Magnetic Quenching Process Of Thermal Elastic-plastic Constitutive Equation And Its Numerical Simulation,

In this paper, based on a heat conduction governing equations involves variant thermal physical properties, phase transformation, sub-cooling boiling boundary and the effect of magnetic field which is obtained in earlier work, according to the theory of thermal non-elasticity, heat transfer, phase transformation and electromagnetic, taking advantage of the abnormal phenomena of heat expansion coefficient of iron-magnetism nearby the Curie terrperature and magneto-elasticity, a new constitutive equation considering effects of phase transformation is proposed. And then, the change of elastoplastic matrix, parameters of material mechanics performance with temperature were considered, from thermal elastoplastic constitutive relation and applying the theory of thermal elastoplastic increment, the theoretical finite element equation was established.Using the large-scale FEM analysis software ANSYS to simulate the quenching process by additional magnetic field of 45 steel workpiece, and the distributing of transient thermal stress and residual stress are obtained and the influencing factors on the thermal stress are analyzed and discussed. Through the calculation, we make out that additional magnetic field reduces the sample's internal stress and diminish the residual stress and deformation, so we can get a workpiece with high mechanics properties.In the course of experiments, we measure the tensile strength, impact strength and hardness of the sample. The result of experiments show that after magnetic field quenching, the hardness of sample waves slightly, but its plasticity and tenacity increased significantly, i.e. we can get a workpiece with high synthesis mechanical properties by means of magnetic quenching.Through the results of calculation and experiments, we can discover that when using magnetic quenching, internal texture stress low, deformation and residual austenite less and mechanic properties better. So the study of magnetic quenching has more extensive perspective. Meanwhile, we also can discover that utilizing heat transfer theory and computer technology to simulate magnetic field quenching process is feasible. The corresponding result is fit to practicality measuring value. It proves that the method used in this paper is correct by and large.