激光功率对激光熔覆FeCrBSi合金组织和性能的影响

Effect of Laser Power on Microstructure and Properties of Laser Cladding FeCrBSi alloy

采用激光熔覆技术在45钢表面制备了FeCrBSi熔覆层,研究了激光功率对熔覆层组织和硬度的影响规律。试验结果表明,激光熔覆FeCrBSi熔覆层上部、中部和下部的组织分别为等轴晶、胞状晶和胞状树枝晶、平面晶。在扫描速率8 mm/s,送粉率33 g/min,光斑直径3.19 mm,激光功率1800~3400 W的条件下,随着激光功率的增加,熔覆层不同位置的显微组织变粗;熔覆层硬度先升高再降低;熔覆层磨损体积先减少后增加;熔覆层的自腐蚀电位先升高后降低;自腐蚀电流密度先降低后升高。当激光功率为2600 W时,熔覆层具有最高显微硬度669 HV_(0.2),熔覆层耐磨性最好,磨损体积为基体59.8%,同时熔覆层的耐蚀性最优,自腐蚀电位为-426.41 mV,自腐蚀电流密度为0.45μA/cm^(2)。

FeCrBSi layer was prepared on 45 steel by laser cladding technology.The effect of laser power on microstructure and hardness of cladding layer was studied.The results showed that the microstructures of the top,middle and bottom parts of the layer were isometric crystal,cystiformgrain and cellular dendrite and plane crystal,respectively.Under the scanning rate of 8 mm/s,powder feeding rate of 33 g/min,spot diameter of 3.19 mm and laser power of 1800~3400 W,with the increase of laser power,the microstructure at different positions of the cladding layer becomes coarser,the hardness and the self-corrosion potential of cladding layer increased first and then decreased;the wear volume and the current density of self-corrosion of cladding layer decreased first and then increased.When the laser power reached 2600 W,the cladding layer exhibited best wear resistance and corrosion resistance.The highest microhardness was 669 HV_(0.2),the wear volume is 59.8%of the matrix,and the self-corrosion potential was-426.41 mV,the self-corrosion current density was 0.45μA/cm^(2).