基于BS 7910的焊缝缺陷剩余寿命分析方法

Residual life analysis method of weld seam with defects based on BS 7910

周道川¹;  王艳婷²

1. 山东省天然气管道有限责任公司;
2. 天然气榆济管道分公司

ZHOU Daochuan¹;  WANG Yanting²

1. Shandong Province Natural Gas Pipeline Co. Ltd.;
2. SINOPEC Yu-Ji Pipeline Company

BS 7910; 焊缝缺陷; 非穿透裂纹; 剩余寿命

BS7910; weld defect; non-penetrating crack; residual life

为预测油气管道焊缝的剩余寿命,对非穿透裂纹的扩展机理及焊缝缺陷寿命预测方法开展了研究,提出以累加法为指导思想,结合BS 7910-2005中失效评定图(FAD)判据,且基于非穿透裂纹扩展模型的动态焊缝剩余寿命计算方法,使用C#语言编制程序实现了具体算法,计算分析了某管道焊缝缺陷的非几何参数对焊缝寿命的影响规律。分析计算结果表明:缺陷的长、短类型,即缺陷的深度与长度之比对缺陷所能承受的循环载荷次数有较大的影响;如果缺陷属于短缺陷,对应不同的缺陷相对深度,缺陷所能承受的循环载荷次数均逐渐减少;如果缺陷为长缺陷,缺陷所能承受的循环载荷次数均呈现先减少后趋于不变的趋势。

To estimate the residual life of pipeline welds, this paper discuses the mechanism of non-penetrating crack growth and the technique to predict the life of weld seam with defects. Accordingly, a dynamic method to calculate the residual life of weld seam is proposed, on the basis of the build-up method and the failure assessment diagram (FAD) indicated in BS 7910-2005, as well as the non-penetrating crack growth model. The C# programming is successfully applied to achieve a specific algorithm and also calculate and analyze how the non-geometric parameters of weld defects of an oil and gas pipeline affect the life of weld seam. The calculation results indicate that the type of defect (long or short), i.e. the ratio of the depth and length of defect, has significant impacts on the number of cyclic loading to be accepted by the defect. In case of short defect, its number of cyclic loading will reduce gradually as a function of relative depth. In case of long defect, its number of cyclic loading will decrease and then tend to be stable.