Editing Stainless steel (section)

=== Precipitation hardening ===
[[Precipitation hardening]] stainless steels are characterized by the ability to be precipitation hardened to higher strength. There are three types of precipitation hardening stainless steels which are classified according to their crystalline structure:<ref>{{Cite book|last=De Cooman|first=Bruno Charles|date=April 2016|others=Pohang University of Science and Technology Korea Graduate Institute of Ferrous Technology|title=Lecture on stainless steel_9|url=https://www.researchgate.net/publication/301692427|doi=10.13140/RG.2.1.1950.2488}}</ref>

* Martensitic precipitation hardenable stainless steels are martensitic at room temperature in both the solution annealed and precipitation hardened conditions. Representative alloys include 17-4 PH (UNS S17400), 15-5 PH (UNS S15500), Custom 450 (UNS S45000) and Custom 465 (UNS S46500). 

* Semi-austenitic precipitation hardenable stainless steels are initially austenitic in the solution annealed condition for ease of fabrication, but are subsequently transformed to martensite to provide higher strength and to be precipitation hardened. Representative alloys include 17-7 PH (UNS S17700), 15-7 PH (UNS S15700), AM-350 (UNS S35000), and AM-355 (UNS S35500). 

* Austenitic precipitation hardenable stainless steels are austenitic at room temperature in both the solution annealed and precipitation hardened conditions. Representative alloys include A-286 (UNS S66286) and Discalloy (UNS S66220).<ref>Precipitation-Hardening Stainless Steels, Stainless Steels for Design Engineers, By Michael F. McGuire, ASM International, 2008, p 137–146, https://doi.org/10.31399/asm.tb.ssde.t52310137</ref>