Zavgorodny O. Improvement of equipment and technology of plasma rotary spraying for the production of metal powders for additive purposes

The purpose of the work is to develop a technology for obtaining spherical powders from nickel and titanium alloys, which are used for additive growth of parts for critical purposes, to improve their quality and ensure the required level of mechanical properties. The object of research is the process of plasma rotary spraying for the production of spherical powders from titanium and nickel alloys, the processes of powder consolidation using additive technologies. The subject of the study is the equipment and technological modes of plasma rotary spraying for the production of spherical powders from titanium and nickel alloys and the parameters of additive technologies for manufacturing various parts from them. The work to improve the production of spherical powders sets the following tasks: 1. To propose changes in the node for supplying the sprayed workpiece and fixing it in order to increase the rotation speed of the consumable electrode. 2. To work out the optimal compositions of the gas medium during rotary spraying of workpieces made of titanium and nickel alloys. 3. To determine the influence of the technological parameters of spraying (the speed of rotation of the workpiece and the composition of the plasma-forming gas mixture) on the fractional composition and quality of powders made of heat-resistant nickel and titanium alloys. 4. To obtain spherical powders of a given fractional composition for certain powder consolidation technologies (for electron beam and microplasma deposition, laser 3D- printing). The scientific novelty of the work is as follows: 1. We have further developed the dependence of the influence of the technological parameter of rotary plasma spraying (consumable electrode rotation speed) on the size of powders from heat-resistant nickel alloys Inconel 718, ВЖ98 and titanium alloy Ti-6Al-4V. The kinematic scheme of the consumable electrode rotation system in the equipment for rotary plasma spraying (PREP) has been improved. The maximum amount (d50) of finely dispersed (30…100 μm) metal powder for the manufacture of gas turbine engine parts by additive technologies has been obtained. 2. For the first time, regression dependences of the influence of the composition of plasma-forming gases (argon, helium) under conditions of ultra-high rotation speeds of the sprayed workpiece (20-30 thousand hv-1) on the fractional composition of metal powders manufactured from Inconel 718, ВЖ98 and Ti-6Al-4V alloys using PREP technology have been established. Optimal technological modes have been established for the manufacture of spherical powders with sizes of 30…60 μm of nickel heat-resistant alloys Inconel 718 and ВЖ98 and from titanium alloy Ti-6Al-4V with a dispersion of 30…60 μm. 3. Scientific substantiation of the influence of fractional compositions of the developed powders on the technological characteristics of additive manufacturing methods (laser 3D printing, microplasma and electron beam layer-by-layer deposition) has been developed. Optimal spraying modes for obtaining metal powders for various purposes in experimental and production conditions have been established: for laser 3D printing – 20...50 μm; for microplasma layer-by-layer deposition – 100...120 μm; for electron-beam growth of products – 45...105 μm. The manufactured powders, ordered by JSC Motor Sich, were used for laser 3D- printing of combustion chamber parts – swirlers made of Inconel 718 alloy. The manufactured parts were tested as part of the engine and laser printing technology is recommended for serial production of swirlers. In the conditions of the E. O. Paton Electric Welding Institute, electron-beam and microplasma layer-by-layer growth of blanks and samples using spherical powders of nickel alloy ВЖ98 and titanium alloy Ti-6Al-4V was successfully carried out, which is confirmed by the relevant acts of implementation.