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目的：研究获得高质量H13激光涂层的工艺。方法以H13合金粉末为熔覆材料,在H13钢退火基体表面制备H13合金涂层,采用均匀设计试验,利用金相法检测涂层的几何形貌参数,得到涂层宽度回归模型,并验证所建立模型的准确性。利用光学显微镜和扫描电镜分析涂层的显微组织形貌,对涂层成分进行分析,通过显微硬度计测试涂层截面的显微硬度分布。对涂层气孔、裂纹和成分偏析进行分析。结果扫描速度22 mm/s ,激光功率1300 W,送粉速率21 g/min时,H13合金涂层与基体呈良好的冶金结合,涂层内组织均匀致密,无裂纹缺陷,截面显微硬度约600~699HV,是H13基体硬度的2.4~3倍。扫描速度14 mm/s ,激光功率1400 W,送粉速率42 g/min 时,涂层的截面显微硬度约为669~698HV,是基体的2.85~3倍。结论在两种工艺条件下,均能获得质量较优的H13合金涂层。

ABSTRACT:Objective To investigate the technology for preparing high-quality H13 alloy laser cladding layers. Methods Laser cladding of H13 alloy powder was undertaken on the surface of annealed H13 steel. A uniform design test was conducted and metal-lographical method was used to detect the geometric parameters of the cladding layers. The width regression model was obtained by regression analysis, and the accuracy of the model was verified. The microstrcucture and elementary composition of the cladding layers were investigated by OM and SEM. The microhardness distribution of the cladding layers was tested by micro-hardness test-er. Holes,cracks and composition segregation of the cladding layer were analyzed. Results The results indicated that using a scan-ning speed of 22 millimeter per second, a laser power of 1300 W, and a powder feeding rate of 21 grams per minute, the metallur-gical combination was implemented between cladding layers and substrates. The uniform and compact microstructure was showed without cracks. The microhardness of the cladding layer reached up to 600~699HV, which was 2. 4 to 3 times higher than that of the H13 steel substrate. At a scanning speed of 14 millimeter per second, a laser power of 1400 W, and a powder feeding rate of 42 grams per minute, the microhardness was 669~698HV, which was 2. 85 to 3 times higher than that of the substrate. Conclu-sion H13 alloy coating with relatively high quality could be obtained under both technological conditions.