Annealing process optimization of 3D coil core based on annealing simulation experiment and thermal mechanical coupling model

Annealing is necessary to reduce the residual stress and no-load loss of 3D coil core. In production, because monitoring the changes in temperature and stress of 3D coil core in real time is impossible, the trial and error method is usually used to formulate the annealing process parameters. The annealing simulation experiment of grain-oriented electrical steel (GOES) is carried out to explore the influence of soaking time on iron loss and magnetic flux density . The mechanical properties of GOES are tested, and the true stress–strain curves at different temperatures are obtained. Based on the existing research and experimental results, an anisotropic thermal mechanical coupling model of 3D coil core is established. An optimization scheme of 3D coil core annealing process is obtained, considering the temperature difference, stress and strain. According to the onsite measured parameters, the annealing process is simulated and optimized by the coupling model. Results show that the total annealing time is shortened by about 18.7% without increasing the stress and strain.