Wear part and method of making the same

Abstract

Incorporating hard particles in a matrix forming the surface of a member can significantly increase wear resistance. Hard particles can degrade when they come in contact with a molten matrix material releasing constituent elements. These elements can locally degrade the matrix material on solidification. Coating the hard particles to limit contact with the matrix material and introducing an alloying element proximate the hard particles improve retention of the particles in the matrix.

1 . A wear part comprising a body having an external wear surface, the body being composed of a metallic matrix material having a coated hard material and an alloying element in the matrix material along the wear surface, the alloying material limiting formation of brittle phases in the matrix material adjacent the hard material. 
     
     
         2 . The wear part of  claim 1  where the concentration of the alloying element decreases with the distance from the wear surface. 
     
     
         3 . The wear part of  claim 1  where the matrix material is primarily iron. 
     
     
         4 . The wear part of  claim 1  where the alloying element includes one or more selected from the alloying group of nickel, chrome and molybdenum. 
     
     
         5 . The wear part of  claim 1  where the hard material includes coated hard particles. 
     
     
         6 . The wear part of  claim 1  where the body is formed as a wear member for earth working equipment. 
     
     
         7 . A method of making a wear part comprising coating hard material with at least one protective layer, locating the coated hard material and an alloying element adjacent the coated hard material in a mold, introducing a molten metallic matrix material into the mold to envelop the coated hard material and the alloying element with the alloying element limiting formation of brittle phases in the matrix material adjacent the hard material, and cooling the molten matrix to form the wear part incorporating the coated particle and alloying element. 
     
     
         8 . The method of  claim 7  where the coated material and the alloying element is located in the mold and incorporated in the wear part along a wear surface. 
     
     
         9 . The method of  claim 8  where the coated hard material includes coated hard particles. 
     
     
         10 . The method of  claim 9  where locating the coated hard particles and alloying element includes adhering the coated particle and the alloying element to a mold surface. 
     
     
         11 . The method of  claim 9  where the matrix material primarily includes iron. 
     
     
         12 . The method of  claim 9  where the matrix material is steel. 
     
     
         13 . The method of  claim 9  including coating the particle with a second layer. 
     
     
         14 . The method of  claim 9  where the alloying material is a carrier that includes the coated hard particles. 
     
     
         15 . The method of  claim 14  where the alloying material is a mesh. 
     
     
         16 . The method of  claim 9  where the alloying element includes one or more selected from a group of nickel, chrome and molybdenum. 
     
     
         17 . A method of making a wear part comprising applying coated hard particles and an alloying element on or adjacent a surface of a mold, introducing a molten metal into the mold to envelop the coated hard particles and the alloying element with the alloying element dispersing into the molten metal to limit the formation of brittle phases in the metal adjacent the hard material, and cooling the molten metal to form the wear part incorporating the coated particle and alloying element. 
     
     
         18 . The method of  claim 17  where the hard particles include carbide or diamond particles. 
     
     
         19 . The method of  claim 17  where the hard particles are coated with two different layers. 
     
     
         20 . The method of  claim 17  where the wear part is a point for an excavating tooth.