Abstract: Considering the mechanics characteristics of AISI 4340 during micro scale machining,a constitutive model of AISI 4340 for micro milling is set up based on the Johnson-Cook constitutive model and strain gradient plasticity theory.And the simulation model of micro milling tool which made by cemented carbide is also built.The Arbitrary Lagrangian-Eulerian (ALE) adaptive grid technique is used to simulate micro slotting.The forces during micro slotting are obtained under different spindle speed and feed rate.The correctness of AISI 4340’s constitutive model is validated by comparing the predicted micro milling force with the corresponding experimental data.It provides the foundation for the further research of micro milling.

Key words: AISI 4340, micro slotting, Johnson-Cook material model, strain gradient plasticity theory, micro milling force