The quenching process of H380 grade heat-treated steel rails is analyzed by computer numerical simulation. The rail heat treatment process is a " continuous isothermal transformation process" between the isothermal transition and the continuous cooling transition. The calculation shows that the temperature drop of the H380 grade heat treatment steel rail is controlled at 200 ~ 250 °C

and the rail head phase transition temperature should not exceed 620°C

the pearlite structure phase transition temperature at the tensile strength sampling position at the rail head should not exceed 650°C

and the phase change incubation period is between 22 〜30 s. In this section

the cooling intensity is strengthened and the pearlite phase transition temperature is lowered. It is beneficial to the deepening of the hardened layer of the rail head

to increase tensile strength of the heat-treated rail of this grade.