Copper Containing Rail Steel

Abstract

Steel railroad rails including carbon, manganese, silicon and greater than 0.45 wt % to 1 wt % copper are provided having greater hardness and yield strength than standard steel rails containing less than 0.45 wt % copper. As an example, the ultimate tensile strength of the steel rails is from 1170 MPa to 1725 MPa. As an additional example, the hardness of the steel rails measured 2 mm from the running surface of the rail is from 35 to 50 on the Rockwell C scale.

We claim: 
     
         1 . A steel rail comprising from 0.7 to 0.95 wt % of C, from 0.8 to 1.2 wt % of Mn, from 0.26 to 0.80 wt % of Si, from greater than 0.45 to 2.0 wt % of Cu and from less than or equal to 0.35 wt % of Cr wherein the balance is composed of Fe and less than 1 wt % additional alloying elements and impurities. 
     
     
         2 . The steel rail of  claim 1  comprising from 0.6 to 1.0 wt % Cu. 
     
     
         3 . The steel rail of  claim 1  comprising from 0.8 to 1.0 wt % Cu. 
     
     
         4 . The steel rail of  claim 1 , further comprising less than or equal to 0.25 wt % Ni. 
     
     
         5 . The steel rail of  claim 1 , further comprising less than or equal to 0.05 wt % Mo. 
     
     
         6 . The steel rail of  claim 1 , further comprising from 0.005 to 0.105 wt % Ti. 
     
     
         7 . The steel rail of  claim 1 , further comprising less than or equal to 0.025 wt % S. 
     
     
         8 . The steel rail of  claim 1 , further comprising less than or equal to 0.01 wt % Al. 
     
     
         9 . The steel rail of  claim 1 , wherein the ultimate tensile strength of the steel rail is from 1170 MPa to 1725 MPa. 
     
     
         10 . The steel rail of  claim 1 , wherein the hardness of the steel rail measured 2 mm from the running surface of the rail is from 35 to 50 on the Rockwell C scale. 
     
     
         11 . A steel rail comprising from 0.9 to 1.1 wt % of C, from 0.8 to 1.2 wt % of Mn, from 0.26 to 0.80 wt % of Si, from greater than 0.45 to 2.0 wt % of Cu and from less than or equal to 0.35 wt % of Cr wherein the balance is composed of Fe and less than 1 wt % additional alloying elements and impurities. 
     
     
         12 . The steel rail of  claim 11  comprising from 0.6 to 1.0 wt % Cu. 
     
     
         13 . The steel rail of  claim 11  comprising from 0.8 to 1.0 wt % Cu. 
     
     
         14 . The steel rail of  claim 11 , further comprising less than or equal to 0.25 wt % Ni. 
     
     
         15 . The steel rail of  claim 11 , further comprising less than or equal to 0.05 wt % Mo. 
     
     
         16 . The steel rail of  claim 11 , further comprising from 0.005 to 0.105 wt % Ti. 
     
     
         17 . The steel rail of  claim 11 , further comprising less than or equal to 0.025 wt % S. 
     
     
         18 . The steel rail of  claim 11 , further comprising less than or equal to 0.01 wt % Al. 
     
     
         19 . The steel rail of  claim 11 , wherein the ultimate tensile strength of the steel rail is from 1170 MPa to 1725 MPa. 
     
     
         20 . The steel rail of  claim 11 , wherein the hardness of the steel rail measured 2 mm from the running surface of the rail is from 35 to 50 on the Rockwell C scale. 
     
     
         21 . A method for manufacturing a steel rail, the method comprising the steps of:
 a) preparing a steel comprising the elements in a range from 0.7 to 0.95 wt % of C, 0.8 to 1.2 wt % of Mn, 0.26 to 0.80 by wt % of Si, from greater than 0.45 to 2.0 wt % of Cu and less than or equal to 0.35 wt % of Cr, wherein the balance of the steel is composed of Fe and less than 1 wt % additional alloying elements and impurities;   b) hot rolling the steel to have a rolling finishing temperature in a range from 800° C. to 1200° C. and thereby forming a rail; and   c) cooling the rail at a selected cooling rate in a range from 0.1° C./sec to 20° C./sec beginning substantially at said rolling finishing temperature and continuing at least until pearlite transformation-completion temperature.   
     
     
         22 . The method of  claim 21  wherein the steel comprises from 0.9 to 1.1 wt % of C.