Research On Inverse Calculation Of Temperature Condition In Free Forging And Thermal Insulation Method

Heavy forgings are the key parts and products of major technology and equipment in the industry, such as electric power, nuclear power and petro chemistry. To a great degree, its manufacturing capacity, technology level and quality represent a country's level of economic development. To manufacture high quality heavy forgings, free forging is the only way to choose. It is very important to research the free forging process. As key process parameters, temperature conditions in free forging direct influence the heavy forging's quality and property. Especially, contact heat transfer coefficient between the forging and die is the main element. To obtain contact heat transfer coefficient(IHTC), finite element simulation and inverse heat conduction problem method are applied to solve the problem based on experiments. If IHTC can be obtained by these methods, process parameters of temperature conditions will be forecasted exactly, then contribute to plan a practical forging process.Based on finite element simulation and inverse heat conduction problem(IHCP) in the article, Tikhonov regularization method and MSC.MARC were applied to identify IHTC between the forging and die. The main work is as follow:1. Heat conduction of forging process was investigated, and transient heat transfer finite element method in forging process was deduced. A new regularization functional was established for solving the IHTC based on Tikhonov regularization theory. The expression of regularization parameter was deduced by a-posteriori strategy. And the solution procedure of the regularization functional was deduced by Taylor's formula, Newton-Raphson iteration method.2. Contact heat transfer experiment and upsetting experiment is implemented, and the measured temperatures are requisite input data to the IHCP. Tikhonov regularization method and MSC.MARC were applied to identify IHTC. The results indicated the Tikhonov regularization method had high precision and stability.3. Based on heat conduction theory and numerical simulation, thermal insulation method for heavy forging was designed. Alumino-silicate fiber felts were used to reduce contact heat transfer. And aluminum skirt-set insulation was designed to reduce convection heat transfer between forging and air and radiation heat transfer on forging surface. Free forging process with skirt-set insulation was simulated by MSC.MARC, and compared to the free forging process without insulation. The results indicated the skirt-set insulation had a good effect.