Stainless Steel Heat Treatment

Tool & Die Heat Treatment for Stainless Steel Hardening

Heat treating stainless steel comes with a number of challenges. Achieving maximum hardness requires a great deal of knowledge with respect to quenching martensitic stainless steels.  Stainless steels can be very difficult to temper as the tempering curves are very steep thus they require superior uniformity with respect to temperature capabilities.

Therm Tech has a great deal of options in vacuum heat treating for processing stainless steel. From high pressure 15 BAR quenching to a vacuum oil quench ThermTech has the abilities and expertise to handle any specification. ThermTech maintains all furnaces to AMS 2750 specifications with respect to pyrometry.  

Capabilities

Because carburization of stainless steels can be very detrimental to the corrosion resistance it is best that vacuum furnaces are utilized for processing stainless steels. ThermTech has a large vacuum heat treating department with furnaces ranging up to 72 inches in length and 10,000 pound capacity.

Process

Hardening stainless steels require austenitizing temperatures that sometimes exceed 1900F.  For this reason distortion is of great concern and care must be given when considering how the parts are racked during hardening.  While most stainless steels do not necessarily require high quench rates for hardening to assure maximum corrosion resistance it must be a consideration.
Tempering stainless steels to levels lower than maximum hardness can be difficult. Tempering curves for most stainless steels are very steep thus small increases in tempering temperatures yield large changes in hardness. This fact requires that tempering furnaces have a high degree of temperature uniformity.  Furnaces must have uniformity of +/- 15 degrees to achieve repeatable results when tempering martensitic stainless steels.

Recommendations

Because of the high austenitizing temperatures care must be used in racking and loading to account for mechanical distortion, especially when heat treating rings. Maximum corrosion resistance is present at maximum hardness and generally declines as tempering temperature is increased. Steel suppliers provide guides that will chart corrosion resistance versus tempering temperature and hardness and thus should be consulted when choosing the hardness of a component.
 

Contact a sales representative today to discuss the benefits of marquench hardening for your machined parts products!