Study On Qualification Of Large Forgings' Hole Seaming And Self- Concrescence In Cooling Process

Large forgings are mostly basic parts of most large or key equipment and devices used in development of economy construct, national defence industry and modern science project. Its throughput and technique level is one of the mostly symbol which can weigh the development level of country's heavy industry. In this article, aimed at the commonness technique problem consist in the production of large forgings, have made a deep research on the seaming of interior hole defects of large forgings. This has important significance to the production quality of large forgings for the future.Constituted physical simulation model of holes defects'forging process, we made press experiment of the hole-defect sample on the Gleeble-3500 material test equipment. Analyzed distortion process of holes defects in the forging process and microcosmic conformation of critical-close holes'interface. Based on the contact dynamo action of holes'close interface, we constituted high temperature diffusion physical model of the close holes'interface that under the effect of pressure or distortion. Used press seal experiment of glazed-surface sample to simulate the seaming process of close holes, educed the connection of holes seaming and pressure, temperature, heat preservation.Adopted the method of finite-element simulation, we constituted the finite element model of large forgings after forging, researched the time distributing curve of the pressure and temperature of the large forgings'cooling process after forging. Use the seaming qualification of close holes that educed by physical simulation as criterion, we elected the best cooling technique for the sample after forging by simulating changes of interior pressure, temperature and so on the thermodynamics parameter on different cooling condition.To validate the veracity and reliability of finite element simulation method, we made the physical experiment of forgings cooling in the air. By contrast with the finite element simulation result, their temperature fields distributing aremostly consistent, validated the reliability of finite element simulation method.In this article we have researched the high temperature diffusion seaming process of holes defects in large forgings, constituted the criterion for repair of interior defects in large forgings, educed the best cooling technique for the forgings after forging and before heat treatment. The research harvest have instructional effect to repair interior holes defects in large forgings and improve the quality of large forgings.