Steel surface hardness using laser deposition and active gas shielding

Abstract

The addition of a steel and titanium carbide mixture is laser melted on a steel surface in air or in a shielding gas having a significant nitrogen content. The resulting steel surface has improved hardness and bead shape.

1 . A method of controlling bead shape in a steel alloy laser deposition process comprising laser melting a premixed titanium carbide powder and steel powder mixture on a steel surface using a shielding gas comprising 1% to 100% nitrogen.  
     
     
         2 . The method of  claim 1  wherein said shielding gas further comprises an inert gas.  
     
     
         3 . The method of  claim 1  wherein said shielding gas further comprises air.  
     
     
         4 . A method of controlling bead shape in a steel alloy laser deposition process comprising laser melting an addition of material comprised of titanium carbide and steel on a steel surface in air.  
     
     
         5 . A method for producing a high-hardness steel surface comprising the steps of: 
 a) introducing an addition of a powder mixture containing 10 to 60 weight percent titanium carbide powder and the balance steel onto a steel surface by preplacing said mixture on the surface, feeding said mixture into the interaction area, or combining the preplacing and feeding of the addition components;    b) laser melting said powder additions and a relatively small amount of the steel surface using 1% to 100% nitrogen as shielding gas; and    c) cooling at a rate such that a steel surface with fine titanium carbonitride particles is formed.    
     
     
         6 . A high hardness martensitic steel surface with distributed carbide particles produced according to the method of  claim 5.