Tungsten carbide and titatnium carbide reinforced manganese steel

Abstract

A composite material includes at least one reinforcing zone composed of tungsten carbide (WC) and titanium carbide (W, Ti)C and a manganese steel matrix; a manganese steel zone that surrounds each of the reinforcing zones; and an interface layer positioned between each of the reinforcing zones and the manganese steel zone. The average grain size of the (W, Ti)C particles in each of the reinforcing zone(s) is between 0.2-2 μm and the average grains size of the WC particles in each of the reinforcing zone(s) is between 20-30 μm.

1 . A composite material comprising:
 a plurality of reinforcing zone, each of the reinforcing zones comprising core-rim tungsten titanium carbide (W,Ti)C, tungsten carbide (WC) and a manganese steel matrix, wherein a core of the core-rim (W,Ti)C is rich in titanium and a rim core of the core-rim (W,Ti)C is rich in tungsten;   a manganese steel zone surrounding each of the reinforcing zones; and   an interface layer positioned between each of the reinforcing zones and the manganese steel zone,   wherein a distance between two neighbouring reinforcing zones is between 1-5 mm,   wherein a wt % of (W,Ti)C in each of the reinforcing zones is between 80-98 and a wt % of WC in each of the reinforcing zones is between 20-30,   wherein a hardness of the reinforcing zones is between 900-1400 HV1 and a hardness of the manganese steel zone is between 300-400 HV1 before work hardening, wherein work hardening occurs as manganese steel in the manganese steel zone is subjected to the impact of crushing forces,   wherein an average grain size of (W,Ti)C particles in each of the reinforcing zones is between 0.2-2 μm and an average grain size of WC particles in each of the reinforcing zones is between 20-30 μm,   wherein the average grain size of (W,Ti)C and WC grains is measured by Scanning Electron Microscopy (SEM) analysis, where several and different areas from samples were analysed and particle sizes were measured using Image J software from which an average particle size was calculated, and   wherein a density in the reinforcing zones is between 83-96% of a theoretical density.   
     
     
         2 . The composite material according to  claim 1 , wherein the composition of the manganese steel in the 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 Fe.   
     
     
         3 . The composite material according to  claim 1 , wherein a thickness of each interface layer is greater than 150 μm, wherein the thickness is measured by Scanning Electron Microscopy (SEM) analysis where several and different areas from the samples were analysed and particle sizes were measured using Image J software from which the average particle size was calculated. 
     
     
         4 . The composite material according to  claim 1 , wherein the interface layer is free of defects when examined using optical microscopy at ×1000 magnification, and wherein the defects are pores or cracks. 
     
     
         5 . The composite material according to  claim 1 , wherein bonding between the WC grains and the manganese steel and between the (W,Ti)C grains and the manganese steel in the reinforcing zones is >99%. 
     
     
         6 . The composite material according to  claim 1 , wherein each of the reinforcing zones has a volume of between 30-75 cm 3 , wherein the volume is measured using X-ray diffraction. 
     
     
         7 . The composite material according to  claim 1 , wherein at least 90% of the WC grains in the reinforcing zones have an irregular prismatic shapes. 
     
     
         8 . A wear part comprising the composite material according to  claim 1 . 
     
     
         9 . A method of producing the composite material according to  claim 1 , the method comprising the steps of:
 a) mixing together 65-98 wt % tungsten, 3-90 wt % titanium, 3-20 wt % carbon and 0-80% catalyst powders, wherein the catalyst powder is selected from Fe, Ni, Mo, Cr, W, Al, or a mixture thereof;   b) compacting the mixed powders together to form at least one compacts;   c) positioning and fixing at least one compact into an interior of a mold, wherein the distance between two neighbouring reinforcing zones is between 1-5 mm;   d) pouring molten casting manganese steel into the mold to surround the at least one compact to initiate a self-propagating high temperature synthesis (SHS) 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.