Salt Bath Hardening

what is salt bath hardening?

Salt Bath Hardening can offer advantages over alternative hardening and tempering methods. Molten salt is often considered the ‘ideal’ heat treating medium. When parts are immersed in the molten salt, heat is transferred by direct contact to the surface.

the process

Salt bath hardening is a hardening technique that ensures the material is highly wear resistant. For this purpose, the component is first brought to the required austenitizing temperature in a molten salt in multiple stages. The supply of temperature takes place evenly and the time at temperature is very short. This is followed by quenching in a hot bath at approximately 550°C.

The advantage of the process is that a fast and intensive heat transfer is possible, which supports a quick and flexible way of working.

fields of application

Since the parts are immersed in the Salt Bath, air cannot contact the work piece and scaling, oxidation and decarburization are avoided. Heat transfer into components is very rapid – much faster than with radiation or convection methods. Additionally, the uniform rate of heat transfer permits components having complex geometries and diverse cross-sections to be heat treated and quenched with minimal distortion. Salt Bath Hardening is ideal for Tool Steels.

Gears, shafts, machine parts and tools are often hardened in a salt bath. Partial hardening as well as the individual hardening of materials can easily be carried out with salt bath hardening.