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近年来,在轨腰处经常发现纵向水平裂纹,分析在各种运行条件下裂纹突进的临界尺寸,对保证行车安全具有重大意义。轨腰纵向水平裂纹与轴重、列车运行速度有关,也受线路平面条件的影响。经计算,直线地段60kg/m钢轨(U74)轨腰纵向水平裂纹临界尺寸为160～260mm,50kg/m钢轨(U71Mn)为90～160mm,而50kg/m(U71Mn)轨在铝热焊缝处由于存在很大的竖向残余拉应力,仅为55～58mm。为了保证行车安全,应重视轨腰水平裂纹并规定出各种类型钢轨在不同运行条件下的容许尺寸。
In recent years, longitudinal horizontal cracks are often found on the rail waist and analyzing the critical size of crack in various operating conditions is of great significance to ensure driving safety. Longitudinal cracks horizontal rail and axle load, train speed, but also by the line plane conditions. It is calculated that the critical longitudinal crack horizontal length of 60 kg / m rail (U74) in straight section is 160-260mm, that of 50kg / m rail (U71Mn) is 90-160mm, and that of 50kg / m (U71Mn) Due to the large vertical residual tensile stress, only 55 ~ 58mm. In order to ensure driving safety, should pay attention to the horizontal crack of railings and stipulate the allowable size of various types of rails under different operating conditions.