Performance optimization for cemented carbide tool in high-speed milling of hardened steel with initial microstructure considered

• Critical parameters of the tool microstructure were determined using image analysis.
• The initial state of the tool was evaluated by micromechanics and damage mechanics.
• A new indicator was brought forward for cutting parameter optimization.
• An optimization method was proposed and it was validated by milling tests.

Investigation on cutting parameter optimization was performed to enhance the cemented carbide tool life in high-speed milling of hardened steel. Image analysis of the tool material microstructure was conducted to determine the average grain diameter and the size of the representative element. The initial state of the tool material microstructure was evaluated based on micromechanics and damage mechanics. Finite element simulation of the milling process was performed to acquire the tool stress. The original damage of the tool and simulated tool stress were integrated based on the concept of damage equivalent stress. Distribution and evolution of the damage equivalent stress on the tool body was analyzed and a new indicator for cutting parameter optimization was brought forward. A cutting parameter optimization method was proposed on the basis of the new indicator. Experimental tests showed that the proposed optimization method can be used to identify the optimum cutting parameter combination and prolong the cemented carbide tool life in high-speed milling process.