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...

I. Abstract: The prediction of the optimal weld bead width is an important aspect in shielded metal arc welding (SMAW) process as it is related to the strength of the weld. This paper focuses on investigation of the development of the simple and accurate model for prediction of weld bead width of butt joint of SMAW process. Artificial neural networks technique was used to train a program in C++...

Within the scope of increase in cutting tools efficiency, a CW CO;! laser beam has been used for butt welding sintered tips containing cobalt and tungsten carbide to a medium carbon steel core. After optimization of the laser processing conditions, full penetrating, sound and homogeneous welds are observed. Hardness is found to be nearly constant across the entire weld bead cross-section. Micro...

In the present research, friction stir welding (FSW) process was used for butt joining of pure copper plate to 316L stainless steel plate. Mechanical properties and microstructural characteristics of the joint were evaluated by microhardness and tensile tests as well as optical and scanning electron microscope (SEM). It was found that microstructure of the weld nugget (WN) has fine grains where...

This thesis presents a collection of theoretical and experimental investigations into various geometrical aspects of hybrid laser-MIG welding. The work is divided up into four parts; 1. A review of the hybrid laser-MIG welding technique with brief summaries of the three papers which make up the remainder of the thesis. 2. A paper entitled “Fundamental analysis of hybrid laser-MIG welding”. This...

To obtain a better joint quality in butt welding of aluminum, the gap filling process and quantification effects on molten pool characteristic bubble formation were realized by three-dimensional thermal-mechanistic-fluid coupled model, with consideration heat transfer, fluid flow, phase change recoil pressure. The model was validated synchrotron-radiation result. competition between solidificat...

Butt fusion is an effective method for joining high density polyethylene (HDPE) pipe on job sites. However, there is lack of quantitative methods to evaluate pipe joint quality. The objective of this study was to develop such a quantitative approach in order to determine the effect of joint contamination on the quality of the fused joints. The study included testing a total of 21 butt-fused HDP...