Quick answer: ASTM A262 testing evaluates susceptibility to intergranular attack in austenitic stainless steel. A useful purchase requirement identifies the applicable practice, material condition, sampling plan and acceptance criteria. Simply writing “A262 passed” does not tell an engineer what was examined or whether the result represents the material being ordered.
For a buyer comparing stainless plate, pipe or bar quotations, the central question is practical: does the inspection package address the risk in the intended component? This guide explains the distinction between a test standard, a material certificate and a project-specific acceptance requirement.
What Intergranular Corrosion Means
Intergranular corrosion follows susceptible regions near grain boundaries. In austenitic stainless steels, certain thermal exposures allow chromium-rich carbides to form, leaving nearby material depleted in chromium. This condition is called sensitisation. Attack then depends on exposure to a corrosive environment; a sensitised material does not necessarily show visible surface rust at delivery.
Low-carbon grades such as 304L and 316L reduce this risk in many welded applications. Stabilised grades use additions such as titanium or niobium to control carbon. Grade selection, however, must be considered alongside fabrication and heat-treatment history. A polished surface is not evidence of a satisfactory internal metallurgical condition. The British Stainless Steel Association explains the mechanism in its intergranular corrosion guidance.
Why the ASTM A262 Practice Must Be Named
ASTM A262 contains several practices, rather than one universal test. Practice A classifies etched structures and can screen certain eligible materials. Practice E uses a copper–copper sulfate–sulfuric acid exposure followed by examination of bent specimens. Other practices use different test environments and evaluation methods. The applicable practice and any screening permission should be agreed using the ordered specification and the standard.
A favourable result does not establish resistance to every chemical environment, pitting or stress-corrosion cracking. Nor is it a numerical prediction of service life. These scope limits are stated in the ASTM A262 standard overview. For this reason, purchasing teams should avoid turning a test result into a general “corrosion-proof” claim.
Translate the Requirement into an Inspectable Order
Identify the material and the condition being assessed
State the grade, product form, dimensions and governing product specification. Then identify whether the requirement applies to material as delivered, a separately heat-treated sample, or a representative fabricated condition. A report for incoming plate and a report for a welded qualification specimen answer different questions. Keep those identities clear when comparing offers.
Define the sampling and acceptance basis
Ask the supplier and testing laboratory to confirm the selected practice, specified edition, sample location, number of samples and applicable acceptance criteria before testing starts. Sampling must relate to the ordered lot or heat according to the purchase specification. Do not invent a universal sampling frequency or acceptance limit for all grades and products.
Keep the result linked to the shipment
A report should be traceable to a sample identity and the associated material records. During receipt, reconcile the report with package identification, material certificates and the purchase order. If a report refers only to an unidentified coupon, request clarification before treating it as acceptance evidence for a shipment.
A Practical Report Review Checklist
- Identity: do the grade, heat or lot reference and product description match the order?
- Test requirement: are the practice and specified edition identified?
- Sample condition: are relevant preparation and thermal-condition details documented?
- Evaluation: is the reported result assessed against the acceptance requirement actually ordered?
- Coverage: is it clear which quantity or batch the evidence represents?
- Outstanding actions: are substitutions, missing information or retests resolved before release?
Consider a purchase order for welded equipment made from 316L plate. The buyer may need both base-material documentation and a separate fabrication qualification. The useful action is to identify which evidence belongs to each stage, not to assume that one laboratory report approves the completed equipment.
Questions Buyers Commonly Ask
Is a material test certificate enough?
Only if its contents meet the ordered inspection requirements. Check whether the requested corrosion test is actually reported or referenced. The document title alone is not a substitute for reviewing its scope.
Should every stainless steel order include A262?
The requirement should follow the product specification, application and engineering assessment. Adding an unrelated test can increase cost without answering the project’s actual acceptance question.
Prepare a Clear Material and Inspection Enquiry
For stainless steel sheet and plate or stainless steel pipe, send the grade, dimensions, quantity and governing specification together with any A262 requirement. SAKYSTEEL can review the requested product testing service and documentation scope before an offer is confirmed.
Post time: Sep-09-2026