AMS 5862 is an aerospace material specification for a premium quality corrosion resistant
precipitation hardenable steel alloy. Common names for the alloy are 15-5 or UNS S15500.
AMS 5862 includes material in the form of sheet, strip, and plate.
This alloy is typically used where a combination of strength and corrosion resistance is required
in applications with service temperatures up to 600 deg F.
AMS 5862 requires consumable electrode remelting to premium aircraft quality standards
Material to this standard is supplied in the solution heat treated condition that can be readily
heat treated to final properties during the manufacture of component parts.
To assure the results of the final precipitation hardening treatment; samples of the product are
precipitation hardened to the H900 condition and tensile tested for conformance to specification
minimum requirements.

For more info on stainless steel grade 15-5 check out the longer video here and the actual 15-5 ph grade page here.