回火热处理对U75V钢轨激光熔覆修复的影响研究  

Study on the Effect of Tempering Heat Treatment on U75V Rail Laser Cladding Repair

作　　者：寇荣魁 朱加雷[1] 童佟 焦向东[1] 李丛伟 苗春雨 朱昱颖 Kou Rongkui;Zhu Jialei;Tong Tong;Jiao Xiangdong;Li Congwei;Miao Chunyu;Zhu Yuying(School of Mechanical Engineering,Beijing Institute of Petrochemical Technology,Beijing 102600,China)

机构地区：[1]北京石油化工学院机械工程学院,北京102600

出　　处：《应用激光》2022年第7期28-33,共6页Applied Laser

基　　金：北京石油化工学院京冶新能源技术与装备创新研发中心开放基金(H2019-003/002)。

摘　　要：针对U75V钢轨的修复需求,进行了激光填丝熔覆工艺试验,并对优化工艺参数下形成的熔覆层进行了回火热处理,通过与母材性能以及钢轨焊补要求对比,研究回火对熔覆层微观组织及性能的影响变化规律。结果表明,300℃回火后,热影响区主要为回火马氏体,硬度无明显变化,熔覆区中靠近熔合线处硬度逐渐增加;600℃回火后,熔覆层整体耐磨性弱于钢轨,熔覆区和热影响区的平均硬度与母材的差距均小于15%;热影响区主要为回火索氏体,其在耐磨性能试验中的磨损量和摩擦因数均小于熔覆层其余部分。600℃回火后熔覆区域的抗拉强度和伸长率与母材基本一致,符合钢轨修复的对应性能要求。In response to the repair requirements of U75 V rails,a laser wire-filled cladding process test was carried out,and the cladding layer formed under the optimized process parameters was tempered and heat treated.By comparing the properties of the base material and the rail welding repair requirements,the effect of tempering on the microstructure and properties of the cladding layer was investigated.Results show that after tempering at 300℃,the heat-affected zone is mainly tempered martensite,the hardness does not change significantly,and the hardness gradually increases near the fusion line in the cladding zone.After tempering at 600℃,the overall wear resistance of the cladding layer is weaker than that of the steel rail,and the difference between the average hardness of the cladding zone and the heat-affected zone and the base metal is less than 15%.The heat-affected zone is mainly tempered sorbite,and its wear amount and friction coefficient in the wear resistance test are smaller than the rest of the cladding layer.The tensile strength and elongation of the cladding area after tempering at 600℃are basically the same as those of the base material,which meets the corresponding performance requirements for rail repair.

关 键 词：回火热处理 U75V钢轨 激光熔覆 

分 类 号：TG156.5[金属学及工艺—热处理]