ОЦІНКА ВПЛИВУ ВМІСТУ АКТИВНИХ ГАЗІВ У ПОРОШКУ НА МЕХАНІЧНІ ВЛАСТИВОСТІ ЗАГОТОВОК ДЕТАЛЕЙ, ОТРИМАНИХ МЕТОДОМ ПЛАЗМОВИХ АДИТИВНИХ ТЕХНОЛОГІЙ

Purpose. Analysis of the influence of powder quality (content of active gases) on the level of mechanical properties of workpieces produced by plasma additive technologies. Research methods. Chemical composion of the powders was determined in accordance with regulatory document. The presence of non-metallic inclusions and contaminants in the powders was determined visualy. To quantify the oxygen in the powders, the vacuum extraction method was used in accordance with ДСТУ ISO 4491-4:2016. Oxygen and nitrogen gas analyser TC 500 (company LECO). Before being loaded into the dosing unit, all powders were dried in an oven (temperature - 250°C, for 1 hour). Samples (size 130×70×14 mm) were produced by additive growth by plasma powder surfacing (PPS) on a specialised robotic device STARWELD 190H. The chemical composition of the grown samples was determined by the spectral method using a SPECTROMAX optical emission spectrometer according to standard methods in accordance with ГОСТ19863.1-19863.12. The content of nitrogen and oxygen in the deposited metal was determined in accordance with TC 500 (company LECO). Microstructural analysis were carried out on the samples in the longitudinal and cross directions before and after heat treatment, after etching in a reagent for electrowinning of heat-resistant alloys (Н3РО4 – 800 ml +CrО3 – 100ml). The mechanical properties of the alloy were obtained on standard cylindrical samples according to ГОСТ 1497-84, ГОСТ 1497-84, ГОСТ 10145-81s. Results. The chemical composition of the deposited metal is determined by the chemical composition of the powder. The content of oxygen and nitrogen in the deposited metal is determined by the content of these elements in the powder itself, as well as by the protection of the weld pool with argon. It has been established that in the alloy ЭП-648ВИ when the powder contains nitrogen in the amount of [N] ≥ 0.03 wt. %, or oxygen in [O] ≥ 0.02 wt. % in the deposited metal at a temperature of 1100 °C, a significant decrease in its deformation capacity (ε ≤ 3.8 %) is recorded, which under the influence of thermal stresses leads to the appearance of hot cracks, and as a result, we see a significant decrease in the strength and plasticity in the longitudinal direction. Scientific novelty. The influence of the quality of the alloy ЕП-648ВИ powder on the properties of workpieces obtained using additive technologies has been established. Practical value.The negative effect of the content of active gases on the mechanical properties of the grown workpieces, established in this work, will allow to screen out powder with an unacceptable content of active gases ([N] ≥ 0.03 wt. %, or oxygen in [O] ≥ 0.02 wt. %) at the stage of incoming inspection.