This specification covers a premium aircraft-quality alloy steel in the form of bars, forgings, and forging stock.
These products have been used typically for parts requiring a combination of high strength, high toughness, and weldability, but usage is not limited to such applications. Product after proper heat treatment should attain a minimum tensile strength of 290 ksi (1999 MPa) and yield strength of 245 ksi (1689 MPa).
All of the requirements of AMS 6478 and AMS 6532 are identical, apart from the final age temperature. The AMS 6478 is very seldom used. The AMS 6478 aging capability test will be included in the new revision of AMS 6532. AMS 6478 will be cancelled and superceded with AMS 6532