Simulate Research Of The Coupling Relationship Between Temperature Field And Thermal Stress Field Of Annealing Process In Full-hydrogen Bell-type Annealing Furnace

With the development of the national economy, the consumption of the cold rolling steel coil is increasing continuously, which asks higher requirement for the quality of the cold rolling steel coil simultaneity. The bonding defect of the cold rolling steel coil is universal in the bell type annealing technology. It is one of the long-term basis standing problems that puzzle the steel rolling researchers and engineers in all over the world.The origin of the cold strip coil cohesion was worked out systematically. The author thought that the pressure, temperature and time were the main causes. The most effective method is to reduce the pressure. The pressure is the thermal stress that arises from the uneven temperature field in the process of annealing. But the changes of the thermal stress effect the heat transfer and the distribution of the temperature field. There is a coupling relationship between the temperature field and the thermal stress.This paper analyzes the annealing process system and the heat transfer, and combined with the cause analysis of bonding defect and the production practice, on the basis of which the mathematical model of temperature field and thermal stress field are established. Heat transfer in different thermal processes, such as heating, heat preservation and cooling, is specified and analyzed in this thesis. According to the coil mechanical character which is anisotropy, the anisotropic axisymmetric two-dimensional non-stable thermal stress's computation model is established accurately and the coil boundary condition in each working procedure is ascertained in this paper. Through finite difference method the stress equation, thermal elasticity displacement equation and boundary condition are discretized, then the thermal elasticity displacement's finite difference equation and the stress finite difference equation are established. Coupling this thermal stress model and the two-dimensional conduction model by the coil radial conduction coefficient and the radial compress coefficient, the distributions of stress and temperature were obtained. Then the effects on the distribution of temperature and thermal stress caused by the two coefficients are analyzed.The research makes out that the steel coil distribution of temperature and thermal stress may be reflected by the mathematical models of thermal stress and temperature pretty well, which is helpful for the optimization of the coil annealing process in full-hydrogen annealing furnace.