/T 6402 or JIS G 0587 instead of ASTM A388?

Where the buyer's quality system or the end user's code requires a national standard, then yes, examination to GB/T 6402 for forgings, GB/T 4162 and GB/T 5777 for wrought metal and tube, JIS G 0587 for forgings or JIS G 0582 for tube eddy current is acceptable, provided the acceptance level is stated and is comparable. The caution is that these standards are not automatically interchangeable with ASTM A388, A578, E213 or E309. They were written with steel in mind, their acceptance classes differ, and an equivalence claim on a certificate must be supported by the level and coverage data. Where a project spans a Chinese or Japanese mill and a European or American engineering contractor, the cleanest route is to specify the ASTM or ASME method standard, which is internationally recognised, and to add the national standard only where a local code demands it. Name the edition as well as the number in every case.

Q11: What is the biggest mistake buyers make with nickel alloy NDT?

The most expensive mistake is a clause that states a method but no acceptance level, coverage or record requirement, which leaves the laboratory free to examine to its own default and produces a certificate that cannot be relied on. The second is specifying magnetic particle testing on an austenitic nickel alloy, which yields a document with no technical content. The third is accepting a report that states a conclusion, such as "material accepted", without the indication log, calibration data and acceptance level behind it. The fourth is confusing PMI with NDT and assuming a chemistry check covers integrity. The fifth is leaving the eddy current reference standard, the ultrasonic reference reflector or the personnel scheme unstated. Each of these is removed by four or five extra lines on the purchase order, and Hangbo Alloy reviews the NDT scope against the applicable code before quoting, so the clause set is agreed before the material is examined.

Conclusion and Buyer Checklist

The acceptance of a nickel alloy order turns on clauses that are decided before the material is examined, not on the examination itself. Fix the method and its standard, fix the acceptance level and the recording level, fix the scan coverage and the reference reflector, fix the report contents and the personnel scheme, and state the inspection document type. The methods themselves are not complicated: ultrasonic testing for internal condition in bar, plate and tube, eddy current for tube and bar surface and wall, penetrant testing for surface on all forms, radiographic testing for welds and castings, and no magnetic particle testing on the austenitic nickel alloys.

Three rules keep an order out of dispute. Never buy "NDT" without a method standard and an acceptance level, because the combination is the requirement. Never copy a clause from a steel specification onto a nickel alloy order without checking whether the method is applicable and whether the acceptance level means the same thing. And never accept a certificate that states a conclusion without the records behind it, because a conclusion is not evidence and cannot be defended years later when the component is in service.

Shanghai Hangbo Alloy Group Co., Ltd. supplies Inconel, Incoloy, Hastelloy, Monel, Nimonic and pure nickel grades in bar, plate, tube, pipe, wire and forgings, with NDT performed to the method standard and acceptance level named on the order, personnel qualified to ASNT SNT-TC-1A, ISO 9712 or NAS 410 as required, and mill certification to EN 10204 type 3.1 or 3.2. Send your method standard, acceptance level and coverage requirement through our contact page and we will confirm the NDT scope and quote the material with the examination requirement stated explicitly.

Contact & Complete Product Range

Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier

Email: sales@hangboalloy.com | WhatsApp (Lisa): +86 13611656360 | www.nickel-alloy.com

All Grades

Ni: NI200-N6 | Monel: 400-502, K-500, R-405 | Inconel: 600-740H, X-750, 725 | Incoloy: 800-27-7MO | Hastelloy: C-276-HYBRID-BC1, N | Super Austenitic: 904L-AL-6XN | Chromium-Rich: Alloy 33 | High-Strength Stainless: Nitronic 50/60, PH13-8Mo | Chlorination: Alloy 45 | Nimonic: 75-263 | Haynes: 25-HR-160 | RA: 330/333 | Precision: 1J22-4J45 | High-Strength: 18Ni250-AerMet100 | Heating: Cr20Ni80/60 | Specialty: Alloy 20-602CA

Product Forms: Bars(6-500mm) | Tubes(OD 6-610mm) | Plates(0.1-100mm) | Forgings | Welded Pipes | Fittings | Wire(0.05-10mm) | Strip(0.02-4.0mm)

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