Technological aspects for formation of defects during welding of main pipelines

2020 ◽  
pp. 343-348
Author(s):  
A.E. Filyakov
Keyword(s):  
Arc Welding ◽  
Welded Joint ◽  
Arc Voltage ◽  
Energy Parameters ◽  
Lack Of Fusion ◽  
Transverse Vibrations ◽  
Slag Inclusions ◽  
Effi Ciency ◽  
Main Pipelines ◽  
Welding Processes

During the construction of main pipelines, welding is the main source of the formation of defects, therefore, to minimize them, monitoring and documentation of welding are performed. Analysis of the characteristic defects of the welds showed the dominance of internal formation defects in the form of pores, slag inclusions and lack of fusion. It is established that the main reason for the formation of such defects is craters on the surface of previous passes, which are formed during arc breaks or underestimated range of electrode transverse vibrations. To increase the effi ciency of monitoring for the arc welding processes with fi xing the current and the arc voltage, it is proposed to develop special intelligent module that estimates the parameters of electrode transverse vibrations, change in the energy parameters of the arc, and based on these data predicts the probability and place of formation of defects in the welded joint.

Virtual study of conditions for occurrence of non-metallic inclusions under consumable-electrode multiple-pass welding of pipe-lines

2020 ◽  
pp. 488-493
Author(s):  
A.E. Filyakov ◽  
S.I. Poloskov ◽  
V.A. Erofeev ◽  
M.A. Sholokhov
Keyword(s):  
Arc Welding ◽  
Complex Oxides ◽  
Slag Inclusion ◽  
Causal Factors ◽  
Lack Of Fusion ◽  
Slag Inclusions ◽  
Diffi Cult ◽  
Metallic Inclusions ◽  
Side Face ◽  
Arc Current

The causal factors for the occurrence of non-metallic inclusions in the form of slags, complex oxides and sulfi des under multi-pass arc welding analyzed. It is assumed that lack of fusion in interlayers and slag inclusions are formed on the surface of the beads of previous passes if slag residues in craters exist arising from short interruptions of arc burning, or lack of fusion at bevelled edges. The virtual study is carried out using physical and mathematical model, the features of which are fi xing the level of the melt at the solidifi ed front of the weldpool and introducing into it description of non-metallic inclusions fi lling cavities in the surface crater or lack of fusion at the side face of the groove. The results of numerical simulation of the remelting process of slag residues in different welding modes and with different sizes of slag inclusion are presented. It is shown that, with signifi cant depth of craters or lack of fusion, comparable with the thickness of the deposited layer, it is diffi cult to create conditions for their rise to the surface of the weldpool even at the maximum permissible arc current.

Features of arc welding of thin plates with various welding processes.

1988 ◽  
Vol 57 (3) ◽  
pp. 164-170
Author(s):  
Akihiko Ihochi ◽  
Tokuji Maruyama
Keyword(s):  
Arc Welding ◽  
Thin Plates ◽  
Welding Processes

Limitations of the Schlieren technique for shielding gas flow visualization in arc welding processes

2021 ◽  
Author(s):  
Mateus Barancelli Schwedersky ◽  
Álisson Fernandes da Rosa ◽  
Marcelo Pompermaier Okuyama ◽  
Régis Henrique Gonçalves e Silva
Keyword(s):  
Flow Visualization ◽  
Arc Welding ◽  
Gas Flow ◽  
Shielding Gas ◽  
Schlieren Technique ◽  
Welding Processes

Advanced submerged arc welding processes for Arctic structures and ice-going vessels

2016 ◽  
Vol 232 (1) ◽  
pp. 114-127
Author(s):  
Pavel Layus ◽  
Paul Kah ◽  
Viktor Gezha
Keyword(s):  
Case Studies ◽  
Arc Welding ◽  
Oil And Gas ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
The Arctic ◽  
Correct Selection ◽  
Advantages And Disadvantages ◽  
Welding Processes ◽  
Submerged Arc

The Arctic region is expected to play an extremely prominent role in the future of the oil and gas industry as growing demand for natural resources leads to greater exploitation of a region that holds about 25% of the world’s oil and gas reserves. It has become clear that ensuring the necessary reliability of Arctic industrial structures is highly dependent on the welding processes used and the materials employed. The main challenge for welding in Arctic conditions is prevention of the formation of brittle fractures in the weld and base material. One mitigating solution to obtain sufficiently low-transition temperatures of the weld is use of a suitable welding process with properly selected parameters. This work provides a comprehensive review with experimental study of modified submerged arc welding processes used for Arctic applications, such as narrow gap welding, multi-wire welding, and welding with metal powder additions. Case studies covered in this article describe welding of Arctic steels such as X70 12.7-mm plate by multi-wire welding technique. Advanced submerged arc welding processes are compared in terms of deposition rate and welding process operational parameters, and the advantages and disadvantages of each process with respect to low-temperature environment applications are listed. This article contributes to the field by presenting a comprehensive state-of-the-art review and case studies of the most common submerged arc welding high deposition modifications. Each modification is reviewed in detail, facilitating understanding and assisting in correct selection of appropriate welding processes and process parameters.

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