圆筒内壁激光熔覆工艺的PLC控制与性能

PLC Control and Properties of Laser Cladding Process for Cylinder Inner Wall

目前,国内外对零部件内壁激光熔覆技术方面的研究较少。采用激光熔覆的方法对圆筒内壁进行了表面改性处理,研究了可编程逻辑控制器(PLC)控制激光熔覆涂层工艺参数对熔覆层横截面形貌、熔覆层成形和稀释率的影响,并对比分析了调质态圆筒基材、平板熔覆层和圆筒内壁熔覆层的耐磨性能。结果表明:调质态35CrMo空心圆筒内壁适宜的激光熔覆工艺参数为激光功率1400 W、扫描速度6 mm/s、送粉速率12 g/min,此时熔覆层成形质量较好;随着与表面层顶部距离的增加,平板熔覆层和内壁熔覆层硬度呈现逐渐减小特征,平板熔覆层和内壁熔覆层以及对应的热影响区硬度都高于35CrMo合金基体。在优化激光熔覆工艺下得到的熔覆层的室温和300℃高温耐磨性相较于圆筒基材有大幅度提升,且内壁熔覆层耐磨性与平板熔覆层相当或略低,可以满足圆筒零部件内壁表面改性高硬度和高耐磨的要求。

Surface modification of cylinder inner wall was carried out by laser cladding,and the effects of process parameters of laser cladding coating controlled by programmable logic controller(PLC) on cross-section morphology,cladding formation and dilution rate of cladding layer were studied,and the wear resistance of quenched and tempered cylinder base material,flat cladding layer and cladding layer on cylinder inner wall was compared and analyzed. Results showed that the suitable laser cladding parameters for the inner wall of 35 CrMo hollow cylinder were as follows: laser power of 1 400 W,scanning speed of 6 mm/s and powder feeding rate of 12 g/min,at which time the forming quality of cladding layer was good. With the increase of distance from the top of surface layer,the hardness of cladding layer and inner wall cladding layer decreased gradually,and the hardness of cladding layer,inner cladding layer and corresponding heat affected zone was higher than that of 35 CrMo alloy matrix. The room temperature and high temperature wear resistance of the cladding layer obtained under the optimized laser cladding process was much higher than that of the cylinder base material,and the wear resistance of the inner cladding layer was equal to or slightly lower than that of the flat cladding layer,which could meet the requirements of the inner surface modification of the cylinder parts for wear resistance.