Comparative Study Of Rail Welding Methods And Qualitities

With the development of CWR track (Continuous Welded Railway), the number of welded joint sharply increases,and the qualities appear unstable and premature failure happened to some welded joints,those problems will endanger traffic safety. A variety of rail welding methods and joint quality engineering cases were reported at present, but still lack of systematic comparative analysis, in particular the lack of theoretical guidance for the failure characteristics of welded joints, causes, improvement measures.So based on a variety of welding methods and quality cases to carry out comparative study of quality of rail welding is necessary, and it is important to provide a scientific basis for rail welding works though choosing safe, reliable, economic and environmental friendly welding methods.This has became one of the focuses of the industry hot topic, which is of great significance.In this paper, the main task is to collect domestic welding joints’overall quality under different rail welding methods in recent years. Based on TB/T1632-2005rail welding standard, comparatively analysis the level of welding quality with different welding methods. Modern materials Physical Metallurgy Analysis Method is dopted to study the defects of flash-butt welding joint and gas-pressure welding joint through rail typical failure cases. For each welding method of typical case of joint defects, analyze the characteristic of morphology and distribution and the sensitivity of different rail welding methods to defects.The results show that:the quality of rail flash welding in factorty and gas-pressure welding on site is fair. Joints’tensile strength is higher than the base material of0to5%, about10%of the elongation is higher than the base material, the gas-pressure welding joints’ impact performance is better than flash welding joints’, the former is73.8%higher than standard requirements and the latter is31.7%higher than standard requirements. The flash-butt welding flat spot defects are mainly distribute in the rail bottom corner, a small parts distribute in the rail base triangle and rail waist, rail head rarely distributed. Gas-pressure welding joints have a certain degree of inclusiveness to the melt inclusions,but is sensitive to the block inclusions, flash-butt welding joints are very sensitive to the inclusion of the two forms.