Track part made of a hypereutectoid steel

Abstract

In a track part, in particular rail for railway vehicles, made of a hypereutectoid steel, comprising a rail foot, a rail web and a rail head portion, a hypereutectoid steel with the following directional analysis is used: 0.98-1.17 wt.-% of C 0.90-1.35% wt.-% of Mn 0.70-1.10% wt.-% of Si 0.15-0.70 wt.-% of Cr and wherein the steel, at least in the head portion of the rail, has a pearlitic structure that is substantially free of secondary cementite networks.

1 . Track part, in particular rail for railway vehicles, made of a hypereutectoid steel, comprising a rail foot, a rail web and a rail head portion, characterized in that the hypereutectoid steel comprises a following directional analysis of:
 0.98-1.17 wt.-% of C   0.90-1.35% wt.-% of Mn   0.70-1.10% wt.-% of Si   0.15-0.70 wt.-% of Cr   
       and the steel, at least in the head portion of the rail, has a pearlitic structure that is substantially free of secondary cementite networks. 
     
     
         2 . Track part according to  claim 1 , characterized in that C is present in amounts of 1.05 to 1.17 wt.-%, preferably 1.06 to 1.15 wt.-%, and particularly preferably 1.08 wt.-%. 
     
     
         3 . Track part according to  claim 1 , characterized in that the hypereutectoid steel additionally contains Al in an amount of 0.01-0.06 wt.-%. 
     
     
         4 . Track part according to  claim 1 , characterized in that the hypereutectoid steel additionally contains V in an amount of 0.07 to 0.20 wt.-%, in particular 0.10 to 0.20 wt.-%. 
     
     
         5 . Track part according to  claim 1 , characterized in that the hypereutectoid steel additionally contains Nb in an amount of 0.01-0.03 wt.-%. 
     
     
         6 . Track part according to  claim 1 , characterized in that the hypereutectoid steel additionally contains Ti in an amount of 0.015-0.05 wt.-%. 
     
     
         7 . Track part according to  claim 1 , characterized in that that the hypereutectoid steel additionally contains V in an amount of 0.07-0.2 wt.-%, in particular 0.10-0.2 wt.-%, together with Nb in an amount of 0.01-0.03 wt.-%. 
     
     
         8 . Track part according to  claim 1 , characterized in that that the hypereutectoid steel additionally contains Al in an amount of 0.01-0.06 wt.-% together with Nb in an amount of 0.01-0.03 wt.-%. 
     
     
         9 . Track part according to  claim 3 , characterized in that the hypereutectoid steel additionally contains N in an amount ranging from 40 to 120 ppm. 
     
     
         10 . Track part according to  claim 1 , characterized in that the hypereutectoid steel, at least in the head portion of the rail, has a tensile strength greater than 1500 MPa, an elongation at break of greater than 8% and a Brinell hardness greater than 460 HB. 
     
     
         11 . A method for producing a track part according  claim 1 , characterized in that the hypereutectoid steel having a composition according to  claim 1  is taken from a furnace at a temperature of 1000-1300° C., then rolled at a final rolling temperature of 850-950° C. and is then subjected to forced cooling to a temperature of 450° C. to 600° C. 
     
     
         12 . The method according to  claim 11 , characterized in that the deformation in the temperature range 1000-850° C. at least in the head portion of the rail has an accumulated comparative degree of deformation of min 1.4. 
     
     
         13 . The method according to  claim 11 , characterized in that the forced cooling takes place at least in the head portion of the rail. 
     
     
         14 . The method according to  claim 11 , characterized in that the forced cooling takes place in a bath of cooling medium not being pure water. 
     
     
         15 . The method according to  claim 11 , characterized in that the forced cooling takes place in a polymer bath having a temperature of 15-50° C. 
     
     
         16 . The method according to  claim 11 , characterized in that the forced cooling is performed at a rate of at least 4° C./sec, preferably at least 8° C./sec, more preferably at least 12° C./sec.