核电用异形锻件一体化成形工艺的仿真分析与研究

为了研究核电用异形锻件的一体化成形工艺,利用法国Forge锻造模拟软件对一体化封头类部件热成形工序进行数值仿真模拟分析。模拟结果表明:成形后期产生径向和轴向应力极值,最大径向拉应力为118.2 MPa,产生在封头穹顶(球冠)内表面处,同时该部位应变为1.05;最大轴向拉应力为30.6 MPa,出现在封头穹顶和连接过渡区近内壁处,同时该处的应变为1.63;按CockcroftLatham断裂准则,这两个部位有产生裂纹的风险。在对凹模(上模)进行局部优化后,模拟结果表明上述危险部位的应力、应变分布情况明显改善。因此,凹模(上模)边缘部位的圆角是此工艺的一项重要参数,对成形后的锻件质量有一定的影响。

Simulation analysis and research on integral forming process of profiled forgings for nuclear power

In order to study the integral forming process of profiled forgings for nuclear power plant, a numerical simulation of hot forming process for integral head forging was carried out by France Forge simulation software.The results show that the radial and axial stress extreme values happen at the later forming stage, and the maximum radial stress of 118.2 MPa and the strain of 1.05 appear on the inner surface of head dome (spherical).Meanwhile, the maximum axial stress of 30.6 MPa and the strain of 1.63 appear near the inner wall of the connection transition zone and the head dome.According to Cockcroft & Latham fracture criterion, the risk of cracking exists at the above positions.After the upper die being optimized locally, the simulation results show that the distributions of stress and strain at the above dangerous positions are improved.Therefore, the fillet of the upper die edge region is one of the important parameters and has a certain influence on the forging quality after forming.