38MnVS6钢中硫元素扩散对激光熔覆涂层形貌和组织的影响

Effect of Sulfur Diffusion in 38MnVS6 Steel on Morphology and Microstructure of Laser Cladding Layers

利用激光熔覆技术在38MnVS6钢基体上熔覆了CoCrW粉末,研究了不同扫描速度下基体中活性元素对涂层形貌和组织的影响。结果表明,当送粉速率为5.60g·min^(-1),扫描速度小于5mm·s^(-1)时,涂层的熔深较大,涂层与基体的结合线向下凹陷;当扫描速度大于6mm·s^(-1)时,涂层的熔深较小,涂层与基体的结合平整光滑。送粉率的增大使得涂层的形貌发生变化。基体中硫元素的含量决定了涂层表面张力温度系数,改变了熔池中马兰戈尼对流方向,并最终影响涂层的成分和组织。

The laser cladding of CoCrW powder on 38 MnVS6 steel substrate is conducted,and the effects of active elements in substrate on the morphology and microstructure of laser cladding layer are investigated.The results show that,when the powder feeding rate is 5.60 g·min^-1 and the scanning speed is smaller than 5 mm·s^-1,the melt pool of cladding layer is relatively deep and the fusion line of cladding layer and substrate is concave downwards.When the scanning speed is higher than 6 mm·s^-1,the melt pool is relatively shallow and the fusion line is smooth.The increase of the powder feeding rate makes the change of cladding layer morphology.The sulfur content in substrate determines the temperature coefficient of surface tension,which changes the direction of Maragoni convection and thus influences the final compositions and microstructures of cladding layers.