As hardened components are rarely suitable for immediate service due to the high degree of brittleness and residual stress associated with hardening treatments Tempering is necessary.
Tempering moderates the hard and brittle structure, delivers an increase in toughness, shock resistance and ductility coupled with a controlled reduction in hardness.
Tempering is always recommended to be carried out after case hardening. It offers real benefits in promoting dimensional stability, reducing brittleness, and the prospects of cracking in grinding.
Even low temperature tempering, which only reduces the surface hardness by one to two points on the Rockwell C scale offers real benefits.
Some steels demand repeated tempering in a tightly controlled regime to generate the required properties to meet design requirements and ensure suitability for purpose in the end use.
Holts can provide tempering systems that are determined by the material grade and include tempers which have a limited time frame, multiple rapid tempers and sub-zero combinations