アルミニウムを 6mass%含有した鋳鉄の表面改質と耐摩耗性

抄録

  Flake graphite cast iron containing aluminum is known as a material having excellent heat-resistance. In this research, the characteristics of the surface modification process and the wear property of surface modified aluminum alloyed cast iron were investigated.
  When flake graphite cast iron containing 6 mass% aluminum was heat-treated at 1273 K in air, alumina precipitated at the positions where graphite existed, showing the same shape of flake graphite. The thickness of alumina dispersed layer reached about 1 mm by heat-treating for more than 72 ks at 1273 K. This material was evaluated by the pin-on-disk method, showing that it has excellent wear property compared to normal flake graphite cast iron. Surface modified layer showed excellent wear-resistance especially at a test speed of 1.0 m/s. Also, at a test speed of 0.1∼0.5 m/s, this layer showed wear resistance better than normal cast iron. Apparently the material surface transforms into an oxidized wear state due to the adhesion of oxides including alumina, resulting in improved of wear resistance.
  This is a new surface modification method applying decarburization of graphite and the easy oxidation feature of aluminum. This method is easy using only heat-treatment in air, and provides a possibility for cast iron to create new characteristics by substituting other substances for the graphite included.