linguistic:paraphrasing, quality:correction
Precipitation hardening

Precipitation hardening stainless steels have corrosion resistance comparable to austenitic varieties, but can be precipitation hardened to even higher strengths than other martensitic grades. There are three types of precipitation hardening stainless steels:

Solution treatment at about 1,040 °C (1,900 °F) followed by quenching results in a relatively ductile martensitic structure. Subsequent aging treatment at 475 °C (887 °F) precipitates Nb and Cu-rich phases that increase the strength up to above 1,000 MPa (150,000 psi) yield strength. This outstanding strength level is used in high-tech applications such as aerospace (usually after remelting to eliminate non-metallic inclusions, which increases fatigue life). Another major advantage of this steel is that aging, unlike tempering treatments, is carried out at a temperature that can be applied to (nearly) finished parts without distortion and discoloration.

Typical heat treatment involves solution treatment and quenching. At this point, the structure remains austenitic. Martensitic transformation is then obtained either by a cryogenic treatment at −75 °C (−103 °F) or by severe cold work (over 70% deformation, usually by cold rolling or wire drawing). Aging at 510 °C (950 °F) — which precipitates the Ni Al intermetallic phase—is carried out as above on nearly finished parts. Yield stress levels above 1400 MPa are then reached.

The structure remains austenitic at all temperatures.

Typical heat treatment involves solution treatment and quenching, followed by aging at 715 °C (1,319 °F). Aging forms Ni Ti precipitates and increases the yield strength to about 650 MPa (94,000 psi) at room temperature. Unlike the above grades, the mechanical properties and creep resistance of this steel remain very good at temperatures up to 700 °C (1,300 °F). As a result, A286 is classified as an Fe-based superalloy, used in jet engines, gas turbines, and turbo parts.