Study On High Chromium Cast Iron Reinforced By Tungsten Carbide

WC reinforced iron-based wear-resistant composite materials are widely used in mining,metallurgy,construction and other industries.In order to solve the problem that the distribution of reinforcing phase is difficult to control in the preparation process of such composites,this paper adopts the combination of prefabricated reinforcing phase array and vacuum casting and osmizing to prepare WC bar reinforced high-chromium cast iron composites.The rule of microstructure evolution and its influence on properties were analyzed.Different methods were used to prepare WC arrays.Combined with vacuum infiltration,WC rod(YG8)reinforced high chromium cast iron with controlled reinforcement distribution was prepared.The WC rods are evenly distributed in the composite material.The interface of the composite layer has no void-like defects.The interface is well combined.The reaction between the WC rod and the high-chromium cast iron generates a transition layer.The length of the transition layer inside the WC is 120?m.The contact interface reaction mainly produces the compound Fe3W3C.The hardness of the composite material increases in the vicinity of the WC rod.Through the analysis of friction and wear experiments,it can be found that the wear performance of the composite material is about 4 times higher than that of the pure high-chromium cast iron material.The fracture mode of high-chromium cast iron is brittle fracture,while the composite material has a few ductile fracture points in the bonding zone.WC cemented carbide rods can effectively enhance the wear resistance of high chromium cast iron and protect the high chromium cast iron.At the same time,the high chromium cast iron matrix effectively supports the hard alloy rods.The combined effect of the two to improve the wear resistance.The WC particles(YG8)reinforced high chromium cast iron was prepared by spark plasma sintering.The particle size of WC particles was 20 mesh and 300 mesh,the content was 25 wt.%,30 wt.%,35 wt.%,and the sintering temperature was 1080?.The interfacial reaction produces a transition layer,and all Fe3W3C carbides are precipitated,so the the reinforcing phase and the matrix bonded well.The hardness of the composite increases with the content of WC particles.When 300 mesh WC particles are added,the abrasion resistance of the composites with the content of 25 wt.%,30 wt.%,and 35 wt.%is about 5 times,7 times,and 9 times that of high-chromium cast iron;20 mesh WC is added In the case of granules,the wear resistance of the composites with 25 wt.%,30 wt.%,and 35 wt.%is about 8 times,10 times,and 11 times that of high-chromium cast iron.The fracture modes of the sintered specimens are all brittle fractures.With the increase of the content of WC particles,the areas of toughness fractures in the sintered specimens increase and the toughness increases.WC particles are compounded with high chromium cast iron.The unmelted alloy particles interact with the precipitates after melting to play a supporting role.Under the combined effect of precipitation strengthening and particle strengthening,the wear resistance of the composite material has improved.