预弯工艺参数对UOE焊管O成形的影响

采用有限元分析方法研究了焊管UOE成形技术预弯工艺参数——预弯弧度和预弯半径对O成形的影响。研究发现,预弯工艺可以改善板料O成形后的曲率分布,在预弯弧度大于25°时,O成形后管坯的边缘直边现象得到明显改善。随预弯弧度的增加,O成形后的管坯曲率逐渐趋于均一,但是成形载荷随预弯弧度的增加而增加。预弯半径为焊管名义半径的1.0～1.3倍时,可以获得较好的形状,过大或过小都会使O成形后管坯的曲率沿弧长方向急剧变化。在相同压缩率的情况下,在上述合理的预弯半径范围内所需成形载荷较大,但是在相同变形载荷下,采用上述预弯半径仍然可以优先获得较好的形状。

Effects of the parameters of prebending on O-forming of pipe in UOE process

Detailed finite element analyses were conducted on the effects of prebending parameters, prebending angle and prebending radius, on the O-froming in UOE process for welded pipe. The analysis shows that prebending process can improve the profile curvature of O-formed pipe. The curvature is markedly improved if the prebending angle exceeds 25 . With the increase of the prebending angle, the curvature of O-formed pipe inclines to homogeneous, while the forming force increases with the prebending angle. The profile of O-formed pipe can be optimized when the prebending radius is within 1.0 to 1.3 times nominal radius of pipe line. The curvature markedly changes along profile if larger or smaller radius is adopted. In the case of constant compress strain, the forming force is larger at the above favorable radius. However, in the case of constant forming force, the above favorable radius is still more favorable on the profile of pipe.