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采用3kW半导体宽带激光器在28CrMoNiV钢基板上进行了激光熔覆试验,并结合热影响区(HAZ)温度场模拟优化了再制造工艺。通过光学显微镜、扫描电镜和X射线衍射仪对HAZ和基体的组织进行了分析。最后通过拉伸试验对修复后的熔覆HAZ进行了性能测试。结果表明,单层熔覆HAZ主要产生了马氏体相变,并在HAZ顶部发现了马氏体和铁素体的不良组织。模拟结果表明,该不良组织可以通过三层以上的多层熔覆方法消除。拉伸性能测试结果表明,三层熔覆HAZ的平均抗拉强度达到927.35 MPa,高于基体或单层熔覆HAZ;断后伸长率达到10.23%,较单层熔覆HAZ有所提高,更接近基体性能。
Laser cladding experiments were carried out on a 28CrMoNiV steel substrate using a 3kW semiconductor broadband laser and the remanufacturing process was optimized by simulating the temperature field in the heat affected zone (HAZ). The microstructure of HAZ and matrix was analyzed by optical microscope, scanning electron microscope and X-ray diffractometer. Finally, the tensile test was carried out to test the performance of the repaired cladding HAZ. The results show that the martensite transformation mainly occurs in the single-layer clad HAZ and the martensite and ferrite defects are found on the top of the HAZ. The simulation results show that the bad tissue can be eliminated by more than three layers of multi-layer cladding method. Tensile test results show that the average tensile strength of the three-layer clad HAZ reaches 927.35 MPa, which is higher than that of the base or single-layer clad HAZ. The elongation after fracture reaches 10.23%, which is higher than that of the single clad HAZ Close to the matrix performance.