轧辊表面宽带激光熔覆Cr12MoV粉末的效果研究

Effects of broad-beam laser cladding of Cr12MoV powder on roll body

材料为Cr12MoV的冷轧辊在轧制过程中受到疲劳应力和热循环的作用而导致辊身出现剥落、裂纹等形式的缺陷,为了解决这一问题,采用宽带激光熔覆设备,以Cr12MoV合金作为熔覆粉末,在Cr12MoV钢表面制备合金涂层。以激光功率、扫描速度、送粉量以及搭接率四个工艺参数为变量,熔覆层表面粗糙度和显微硬度为目标参数,通过正交试验,对目标参数进行极差和方差分析获得优化的变量参数组合。结果表明:最优工艺参数为激光功率2000 W、扫描速度10 mm/s、送粉量10 g/min、搭接率45%。在最优变量参数组合下进行熔覆试验,获得的表面粗糙度为16μm,涂层显微硬度平均为677 HV,硬度值达到了基体材料的96%。熔覆层微观组织均匀,无气孔、裂纹等缺陷。

Cold rolls made of Cr12MoV are subjected to fatigue stress and thermal cycling during the rolling process,resulting in defects in the form of spalling and cracks on the roll body.In order to solve this problem,a broad-beam laser melting equipment is used to prepare an alloy coating on the surface of Cr12MoV steel by using Cr12MoV alloy as the cladding powder.Taking the laser power,scanning speed,powder feed rate and overlap ratio as variables and the surface roughness and microhardness of the cladding layer as the optimized target parameters,orthogonal tests are carried out and the optimized combination of the variable parameters is obtained by using the methods of range analysis and variance analysis to analyze the target parameters.The results show that the optimum variable parameters combination is laser power 2000 W,scanning speed 10 mm/s,powder feed rate 10 g/min and overlap ratio 45%.The cladding test is conducted under this variables combination,the obtained surface roughness is 16μm,and the average microhardness of the coating is 677 HV which reaches 96%of the value of the base material,and the cladding layer has a uniform microstructure without defects such as porosity and cracks.