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60kg/mP74重型钢轨使用时间不长,有的钢轨就发生脆性断裂。通过性能测定、金相组织观察及化学成份分析,发现这种钢轨的塑性及韧性低,容易脆断,其主要原因是钢轨存在严重的不均匀带状组织。而不均匀组织的形成又是和化学成份区域偏析及严重的夹杂物同向分布有关。同时,还发现不均匀带状组织及较多的夹杂物主要存在于钢轨轨腰部位。 本文还研究了不同温度回火、正火及过热处理对该型钢轨性能的影响,为进一步改善钢轨及其焊接后的性能提供了依据。
60kg / mP74 heavy rail use time is not long, brittle fracture occurred on some rails. Through the determination of properties, microstructure observation and chemical composition analysis, it is found that the plasticity and toughness of this kind of rail are low and brittle easily. The main reason is that the rail has a serious non-uniform ribbon structure. The formation of inhomogeneous structure is related to the segregation of chemical composition and the same distribution of inclusions. At the same time, it is also found that uneven banding and more inclusions mainly exist in the rail rail waist area. This paper also studied the different temperature tempering, normalizing and overheating on the performance of the rail, in order to further improve the rail and its performance after welding provides the basis.