Predict the flow stress of the hardness for AISI 4340

Micro-machining technology has gradually become the frontier and hotspot of modern scientific research. The flow stress described by high strain, strain rate, and temperature is usually applied to simulate the machining process under various conditions. In this work, a novel method to predict the flow stress for various hardness of AISI 4340 was proposed using the micro-milling process simulation. The phase fraction for different hardness is calculated combined with a Johnson-Cook (JC) constitutive model to develop flow stress mathematics model, and then the model is modified and used to simulate the micro-milling process and predict the cutting force in different depths of cut. All results showed a good agreement with the experimental data. The research also provides a reference method for predicting the flow stress of other materials.