Influence of Heat Treatment on Friction and Wear of Ductile Iron: Role of Chromium and Nickel

In the present work the effect of heat treatment on friction coefficient and wear of ductile iron containing chromium and nickel was investigated. Heat treatment processes applied in the present work were normalizing, compressed air quenching, oil quenching, water quenching, and austempering. The tribological behaviour of the tested specimens was evaluated by scratch test through measuring scratch width, friction coefficient and hardness. The experimental results showed that the highest hardness values of GGG 60 were displayed by test specimens quenched in water and air. Friction coefficient of as-cast DI displayed the highest values. Oil and water quenched test specimens showed the lowest friction coefficient. Minimum wear was displayed by test specimens quenched in oil followed by that quenched in water. Cr-DI showed significant increase in hardness after heat treatment processes. Maximum hardness was displayed by water quenched specimens (600 Hv). Specimens quenched in oil displayed the lowest friction coefficient, where the highest value did not exceed 0.2. Oil, water and compressed air quenched specimens showed the lowest wear. Finally, heat treated specimens of Ni-DI showed significant increase in hardness. Normalized specimens displayed the lowest values of friction followed by oil, water and compressed air quenched specimens. Normalized as well as oil, water and air compressed quenched test specimens of Cr-DI and Ni-DI showed reasonable values of friction coefficient and wear which recommend them for wide application.