含平底方形缺陷X80管线钢剩余强度的研究

Study of Residual Strength of X80 Pipe Used Steel with Flat Bottom Square Shape Defect

X80管线钢由于其优良的综合力学性能,越来越多地服役于石油天然气输送。X80管线钢在服役过程中,不可避免地受到各种腐蚀因素的影响,产生具有危险性的腐蚀缺陷,进而使管道材料的强度降低,寿命缩短,影响了管道运输的安全可靠性,并且会造成材料的浪费和对环境的污染。因此,笔者以X80管线钢平底方形缺陷作为研究对象,借助ANSYS有限元分析软件,通过改变缺陷长度、缺陷深度,考察其对最大等效应力和剩余强度和的影响;通过改变内压,考察其对最大等效应力和最大等效应变的影响,借助数学拟合的方法,对基于应变和基于应力管道的剩余强度与缺陷深度的关系进行拟合,所得结论对于X80管线钢剩余强度的求解有一定的指导意义。

In view of its excellent comprehensive mechanical properties, X80 pipeline steel is more and more used in petroleum and natural gas transportation. In its service, X80 pipeline steel is inevitably affected by various corrosion factors, and dangerous corrosion defects may be resulted, which will reduce the strength of thematerial, shorten the life of pipeline, affectthe safety and reliability of pipeline in service, and cause material lass and thepollution in environment. Therefore, in this paper, flat bottom square defect of X80 pipeline steel was used as studying material, by use of ANSYS finite element analysis software, the influences on maximum equivalent stress and residual strength were investigated by changing length and depth of defects, and the influences on maximum equivalent force and maximum equivalent strain were investigated by changing internal pressure. The fitting method was used to fit relationship between the residual strength based on strain and stress and thedepth of defect. The conclusions obtained have certain guiding significance for the determination of residual strength of X80 pipeline steel.