【作者】 王梦寒；

【导师】 周杰；

【作者基本信息】 重庆大学 ， 材料加工工程， 2005， 博士

【摘要】 支撑座是铁路货车转向架上的关键及重要部件,其产品质量和性能对铁路货车提速、重载有着重要影响。支撑座产品目前在世界上广泛采用铸造工艺成形。近年来,随着铁路运输对重载、高速要求的提高,对关键部件支撑座的性能要求也在提高,铸钢支撑座产品存在的固有缺陷(铸钢件本身的机械性能、疲劳韧性、抗冲击性能都不高,铸件产品无法避免地存在气孔、缩松、夹杂、裂纹等)对铁路高速安全运行已构成威胁。提高支撑座产品的综合机械性能是中国铁道部为解决铁路运输所面临的重大改革和结构性调整,实施重载、提速、安全的发展技术,提高运输效益和效率的需要解决的重大课题。为确保铁路货车提速后运行的安全性和可靠性,论文创造性地提出了对支撑座进行铸改锻的工艺方案,以提高其综合机械性能。由于原铸钢支撑座产品形状复杂,精铸的支撑座产品存在高筋、薄壁的结构,给支撑座铸改锻带来加大困难。为了缩短锻钢支撑座新产品的开发周期,降低新产品开发成本,论文采用数值仿真技术对支撑座进行产品结构改进和成形工艺优化。本文的主要研究内容和结构如下: 在对结构有限元分析中的关键技术问题进行深入研究的基础上,利用通用有限元分析软件ANSYS,首次对铁路车用转8AG 支撑座进行了结构力学分析,分别得出了铸钢(材料为ZG25Mn Ni)支撑座零件和锻钢(材料为Q235D)支撑座零件在工作负荷作用下的应力、应变分布,通过有限元软件ANSYS 分析计算,优化了锻钢支撑座的结构及形状尺寸,对转8AG 锻钢支撑座零件结构进行了改进,有效地提高该零件的安全系数,为工艺设计提供了技术依据,并以此指导其它同类锻钢支撑座零件的结构改进。在对转8AG 支撑座锻造过程三维刚塑性/刚粘塑性有限元模拟分析中关键技术问题进行深入研究的基础上,利用塑性成形模拟软件DEFORM-3D,首次对转8AG 支撑座锻造过程进行了模拟,分析了坯料在成形过程中的金属流动规律及力学量场分布情况,对数值模拟中的一些关键技术问题进行处理。通过对支撑座锻造成形过程的不同工艺方案进行数值模拟,优化了支撑座的锻造成形工艺方案。首次采用并实现了一模两件,左、右支撑座合二为一的锻造新工艺及新方法。以转8AG 支撑座为研究对象,采用改进后的支撑座结构和优化的锻造工艺方案对锻钢支撑座进行了生产试制,试制结果表明:采用一模二件锻造工艺成形支撑座,工艺可行、支撑座锻造工艺方案与模具设计合理,支撑座产品性能稳定可靠,并推广应用到其它同类转K2、转8G 等型号的锻钢支撑座的开发制造。更多还原

【Abstract】 Supporting pedestal, whose product quality and property have a significant influence on speedup and heavy load of railroad lorry, is the key part of railroad lorry bogie. At present, the products of supporting pedestal are widely formed by the casting technology in the world. In recent years, with the advanced requirements for speedup and heavy load from rail transport, the advanced requirements for the property of supporting pedestal have been proposed. The inherent defectivenesses which include the low mechanical property, low fatigue ductility and low shock resistance of cast-steel product, and the avoidless gas cavity, shrinkage porosity, inclusion, crack, etc in cast-steel product, existed in the product of Cast-steel supporting pedestal, have threatened the high speed and safe running of railroad. Thus, improving the comprehensive mechanical property of supporting pedestal is a grave thesis need to be solved by the Ministry of Railways of China for solving the grave reform and structural adjustment confronted by the rail transport, implementing the advanced technology of heavy load, speedup, and safety, and increasing the transport benefit and efficiency. In order to insure the safety and reliability of running after railroad lorry speedup, a technology that the supporting pedestal is formed by forging instead of casting has been proposed in this thesis to improve the comprehensive mechanical property of supporting pedestal. As the cast-steel product has complex shape and the precise formed cast-steel product has a structure with high rid and thin wall, it is quite difficult to implement the technology of forming supporting pedestal by forging instead of casting. For the sake of reducing the development cycle and cost of the new product, the thesis adopt numerical simulation to improve the product structure and optimize the forming process. The main researches and results are as follows: On the basis of deep research of the key technical matters of structural finite element simulation, the structural mechanics analysis is performed for the railroad lorry turn 8AG supporting pedestal for the first time, using the universal finite element analysis software ANSYS. From the analysis, the stress distribution, strain distribution and safety factor of cast-steel (material is ZG25MnNi) product and forging-steel (material is Q235D) product under workload are obtained respectively. Through the analytical calculation of finite element software ANSYS, the structure and shape dimension of forging-steel supporting pedestal is optimized, the structure of turn 8AG forging-steel product is improved, and the safety factor of product is increased effectively, which provide the technical basis for technology design, and give the guidance for the structure improvement of the other similar forging-steel product. On the basis of deep research of the key technical matters of three-dimensional rigid visco-plastic finite element simulation of the turn 8AG supporting pedestal’s forging process, the simulation is performed for the forging process of turn 8AG supporting pedestal for the first time, with the plastic forming simulation software DEFORM-3D. From the simulation, the flow law of metal and the distribution of mechanical field in the blank’s forming are analyzed, and some key technical matters in the numerical simulation are handled. Through the numerical simulation for the different technology of supporting pedestal’s forging process, the forging technology of forging-steel supporting pedestal is optimized, and a new forging technology and method that two forging-steel products formed in one die and left and right supporting pedestal united as one is adopted and realized for the first time. The turn 8AG supporting pedestal is taken as the study object, and the pilot production of forging-steel supporting pedestal is performed with the modified structure and the optimized forging technology. The results of the pilot production suggest that adopting the forging technology that two products formed in one die is feasible, the forging technology and die design are reasonable, the property of product is stable and credible, and the technology is also spread and applied for the development manufacture of other forging-steel supporting pedestal with the similar type such as turn K2, turn 8G, etc. Failure theory, forging theory, numerical simulation, etc are applied comprehensively in this thesis, the research results of which is a successful example for high and new technology upgrading the traditional forging industry. The researched forging-steel supporting pedestal, whose technology is advanced, scheme is novel, has been ranked as the technological innovation item of Chongqing Science and Technology Committee in 2003. With the research of this thesis, the conclusions are as follows: ①The structural finite element stress analysis is performed for the forging-steel supporting pedestal product with ANSYS for the first time. From the analysis, the structure and shape of the supporting pedestal is optimized, and the structure improvement of product is realized. ②The simulation analysis is performed for the forming process of the forging-steel supporting pedestal with the three-dimensional simulation softwareDEFORM for the first time. From the simulation, the forging technological parameters of the forging-steel supporting pedestal are optimized, and the new forging technology and method that two forging-steel products formed in one die and left and right supporting pedestal united as one is adopted and realized for the first time. ③The pilot production of the product whose structure and technology have been optimized is performed. The results of the pilot production suggest that adopting the forging technology that two products formed in one die is feasible, scheme and die design are reasonable, and the property of product is stable and credible. ④With the numerical simulation technology, the technology that the supporting pedestal is formed by forging instead of casting is realized, and the mechanical property and safety of the product are improved. ⑤The research results of the thesis have been applied for the mass production of the supporting pedestal product successfully, which provides a successful example for the information technology updating and advancing the traditional forging, and bring the remarkable economic benefit and social benefit to the enterprises. Regarded by identify-committee organized by Ministry of Education, the research method of the thesis is advanced, the analysis is reasonable, and the design development of the forging-steel product of the railroad lorry bogie supporting pedestal is solved with digital design and simulation. The research results are placed with the leading position in domestic field.更多还原