论文部分内容阅读
数值模拟对轧制、锻造及挤压等体积成形过程的研究具有重要作用。我们模拟常用材料的成形过程是为了还原材料,并且找到可能的缺陷。在近来的研究课题中,几种变形材料如镍基合金引起了我们极大的兴趣。为了采用尽可能少的成形道次得到坯料形状,必须优化成形条件。由于径向锻造机不能过载,718合金的成形性能受到限制。就径向锻造而论,该设备的工艺参数,例如温度、锤头速度、坯料进给速度、锻件旋转角度、锤头形状及摩擦等必须精确协调。变形过程的结果随设备工艺参数而变化,本文利用DEFORM3DCOGGING(tm)模拟718合金的径向锻造。坯料经过4道次从大约280mm的原始直径锻造成最终直径224mm。由于坯料在第一道次后弯曲,使得数值模拟很复杂。弯曲的原因主要由锤头、操作机与坯料的接触情况引起。于是,一些合适的参数如单元数、网格对称性、操作机的位置及移动距离需要精确设定。此外,还需要改变锤头的运动性能。在成形过程中,需要研究成形力、温度和金属流动。
Numerical simulation of rolling, forging and extrusion volume forming process plays an important role. We simulate the forming of common materials in order to reduce the material, and find possible defects. In recent research projects, several deformation materials such as nickel-based alloys have aroused great interest. In order to obtain a blank shape with as few forming passes as possible, the forming conditions must be optimized. Due to the radial forging machine can not be overloaded, 718 alloy forming performance is limited. For radial forging, the process parameters of the equipment such as temperature, hammer speed, stock feed speed, forging rotation, hammerhead shape and friction must be precisely coordinated. The result of the deformation process varies with the process parameters of the equipment. In this paper, DEFORM3DCOGGING (tm) is used to simulate the radial forging of 718 alloy. The billet was forged 4 times from its original diameter of about 280 mm to a final diameter of 224 mm. Because the blank is bent after the first pass, the numerical simulation is complicated. The main reason for the bending is caused by the contact of the hammerhead and the manipulator with the billet. Thus, some suitable parameters such as number of cells, grid symmetry, manipulator position and travel distance need to be precisely set. In addition, the need to change the hammer performance. In the forming process, the need to study the forming force, temperature and metal flow.