This specification covers a low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. These products have been used typically for parts required to meet stringent magnetic particle inspection criteria, having sections 3.5 inches (89 mm) and under in nominal thickness at time of heat treatment, and requiring a through-hardening steel capable of developing a minimum hardness of 40 HRC when properly hardened and tempered and also for parts of greater thickness but requiring proportionately lower hardness, but usage is not limited to such applications. Certain design and processing procedures may cause these products to become susceptible to stress-corrosion cracking after heat treatment; ARP 1110 recommends practices to minimize such conditions. These products are not recommended for use in parts heat treated to a hardness greater than 46 HRC (ultimate tensile strength over 220 ksi (1517 MPa)) or where the high transverse properties of remelted steel are required.
SAE AMS6409D-2012 Referenced Document
ASTM A255-10 Standard Test Methods for Determining Hardenability of Steel*， 2024-04-19 Update
ASTM A370-12 Standard Test Methods and Definitions for Mechanical Testing of Steel Products*， 2024-04-19 Update
ASTM E112-10 Standard Test Methods for Determining Average Grain Size*， 2024-04-19 Update
ASTM E381-01 Standard Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings*， 2024-04-19 Update
ASTM E384-11 Standard Test Method for Knoop and Vickers Hardness of Materials*， 2024-04-19 Update