Martensitic Transformation of a High-speed Tool Steel During Continuous Heat Treatment

Directed energy deposition and characterization of high-carbon high speed steels

“…To maintain a high micro-hardness, it is significantly important to strengthen the martensitic matrix which constitutes the larger part of the microstructure. It was reported that multiple laser reheating of HSS can drastically deteriorate the micro-hardness due to tempering of martensite during short holding time [37,38], as a result affecting the performance characteristics. Short thermal cycles precipitate more secondary carbides, leaving less alloying elements and low C concentration in the solid solution, consequently yielding a soft martensite [39].…”

Development and characterization of multilayer laser cladded high speed steels

“…Phenomenologically, during cladding of the subsequent layers, the heat accumulated during previously cladded layers transformed a part of retained austenite to martensite, but also resulted in tempering of existing lath martensitic matrix. The hardness of HSS is a function of tempering time and temperature, the softening of martensitic matrix was possibly due to shorter holding time [41]. Additionally, hardness drop could be result of yielding soft martensite (450 HV to 550 HV) during re-heating [42].…”