Cr12MoV钢表面激光熔覆Ni60合金制备无开裂涂层及摩擦磨损性能研究

Study on the Preparation and Friction and Wear Properties of Laser Cladding Ni60 Alloy on Cr12MoV Steel

为了实现损伤Cr12MoV钢激光再制造,采用激光熔覆Ni60合金制备无开裂涂层。利用着色探伤剂、硬度计、光学显微镜(OM)、X射线衍射仪(XRD)和摩擦磨损仪对所制备Ni60合金涂层的表面开裂、硬度、金相组织进行分析,并用摩擦磨损试验机对比研究了Ni60合金涂层和Cr12MoV钢的摩擦磨损性能。结果表明,当Ni60合金涂层长度L≤9 mm时,涂层表面无开裂;当Ni60合金涂层长度L>9 mm时,开裂区出现在母材邻近区,且随着涂层长度增大,开裂区也出现在涂层表面。要抑制激光熔覆过程中Ni60合金近母材区开裂,关键在于减少热输入对母材区的作用时间。最后,通过优选表面硬度相近的Ni60合金涂层和Cr12MoV钢进行摩擦磨损性能测试,发现两者的摩擦系数与耐磨性能相近,可望为损伤Cr12MoV钢激光再制造提供参考。

In order to realize laser remanufacturing of Cr12MoV steel with damage,laser cladding Ni60 alloy was used to prepare crack free coating.The surface cracking,hardness and metallographic structure of the Ni60 alloy coating were analyzed by means of dye penetrant,hardness tester,optical microscope(OM),X-ray diffraction(XRD)and friction and wear tester.The friction and wear properties of Ni60 alloy coating and Cr12MoV steel were compared by means of friction and wear tester.The results show that when the length of Ni60 alloy coating L≤9 mm,there is no crack on the coating surface;When the length of Ni60 alloy coating L>9 mm,the cracking zone appears in the vicinity of the base metal,and with the increase of the coating length,the cracking zone also appears on the coating surface.In order to restrain the cracking of Ni60 alloy near the base metal during laser repair,the key is to reduce the action time of heat input on the base metal.Finally,the friction and wear properties of Ni60 alloy coating and Cr12MoV steel with similar surface hardness were tested,and it was found that their friction coefficients and wear resistance were similar,which could provide a reference for laser remanufacturing of damaged Cr12MoV steel.