This document provides recommended practices for batch-type heat treatment, continuous-type heat treatment, and processing of qualification testing coupons (QTCs) for carbon, micro-alloyed, and low-alloy steel wrought and cast components. It is intended to provide a means for the QTC to represent the properties in a part.

This recommended practice (RP) is intended:

— for use on components being manufactured for conformance to API product specifications or standards; and

— to supplement the heat treatment and testing requirements found in the API product specifications or standards.

This RP is the result of updating the requirements from API Recommended Practice 6HT, Second Edition. This revision is developed based on input from the technical experts on the API SC06 Valves & Wellhead Equipment subcommittee. The third edition moves this RP to a higher level of guidance for the petroleum and natural gas industry. 

Batch and continuous heat treatment and testing of hot isostatically pressed products or additively manufactured metallic products are outside the scope of this RP.