MIL-S-7108A, MILITARY SPECIFICATION, STEEL, ALLOY (MANGANESE-SILICON-NICKEL), BARS AND FORGING STOCK (AIRCRAFT QUALITY) (ASG) (23 AUG 1955) [S/S BY SAE-AMS6425]., This specification covers manganese-silicon-nickel alloy steel bars and forging stock of aircraft quality and suitable for heat treatment to 220,000 psi tensile strength.