Mehta Sanghvi & Company

The copper sulfate test is intended to verify the effectiveness of the stainless steelpassivation treatment. It can also be used to determine if there is a need for passivation.The purpose of the copper sulfate test is to determine the presence of free iron which is often transferredonto the surface of a part during fabrication with steel components. The principle of the test is based on anoxidation-reduction reaction which causes the dissolved copper ions to deposit or plate out onto thelocations of free iron particles.This test is recommended for the detection of free iron on the surface of austenitic stainless steels in the200 and 300 series, precipitation hardened stainless steels, and ferritic 400 series stainless steels having aminimum of 16 % chromium. This test is not recommended for martensitic 400 series stainless steels orfor ferritic 400 series stainless steels with less than 16 % chromium because these steels will typicallygive a positive indication irrespective of the presence or absence of anodic surface contaminants (a falsefailure). This test is also not recommended for laser marked areas.