Sensitivity Analysis of Laser Quenching Parameters of ASTM 1045 of Disk Laser Based on Response Surface Method

Abstract

Laser hardening is an important branch of laser surface hardening technology, which is widely used in metallurgy, transportation, machinery manufacturing, aerospace and other fields. At present, relying entirely on experience or process trial-and-error method, it can not effectively reveal the transient mechanism of laser quenching of disk laser, which is not conducive to shortening the research and development cycle and saving costs. The numerical simulation provides an effective way to obtain the dynamic evolution law of multi-field coupling in laser quenching process. In this paper, a thermo-mechanical coupling model of ASTM 1045 laser quenching process by disk laser is established. In the model, the temperature-dependent physical parameters were calculated by CALPHAD method. The transient law of temperature and microstructural transformation during quenching was obtained by solving the model. The formation and transformation degree of martensite were characterized by the dynamic changes of the depth and width of quenched transformation layer. The quenching structure and transformation hardening law were observed by Axioskop 2 SEM and Zeiss-IGMA HD FE-SEM to verify the accuracy of the simulation results. On this basis, the process parameters of laser quenching were sampled by Monte-Carlo method based on response surface methodology. The sensitivity effects of different process parameters on the temperature field and phase change field of laser quenching were analyzed, which laid a theoretical foundation for the optimization of process parameters. (1) Establish a thermo-mechanical coupling model for quenching process of ASTM 1045, and the sensitivity of the system is calculated. (2) The model can accurately reproduce the transient process of temperature and phase transformation field during laser quenching. (3) The laser power and laser incident angle are positively correlated with the response value. (4) The spot diameter and scanning speed are negatively correlated with response value. (5) The model can effectively calculate the sensitivity of laser quenching, predict the width and depth of quenching layer, and optimize process parameters.