基于芯棒控制的空心轴类零件楔横轧精确成形与控性制造技术基础研究

A new precision forming method based on mandrel-controlled cross wedge rolling for hollow shafts, which are the lightweight parts commonly used in automobile, high speed trains, tractors, engineering machinery, and motor, is proposed in the project. The new method can realize precision forming of outside diameter and inside diameter of hollow shaft at same time, while get better the microstructure and property. It is a new method characterized by lightweight, precise, and high efficient for near net forming of hollow shafts..Studying the basic scientific problem involved in the mandrel-controlled precision cross wedge rolling and property control of hollow shafts in depth and systematically, via theoretical analysis, numerical simulation and material simulation experiment combined with rolling experiment. The effects and mechanism of the mandrel-controlled precison cross wedge rolling will be studied throughly, and the control law of process paramaters on the coordination deformation of outside diameter and inside diameter of hollow shaft will be revealed..A unified viscoplastic constititutive model will be developed by considering the effects of strain hardening, static recovery, static recrystallization, dynamic recovery, dynamic recrystallization, and grain growth. The multiscale simulation technology will be employed to investigate the physical mechanism and the mechanical mechanism of the geometric accuracy changes of the outside diameter and inside diameter of hollow shaft take place. This study can reveal the control law of process paramaters on the coordination deformation of outside diameter and inside diameter of hollow shaft, and the relationship between macroscopic deformation, microstructure evolution and mechanical properties will also be revealed in the rolling process. .Then, the control method of geometric accuracy and microstructure performances will be proposed to provide a scientific basis for the development and application of the new precision cross wedge rolling for the hollow shafts.

针对轻量化发展所需的空心轴类零件，提出了一种基于芯棒控制的空心轴类零件楔横轧精确成形控性制造新技术，在实现空心轴件外形精确成形的同时实现轴孔的精确成形，并实现材料微观组织性能的控制，是一种轻量化、精密化、高效化的空心轴类零件近净成形新技术。.采用理论分析、数值模拟、材料模拟实验与轧制实验研究相结合的方法，开展空心轴轧制成形过程中芯棒作用机制的研究，揭示基于芯棒控制的空心轴轴孔与轴径协调变形控制规律。建立综合考虑应变硬化、静态回复、静态再结晶,动态回复、动态再结晶和晶粒长大影响的大变形粘塑性本构模型与微观组织演变模型。开展空心轴轴颈与轴孔轧制成形尺寸精度波动的物理、力学机制研究，揭示工艺条件、宏观精度、微观组织相互作用规律。提出空心轴类零件几何精度和组织性能控制方法，为空心轴类零件精确轧制成形控性新技术开发和应用提供理论指导。

针对轻量化发展所需的空心轴类零件，提出了一种基于芯棒控制的空心轴类零件楔横轧成形成性制造新技术，在实现空心轴件外形精确成形的同时实现轴孔的精确成形，并实现材料微观组织性能的控制，是一种轻量化、精密化、高效化的空心轴类零件近净成形新技术。.采用理论分析、数值模拟与实验研究相结合的方法，开展空心轴轧制成形过程中芯棒作用机制的研究。揭示了基于芯棒控制的空心轴轴孔与轴径协调变形控制规律，建立了外径与内孔瞬时减径量的表达式。空心轴在模具与芯棒的作用下发生减径与壁厚减薄变形，空心轴内径随外径减径而逐渐减小，由于壁厚在发生压缩减薄变形的同时发生圆周方向延伸变形，使空心轴内径与外径同时周向增大，发生一定程度扩径轧制作用。.揭示了轧件内孔螺旋痕的形成机理，分析了芯棒尺寸对轧件内孔螺旋痕的影响规律。内孔螺旋痕是由于已变形区受相邻变形区金属纵向变形拉动作用而发生径向位移所产生的。随着相对芯棒直径的增加，内孔表面螺旋痕越来越不明显，芯棒直径对轧件内表面螺旋痕的形成有明显抑制作用，芯棒直径越大抑制作用越明显。提出了空心轴类零件几何精度和组织性能控制方法，为空心轴类零件精确轧制成形控性新技术开发和应用提供理论指导。.建立了综合考虑应变硬化、静态回复、静态再结晶,动态回复、动态再结晶和晶粒长大的微观组织演变模型。揭示了空心轴楔横轧成形过程中，芯棒相对直径、轧制温度以及坯料相对壁厚对空心轴楔横轧微观组织演变的影响规律。.项目研究取得系列成果：完成了2个空心轴精确轧制成形控性的实验室样件的开发试制；技术成果（专利）转移1项，经费收入70.0万元；申请与获授权国家发明专利22项，其中获授权专利10项；申请与获授权国际发明专利4件，其中获授权（美国、欧盟）专利2项；发表学术期刊论文23篇；做大会特邀报告1个，参加国际学术会议4人次，做分组学术报告4个；培养博士研究生5名，培养硕士研究生6名；获北京市科技进步一等奖1项。