【摘要】 钢轨焊接接头经过热循环后形成热影响区,该区域内存在不完全相变重结晶区域,导致其硬度下降,出现软化,而软化严重的接头在上道服役后会产生马鞍形磨损,导致线路不平顺。通过试验研究了不同冷却条件下高强耐磨钢轨气压焊接头软化区硬度的变化规律。结果表明:冷却过程采用喷风、喷雾等方式提高冷却速度,对缩小接头软化区宽度有显著作用。高强耐磨钢轨气压焊接头软化区最软点硬度随母材强度升高而升高,但钢轨强度级别越高,接头最软点与母体硬度的比值越低。1 280 MPa级及以上强度级别的钢轨,很难稳定达到压焊接头软化区硬度标准要求(H_J1/H_P≥0.8),建议修改或降低指标要求。更多还原

【Abstract】 The welded joint of rails will form a heat-affected zone after thermal cycling. In the heat affected zone,due to the existence of incomplete phase transformation affected zone,the hardness decreases and the softening occurs. Severely softened joints will produce saddle-shaped wear after service,resulting in uneven lines. In this paper,the variation of hardness in softening zone of high-strength wear-resistant steel rail gas pressure welding joints under different cooling conditions are studied. The results show that in the cooling process,the cooling rate is increased by jet-air and spraying,which has a significant effect on reducing the width of softening zone of the joint. The hardness of the softest point of the welded joint increases with the strength of the base metal,but the higher the strength of the rail,the lower the ratio of the softest point to the hardness of the base metal. When the rail is at the strength level of 1 280 MPa and above,the hardness standard requirement of the softening zone of the pressure welding joint(H_J1/H_P≥0.8) is difficult to be stably met. It is recommended to modify or reduce the index requirement.更多还原