大型对焊法兰四点弯曲JCO成形新工艺

Four-point bending JCO process:a new technology for forming large butt welding flange

提出一种大型对焊法兰四点弯曲JCO成形新工艺,该工艺无需预弯工序,且具有成形道次少、形状精度高和模具柔性化程度高等优点。采用相似性原理,将大型法兰环形件按照1∶15的比例缩小,利用有限元模拟软件ABAQUS对大型对焊法兰四点弯曲JCO成形过程进行数值模拟,得到了摩擦系数、凸模圆角半径和凹模圆角半径对卸载前弯曲半径的影响规律,并且通过调整凸模跨距和凹模跨距,将模拟成形法兰环形件的椭圆度控制在约0.5%。通过物理实验对成形工艺的可行性进行了验证,实验法兰环形件的最大椭圆度<3%,满足工程实际要求。

This paper presents a new forming process for large butt welding flange, which has unique advantages of the dispensing with crimping process, fewer forming steps, better forming quality and higher flexibility. According to the theory of similarity, the large flange is scaled down in accordance with the ratio of 1 ： 15. The simulation model of the four-point bending JCO process is developed. Base on the simulation, the effects of the punch radius, the die radius and the friction coefficient on the bending radi us before unloading are obtained. Through the adjustments of the punch span and die span, the ovality of the formed flange could be controlled as 0. 5 %. Finally, the physical experiments are carried out, and the maximum ovality of the flanges is less 3 %, which completely meets the requirements of the project and shows feasibility of the four-point bending JCO process.