SAE AMS6290H

This specification covers an aircraft-quality, low alloy steel in the form of bars, forgings, and forging stock.These products have been used typically for carburized parts which require low minimum core hardness and allow wide hardness range in sections 0.375 in. (9.50 mm) and under in nominal thickness, but usage is not limited to such applications. The core may or may not be machinable after hardening.