This specification covers an aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.These products have been used typically for parts 0.750 inch (19.05 mm) and under in nominal section thickness at time of heat treatment requiring a through-hardening steel capable of developing minimum tensile strength of 180 ksi (1241 MPa) at the section center when properly hardened and tempered and for parts of greater section thickness but requiring proportionately lower strength, but usage is not limited to such applications.
