The effect of grain size and hardness of wrought Alloy 718 on the wear of cemented carbide tools

The effects of grain size and hardness of wrought Alloy 718 on the wear of cemented carbide tools were examined by measuring the actual progression of wear in a specific transverse turning operation. Four different conditions of the same material from the same batch were studied—fine grain material in the soft, solution annealed state and in the precipitation hardened state, and large grain material in the same two conditions. While flank wear, as expected, correlated strongly with hardness the effect of grain size was much more limited. A striking effect was that of the grain size on the notch wear – one of the limiting factors for tool life – which could be clearly related to the amount of burrs formed in the large grain size material both in the solution annealed and fully precipitation hardened condition. The influence of grain size and hardness on the deformed layer of the work piece material and on the morphology of the chips was clearly visible.