Tungsten carbide reinforced manganese steel

Abstract

A composite material including at least one reinforcing zone of tungsten carbide and a manganese steel matrix. A manganese steel zone surrounds the at least one reinforcing zone. An interface layer is positioned between the reinforcing zone and the manganese steel zone. An average grain size of the WC particles in the reinforcing zone is between 7-12 μm.

1 . A composite material comprising:
 at least one reinforcing zone including tungsten carbide and a manganese steel matrix;   a manganese steel zone surrounding the at least one reinforcing zone; and   an interface layer positioned between the at least one reinforcing zone and the manganese steel zone, wherein an average grain size of WC grains in the at least one reinforcing zone is between 7-12 μm.   
     
     
         2 . The composite material according to  claim 1 , wherein a wt % of WC in the at least one reinforcing zone is between 70-98. 
     
     
         3 . The composite material according to  claim 1 , wherein a composition of the manganese steel in manganese steel zone has a chemical composition by weight of:
 carbon: 0.5 to 2.0%;   manganese: 11 to 22%;   silicon: 0.2 to 1.0%;   chromium: 1 to 2%;   nickel: up to 0.6%;   molybdenum: up to 0.5%; and   a balance of iron.   
     
     
         4 . The composite material according to  claim 1 , wherein a hardness of the at least one reinforcing zone is between 580-780 HV1 and a hardness of the manganese steel zone is between 200-300 HV1 before work hardening. 
     
     
         5 . The composite material according to  claim 1 , wherein a thickness of the interface layer is between 90-295 μm. 
     
     
         6 . The composite material according to  claim 1 , wherein the interface layer is free of defects. 
     
     
         7 . The composite material according to  claim 1 , wherein wettability between the WC grains and the manganese steel in the at least one reinforcing zone is >99%. 
     
     
         8 . The composite material according to  claim 1 , wherein the at least one reinforcing zone has a volume of between 30-75 cm 3 . 
     
     
         9 . The composite material according to  claim 1 , wherein at least 95% of the WC grains in the at least one reinforcing zone has a triangular prismatic shape, wherein the triangular prismatic shape is a polyhedron having 5 faces, 6 edges and 9 vertices, and wherein a percentage of WC grains having a triangular prismatic shape is calculated by counting from a SEM fracture surface image. 
     
     
         10 . The composite material according to  claim 1 , wherein there are a plurality of reinforcing zones and the distance between two neighbouring reinforcing zones is between 1-5 mm. 
     
     
         11 . A wear part comprising the composite material according to  claim 1 . 
     
     
         12 . A method of producing the composite material according to  claim 1 , the method comprising the steps of:
 a) mixing together 60-95 wt % tungsten, 3-8 wt % carbon and 0-40% catalysis powders;   b) compacting the mixed powders together to form at least one compact;   c) positioning and optionally fixing the at least one compact into an interior of a mold;   d) pouring molten casting manganese steel into the mold to surround the at least one compact to initiate a self-propagating high temperature synthesis reaction to produce a cast;   e) heat treating the cast; and   f) quenching the cast, wherein in step b) the powders are compacted with a pressure of between 400-700 mPa.   
     
     
         13 . The method according to  claim 12 , wherein the catalysis is selected from iron, cobalt, nickel, molybdenum, chromium, tungsten, aluminum or a mixture thereof.