【作者】 周红梅；

【导师】 戴虹；

【作者基本信息】 西南交通大学 ， 材料科学与工程， 2013， 硕士

【摘要】 随着无缝线路的发展,焊接接头数量日益增多,接头质量出现波动而过早失效,将会危及行车安全。目前虽然各种焊接方法及质量情况的工程案例报道较多,但尚缺乏系统对比分析,尤其是焊接接头失效的特征、产生原因、改进措施缺乏理论指导。因此,根据各种焊接方法与质量的工程案例,系统开展钢轨焊接质量对比研究,为焊轨工程合理选择安全可靠、经济环保的焊接方法提供科学依据,成为业内十分关注的热点问题,具有重要意义。本论文的主要工作是搜集统计国内近年来不同轨道焊接方法接头的整体质量,依据TB/T1632-2005钢轨焊接标准,对比分析不同焊接方法接头的质量水平。采用现代材料物理冶金分析方法研究闪光焊和气压焊接头失效典型案例的接头缺陷,分析其成分、形貌特征及分布情况,对不同焊接方法缺陷的敏感性进行分析。结果表明：钢轨闪光焊、气压焊接头在正火状态下质量相当,接头的抗拉强度都高于母材0-5%,断后伸长率高于母材10%左右；气压焊接头的冲击性能较闪光焊接头好,气压焊接头冲击功是标准要求的173.8%,闪光焊是标准要求的131.7%。闪光焊灰斑缺陷主要分布于轨底角,较少分布于轨底三角区和轨腰,少见于轨头。气压焊接头对熔融状夹杂物有一定的包容性,对块状夹杂物敏感,闪光焊则对两种形态的夹杂物都非常敏感。更多还原

【Abstract】 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.更多还原