在300KN摆辗机上对国内粉末台金制品中常用的Fe-Cu-C烧结体进行了自由摆辗镦粗实验。实验结果表明，粉末烧结体在摆辗过程中的成形性能较低。通过测定烧结体在辗压破坏前的高度方向压缩率和径向扩展比，得出了在摆辗过程中烧结体的高径比和初始密度对自由镦粗变形的影响规律，并对实验数据进行了回归处理。

在中国国家自然科学基金项目《锻造成形微观组织优化方法研究及应用》资助下，为提供一种控制锻造成形制品微观晶粒尺寸的理论方法和途径，开展基于变形均匀性的锻造过程微观组织优化研究。 认为，锻造生产除保证产品的基本形状要求，更重要的是通过材料的塑性变形提高产品的综合机械性能。因此，金属塑性成形过程微观组织模拟与优化研究具有应用价值。 在描述金属在高温塑性变形中组织变化机制基础上，提出材料在热锻成形过程中动态再结晶、静态再结晶，以及晶粒长大等微观组织演变机理。金属塑性变形是以位错运动来实现的，随着变形的进行，位错密度不断增加，高位错密度聚集的能量使材料处于不稳定状态。对于低层错能金属（碳钢）的热塑性变形，因其动态恢复缓慢而不能充分消除高密度层错能。动态恢复之后紧接着会出现动态再结晶现象。未能经过动态恢复和动态再结晶充分软化的金属停止变形后，其组织将发生静态再结晶。再结晶过程完成后的新组织是亚稳定的，为获得更稳定的组织，需要释放晶粒内部的潜能。因此，再结晶完成后，要发生进一步的晶粒长大来减少单位体积内的晶界面积。 认为锻造过程的变形均匀性对微观组织具有重要影响。锻造过程中存在着变形场、应力场、应变场，以及温度场的变化，这些场量的综合作用决定了变形体变形的均匀程度。从锻造过程微观组织演变过程看，无论是动态再结晶、静态再结晶，还是晶粒的长大，其晶粒尺寸的变化除了与材料特定的特性参数以外，都是应变速率、应变和温度的函数，即晶粒尺寸直接决定于变形过程中的应变场、应变速率场，以及温度场。锻件变形越均匀，整个变形体内部的应变场、应变速率场以及温度场等的分布也越均匀，其晶粒组织也越趋于一致。 对与锻造过程变形均匀性相关的指标进行数学描述，包括应变梯度的定义及其数学描述，任意应变与平均等效应变差的平方和的定义及其数学描述。为有效衡量变形均匀程度，提出变形均匀因子的概念和定义，给出变形均匀性因子的物理含义和数学表达。 以变形均匀性为基础，给出形状控制子目标函数、温度均匀性子目标函数、变形均匀性子目标函数，以及晶粒度细小均匀子目标函数的数学定义，并通过无量纲化处理构建出实现形状控制和微观组织晶粒度细小均匀的多目标函数。 以材料高温成形微观组织演变机理为基础，与刚塑性有限元热力耦合数值模拟技术相结合，以锻造过程工艺参数及预成形模具形状作为优化设计变量，以变形均匀性和微观组织晶粒度细小均匀为优化目标，建立锻造成形过程微观组织优化体系，开发出基于微观遗传算法和灵敏度分析方法的锻造过程微观组织优化软件系统（MOSForge）。 利用MOSForge，进行典型热镦粗和H 型锻件锻造工艺参数和锻造预成形模具形状的优化实验，实现锻造过程微观组织晶粒度细小均匀控制。平板热镦粗工艺参数优化使平均晶粒尺寸下降20µm；结合预成形形状的优化，热镦粗成形的平均晶粒度下降66µm；H 型锻件预成形模具形状的优化，使得平均晶粒尺寸下降25.2 µm。上述实例应用中不但晶粒尺寸得到细化，而且晶粒度的分布均匀程度也得到明显提高。

The deformation of a ring workpiece by the rotary forging process is analyzed using a three-dimensional rigid

In order to obtain high property powder metallurgy products, at present rotary forging process has often been used to further densify the sintered powder compact, but the densification law and property analysis have very rarely been studied, therefore the densification laws of sintered powder compacts being composed of Fe-0.8%C-4.0%Cu-0.2% zinc stearate and formed as cylindrical shape by double action pressing, and then further densified as well in a rotary forging process was studied by orthogonal experiment and regression analysis. The experimental results show that the H/D ratio and the rotary forging force are major factors affecting the density of the sintered powder compacts in the rotary forging process. The effect of the H/D ratio and the rotary forging force on the density were discovered. By determining both the density and the hardness of compacts, it was found that the density distributions show no difference from the hardness dis-tributions and that the gradients of the density and the hardness in the axial direction are larger than those in the radial di-rection.

The support shaft is a key part in the automobile industry. Its annual production quantity is usually very large. The current manufacturing process is conducted with much machining work including drilling the hollow, which results in a great waste of material. This paper gives a new manufacturing method by the implementation of extrusion processes. It can not only save much material but can also improve properties of the support shaft. The new manufacturing processes include a two-stage extrusion process. A reasonable preform shape was determined through finite element based simulation. Thewhole forming process is simulated and verified by the finite element method using the DEFORMTM system. The die designs of the two extrusion processes are also given. The two-stage extrusion process and related die designs were recommended to one forging company that presently manufactures the support shaft with the traditional method.