[en] Properties of Zr-2.5% Nb alloy joints, welded by electron beam and electric arc welding with different ersions of welding zone protection from ambient atmosphere were studied. Welded joint quality was evaluated with respect to gas concentration in weld metal, mechanical properties and weld formation. The structure and phase composition of welded joints were investigated. Electric arc one-pass welding with je protection of weld face and back can be used for jointing zirconium and its alloys of 3 mm thickness. The absence of film on metal surface can be the criterion of quality of joint zone protection. Oxygen content in weld metal is decreased during electron beam welding because of its vacuum extraction from metal. Electric arc welding in controlled atmosphere enables to conserve the concentration of gaseous alloying elements on the level of basic metal

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[en] Qualitative and quantitative content of introduction elements in solid solution of welds of sheet (the sheet is 1 mm thick) non-alloyed vanadium and alloy V-2.3 weght% Zr-0.3% C with additions of rare earth metals during welding in helium atmosphere with dosed nitrogen content have been determined. It is shown that vanadium alloying with zirconium results in the effective bonding of interstitials into the second phase. In the limits of solid solution oxygen is localized near vanadium atoms, and nitrogen - near zirconium ones, forming complexes of different complicacy. It is established that saturation of solid solution of welded joints of non-alloyed vanadium and alloy V-2.3 weight%, Zr-0.3% C with nitrogen with the change of its content in helium atmosphere from 10^-₄ to 1 vol.% is observed from 10^-₄ vol.% and increases sharply above 10^-₁ vol.%. Nitrogen content in the alloy solution is lower than in non-alloyed vanadium

[en] Technique of the protective atmosphere preparation with the minimum amount of harmful admixtures in microchambers for the arc welding of tube constructions of niobium, vanadium and molybdenum is studied. Preparation conditions ensuring the minimum level of harmful admixtures in the welding atmosphere are determined. It is established that the maximum effect is achieved during evacuation of the chamber and the product with simultaneous inert gas washing

[en] Experimental data characterising physicochemical properties of different areas of niuobium welded joint are processed, interpolation polynomials being derived on this basis. Main regularities of physical and chemical heterogeneity along the welded joint cross section are established. It is shown that local increase of dislocation density, micro- and macro-stresses values, interstitial impurity concentration into the heat affected zone promotes the embrittlement of this metal zone in consequence impact strength and resistance to crack propagation of welded joints decrease

[en] A study was made on the effect of crystallographic texture and structure on properties of Zr+2.5%Nb alloy sheets under heat treatment in α- and β-structural regions. Anisotropy of physicomechanical properties of initial sheets is determined mainly by crystallographic texture, which is preserved during annealing in α-region. Sheet annealing in β-region leads to removal of anisotropy of mechanical properties

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[en] Effect of a nitrogen content in helium protective atmosphere on the structure and cold brittleness temperature of welded joints of molybdenum alloys was studied. It is found that the optimum combination of ultimate strength, impact strength and ductility in molybdenum alloy welded joints can be obtained using helium with 1.2% nitrogen content

[en] Tendencies of Zr-2.5%Nb alloy welded joints to hydrogenation with various structural state were studied in sulfuric acid. Zr-2.5%Nb alloy welded joints independent of structural state were shown practically not to tend to hydrogenation in 0.9-50% sulfuric acid solution at elevated temperatures and pressure (450 K and 1.5 MPa). The welded joints preserved high stability of mechanical properties under samples static and impact bending in case of durable exposure in 3- and 50-% solution of H₂SO₄