This standard specifies the specimen, test solution, test apparatus, test condition and procedure, as well as test result evaluation and test report of corrosion test for intergranular corrosion susceptibility of high-Cr ferritic stainless steels.
This standard is applicable to the intergranular corrosion test of ferritic stainless steel with Cr content no less than 16%. There are the following four test methods (designations of stainless steel applicable to different methods are given in Table A.1 in Annex A):
a) Method W: Method of 10% Oxalic Acid Etch Test
It is applicable to the screening test for intergranular corrosion sensitivity of ferritic stainless steel. After specimen is subjected to electrolytic etching in 10% oxalic acid solution, observe the metallographic structure of the etched surface under a microscope to judge whether long-term hot acid test as specified in Method X, Method Y and Method Z is required.
b) Method X: Method of Sulfuric Acid - Ferric Sulfate Corrosion Test
It is applicable to the evaluation of intergranular corrosion tendency by loss-weight or microscope observation after subjecting ferritic stainless steel to boiling test in sulfuric acid - ferric sulfate solution.
c) Method Y: Method of Copper - Copper Sulfate - 50% Sulfuric Acid Corrosion Test
It is applicable to the evaluation of intergranular corrosion tendency by loss-weight or microscope observation after subjecting ferritic stainless steel to boiling test in copper - copper sulfate - 50% sulfuric acid solution.
d) Method Z: Method of Copper - Copper Sulfate - 16% Sulfuric Acid Corrosion Test
It is applicable to the evaluation of intergranular corrosion tendency according to bending or metallography after subjecting ferritic stainless steel to boiling test in copper - copper sulfate - 16% sulfuric acid solution.
GB/T 32571-2016 The following standards are cited：
