This paper presents a full-scale deep-water steel catenary riser fatigue test system. The proposed system can carry out tests on risers, hoses, and subsea pipelines up to 21 m in length, ranging from 8 24 inches diameter. was realized by mechanical loading with control systems, could axial tension compression, bending moment, torsion, internal pressure simulate all load types risers or pipeline...

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...

In order to achieve integrated condition in the girth welding of high pressure natural gas transmission pipelines, the weld zones and its surrounding area should have good mechanical properties. Residual stresses are an important defect especially in the girth welding of the pipeline. In this study, two API X70 steel pipes (with spiral seam weld) of 56 inches outside diameter and 0.780 inch wal...

Pipe girth welds are prone to incomplete fusion problems in the automatic welding process of long-distance pipelines, which is often related temperature inhomogeneity weld bead. The narrow gap and micro-swing technique was applied pipeline construction improve quality. manuscript provides a detailed investigation with combination experiments numerical simulation. A swing strategy proposed accor...

Economical design with sufficient fracture resistance is of high importance in any offshore pipeline projects. Using an Engineering Critical Assessment (ECA), alternate acceptance criteria for pipeline girth weld inspection can significantly reduce the cost of constructing of offshore oil and gas pipeline by minimizing unnecessary repairs. Offshore pipelines consist of short pipeline segments c...

Some pipelines face global plastic straining due to the nature of their installation process or harsh environmental conditions during operation. The ability of the girth welds to withstand these plastic strains is often evaluated on the basis of wide plate tests. Key for the validity of these tests is a representative measurement of remote strain, mostly obtained by linear variable differential...

Residual stresses created from welding have a direct influence on fracture mechanisms of cracks and flaws in around welded regions. Excessive residual stress can lead to unexpected failures an important property fitness-for-service calculations. In this work, experimental database the low heat input austenitic girth welds is analysed for statistical correlation. The combined measurement profile...

In this work, the hydrogen fatigue of pipeline steel X60, its girth welds and weld defects were investigated through in situ testing. A novel gaseous charging set-up was developed, which involves a sample geometry that mimics small-scale with high internal gas pressure. The effect by measuring crack initiation growth, using direct current potential drop (DCPD) set-up, probes outer surface speci...