电力机车高强钢零部件焊修工艺技术研究  

Research on Welding Repair Technology for Key Components of Rail Vehicles

作　　者：刘静[1] 李巧艳[1] 徐海龙[1] 王宸[1] 薛子奇 LIU Jing;LI Qiaoyan;XU Hailong;WANG Chen;XUE Ziqi(Dalian Locomotive and Rolling Stock Co.,Ltd.,Dalian 116021,China;School of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China)

机构地区：[1]大连机车车辆有限公司,辽宁大连116021 [2]大连交通大学材料科学与工程学院,辽宁大连116028

出　　处：《电焊机》2024年第9期47-54,共8页Electric Welding Machine

摘　　要：为了研究焊修次数对电力机车转向架关键零部件30CrMo合金钢空心轴组织及性能的影响,并优化其焊修工艺,对30CrMo合金钢空心轴行了三次焊修试验,并对每次焊修后的接头进行了静强度试验、金相试验和疲劳试验。静强度试验包括拉伸和弯曲试验,金相试验观察了接头各区域的显微组织,疲劳试验采用旋转弯曲加载方式,以确定接头的疲劳极限。结果表明:多次焊修后,接头的拉伸性能良好,拉伸试件断于母材;弯曲性能良好,弯曲角度达180°时无断裂或裂纹产生;室温和低温冲击性能在多次焊修后略有下降,符合标准要求;三次焊修焊缝硬度在330~340 HV之间,明显高于母材及热影响区硬度值。金相组织分析表明,空心轴母材的组织为回火索氏体、上贝氏体及块状铁素体,热影响区的主要组织为回火索氏体和少量块状铁素体,熔合区的组织为回火索氏体,焊缝组织为经过调质后产生的回火索氏体。接头疲劳极限满足强度要求,第三次焊修中值疲劳极限最高,在指定寿命为1×10^(7)次循环下的中值疲劳极限为399 MPa。焊后调质处理可以有效地改善多次焊修对接头性能的影响。多次焊修后的30CrMo合金钢空心轴接头具有良好的拉伸、弯曲和疲劳性能,且随着焊修次数的增加,接头的疲劳强度逐渐提高。该研究结果为电力机车转向架关键部件的焊修工艺优化提供了理论依据。To study the effect of repair welding times on the microstructure and properties of the 30CrMo alloy steel hollow shaft,a key component of the power locomotive bogie,and to optimize its repair welding process,three repair welding tests were conducted on the 30CrMo alloy steel hollow shaft.Static strength tests,metallographic tests,and fatigue tests were performed on the joints after each repair welding.Static strength tests included tension and bending tests.Metallographic tests observed the microstructure of various regions of the joint.Fatigue tests used rotating bending loading to determine the fatigue limit of the joint.The results showed that after multiple repair weldings,the joint had good tensile properties,and the tensile specimens broke at the base metal;the bending performance was good,and no fracture or crack occurred when the bending angle reached 180°;the impact properties at room temperature and low temperature decreased slightly after multiple repair weldings,meeting the standard requirements;the hardness of the weld after three repair weldings was between 330~340 HV,which was significantly higher than the hardness of the base metal and the heat-affected zone.Metallographic analysis showed that the microstructure of the hollow shaft base metal was tempered sorbite,upper bainite,and massive ferrite,the main microstructure of the heat-affected zone was tempered sorbite and a small amount of massive ferrite,the microstructure of the fusion zone was tempered sorbite,and the weld microstructure was tempered sorbite produced after quenching and tempering.The fatigue limit of the joint met the strength requirements,and the median fatigue limit was the highest in the third repair welding,which was 399 MPa at a specified life of 1×10^(7) cycles.Post-weld quenching and tempering could effectively improve the effect of multiple repair weldings on joint properties.After multiple repair weldings,the 30CrMo alloy steel hollow shaft joint had good tensile,bending,and fatigue properties,and the fatigue strength

关 键 词：30CrMo合金钢空心轴 焊修次数 金相组织 力学性能 疲劳性能 

分 类 号：TG441.7[金属学及工艺—焊接]