Figure 4 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Source publication
Crack defects in the girth welds of pipelines have become an important factor affecting the safe operation of in-service oil pipelines. Therefore, it is necessary to analyze the factors affecting the safe operation of pipelines and determine the ultimate load during pipeline operation. Based on the failure assessment diagram (FAD) method described...
Context in source publication
Context 1
... multiple cracks exist, the interaction of each crack with the adjacent cracks should be assessed based on the original size of each crack, and, if necessary, combined into a single crack. Based on the combined crack method in BS 7910, a circumferential surface defect was assumed to exist on the outer surface of the pipe girth weld (Figure 4). ...
Similar publications
Digitalisation trends of Industry 4.0 and Internet of Things led to an unprecedented growth of manufacturing data. This opens new horizons for data-driven methods, such as Machine Learning (ML), in monitoring of manufacturing processes. In this work, we propose ML pipelines for quality monitoring in Resistance Spot Welding. Previous approaches most...
Citations
... For the technical staff, in the daily process of large diameter long distance pipeline construction, they need to pay more attention to the process of the welding process. In the process of welding to promote defects or quality problems, corresponding technical researchers need to take timely remedial measures to remedy defects, to ensure that the daily use of large diameter long-distance pipeline safety performance will not be affected [1][2][3][4][5][6][7]. In order to be able to make the use of large diameter long distance pipelines play a more important role in the process, in order to ensure the use of large diameter long distance pipeline safety performance, technology researchers tried on large diameter long-distance pipeline daily use process, quality inspection and safety performance on a regular basis to check, large diameter long distance pipeline transportation quality can gain greater protection. ...
In this study, the performance test and defect anatomy analysis were carried out for a girth weld of the pipeline. The results of the girth weld tensile test, groove hammer break test and Vickers hardness test showed no obvious abnormality, and the impact toughness and bending test results were not ideal. In the conventional inspection process, it was found that there were tiny unfused girth welds at 6 o 'clock and 9 o 'clock positions, and the maximum direction size of defects on the wall thickness section was 1.57 mm. The defects at the position from 6 o 'clock to 7 o 'clock found by on-site X-ray detection were identified as the existing non-fusion defects by anatomical analysis, and should be considered as the root of incomplete welding defects that could not be completely eliminated during repair welding. The length and height of the defects are 9 mm and 1.38 mm.
... Long-distance oil and gas transportation pipelines and station and yard facilities pipelines are almost completed by the welding process. [1][2][3][4][5][6][7] The welding quality directly affects the service safety of pipeline and station and yard facilities along the line. A welding joint was found to have excessive defects in the inspection process of the pipeline. ...
The suspected circumferential weld defects found in the pipeline inspection process were tested and studied. It was found that there was slag inclusion in the girth weld at 9 o’clock, which had not been found in the early stage or in the laboratory nondestructive testing process. The defects are most likely due to incomplete slag removal between layers and low welding wire energy. There was a root crack at the 6 o’clock position of the weld, and the crack length was 10 mm, which was close to the original film and the detection result of excavation. The misjudgment of the field rebeat and the laboratory test results may be caused by the pits in the weld cover and the bottom weld. The crack is caused by the crystal crack formed along the middle of the columnar crystal during the solidification process of backing welding due to the increase of residual stress caused by the reduction of welding layers and the group stress caused by the steel tube.
