Evaluation method used for residual intensity of X80 pipeline circumferential weld crack type defect

Abstract

The invention discloses an evaluation method used for the residual intensity of an X80 pipeline circumferential weld crack type defect. The evaluation method comprises the following steps that: 1) calculating the loading ratio of an X80 pipeline to be evaluated, and calculating the ductility ratio of the X80 pipeline to be evaluated, wherein the X80 pipeline to be evaluated is provided with the circumferential weld crack type defect; 2) according to the loading ratio and the ductility ratio of the X80 pipeline to be evaluated, drawing a data point in a coordinate system; and 3) constructing the critical failure assessment curve of an X80 pipeline circumferential weld sample, inserting the critical failure assessment curve of the X80 pipeline circumferential weld sample into a coordinate system in the 2), and evaluating the residual intensity of the circumferential weld crack type defect of the X80 pipeline to be evaluated according to the critical failure assessment curve of the X80 pipeline circumferential weld sample and the position relationship of the data point in the 2). By use of the method, the evaluation of the residual intensity of the X80 pipeline circumferential weld crack type defect can be realized.

Description

technical field [0001] The invention belongs to the technical field of pipeline design and manufacture, and relates to an evaluation method for the residual strength of crack-type defects in girth welds of X80 pipelines. Background technique [0002] As the weak environment of the pipeline transportation system, the girth weld is the most prone to failure. In 2014, a number of oil and gas pipeline girth weld leakage and rupture incidents occurred in CNPC Changqing Oilfield, Western Pipeline and other enterprises, causing relatively serious negative social impact and economic losses. According to the 2015 Fujian Gulei PX Explosion Accident Investigation Report, the direct cause was cracking of the pipeline girth weld. Therefore, ensuring the safe service of girth welds of oil and gas pipelines is an important task for all parties involved in pipeline operations. [0003] For the X80 gas pipeline, as the pipeline with the highest steel grade, the highest service pressure and...

AI Technical Summary

Problems solved by technology

In terms of steel pipe chemical composition, pipe making process, girth weld welding process, etc., the situation at home and abroad is not consistent, so the welding quality, especially the fracture toughness, is not the same. Therefore, the residual strength evaluation method proposed by international research, especially the crack type defect The critical failure assessment curve is not necessarily suitable for domestic X80 steel pipes and girth welds

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