Preparation And Properties Of WC Particle Reinforced High Chromium Cast Iron Composites

Wear causes material loss and energy consumption.At present,the annual domestic consumption of metal wear-resistant materials come up to 700t.It not only consumes a large amount of metal materials,but also has a great impact on energy consumption and environmental pollution.High-chromium cast iron is currently the most common used type of wear-resistant cast iron and is widely used in the preparation of wear-resistant parts.But improving the wear resistance of high-chromium cast iron becomes inevitable in the face of more complex working conditions and national energy conservation and environmental protection requirements.The composites can combine the excellent plasticity and good formability of the matrix with the bearing capacity and rigidity of the reinforcement,and have comprehensive properties unmatched by a single metal,including high strength,good abrasion resistance,corrosion resistance,creep resistance and improve stiffness.WC particles have high hardness,abrasion resistance,good wettability and corrosion resistance in combination compared with high-chromium cast iron.With rich tungsten reserves in China and low cost,WC particles are ideal for high-chromium cast iron.Enhancements.This article uses casting WC preform particles and YG-8 cemented carbide particles as reinforcement,by controlling different particle size and adding quality,using stirring casting method to prepare WC particle reinforced high-chromium cast iron composites.The microstructure morphology,mechanical properties and wear resistance of the fabricated composites were studied and the following conclusions were obtained:1.Preform preparation process:200 mesh cast WC granules,150 mesh high carbon ferrochromium,300 mesh iron powder according to 40wt.%,50wt.%,10wt.%ratio were chosen as reinforcement,using zinc stearate,polyvinyl alcohol saturated solution as a binder.After evenly mixed by ball milling for 30 minutes and the mixed particles were pressed under a 200t press to form a compact.With a heating rate of 10o{Al,2007#40}C/min,they were incubated at 450℃ for 1 h and at 1000 0C for 1 h to prepare cast WC pellet preforms with high bonding strength and density similar to that of high chromium cast iron.2.Adding 3wt.%,5wt.%,and 7wt.%of WC particles with 40 mesh,80 mesh and 120 mesh cast WC preform particles to the high chromium cast iron by stir casting method to fabricate WC particle reinforced high chromium cast iron composites.Different reinforcements were prepared by adding 3wt.%,5wt.%,7wt.%,and 9wt.%of YG-8 cemented carbide particles with particle sizes of 20 mesh,40 mesh,80 mesh,and 120 mesh respectively to high chromium cast iron.Content of hard alloy particles reinforced high chromium cast iron composites.By comparison with the fabricated composites,the addition of the two reinforcements has strong similarities.There is precipitation of carbides of Fe3W3C at grain boundaries.The grain size,hardness and impact toughness of the composites are added along with the amount of reinforcing particles increased slightly,and there was no apparent relationship with the number of mesh particles added.The impact fracture is mainly brittle fracture mechanism,but some ductile fracture regions appear with the increase of the reinforcement.3.Abrasion resistance tests were carried out on composite materials of two different reinforcement types.It was found that the wear resistance was significantly improved,and the wear resistance was not significantly related to the size of the reinforcement particles.With the increase in the amount of reinforcement added,the amount of wear of the composite material gradually decreases.Both reinforcement have the same effect on the improvement of the material wear resistance.When the mass content of the cast WC particles is 7wt.%,the wear resistance is 2 to 3 times higher than that of the high-chromium cast iron matrix,and when the cemented carbide content is 9wt.%,the resistance is 3 to 4 times higher than that of high chromium cast iron.The main mechanism for the improvement of the wear resistance of the composites is the combined effect of precipitate strengthening and particle strengthening of undissolved reinforcement particles and formation precipitate.