API STD 20N:2019

This standard specifies requirements for the qualification of suppliers of continuous line heat treatment services used in the manufacture of equipment for the petroleum and natural gas industries.
This standard is applicable to suppliers providing heat treatment services where API product standards specify this standard as a requirement for conformance. The requirements of this standard apply to continuous and semi-continuous heat treatment operations that can establish or affect the final mechanical properties. For batch type heat treatment refer to API 20H. This standard is applicable to products in tubular, bar, plate, forgings, castings and upset forged forms. Heat treat that imparts surface hardening or case hardening is outside the scope of this document.