WC Particles Reinforced Iron Matrix Surface Composites And Erosive Wear Properties Studies

This thesis fabricated successfully a WC particle reinforced iron matrix composite using a vacuum infiltration process for severely erosion and application in the slurry pump. The casting process was optimized. The microstructure and wear resistance were researched and analyzed. On the basis of these researches, a cover parts of slurry pump was produced successfully.The reinforcing effect has been researched, with WC of 40~60 mesh dimension and 10~52 wt % volume fraction. The matrices were grey cast iron and low chromium cast iron. The results show that, composite could be fabricated on the complicated surface by means of sodium silicate sand mold combination with vacuum infiltration process. When the substrate was 10 mm, composite layers reached 3 mm to 5 mm in thickness with high strength interface and less casting defect.Microstructures of grey cast iron and low chromium cast iron matrix composites with various volume fraction has been analyzed. The results show that, when the volume fraction of WC is 52 wt %, the matrix of interface structure is that of grey cast iron. The particles distributed hi the matrix of grey cast iron ,but some contact each other. The composite layer extend gradually into the substrate .When volume fraction of WC is 36 wt % and 27 wt %, the matrix of the composite is high chromium cast iron, consist of white carbide bars and the austenite. WC particles distributed uniformly, retaining approximately quondam granular form in the composite layer which has an evident interface area with the substrate, with good bonding strength.Erosive resistance of grey cast iron matrix composite has been investigated, on the condition of different volume fraction of WC and erosive angles and volume fraction of. The results showed that, the erosive resistance of composite with volume fraction of 27 wt % was the best; Volume abrasion rate ofcomposites with different erosive angles was maximum at 50 angle , but Volume abrasion rate was less at 0 and 70 angle; On condition of the same volume fraction of WC and larger size of quartz sand in slurry, volume abrasion rate increased.