Two-dimensional finite element modeling procedures are addressed to predict the residual stresses for multipass welds. A generalized plane strain model with a five-pass weld in a plate and an axisymmetric model with a six-pass girth weld in a pipe are considered. Element rebirth and pass-lumping techniques are employed in both models. The combined heat input using surface and body flux componen...

Girth weld cracking is one of the main failure modes in oil and gas pipelines; girth weld cracking inspection has great economic and social significance for the intrinsic safety of pipelines. This paper introduces the typical girth weld defects of oil and gas pipelines and the common nondestructive testing methods, and systematically generalizes the progress in the studies on technical principl...

offshore pipelines are an effective tool for transportation of oil and gas which are usually assembled by the use of girth welds. since flaws may naturally exist at such welds, fracture assessment of girth welded offshore pipelines is substantial. current fracture assessment procedures like bs 7910 consider identical material properties for the weld and the base metals. however the strength dif...

Welding quality control is an important parameter for safe operation of oil and gas pipes, especially for high-strength steel pipes. Size control of welding defect is a bottleneck problem for current pipe construction. As a key part of construction procedure for butt-welding of pipes, pore defects in girth weld is difficult to ignore. A three-dimensional non-linear finite element numerical mode...

As part of a programme investigating the structural integrity of welds, the Digital Image Correlation (DIC) technique was used to obtain the full-field strain distribution during tensile testing of cross-weld specimens cut from a multi-pass girth welded pipe. The displacement maps were analyzed using Matlab scripts to compute local stress-strain variations from which the local proof stress valu...

As part of a programme investigating the structural integrity of welds, the Digital Image Correlation (DIC) technique was used to obtain the full-field strain distribution during tensile testing of cross-weld specimens cut from a multi-pass girth welded pipe. The displacement maps were analyzed using Matlab scripts to compute local stress-strain variations from which the local proof stress valu...

Multi-layer/multi-pass welding (MLMPW) technology is widely used in the energy industry to join thick components. During automatic welding using robots or other actuators, it is very important to recognize the actual weld pass position using visual methods, which can then be used not only to perform reasonable path planning for actuators, but also to correct any deviations between the welding t...

The complicated temperature field distribution during multi-pass single-layer weldbased rapid prototyping induces complex thermal stress evolutions and residual stress distributions. In this paper, a three-dimensional finite element model with temperature-dependent material properties is presented to investigate the temperature field and thermal stress distributions in multi-pass single-layer w...