碟片激光器激光淬火过程数值模拟与试验研究

Numerical Simulation and Experimental Study on Laser Quenching Process of Disk Laser

目的通过模拟计算得出45钢激光淬火温度场的瞬变规律和微观组织相变规律,得出马氏体的形成与转变程度,测出淬火相变硬化的层深与层宽。方法基于COMSOL Multiphysics建立碟片激光器对45钢激光淬火过程的热力耦合模型,利用JMatpro计算45钢激光淬火过程中的物性参数变化,对模型物性参数进行修改,并以4000W碟片激光器对45钢进行激光淬火试验,通过Axioskop2扫描电子显微镜、Zeiss-∑IGMA HD场发射电子显微镜、HXS-1000A显微硬度仪分析45钢淬火组织和相变硬化规律。结果相同功率下,碟片激光器与传统激光器相比,激光淬火相变硬化层及热影响区明显增大,相变界限清晰,淬火影响区呈高斯分布,完全相变区组织转变效果较好,热影响过渡区沿高斯弧线近似等距分布。激光淬火层由表及里依次为完全淬火相变区、不完全淬火区和芯部基体,完全淬火区形成致密细小的针状马氏体和少量残余奥氏体,淬硬层呈高斯分布,深达1084.589μm,最大宽度9761.989μm,硬度达到799HV,不完全淬火区厚度为361.533μm。结论试验结果与模拟计算结果吻合,COMSOL可实现对激光淬火过程的有效模拟。

The work aims to obtain the transient law of laser quenching temperature field and microstructure transformation law of 45 steel obtained through simulation calculation, get the formation and transformation degree of martensite, and measure the layer depth and width of quenching phase transformation hardening. Based on COMSOL Multiphysics, the thermodynamic coupling model for laser quenching process of 45 steel plate laser was established and the changes of physical parameters during laser quenching were calculated by JMatpro to modify the physical parameters of the model. At the same time, based on 4000 Wdisk laser, a quenching experiment of 45 steel was carried out. The quenching microstructure and phase change hardening law of 45 steel were observed by Axioskop 2 scanning electron microscope, Zeiss-∑IGMA HD field emission electron microscopy and HXS-1000A microhardness tester. Under the same laser power, the hardened layer and heat-affected zone of disk laser quenching were obviously larger than those of conventional laser quenching, the boundary of phase transformation was clear, the quenching affected zone showed Gaussian distribution, and the microstructure transformation effect in the complete phase transformation zone was better, and the heat-affected transition zone was approximately equidistant along the Gaussian arc. The laser quenching layer was composed of completely quenched phase transformation zone, incomplete quenched zone and core matrix, from the outside to the inside. Fine needle like martensite and a small amount of retained austenite were formed in the complete quenching zone;the hardened layer showed Gauss distribution, the depth was 1084.589 μm, the maximum width was 9761.989 μm and the hardness was 799HV. The thickness of incomplete quenched zone was 361.533 μm. All the experimental results coincide with the simulation results, and COMSOL Multiphysics can achieve an effective simulation of laser quenching process.