长输管道焊缝的内应力分析

从钢管壁上任意一点的环向应力入手,分析了长输管道焊缝的内应力。该内应力由环向应力和轴向应力构成,据此推导出了焊缝处的合成应力。通过直缝与环缝处的应力比较,得出了直缝承受压力最大、环缝承受压力最小、螺旋焊缝介于二者之间的结论。认为管径和壁厚在所受压力相同的条件下,若管道发生爆裂,其爆裂起点一般不会位于螺旋焊缝处,因而螺旋焊缝管的安全性优于直缝焊接管。计算表明,在上述条件相同的情况下,若采用螺旋焊缝管,其管壁厚度可以相应减薄,能够节省投资,提高经济效益。

Internal Stress Analysis of ihe Welds Seam in Long Distance Pipeline

Internal stress of welds seam for long distance pipeline is analyzed starting with any point of circumferential stress on pipe wall. The internal stress is consisting of circumferential stress and axial stress, from which the compound stress of the weld seam is derived. Through comparing stresses oh longitudinal seam, and circumferential seam, it is concluded, that the longitudinal seftm has highest pressure-bearing capacity , the circumferential seam lowest, while the spiral seam goes in between the two . It is considered that the explosion origin generally is not located at the spiral seam if explosion occures in the pipelines with same diameters, same wall thickness, and also same pressure as in longitudinal welded pipe. As a result, the safety of the spiral welded pipe is helieved higher than longitudinal welded pipe. The calculations show that wall thickness can be reduced accordingly if the spiral welded pipe is used in the same case said above, and the capital can be saved to increase economical benefits.