Method for repairing die cast dies

Abstract

Methods are provided for repairing a worn surface of a steel die-cast die. The method includes heating an amorphous material to a predetermined temperature with a laser beam and allowing the melted amorphous material to solidify to thereby form an amorphous layer over the worn surface. These processes are useful for eliminating or minimizing cracking and/or part distortion and minimize heat-affected zone during welding. In addition, the formation of an amorphous layer over the worn surface allows the repaired die-cast die to better withstand typical operating environments than previous repair materials. These methods combine low heat input welding with amorphous alloys to effectively repair die-cast dies.

1 . A method for repairing a worn surface of a steel die-cast die, the method comprising the steps of: 
 depositing an amorphous material onto the worn surface, the amorphous material formulated to form an amorphous layer after being heated to a predetermined temperature and cooled;    heating the amorphous material to the predetermined temperature with a laser beam, and without compressing the amorphous material, to form a repair layer over the worn surface; and    allowing the heated amorphous material to solidify to thereby form the amorphous layer.    
   
   
       2 . The method of  claim 1 , wherein the amorphous material comprises chromium, boron, silicon, carbon and iron.  
   
   
       3 . The method of  claim 2 , wherein the chemical compositions of the amorphous material (by weight percent) comprises between about 50% and about 50% chromium, between about 5% and about 7% boron, between about 1% and about 3% silicon, up to about 1% carbon, and balance iron.  
   
   
       4 . The method of  claim 1 , wherein the amorphous material is a powder.  
   
   
       5 . The method of  claim 1 , wherein the amorphous layer has a Rockwell hardness of between about Rc65 and about Rc73.  
   
   
       6 . The method of  claim 1 , wherein the laser used for heating comprises one of a Nd:YAG laser, a fiber laser, a diode laser and a CO 2  laser generator.  
   
   
       7 . The method of  claim 1 , wherein the step of heating comprises supplying a laser power output of about 50 watts or higher.  
   
   
       8 . The method of  claim 1 , further comprising machining the repair layer.  
   
   
       9 . The method of  claim 1 , further comprising the step of pre-treating the worn surface to receive the amorphous material.  
   
   
       10 . The method of  claim 9 , wherein the step of pre-treating comprises a treatment selected from the group consisting of machining, degreasing, and grit blasting.  
   
   
       11 . The method of  claim 1 , further comprising the step of heat treating the die.  
   
   
       12 . A method for repairing a worn surface of a steel die-cast die, the method comprising the steps of: 
 heating a solid amorphous material with a laser beam to a predetermined temperature to form a liquid, which solidifies to form an amorphous layer after cooling;    depositing the liquefied amorphous material onto the worn surface, without compressing the liquefied amorphous material, to form a repair layer thereover; and    allowing the amorphous material to cool to form the amorphous layer.    
   
   
       13 . The method of  claim 12 , wherein the amorphous alloy has a Rockwell hardness of between about Rc65 and about Rc73.  
   
   
       14 . The method of  claim 12 , wherein the step of heating comprises supplying a laser power input of about 50 watts or greater to the laser.  
   
   
       15 . The method of  claim 12 , further comprising the step of pre-treating the worn surface to receive the amorphous material.  
   
   
       16 . The method of  claim 15 , wherein the step of pre-treating comprises a treatment selected from the group consisting of machining, degreasing, and grit blasting.  
   
   
       17 . The method of  claim 12 , wherein the amorphous material comprises chromium, boron, silicon, carbon and iron.  
   
   
       18 . The method of  claim 17 , wherein the chemical compositions of the amorphous material (by weight percent) comprises between about 40% and about 50% chromium, between about 5% and about 6% boron, between about 1% and about 3% silicon, up to 1% carbon, and balance iron.  
   
   
       19 . (canceled)  
   
   
       20 . (canceled)