Study on the relationship between permeability, hardness of ferromagnetic structure and quenching, tempering temperature

Abstract

Taking 40Cr steel round bar specimens as the research object, the magnetic permeability characteristics and material hardness of the specimens under different quenching and tempering temperature conditions were measured. The relationship model between magnetic permeability signal, hardness and heat treatment temperature is established. The results show that within a certain quenching temperature range, the magnetic permeability signal and material hardness of the component are related to the quenching temperature and tempering temperature. The magnetic permeability signal decreases with the increase of the quenching temperature and increases with the increase of the tempering temperature; the hardness of the material increases with the increase of the quenching temperature, and decreases with the increase of the tempering temperature. The relationship between the permeability signal and hardness and the quenching and tempering temperature is explored, which can provide a reference for determining the performance, structure and heat treatment temperature parameters of the component based on the hardness and permeability signal.