Solution Annealing

Solution Annealing– PWHT

The process of solution annealing is typically applied to stainless steels and high nickel alloys for heat resistant and corrosion resistant applications. These are generally high temperature processes requiring rapid quenching.

Solution Annealing is a heat treatment process which alters the metallurgical structure of a material to change its mechanical or electrical properties. Typically, this process is used to decrease metal crack sensitivity of aged material that needs to be returned to a weldable state. Solution Annealing will affect secondary carbides precipitated during extended high temperature service by increasing ambient temperature ductility and fracture toughness. This process involves air quenching post heat application.

The most common application of the solution annealing process is used for austenitic stainless steels.

Solution annealing 300 series stainless steels improves corrosion resistance by putting carbides into solution in the microstructural matrix.

A rapid quench inhibits carbides from reforming during cooling. Austenitic stainless steels are not solution annealed to appreciably change mechanical properties.

Many other materials receive solution annealing for reasons of changing mechanical properties.

Some materials, such as 17-4 stainless steel & some Inconels, are solution annealed as a pre-treatment for age hardening. This ultimately provides the required mechanical properties for the part application.