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利用有限元软件ANSYS对激光束扫描试样的温度场进行数值模拟,研究其温度分布规律。研究激光束扫描对试样显微组织和性能的影响,探讨激光功率和扫描速度等工艺参数对相变硬化层组织性能的影响。采用光学显微镜分析45钢激光相变硬化区的显微组织,用显微硬度计进行硬度测量。结果表明:45钢经激光束扫描后,硬化层的显微组织为针状或板条状的马氏体,组织更加均匀、细小,试样表面硬度最高可达57.5 HRC,相比调质处理提高约1倍,激光扫描区域组织沿深度方向上成梯度分布规律,从表层往深度方向依次为相变硬化区、过渡区和基体。激光工艺参数对硬化层显微组织和性能有较大的影响,相变硬化层的深度和宽度随着激光功率的增加而增加,随着扫描速度的增加而减小;硬化层的截面硬度随着激光功率和扫描速度的增加呈现先增加后减小的变化规律。
The finite element software ANSYS was used to simulate the temperature field of laser beam scanning specimen, and the temperature distribution was studied. The effect of laser beam scanning on the microstructure and properties of the sample was studied. The effects of laser power and scanning speed on the microstructure and properties of the phase-change hardened layer were investigated. The microstructure of 45 steel laser transformation hardening zone was analyzed by optical microscope, and the hardness was measured by microhardness tester. The results show that the microstructure of hardened layer is needle-like or lath-shaped martensite after 45 steel is scanned by laser beam. The microstructure of 45 steel is more uniform and fine. The surface hardness of the 45 steel is up to 57.5 HRC, About 1 times. The gradient distribution of the laser scanning zone along the depth direction is the phase transition hardening zone, the transition zone and the matrix from the surface to the depth direction. The laser process parameters have a great influence on the microstructure and properties of the hardened layer. The depth and width of the hardened layer increase with the increase of the laser power and decrease with the increase of the scanning speed. The cross-section hardness The increase of laser power and scanning speed first increased and then decreased.