Standard STEEL 0.8Cr - 0.85Ni - 0.2Mo - B (0.35-0.40C) (Modified 98B37) 1951-11-01 HISTORICAL AMS6421
Standard STEEL 0.8Cr - 0.85Ni - 0.2Mo - B (0.38-0.43C) (Modified 98B40) 1951-11-01 HISTORICAL AMS6422
Standard STEEL 0.8Cr - 0.85Ni - 0.2Mo - B (0.38-0.43C) (Modified 98B40) 1952-11-01 HISTORICAL AMS6422A
Standard STEEL 0.8Cr - 1.8Ni - 0.35Mo - 0.2V (0.33 - 0.38C) Special Grade 1961-01-15 HISTORICAL AMS6430