The article presents results of researches on manual arc welding efficiency development. It is proved that the arc welding inverter power source, compared with the diode rectifier, increases coefficient of transition of alloying elements into the weld joint; it also reduces the rate of alloying elements transition into slag and gaseous components and in addition reduces the harmful effects of welding on human organisms.

The given work considers the influence of the power supply type (diode rectifier DR-306 and inverter Nebula-315) upon the chemical composition, microstructure, mechanical properties of weld joints and upon health characteristics of the manual arc welding process.It has been ascertained that the power supply type has a significant influence upon the weld joints properties and health characteristics of the manual arc welding process. Using a new generation inverter power supply allows less heat input into the weld bead, thus, decreasing silicium and manganese burning, improving impact resistance of weld joints under low (negative) temperature and reduces the risk of respiratory diseases for the workers.

Experimental research has been carried out to determine quantitative content of solid and gas component of welding aerosol in mechanized gas-shielded welding with constant and pulsewise electrode wire supply. As a result, it has been established that the pulsewise electrode wire supply reduces the release of harmful components of welding aerosol (welding dust СО and SiO2) by 20-25% thanks to lower energy characteristics (the transfer frequency of electrode metal droplets and the time of their exposure to critical temperatures at a short-circuit).

This work aims to develop technical solutions that allow providing the specified parameters of the accuracy of the shape of parts in the cross-section during processing on a CNC machine. Experimental studies were performed on a screw-cutting lathe. An acoustic signal in the range from 6 to 12 kHz was used as a diagnostic sign to assess the wear of the cutting tool, since during preliminary studies, it was found that this range is most sensitive to changes in processing modes. Studies were performed at different values of wear of the cutting tool (estimated by the width of the wear chamfer). For estimating the life of a cutting tool, a neuro-fuzzy model has been developed. Using models of this class allows adjusting to specific conditions (machine, tool), and correctly evaluating the tool life. The model error for the test sample does not exceed 10%. The test results showed that using the proposed solutions makes it possible to increase the accuracy of the manufacturing of shut-off valve parts by 20-30%.

The paper investigates the effect of welding mode parameters on the uniformity of the deformation capacity of AISI 316 austenitic steel samples, namely, the influence of the welding current and purging gas consumption on the samples’ ability to perceive the force of cold cupping. Punch diameters of 3 and 8 mm were employed for the Erikson test to establish the dependence of the purge gas flow rate on the depth of the hole before the formation of cracks. The conducted metallographic studies confirmed an increase in the homogeneity of the dendritic structure in the weld zone due to the redistribution of heat input, as well as the absence of uneven grains and a decrease in the spread of grain sizes, which were in the range of 0.068–0.045 mm. The study resulted in determining the optimal range of technological parameters for the manufacture of flexible expansion elements to ensure their high operational properties.