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Dear Colleagues,

ASTM A262, a standard of corrosion tests for austenitic stainless steels, requires sensitizing treatment for extra-low-carbon grades and stabilized grades prior to all tests.  It is understandable why it is needed for stabilized grades, to confirm that the materials have been stabilized appropriately.  What is the purpose to sensitize ultra-low-carbon grades?  If it is an ultra-low-carbon grade, it shouldn't be sensitizable by the treatment with the parameter specified in ASTM A262 and the result is expected to pass.  If the concern is about the truth of ultra-low-carbon, is a chemical analysis not considered sufficient?  Does a failure of ultra-low-carbon grade in one of the tests after sensitization treatment suggest something else may not be right in the material besides carbon content?  Is it to make sure that surface contamination of carbon has not happened and no sensitization on surfaces?  I would like to understand the reasons for sensitizing ultra-low-carbon grades.  Thanks!

Dear Colleagues,

ASTM A262, a standard of corrosion tests for austenitic stainless steels, requires sensitizing treatment for extra-low-carbon grades and stabilized grades prior to all tests.  It is understandable why it is needed for stabilized grades, to confirm that the materials have been stabilized appropriately.  What is the purpose to sensitize ultra-low-carbon grades?  If it is an ultra-low-carbon grade, it shouldn't be sensitizable by the treatment with the parameter specified in ASTM A262 and the result is expected to pass.  If the concern is about the truth of ultra-low-carbon, is a chemical analysis not considered sufficient?  Does a failure of ultra-low-carbon grade in one of the tests after sensitization treatment suggest something else may not be right in the material besides carbon content?  Is it to make sure that surface contamination of carbon has not happened and no sensitization on surfaces?  I would like to understand the reasons for sensitizing ultra-low-carbon grades.  Thanks!