The Paton Welding Journal, 2014, №02



2014 №02 (04)

DOI of Article 10.15407/tpwj2014.02.05

2014 №02 (06)

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The Paton Welding Journal, 2014, #2, 37-41 pages

ELECTRON BEAM WELDING OF LARGE-SIZE THICK-WALL STRUCTURES OF MAGNESIUM ALLOYS

V.M. NESTERENKOV and A.A. BONDAREV

E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
In the nearest future in erection of space platforms and other large-size thick-wall structures the application of light magnesium alloys will be challenging. Therefore, the investigations on their updating and evaluation of a feasibility of producing the quality welded joints are urgent. In this work the results of experimental investigation of weldability of magnesium MA2 alloy of 100 mm thickness by electron beam and optimizing the technology of manufacture of large-size structures of this alloy are described. The variants of preparation and treatment of surface of edges to be welded and areas of base metal adjacent to it before welding are offered. From the results of penetration of metal across the whole thickness of the plate and metallographic investigations of peculiarities of weld formation, the optimal conditions of welding by accelerating voltage, beam current, focusing current, scanning parameters, deepening of focal spot and spatial butt position were established. The technical documentation was worked out and ready-metal assembly-welding stand was manufactured to perform assembly for EBW of billets of plates of 3000 Ф 3000Ф 100mm size. To prevent defects in external formation of joints, it was offered to use cover plates on the face side of a butt and backings on the side of a weld root, which are arranged along the whole length of a butt and manufactured of the same alloy. They should be fastened to the product to be welded on the tacks made by argon arc welding just after assembly on the stand. Considering the results of carried out investigations the plate structure of 3000 Ф 3000 Ф 100 mm size was manufactured of magnesium MA2 alloy using EBW. 5Ref., 3Tables, 6 Figures.
 
 
Keywords: electron beam welding, magnesium alloys, large thicknesses, large-size structures, cathodes of welding guns, optimal welding parameters, coefficient of strength of joints, ultrasonic testing
 
 
Received:                10.11.13
Published:               28.02.14
 
 
References
1. (1978) Magnesium alloys: Refer. Book. Vol. 1: Metals science of magnesium and its alloys; Vol. 2: Technology of production and properties of castings and deformed semi-products. Moscow: Metallurgiya.
2. Olshansky, N.A., Khokhlovsky, A.S. (1985) Properties of EB-welded joints of aluminium and magnesium alloys of large thickness. In: Actual problems of welding of nonferrous metals. Kiev: Naukova Dumka.
3. Nazarenko, O.K., Matvejchuk, V.A. (2012) Influence of violations of welding gun axial symmetry on focal spot position. The Paton Welding J., 7, 38-41.
4. Paton, B.E., Nazarenko, O.K., Nesterenkov, V.M. et al. (2004) Computer control of electron beam welding with multi-coordinate displacements of the gun and workpiece. Ibid., 5, 2-5.
5. Bondarev, A.A., Nesterenkov, V.M. (2013) Study of weldability of MA2 magnesium alloy by electron beam in vacuum. Kompres. Mashinostroenie, 2, 21-28.

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