Rail of railway with passenger and freight mixed traffic and manufacturing method thereof

Abstract

In view of the low comprehensive strength and toughness of pearlitic rail manufactured by existing techniques, the invention provides a manufacturing method for rail of railway with passenger and freight mixed traffic, including the following steps: a. hot roll steel billet into rail, with a final rolling temperature of 900-1000° C.; b. blow a cooling medium to the top surface of railhead, the two sides of railhead and the lower jaws on two sides of railhead when the center of top surface of rail is air-cooled to 800-850° C.; and then air-cool the rail to the room temperature after the center of top surface of rail is cooled to 520-550° C. By controlling the composition of steel and adopting a two-stage accelerated cooling, the invention is able to produce a rail with better performance which is suitable for railway with passenger and freight mixed traffic.

What is claimed is: 
     
         1 . A manufacturing method for a rail of a railway for mixed passenger and freight traffic, said manufacturing method comprising the following sequential steps:
 (a) hot rolling a steel billet to form the rail with a final rolling temperature range of 900-1000° C.;   (b) air cooling the rail until a center of a top surface of a railhead of the rail is cooled to 800-850° C.;   (c) blowing a cooling medium to the top surface of the railhead of the rail, two sides of the railhead and lower jaws on the two sides of the railhead until the center of the top surface of the railhead of the rail is cooled to 520-550° C.; and   (d) further air cooling the rail to room temperature.   
     
     
         2 . The manufacturing method according to  claim 1 , wherein the rail comprises:
 (i) 0.70 wt. % to 0.85 wt. % C;   (ii) 0.15 wt. % to 0.60 wt. % Si;   (iii) 0.70 wt. % to 1.05 wt. % Mn;   (iv) 0.15 wt. % to 0.50 wt. % Cr;   (v) at least one of 0.02 wt. % to 0.10 wt. % V, 0.001 wt. % to 0.030 wt. % Ti and 0.005 wt. % to 0.08 wt. % Nb; and   (vi) Fe.   
     
     
         3 . The manufacturing method according to  claim 1 , wherein the cooling medium is at least one of compressed air and a water-air spray mixture. 
     
     
         4 . The manufacturing method according to  claim 1 , wherein a cooling rate in step (c) is 3.0-7.0° C./s. 
     
     
         5 . A rail of railway for mixed passenger and freight traffic manufactured by the manufacturing method according to  claim 1 , wherein the rail comprises:
 (i) 0.70 wt. % to 0.85 wt. % C;   (ii) 0.15 wt. % to 0.60 wt. % Si;   (iii) 0.70 wt. % to 1.05 wt. % Mn;   (iv) 0.15 wt. % to 0.50 wt. % Cr;   (v) at least one of 0.02 wt. % to 0.10 wt. % V, 0.001 wt. % to 0.030 wt. % Ti and 0.005 wt. % to 0.08 wt. % Nb; and   (vi) Fe.