Commonly used intergranular corrosion tests:

- Copper sulfate–sulfuric acid method (GB/T 4334 Method E / ASTM A262 Practice E): suitable for austenitic stainless steels, to check sensitization tendency. - Nitric acid method (Practice C): boiling 65% nitric acid, to assess long-term corrosion resistance. - Ferric sulfate method (Practice B): rapid screening.

Basis for selection: material type, service medium, and customer requirements. For welded components, specimens should be taken from the weld and heat-affected zone.

Evaluation: observe cracks after bending or measure the weight-loss rate. The report must state the test method, duration, and evaluation criteria.