研究了不同工艺参数对304不锈钢表面激光熔覆Ni基合金后熔覆层微观组织及硬度、耐磨、耐蚀性能的影响,并寻求最佳激光工艺参数,以期获得冶金结合较好,耐磨、耐蚀性能良好的熔覆层.根据组织与性能的综合分析可知,最优激光工艺参数为激光功率2.5 kW、扫描速度4 mm/s、送粉速率300 mg/s.利用优化工艺参数熔覆后的熔覆层宏观形貌平整、光滑,熔覆层宽度为14.36 m m,高度为1.612 m m,熔池深度为0.248 m m,稀释率为13.33,硬度较高,平均显微硬度为646.4 H V,并且耐磨损性能较好,磨损量较低.此外,熔覆层的耐腐蚀性能也较好,自腐蚀电位为-286.77 m V.在一定的激光工艺参数下,组织从结合区至熔覆层表层依次为平面晶、胞状晶、柱状晶、树枝晶、等轴晶.激光功率、扫描速度、送粉速率不同,熔覆层中组织粗细变化呈现一定的规律性:随着激光功率的增大,组织由细小逐渐变的粗大;随着扫描速度的增大,组织先变细小,然后变粗大;随着送粉速率的增大,组织逐渐变细小.合金的耐磨性与耐蚀性不仅与组织大小有关,而且与组织物相组成密切相关.%The effect of different processing parameter on the microstructure ,wear-resistance and corrosion-resistance of laser cladding Ni-based alloy on the surface of 304 stainless steel was investigated .According to the analysis of the microstructure and mechanical properties ,the optimized parameters were the laser power of 2.5 kW ,the scanning speed of 4 mm/s and the powder feeding rate of 300 mg/s .The optimized parameters made the cladding layer smooth ,and the cladding layer width was 14.36 mm , height was 1.612 mm ,the depth of molten pool was 0.248 mm ,and the dilution rate was 13.33. Moreover ,the laser cladding made the hardness higher ,and the average microhardness was 646.4HV ,hence the abrasion loss was low .In addition ,the corrosion resistance of cladding layer was improved ,and the corrosion potential was of -286.77 mV .Under certain laser process parameters , the microstructure from the area to the cladding layer surface followed by planar crystal ,the cellular crystal ,columnar crystal , branches crystal and isometric crystal .Different laser power ,scanning speed and feeding rate made the microstructure of cladding layer present certain regularity .With the increase of laser power ,the microstructure gradually changed from fine to coarse .When scanning speed was improved ,the microstructure became finer ,and then turn coarse .Due to the increase of feeding rate ,the microstructure gradually became finer .The wear resistance and corrosion resistance of the alloy were not only related to the size of the microstructure ,but also closely related to the phase composition of the microstructure .
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