大轴重下钢轨铝热焊接头伤损原因与改进措施

通过宏观形貌观察、化学成分测试、踏面硬度测试、显微组织观察、扫描电镜分析、能谱成分测试等方法,结合铝热焊接头服役过程中的平直度数据,对35.7 t轴重重载试验条件下半径350 m曲线上股的铝热焊接头伤损进行分析,并对铝热焊焊接工艺进行优化试验.结果表明:断口裂纹源附近的疏松缺陷是焊接接头轨距角剥离裂纹伤损产生的原因;焊...

Damage Causes and Improvement Measures of Rail Thermit Welding Joint Under Large Axle Load

Through the methods of macro morphology observation,chemical composition test,tread hardness test,microstructure observation,scanning electron microscope analysis and energy spectrum composition test,combined with the flatness data of thermit welding joint in service,the damage of thermit welding joint on the upper strand curve with radius of 350 m under the condition of 35.7 t axle load heavy load test was analyzed,and the optimization test of thermit welding process was carried out.The results show that the loose defect near the fracture crack source is the cause of the gauge angle peeling crack of the welding joint.The low collapse of welding seam is related to the occurrence of damage to a certain extent.When 28 mm rail seam is adopted,there is no obvious loose defect in the weld center.It is suggested to properly reduce the rail gap under the condition of large axle load to reduce loose defects,and timely repair and polish the low collapse thermit welding joint during operation to improve the smoothness of the joint.