Tungsten carbide composite lining material for centrifugal casting and tungsten carbide composite lining layer

摘要

PURPOSE:To improve the wear resistance, thc corrosion resistance and the strength of the inner surface of a cylinder of an injection molding machine at a low cost. CONSTITUTION:In a tungsten carbide composite lining material for centrifugal casting having the composition consisting of 30-45% tungsten carbide, 35-50% (in total) of nickel and cobalt, =1% molybdenum, =10% chromium, 1-3% boron, =2% manganese, 8-25% iron, =1% carbon, powder of spherical tungsten carbide of 6-12mum in mean grain size are used. The coefficient of thermal expansion of the lining material is smaller than that of the material to be lined by the difference of 3X10-6 deg.C. The coefficient of cubical expansion of tungsten carbide in the lining layer is 25-45%, and the grain spacing is 8-20mum in mean free path. The inexpensive centrifugal casting method forms thc lining excellent in the wear resistance, the corrosion resistance and the strength on the inner surface of a cylinder. The attackability to the counterpart can be reduced by adjusting the shape and grain size of tungsten carbide, and the machinability can also be improved.