摘要
在钢轨闪光焊接过程中,母材中的MnS夹杂物从焊接过热区溶于焊缝金属。在焊接末期的连续闪光阶段,出现大的过梁爆破,形成暴露于空气的空洞,使焊缝金属中的Mn和Si在高温下与氧气发生反应,形成硅酸盐夹杂物,构成灰斑缺陷,其中Mn约占40%～50%。对比试验发现,U71Mn钢轨的MnS夹杂物和Mn含量分别是U75V钢轨的2倍和1. 2倍;对U71Mn和U75V钢轨闪光焊接头分别进行静弯和落锤试验,经统计,U71Mn钢轨断口灰斑面积分别是U75V钢轨的4. 5倍和2. 3倍。试验结果表明,钢轨母材中的MnS含量与焊缝金属中灰斑面积成正比。控制母材中的MnS含量可有效降低焊缝断口灰斑面积,从而提高钢轨闪光焊接头强度。
During the course of rail f lash butt welding,the MnS inclusions in the base metal dissolve in the weld seam metal from welding overheated areas.During the continuous f lashing phase of the end of welding process,large lintel burst occurs and forms a cavity exposed to the air,causing Mn and Si in the weld seam metal to react with O at high temperature to form silicate inclusions,namely,grey spot defects,among which Mn accounts for about 40%~50%.The comparison test found that MnS inclusions and Mn contents of U71Mn rail were 2 times and 1.2 times those of U75V rail,respectively.Static bending and falling hammer tests were performed on the f lash butt welding joints of U71Mn and U75V rail,respectively.According to statistics,the grey spot areas of the fracture of U71Mn rail were 4.5 times and 2.3 times those of U75V rail,respectively.Thus,the MnS content of the rail base metal is proportional to the grey spot area in weld seam metal.Controlling the MnS content of the base metal can effectively reduce the grey spot area on the weld seam fracture,so as to improve the strength of the rail f lash butt welding joint.
作者
丁韦
李力
赵国
王莹莹
高振坤
宋宏图
DING Wei;LI Li;ZHAO Guo;WANG Yingying;GAO Zhenkun;SONG Hongtu(Institute of Metals and Chemistry,China Academy of Railway Sciences Group Co.Ltd.,Beijing 100081,China)
出处
《铁道建筑》
北大核心
2018年第10期128-131,共4页
Railway Engineering
基金
中国铁道科学研究院金属及化学研究所基金(2016SJ06)
关键词
钢轨焊接
灰斑缺陷
试验研究
夹杂物
闪光焊
Rail welding
Grey spot defect
Experimental study
Inclusion
Flash butt welding
作者简介
丁韦(1960—),男,研究员,硕士。E-mail:ding2000@sina.com。
