关键词: 直缝埋弧焊管, JCO, 四点弯曲, 弹复, 曲率, 行程

Abstract:

This paper presented a new technology for forming LSAW pipes called by “four-point bending JCO process”. In the manufacture of LSAW pipes through this new technology, the end surface is a circle of equal curvature. Other advantages of the new technology include fewer steps in formation and higher productivity. The theoretical analysis was verified by the experimental results. These will provide a theoretical basis to control the forming curvature by adjusting the punch displacement during each stage of bending in real manufacturing. Both the theoretical and the experimental results show the linear relation between bending and forming curvatures, thus provide a convenient means to intelligent control over the four-point bending JCO forming process. Based on the above theory and with the help of the new technology, the ideal LSAW  forming pipe is obtained in only 13 steps. Since the traditional process entails 25 steps, productivity is significantly increased.

Key words: longitudinally submerged arc welding(LSAW), JCO, four-point bending, springback, curvature, punch displacement