Key Techniques on Cylinder Block Production of High Strength Grey Iron
Three key techniques are discussed to manufacture 300 MPa high strength cylinder block castings.The first one is the design of grey iron chemical composition.The optimized chemical composition used for production is as follows(wt%): 3.20 ～3.30C,1.60 ～1.80Si,0.70 ～1.00Mn,S 0.10,P 0.06,0.70 ～0.80Cu,0.25 ～0.35Cr,0.30 ～0.40Ni and 0.06~ 0.08Sn;the stream inoculation is adopted.The second is to increase the chilling effect of casting mold.A kind of ceramic sand mainly composed of electric fusion bauxite gives much stronger chilling effect,which can be used in the production of high strength cylinder block castings.The tensile strength can be 20 MPa higher compared with ordinary silica sand.The third is to use the technology of synthetic cast iron.The 300 MPa cylinder block is successfully produced if above three conditions are met.