The paper is devoted to identifying features of structural non-homogeneities formation in dissimilar welded joints of carbon steel 20 to corrosion-resistant austenitic 12Kh18N10T steel, obtained by tungsten inert gas welding (TIG), as well as studying of their influence on the mechanical characteristics of welded joints under static and cyclic loading. Differences in the formation of a diffusion carbide interlayer in weld metal alloyed with nickel and manganese are established. When austenite is alloyed with nickel, bulk carbon diffusion occurs, while in manganese austenite boundary diffusion becomes the main mechanism for carbon diffusion, which occurs mainly along grain and sub-grain boundaries of austenite. As a result of mechanical tests, it was established that under static tension welded joint works under conditions of strengthening by a soft (ferritic) layer due to the restraint of transverse deformations by more solid (carbide) layer. The limits of soft interlayer dimensions, under which the softening of welded joint does not occur, are established that will allow to proceed to the extreme temperature-time parameters of heat treatment and operation of welded joint.

An improved method for calculating the minimum permissible electron beam welding (EBW) speed with continuous penetration is described. Calculations are carried out to construct nomograms for determining the welding speed in relation to the thickness of the welded joint and the width of the vapour-gas channel for 40Kh13 steel, 5V titanium alloy and D16 aluminium alloy. To confirm the efficiency of the proposed method, the results of experiments with EBW with continuous penetration at different welding speeds are presented.

The results of studies of magnetic and thermoelectric properties of pearlite, martensitic and austenitic steels are given. The magnetization curves for the materials under study, as well as dependences of absolute thermoelectric power on the material temperature are obtained. The data of magnetic induction changing at the control points above the welded samples during EBW are achieved. The simulation of the magnetic field distribution during electron beam welding of dissimilar steels under the conditions of the thermopower currents generation is carried out. The shape of the electron beam being deflected in the magnetic field of thermoelectric currents is calculated. The calculated values are compared to the experimental results.