Effect of tempering on the microstructure and hardness of ledeburitic chromium steel X155CrVMo12.1

Ledeburitic chromium steel X155CrVMo12.1 for cold-work tools was investigated in the quenched and tempered condition. Using appropriate investigative methods the evolution of the microstructure in all conditions was characterized. The change in state of a multicomponent matrix during tempering is crucial for attaining the required properties of this steel. In the material investigated, shape, size, fraction and distribution of eutectic (primary) carbides played a secondary role. The evolution of tempered marten-site and precipitation of secondary hardening carbides of M23C6-type and MC-type from the supersaturated matrix during tempering led to secondary hardening and a secondary hardness peak at about 530 degrees C. The results show that steel X155CrVMo12.1 also exhibits performance ability at moderately elevated temperatures.