Influence of Laser Radiation on the Depth of Hardened Layer of Tool Steel Cutting Dies.

The results of experimental studies into the impact of laser radiation on the depth of the hardened layer of cutting dies made of carbon and alloy tool steels U8, 40KhN2MA, 5Kh2S, 9KhS, and KhI2M are presented. Following laser hardening, the amount of retained austenite was found to be 1.5–2.5 times higher than following volumetric hardening. It was established that, following laser processing, steels of various structural groups exhibit different depths and hardness within the hardened layer. The highest depth and hardness are observed for eutectoid steel U8 and hypereutectoid steels 9KhS, while the lowest values are found in pre-eutectoid steel 40KhN2MA and ledeburite steel Kh12M. Processing experimental data showed that, in the first approximation, the depth of the first zone of the hardened layer is proportional to the thermal conductivity coefficient. For the parts that require larger depth of the hardened layer subjected to the operating conditions, it is recommended to use steels with a high silicon content, especially within the surface layer. [ABSTRACT FROM AUTHOR]