This specification covers forged low alloy and stainless steel piping components for use in pressure systems. Included are flanges, fittings, valves, and similar parts to specified dimensions or to dimensional standards such as the ANSI specifications that are referenced in Section 2. 

Other forgings for other applications may be made to this specification. 

Thirty-three grades are covered including sixteen ferritic or martensitic steels and seventeen austenitic stainless steels.  Selection will depend upon design and service requirements. 

Supplementary requirements are provided for use when additional testing or inspection is desired.  These shall apply only when specified individually by the purchaser in the order. 

Note 1 - The values stated in the U.S. customary units are to be regarded as the standard.