The invention discloses a hypoeutectoid steel rail post-weld
heat processing method, and belongs to the technical field of railway steel rail manufacturing. The hypoeutectoid steel rail post-weld heatprocessing method can achieve the effects that the
tread longitudinal
hardness of a hypoeutectoid steel rail
welding joint can be controlled within a reasonable range. The
heat processing method sequentially comprises the following steps that A, first cooling is carried out on the
welding joint with the temperature of 1100-1400 DEG C to be not higher than 200 DEG C, wherein
welding joint is obtained by welding hypoeutectoid steel rails, and the first cooling mode is natural cooling in air; B, the
welding joint is heated to 840-920 DEG C; and C, second cooling is carried out on the
welding joint, the second cooling is stopped when the
welding joint is cooled to 320-400 DEG C, then third cooling is carried out until the welding joint reaches 5-40 DEG C, and the welding joint with the longitudinal
hardness of the rail head
tread being 85%-90% of the average
hardness of the steel rail base material is obtained, wherein the second cooling mode is rapid cooling in which a
cooling medium isapplied, the
cooling temperature of the second cooling is 800 DEG C or above, and the third cooling mode is natural cooling in the air.