This specification covers the passivation by electropolishing of stainless steel alloys in the 200, 300, and 400 series, as well as precipitation-hardened alloys. Basis materials shall be free of clearly visible defects, and if necessary, shall undergo preparatory cleaning procedures prior to electropolishing. Post-coating procedures such as post dip and final rinsing shall be performed as well. The performance of the specimens during passivation shall be evaluated by one or more of the following procedures: water immersion test; humidity test; salt spray test; copper sulfate test; and modified ferroxyl test for free iron.

1.1 This specification covers the passivation of stainless steel alloys in the 200 (UNS2XXXX), 300 (UNS3XXXX), and 400 (UNS4XXXX) series, and the precipitation-hardened alloys, using electropolishing procedures.

Note 1—Surface passivation occurs simultaneously with electropolishing under proper operating conditions. The quality of passivation will depend on the type of stainless steel, the formulation of the electropolishing solution, and the conditions of operation. Free iron on the surface of the stainless steel is removed resulting in improved corrosion resistance. Surface smoothing obtained by electropolishing will also improve corrosion resistance. Electropolishing will also remove heat tint and oxide scale.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This specification may involve hazardous materials, operations, and equipment. This specification does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.