U71Mn钢轨闪光焊接头暗色灰斑成因及消除方法

Causes and Elimination Methods of Dark Gray Patches on U71Mn Rail Flash Welding Joint

针对U71Mn钢轨闪光焊中容易出现暗色灰斑的现象,分析暗色灰斑的成分。从钢材焊接角度,探究暗色灰斑形成原因。U71Mn钢轨的Mn含量较其他类型钢轨高,因而在焊接过程形成锰酸盐的几率高,表现为暗色灰斑。当顶锻前的过热区过宽时,这类锰酸盐的聚集无法在顶锻过程中被挤出,暗色灰斑会残余在焊缝中。为尽可能消除暗色灰斑,开展消除暗色灰斑试验。分析3组不同参数焊接的钢轨接头暗色灰斑情况,为确定闪光焊工艺参数提供参考。

In view of the dark gray patches that is easy to appear in the flash welding of U71Mn rail,the composition of dark gray patcheswas analyzed.From the perspective of steel welding,this paper explores the reasons for the forma⁃tion of such dark gray patches.It is believed that the content of Mn in the rail of U71Mn is higher than that of other types of rail,and thus the rate of the formation of manganate is higher,which is manifested in the form of dark gray patches.In order to eliminate the dark gray patches as much as possible,the dark gray patches elimination test was carried out to analyze the dark gray patchesof rail joints welded under three groups of different parameters,so as to provide reference for correcting the process parameters of flash welding machine.