焊前预热对40Cr钢脉冲冷焊接头组织和性能影响  

Effect of preheating before welding on the microstructure and properties of 40Cr steel pulse cold welding joint

作　　者：于长远 刘德义[1,2] YU Changyuan;LIU Deyi(School of Materials Science and Engineering,Dalian Jiaotong University,Dalian,116028 Liaoning,China;Key Laboratory of Key Materials of Rail Transit in Liaoning Province,Dalian,116028 Liaoning,China)

机构地区：[1]大连交通大学,材料科学与工程学院,辽宁大连116028 [2]辽宁省轨道交通关键材料重点实验室,辽宁大连116028

出　　处：《机械制造文摘（焊接分册）》2024年第5期1-5,26,共6页Welding Digest of Machinery Manufacturing

摘　　要：为实现转向架牵引拉杆的高性能修复,采用焊前局部低温预热方法对40Cr调质钢脉冲冷焊堆焊修复接头组织及性能的影响进行了研究。通过金相、显微硬度、拉伸试验及侧弯试验,对比分析室温、预热条件下堆焊修复接头组织及性能,研究焊前低温预热工艺对接头组织及性能的改善机理。结果表明,预热条件下堆焊接头与室温接头组织大体相似,其主要区别在于完全淬火粗晶区有贝氏体的生成。与室温对比,预热后完全淬火粗晶区硬度高点降低62 HV,回火区硬度降低30 HV左右;堆焊层及热影响区的抗拉强度降低了2%左右。通过采取100℃的焊前预热,对40Cr脉冲冷焊接头强度影响不大,仅略微下降,但补焊层硬度得以改善,最高点下降到符合ISO15614的规定,可以用于牵引拉杆内孔局部缺陷的修复。In order to realize the high-performance repair of traction tie rods,the effect of local low-temperature preheating method before welding on the microstructure and properties of 40Cr quenched and tempered steel pulse cold surfacing joints was studied.The microstructure and properties of the weld repair joints under the conditions of preheating and non-preheating were compared and analyzed,and the improvement mechanism of the microstructure and properties of the joints by the low-temperature preheating process before welding was studied through metallographic,microhardness,tensile and lateral flexure tests.The results show that the struc-ture of the surfacing joint is similar to that of the joint at room temperature under the preheating condition,and the main difference is the formation of bainite in the coarse grain area of complete quenching.Compared with room temperature:after preheating,the high point of hardness of the coarse grain zone is reduced by 62 HV,and the hardness of the tempering zone is reduced by about 30 HV;The tensile strength of the overlay and heat-affected zone has been reduced by about 2%.By taking 100°C preheating before welding,the strength of the 40Cr pulse cold welding joint is not affected,and only slightly decreased,but the hardness of the repair welding layer is improved,and the highest point is reduced to meet the requirements of the IS015614,which can be used to repair the local defects in the inner hole of the traction tie rod.

关 键 词：脉冲冷焊 40Cr 牵引拉杆 显微组织 性能 

分 类 号：TG455[金属学及工艺—焊接]