基于离心铸坯的双金属环件热辗扩成形基础理论与关键技术

A new method, centrifugal casting-ring rolling compound forming, to produce large bimetal rings was proposed. Theory analysis and thermal-mechanical simulation tests are used to research the thermo-mechanical behavior of different layer of casting billets(external layer, internal layer and intermediate composite layer). The microstructure evolution mechanics and thermo-mechanical condition of transformation from casting microstructure to forged microstrucutre will be ascertained. Diffusion theory, molecular dynamics simulation and thermal-mechanical simulation tests are used to research diffusion phenomenon between different layer, the diffusion mechanics will be revealed. The ability to deform and its influence factors of different layer metal will be studied. The influence rule of the process parameters on the integrate deformation of the different layer metals and diffusion between different layer will be determined. The integrate deformation condition will be obtained. The ring rolling process based on casting bimetal ring billets will be built. Two metals are bounded tightly at intermediate composite layer during ring rolling. High performance bimetal compound rings will be manufactured with the new short process process, and shape and performance will be controlled simultaneously.

项目提出并研究一种利用离心铸造环坯热辗扩成形大型双金属环件的新工艺。采用理论分析和热力模拟实验相结合的方法，研究离心铸造环坯内、外层和结合层金属的热力学行为，探明其组织演变机理和铸态组织转变为锻态组织的热力学条件；以固体扩散理论为基础、采用分子动力学模拟和热力模拟实验研究金属结合层的扩散规律，揭示其扩散机理；研究离心铸造双金属环坯内、外和结合层金属在热辗扩时的变形能力及影响因素，揭示热辗扩工艺参数对金属协调变形和层间扩散的影响规律，获得不同区域金属在热辗扩时的协调变形条件。制定离心铸造双金属环坯热辗扩工艺，实现热辗扩过程中双金属环件结合层的紧密结合，达到高性能双金属复合环件短流程控形控性一体化制造的目的。

项目提出并研究了一种铸辗复合成形大型双金属环件的新工艺。研究了40Cr/Q345B双金属离心铸造过程，得到了控制双金属充分冶金结合的离心铸造方法。利用热压缩实验和分子动力学模拟，研究并获得了环坯的热变形行为、组织演变规律以及界面元素扩散机理，推导了材料本构模型和动态再结晶模型。利用Abaqus软件进行了热辗扩过程模拟，得出了有利于双金属环件协调变形的热辗扩工艺参数。进行了双金属环坯热辗扩实验和热处理实验，获得的环件满足机械性能要求。项目提出了有效的双金属环坯铸造和热辗扩过程中界面结合和协调变形的控制方法，为新工艺的推广应用提供理论技术支撑。