Precipitation hardening increases the yield strength of steel. The main difference between precipitation hardening steels is that they contain elements such as copper, aluminum, phosphorus or titanium, which not only increase the strength of the steel but also maintain sufficient toughness, a type of high-strength stainless steel, referred to as PH steel. To activate the precipitation hardening properties, the steel is first solution treated and then age hardened. The age hardening process heats the material over an extended period of time, causing the added elements to precipitate - forming solid particles of varying sizes - which increases the material's strength.
