Automatic Welding, 2016, №03



2016 №03 (06)

DOI of Article 10.15407/as2016.03.07

2016 №03 (08)

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Avtomaticheskaya Svarka (Automatic Welding), #3, 2016, pp. 49-56
 

Development of technology of mechanized arc welding in repair of pressurized main gas pipeline

O.I. Olejnik, S.Yu. Maksimov, A.P. Paltsevich And E.I. Goncharenko

E.O. Paton Electric Welding Institute, NASU. 11 Kazimir Malevich Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
Abstract
Complex of investigations was carried out on development of a technology of mechanized gas-shielded arc welding applicable to repair of main gas pipelines by reinforcing structures. Determined are the conditions for prevention of pore formation in welded joints due to break of gas shield under effect of wild blast. The tests were made with weld metal of the butt and lap-butt joints, welded using modern flux-cored wires and solid wire Sv-08G2S. Effect of butt joint welding practice on mechanical properties and impact toughness of the weld metal is shown. Influence of factors, determining a risk of cold crack formation in welded joints from X70 strength class low-alloy steel, is investigated. It is determined that Sv-08G2S, E71T-1 and DW-A55 welding wires correspond to the requirements on providing a necessary level of mechanical characteristics and impact toughness of weld metal, content of diffusion hydrogen in deposited metal and can be recommended for further technology approval under conditions of field repair of in-service pipelines. Main recommendations on the welding practice of butt and lap-butt welded joints and approximate modes of welding in different spatial positions are stated. 19 Ref., 6 Tables, 7 Figures.
 
Keywords: main gas pipeline, arc welding, welded joints, flux-cored wire, cold cracks, pre-heating, diffusion hydrogen
 
Received:                02.02.16
Published:               28.04.16
 
 
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