预留打磨量和打磨温度对钢轨铝热焊接头平直度的影响

Influence of Reserved Grinding Quantity and Grinding Temperature on Flatness of Rail Thermit Welding Joint

首先分析了铝热焊接头焊缝低塌的原因,然后通过现场试验测量初打磨后接头的最高温度、不同终打磨温度下焊缝中心低塌量以及接头冷却过程中温度的变化,分析初打磨轨顶焊筋的预留打磨量、终打磨温度对铝热焊接头焊后平直度的影响.结果表明:焊接60 kg/m钢轨铝热焊接头时,初打磨后轨顶焊筋应预留1.3 mm以上的打磨量;终打磨温度越低焊缝低塌量越小,随终打磨温度降低焊缝低塌量减小幅度逐渐变缓,终打磨温度为300℃时焊缝低塌量较小,终打磨温度低于200℃时焊缝无低塌现象;采用"初打磨+终打磨"的打磨方式可避免铝热焊接头焊缝低塌,提高打磨效率.

Firstly,the causes of the welding seam collapse of the thermit welding joint were analyzed.Then the maximum temperature of the joint after the primary grinding,the low collapse of the welding center under different final grinding temperatures and the temperature change during the cooling process of the joint were measured through the field tests.The influence of the reserved grinding quantity of the welded ribs on the top of the rail after primary grinding and final grinding temperature on the flatness of the thermit welding joints after welding was analyzed.The results show that when welding 60 kg/m rail thermit welding joint,the grinding quantity of rail top welding rib after primary grinding shall be more than 1.3 mm.The lower the final grinding temperature is,the smaller the quantity of welding seam collapse would be,the decreasing range of welding seam collapse gradually slows down with the decrease of final grinding temperature,when the final grinding temperature is 300℃,the quantity of welding seam collapse is small,and when the final grinding temperature is lower than 200℃,there is no welding seam collapse.The grinding method of“initial grinding+final grinding”can avoid the welding seam collapse of the thermit welding joint and improve the grinding efficiency.