大口径长输管道用弯管的设计制造

在国内外缺少适用于大口径长输管道用的大曲率半径的弯管设计、制造规范的情况下，建议在符合现有规范的条件下设计时，应考虑曲率半径的选取尽可能小，以减小所需变制设备、芯模的规格尺寸和空间场地；当弯管和与之相连的直管材质不同时，应在壁厚计算公式中乘以两种不同材质的屈服强度比值；为节省投资和合理利用钢材，应慎重确定弯管制造的壁厚减薄量；为保证弯头质量，在选材上不宜选用螺旋焊缝钢管，而应选用高强度低合金钢管或

On the Design and Fabrication of the Bends Used in Large Diameter Pipeline.

With the absence of national and international specifications for the design and fabrication of bend pipes with large curvature radius for large diameter pipeline, it is suggested that, as long as the current code can be satisfied , smallest curvature radius shall be selected so as to minimize the sizes of the equipment and moulds for bend fabrication. When the bend and its adjacent straight line are of different materials , the wall thickness of the bend shall be multiplied by the ratio of their yield strengths. Bend wall thickness shall be reduced with care so as to cut down steel consumption. Longitudinally-welded (rather than spiral seamed) bend pipes of high strength and low alloy steel shall be used to guarrantee bend quality. Many more advantages exist in hot pushing pipes than in hot bent pipes : uniform wall thickness, small roundness,and no fold.