This document specifies the procedure and requirements for heat treating low-alloy and tool steels and for their subsequent gas nitriding by the use of raw or dissociated ammonia. Specific process parameters are given for Nitralloy 135M, Nitralloy EZ, Nitralloy N, 4140, 4340, D6AC and H11 steels. Additional alloys and steel families (e.g., stainless steels) can also be nitrided using parameters acceptable to the cognizant engineering organization.

Application:

The nitriding process described herein has been used typically for producing a wear resistant and fatigue resistant surface on steel parts but usage is not limited to such applications. This process only applies to gas nitriding. Other processes, such as salt bath nitriding, or ion nitriding, are not included.

Classification:

Processes covered by this specification are classified as follows:

Class 1: Two-stage nitriding with first stage at 940 to 1050 °F (504 to 566 °C) and second stage at 975 to 1050 °F (524 to 566 °C).

Class 2: One-stage nitriding at 940 to 1050 °F (504 to 566 °C).

If no class is specified, either Class 1 or Class 2 may be used.