Precipitation Hardening is a process in which when the metal is heated, it precipitates or solid impurities are formed on the surface, preventing the movement of dislocations in the material. The critical thing to remember here is that dislocations are related to plasticity in the material. Therefore, as impurities prevent the movement of dislocations, the material is hardened, making the material more durable.

In precipitation hardening process the metal becomes stronger, and leads to several other significant manufacturing advantages such as,

• Reduced flexibility
• Machinability becomes significantly easier
• Durability and strength is increased exponentially
• Materials receive higher yield and tensile strength ratings

The strengthening method of precipitation hardening can be used on a variety of metals and other alloys such as, stainless steel, nickel, titanium, aluminum, magnesium and others are all capable of surviving and benefitting from the entire process. The increased strength and durability that is achieved through this process make it an excellent option for metal fabrication and product production because it will improve the longevity of certain applications.

Precipitation hardening process involves heating a mixture to a high temperature, then cooling, then heating to a medium temperature, and finally cooling again. Here’s a more detailed overview of the precipitation-hardening process:

• A group of meta-stable alloys (17-4PH for example) require several intermediate processing steps after solution treating to achieve the desired properties before precipitation age hardening. These steps include an austenite conditioning treatment and a freeze to ensure complete austenite to martensite transformation.
• Precipitation age hardening is typically performed at temperatures ranging from 900 to 1150°F in vacuum, inert atmosphere or air for hold times ranging from 1 hour to 4 hours depending on exact material and characteristics specified.