Study on damage behavior of carbide tool for milling difficult-to-machine material

Abstract

Water chamber head is an important component of nuclear power unit, and the main material is 508 III steel of difficult-to-machine material, which has the characteristics of high hardness, high strength, high plasticity and high profile shrinkage, etc. During the milling process, the tool is subjected to the cyclic impact load, which make cutting force and cutting heat change violent and occurrence of tool damage failure accelerate. In this paper, the damage behavior of carbide tool for milling difficult-to-machine material is studied first, and then field experiment was carried out on 508 III steel material, tool failure modes were analyzed, which include impact damage and fatigue fracture, and the failure theory and the crack propagation of carbide material were investigated in the process of tool damage. Then, the impact damage model of carbide tool is established based on the classical strength theory, and the critical condition of impact damage is determined according to simulation analysis. Finally, the theoretical model of carbide tool fatigue life is established and the tool fatigue limit is analyzed. Theoretical basis and technical support are provided for the tool failure mechanisms analysis, life prediction, parameter optimization, tool design and development aspects during the study.