SAE AMS2550F covers the engineering requirements for a
to provide enhanced corrosion resistance to sheet metal parts, such
as brackets, spacers, and washers, fabricated from martensitic
resistant steels, usually AMS 5504 or AMS 5508 and having hardness not higher
than 40 HRC, or ferritic corrosion-resistant steels, usually AMS 5506. The
treatment is not for use on parts subject to impact in service.