Microstructural Temper Resistance
Tempering resistance is a steel's resistance to hardness loss and grain coarsening under thermal exposure. It is increased by additions like tungsten and molybdenum.
Physical-chemical mechanism
Tempering resistance refers to a steel's ability to retain its mechanical properties under repeated thermal loads. This is achieved by using special carbide formers like tungsten and molybdenum, which stabilize the structure and prevent hardness loss.
Metallurgical relevance & risks in welding
With poor tempering resistance, the steel can become prone to hardness loss and grain coarsening when repeatedly thermally stressed. This reduces its mechanical properties and increases susceptibility to cracking and wear.
Workshop practice & instructions
To ensure tempering resistance, use strict temperature control and careful cooling during welding. For highly stressed applications, use steels with high tungsten or molybdenum content. When choosing the welding process, prefer methods that cause low thermal stress and allow fast cooling.