Carburized Wire and Method for Producing the Same

Abstract

Methods are taught for processing low carbon steel wire into high carbon steel wire having improved characteristics for use in vehicle tire construction and other applications, including increased wire strength, corrosion resistance and rubber adherence. Low carbon steel wire is carburized to raise carbon content, resulting in increased strength and corrosion resistance. According to other aspects of the invention, the carburization process may occur in the presence of rubber adherence agents, which adhere to the steel wire, resulting in improved steel rubber adherence in a single processing step.

1 . A method for improving steel wire for use in vehicle tire construction, the method comprising the steps of: 
 providing a length of steel wire having a carbon content at a first carbon level,    providing at least a first carburizing agent,    providing at least a first rubber adherence agent,    contacting the at least a first carburizing agent and the at least a first rubber adherence agent with the length of steel wire,    providing a heating means for heating the length of steel wire,    operatively coupling the heating means to the length of steel wire,    heating the length of steel wire to a first temperature, wherein the first temperature is between approximately 950° C. and 1350° C., and    heating the length of steel wire at approximately the first temperature until the carbon content of the length of steel wire is at a second carbon level, wherein the second carbon level is higher than the first carbon level.    
   
   
       2 . The method of  claim 1 , wherein the length of steel wire has a diameter of between approximately 0.2 millimeters and approximately 2.0 millimeters, and 
 wherein, the first carbon level of the length of steel wire is less than approximately 0.5%.    
   
   
       3 . The method of  claim 2 , wherein the first carbon level of the length of steel wire is less than approximately 0.25%, and 
 wherein, the second carbon level of the length of steel wire is greater than approximately 0.6%.    
   
   
       4 . The method of  claim 3 , wherein the first temperature is between approximately 1200° C. and approximately 1350° C.  
   
   
       5 . The method of  claim 4 , wherein: 
 the at least a first carburizing agent is selected from the group consisting of solid carburizing agents, liquid carburizing agents and gaseous carburizing agents, and    wherein the at least a first rubber adherence agent is selected from the group consisting of copper containing rubber adherence agents and cobalt containing rubber adherence agents.    
   
   
       6 . The method of  claim 4 , further comprising quenching the length of steel wire to a second temperature, wherein the second temperature is lower than approximately 200° C., and 
 tempering the length of steel wire.    
   
   
       7 . The method of  claim 1 , further comprising the step of providing at least a first corrosion resist agent, and 
 contacting the at least a first corrosion resist agent with the length of steel wire before the step of heating the length of steel wire to a first temperature.    
   
   
       8 . A method for producing high carbon steel wire for use in vehicle tire construction, the method comprising the steps of: 
 providing a length of steel wire having a carbon content at a first carbon level, wherein the first carbon level of the length of steel wire is less than approximately 0.25%    providing at least a first carburizing agent,    contacting the at least a first carburizing agent with the length of steel wire,    providing a heating means for heating the length of steel wire,    operatively coupling the heating means to the length of steel wire,    heating the length of steel wire to a first temperature, wherein the first temperature is between approximately 1200° C. and 1350° C., and    heating the length of steel wire at approximately the first temperature until the carbon content of the length of steel wire is at a second carbon level, wherein the second carbon level is greater than approximately 0.6%.