Control method of hypereutectoid rare earth steel rail network carbide

Abstract

The invention discloses a control method of a hypereutectoid rare earth steel rail network carbide, which comprises the following steps: after finishing rolling of a steel rail, the steel rail directly enters an on-line heat treatment production line for accelerated cooling and air blast cooling, the temperature of the steel rail entering a quenching line is 730-780 DEG C, the rail head cooling speed of a first cooling section and a second cooling section is controlled at 6-7 DEG C / s, and after the steel rail is rapidly cooled by the first cooling section and the second cooling section, till temperature of the rail head reaches 580-630 DEG C, enabling steel rail to be rapidly cooled in a third cooling section and a fourth cooling section so that cooling speed is reduced, controlling the cooling speed of the rail head to be 2-3 DEG C / s, taking the steel rail out of an online heat treatment unit after the third cooling section and the fourth cooling section are finished, controlling the temperature of the rail head to be 540-560 DEG C at the moment so that the steel rail is taken out of a quenching line and naturally cooled to the room temperature. The pearlite structure with smaller interlamellar spacing is obtained, the density of cementite phase in the pearlite is higher, precipitation of network cementite in the hypereutectoid steel rail is effectively reduced, and the toughness of the steel rail is improved.

Description

technical field [0001] The invention relates to the field of metallurgical materials, in particular to a control method for hypereutectoid rare earth rail network carbides. Background technique [0002] At present, with the rapid development of my country's railways, the traffic volume of the lines is increasing year by year, and the service conditions of the rails used for heavy-duty railways are becoming more and more stringent. According to the service effect of the rails on the Daqin Railway Line in my country, how to extend the service life of the rails, improve the wear resistance of the rails, Ensuring transportation safety is an urgent problem to be solved. At present, the way to improve the wear resistance of rails is to improve the strength and toughness of the rails. The main way is to increase the carbon content and alloy content of the rails, and cooperate with the rapid cooling process after the rails are rolled. The main method is to use compressed air or The ...

AI Technical Summary

Problems solved by technology

Production practice shows that increasing the carbon content of the rail to make the rail composition reach the hypereutectoid pearlite composition range will lead to the precipitation of reticular cementite at the grain boundary, making it easy for cracks to form at the cementite and continue along the network. Expand, reduce the grain boundary energy, so that the toughness of the rail is greatly reduced

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