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    Q235B钢表面冷金属过渡熔覆316L不锈钢的工艺优化

    Process Optimization for Cold Metal Transition Cladding 316L Stainless Steel on Q235B Steel Surface

    • 摘要: 采用冷金属过渡(CMT)熔覆技术在Q235钢表面制备316L不锈钢熔覆层,通过设计三因素三水平的正交试验,系统研究了送丝速度(5.0,5.5,6.0 m·min−1)、焊接速度(2.0,2.5,3.0 mm·s−1)和摆动宽度(12,14,16 mm)对熔覆层显微组织、显微硬度、稀释率、耐磨性能和耐腐蚀性能的影响,以获得最优的熔覆工艺。结果表明:不同工艺制备的熔覆层与基体之间均形成良好冶金结合,熔覆层底部均由柱状晶以及少量等轴晶和树枝晶组成,顶部则主要由等轴晶和少量柱状晶组成;不同工艺下熔覆层的平均硬度为246.3 HV,约为基体的1.54倍,平均摩擦因数和平均磨损质量损失分别为0.3025,3.8 mg,均低于基体(0.392 4,6.5 mg)。CMT熔覆工艺参数对熔覆层质量影响的主次顺序为送丝速度、焊接速度、摆动宽度;最优工艺参数为送丝速度6.0 m·min−1、焊接速度3.0 mm·s−1、摆动宽度14 mm,此时熔覆层的硬度最高,为259.8 HV,自腐蚀电流密度较低,为0.1326 mA·cm−2,磨损质量损失为3.3 mg,稀释率为9.80%。

       

      Abstract: 316L stainless steel cladding layer was prepared on the surface of Q235 steel by cold metal transition (CMT) cladding technique. Through the design of a three-factor and three-level orthogonal test, the effects of wire feeding speed (5.0, 5.5, 6.0 m·min−1), welding speed (2.0, 2.5, 3.0 mm·s−1) and swing width (12, 14, 16 mm) on the microstructure, microhardness, dilution rate, wear resistance and corrosion resistance of the cladding layer were systematically studied, and the optimal cladding process was obtained. The results show that the cladding layer prepared by different processes all formed good metallurgical bond with the substrate. The bottom of the cladding layers was composed of columnar crystals, a small amount of equiaxed crystals and dendritic crystals, while the top was mainly composed of equiaxed crystals and a small number of columnar crystals. The average hardness of the cladding layer under different processes was 246.3 HV, approximately 1.54 times that of the substrate. The average friction coefficient and the average wear mass loss were 0.302 5 and 3.82 mg, respectively, both lower than those of the substrate (0.392 4, 6.5 mg). The order of influence of CMT cladding process parameters on the quality of the cladding layer from high to low was wire feeding speed, welding speed, and swing width. The optimal process parameters were wire feeding speed of 6.0 m·min−1, welding speed of 3.0 mm·s−1, and swing width of 14 mm. At this time, the hardness of the cladding layer was the highest, at 259.8 HV, the free-corrosion current density was relatively low, at 0.132 6 mA·cm−2, the wear mass loss was 3.3 mg, and the dilution rate was 9.80%.

       

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