MSS SP-157-2024 ✓ Most Recent

This Standard Practice covers requirements for the application of phosphate coatings on ferrous metal valves, fittings, and related steel piping components that necessitate surface protection.

The phosphate surface conversion methods detailed in this Standard Practice provide surface protection and are intended for valves, fittings, and steel piping components where surface protection and dimensional tolerances are maintained after coating.

Phosphate coatings in this Standard Practice utilize zinc and iron manganese and require a supplementary water soluble oil treatment after phosphate coating to enhance surface protection.

This Standard Practice includes a surface protection test method and acceptance criteria for verifying conformance to the Standard Practice.