PERFORMANCE CHARACTERISTICS OF NICKEL-CONTAINING STEEL STRUCTURES DURING MECHANIZED WELDING-SURFACING WITH MODIFIED (DOSED) ELECTRODE WIRE FEEDING

Purpose. To study and analyze in a comparative order the influence of factors of the controlled pulse process of electrode wire supply on some basic mechanical characteristics of seams and welded rollers in the processes of welding and surfacing of nickel-containing steels. Methods of research. The study the mechanical characteristics of seams and welded rollers was carried out using modern laboratory equipment and appropriate techniques. This made it possible to determine how the pulse feed parameters affect the strength characteristics of the weld and near the weld zone over the entire cross-sectional area of the weld or weld layer. Detailed characteristics of feed pulses were determined using a welding process analyzer to obtain oscillograms of power parameters of arc combustion with their analysis, including determining the stability of the arc process for different types of pulses. Important for the improvement of welding results is the controlled nature of the electrode metal transfer synchronous with the pulsed movement of the electrode. It is noted that the energy consumption of the arc process during the pulse supply of the electrode wire with an indication of its reduction compared to traditional welding. Experimental work was performed using a special electrode wire, which is usually used for welding and surfacing of nickel-containing steels. These processes were carried out in a protective environment of CO2 in automatic mode. Results. Due to the fact that the strength characteristics of the weld are among the most important, attention is paid to their definition and analysis. The strength characteristics depend on many parameters, in particular the thermal characteristics of the process, the structure of the weld metal, the presence of non-metallic inclusions and so on. All these factors were studied with the help of appropriate instruments, and on the basis of numerous comparative photos of microstructures on sections of the cross section. The analysis of the sections revealed the types of microstructures obtained, the presence of inclusions and more. It is determined, in particular, that the structure of weld metal in pulsed electrode wire welding differs significantly from the structure of traditional welding in reducing inclusions, finer grains, etc., which improves the mechanical properties of the weld and seam area. Scientific novelty. Based on a series of experimental studies, the use of pulse algorithms for the movement of the electrode wire with certain parameters in automatic mode for welding and surfacing of nickel-containing steels to improve the mechanical properties of seams and welded rollers. Practical value. It is determined that the method of pulse welding of electrode wire to the controlled variant, including nickel-containing steels is effective and can be widely used in industry using specially designed equipment that provides a suitable process with stronger characteristics.