[en] A study was made on change in geometrical parameters of bath during welding of thin plates of vanadium and tungsten alloys in helium by nonconsumable electrode. Analytic relations enabling to perform engineering calculations for choosing optimal parameters of bath were determined at high accuracy

[en] Effect of nitrogen on structure, phase composition and mechanical properties of compounds made with welding by means of a nonconsumable electrode in inert helium and argon atmosphere with controlled content of active impurities has been investigated. It is established that with exceeding the nitrogen concentration of 1:10^-1% in the protective welding atmosphere the intense saturation of weld metal with nitrogen occurs. It is shown that the increase of nitrogen content in weld metal causes the increase of welded joint cold brittleness temperature which reaches 413 K at 10% volumetric share of nitrogen in helium and 553 K-at 20% of N₂ in argon. Electronmicroscopic and probe analyses were used to investigate the nature of defects and phases formed in weld metal during its saturation with nitrogen. Correspondence between structural transformations and mechanical properties of welded joints have been established

[en] Peculiarities of weld formation in low-alloyed chromium during arc fusion welding in controlled helium atmosphere have been investigated. Dependence of structure nature on welding rate has been established. Favourable weld shape and a low level of residual stresses are obtained on samples welded at 2.8-5.6 mm/s rates. The investigations carried out permit to differentiate crystallographic and structural orientations of cast crystallites in a weld as well as different processes responsible for their formation

[en] Mechanical properties of low-alloyed chromium welded joints produced at welding rates of 2.8, 5.6, 11.2, 22.4 mm/s have been studied during bending test in the ductile-britte transition temperature range. The dependence of cold brittleness temperature on welding rate has been established. The welding rate increase from 2.8 up to 22.4 mm/s decreases the cold brittleness temperature from 330 to 210 K, that is considerably below the Tsub(c) value for base metal (305 K). The welded joint fracture obtained at different welding rates takes place in definite zones independently of the test temperature. The welded joint ductility produced at low welding rates does not exceed corresponding properties for base metal. The low-alloyed chromium welds strength is at the level of values for base metal and is not essentially dependent on a welding rate