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钢轨焊接接头由于内部组织与母材不同,上道服役后会产生马鞍形磨耗,导致线路不平顺。我国铁路行业标准规定:接头焊后都必须采用正火热处理,达到提高接头组织强韧性,保证平顺性的目的。本文采用火焰正火方法,研究了现场闪光焊和气压焊焊接接头的表面硬度。结果表明:气压焊U75VG钢轨正火喷风冷却比焊态自然冷却接头硬度高,为308 HBW,硬度值波动范围也增大到4.4%,软化区宽度平均值减小到5.69 mm;气压焊U71MnG钢轨正火喷风冷却性能最好,接头硬度值为306 HBW,软化区宽度最窄,均值为1.55 mm,硬度波动范围为6.7%;闪光焊U75VG正火喷风冷却较焊态自然冷却接头硬度高,为320 HBW,硬度值波动范围提高到2.6%,软化区宽度平均值减小到3.89mm,焊缝处由于碳烧损,存在硬度值的下降。
Rail welded joints due to the internal organization and base metal is different from the service on the saddle will produce wear, resulting in irregular lines. China’s railway industry standards: welding joints must be used after normalizing heat treatment, to improve the toughness of joints, to ensure the smoothness of the purpose. In this paper, the flame normalizing method was used to study the surface hardness of flash and gas welding joints. The results show that the air jet welding U75VG rail normal air blast cooling is 308 HBW higher than that of the welded natural cooling joint, the fluctuation range of the hardness value also increases to 4.4% and the average width of the softened zone decreases to 5.69 mm. The air pressure welding U71MnG The FWHM cooling performance is the best, the joint hardness is 306 HBW, the width of the softening zone is the narrowest, with an average of 1.55 mm and the range of hardness fluctuation is 6.7%; flash welding U75VG normal air blast cooling is more than that of the welded natural cooling joint High, 320 HBW, the fluctuation range of hardness value increased to 2.6%, the average width of softening zone decreased to 3.89mm, and the hardness value decreased due to carbon burning at the weld.