Formation of cracks in the selective laser melting of objects from powdered stainless steel 17-4 PH

In the work, the process of selective laser melting of thick-walled objects of molds for wax models of 17-4PH steel powder on a ProX 300 was studied. The microstructure of the surface has been studied, the formation of cracks has been revealed and the possible reasons for their formation and propagation have been proposed. Analysis of selective laser melting of thin-walled objects revealed no cracks. To prevent the occurrence of cracks, it is necessary to warm the working platform to 200 °C

Influence of plasma-electrolyte discharge to the glass surface

© Published under licence by IOP Publishing Ltd. Gas discharges with liquid electrodes are known more than a hundred years. For these discharges typical is the fact that one of the electrodes is a conductive solution of electrolyte. The research resulted in found that the mechanisms of removal of glass for anodic and cathodic regimes differ. At cathodic regime occurs mainly thermal effect from the discharge. And at anodic regime occurs mainly glass etching by plasma of discharge

Investigation of the process of plasma-electrolyte formation surface microrelief of cobalt chromium alloy

© Published under licence by IOP Publishing Ltd. The goal is to investigate the possibilities of plasma-electrolytic formation of microrelief for replacement method of sandblasting. We found that with the cathode mode of plasma electrolytic surface treatment, CoCr-alloy has two kinds of structures: "porous" and "reflow". "Reflow" the surface was also covered with tubercles, the size of 200 - 300 nm. Analysis of roughness parameters and surface microrelief showed the possibility of replacing the sandblasting on the plasma-electrolytic treatment

Plasma electrolyte produce 17-4PH powder for use in 3D MicroPrint technology

© Published under licence by IOP Publishing Ltd. The work is devoted to the investigation of the processes of obtaining fine powders from steel 17-4PH, for the purpose of their further application in 3D MicroPrint technology. This technology is a type of selective high-resolution laser melting of ∼ 30 μm. In 3D MicroPrint technology, a powder of less than 5 microns is used, which in turn necessitates the development of new cheap methods for obtaining spherical fine powders. The process of plasma-electrolyte powder production of 17-4PH steel was studied, the discharge burning conditions and conditions for the arrangement of the electrode system for obtaining powders with dimensions less than 5 μm were selected. The proposed method is simple and does not require expensive equipment

Research of the impact acidity of electrolytic cathode on the course of the plasma-electrolytic process

The object of research is a gas discharge with an electrolytic cathode, namely the influence of the nature of the cathode on the discharge. Is established that with decreasing the acidity of electrolytic cathode voltage of discharge ignition decreases. A mechanism is proposed to maintain the discharge at the gas-electrolyte interface. © Published under licence by IOP Publishing Ltd

Investigation of the influence of plasma-electrolytic processing on the surface of austenitic chromium-nickel steels

Investigated the plasma-electrolytic processing of austenitic chromium-nickel steel. Determined that the treatment process consists of three parts: the anodic dissolution of metal anode microdischarge area burned and the area in which the combustion gas discharge-Glow vapor-gas layer around the electrode without the occurrence of certain microdischarge. The effect of processing parameters on the morphology of the surface. © Published under licence by IOP Publishing Ltd

Research of plasma-electrolyte discharge in the processes of obtaining metallic powders

© Published under licence by IOP Publishing Ltd. The use of the plasma electrolyte process has never been considered as a simple, cheap and fast method of obtaining powders used in selective laser melting processes. Therefore, the adaptation of the plasma-electrolyte process to the production of metal powders used in additive production is an urgent task. The paper presents the results of studies of gas discharge parameters between a metal and liquid electrode in the processes of obtaining metallic iron powders. The discharge combustion conditions necessary for the formation of metal powders of micron size are determined. A possible mechanism for the formation of powder particles in a discharge plasma is proposed

Research methods of hardening the surface of medical instruments

© Published under licence by IOP Publishing Ltd. The use of additive technologies for the manufacture of medical devices and equipment is becoming more widespread. However, manufactured products require additional processing to improve performance. Therefore, the aim was to investigate the processes of borating and electrophysical processing of the working surfaces of articles obtained by selective laser melting

Analysis and development of methods for obtaining metallic powders for selective laser melting

The paper compares the existing methods for obtaining metal powder compositions and reveals their shortcomings. A technique for evaluating the properties of powders for suitability for use in selective laser melting (SLM) processes is proposed. Analysis of methods for obtaining powders has shown the need to investigate the possibility of using a plasma-electrolyte process in the production of consumables for SLM technology

Influence of the electrolytic cathode temperature on the self-sustaining mechanism of plasma-electrolyte discharge

© 2018 IOP Publishing Ltd. The work is focused on studying the low-voltage (0-350 V) gas discharge with a liquid electrolytic cathode at various temperatures of an electrolyte. An aqueous solution of sodium hydroxide was used as a liquid cathode. The change in the discharge structure with increasing temperature is revealed, in particular, the transition from the bulk diffusive discharge to the leader discharge. The increase in the electrolyte temperature leads to the decrease in the intensity of hydrodynamic perturbations down to their disappearance. In addition, the anomalous growth of the vapor-air space between the metal anode and liquid cathode is observed. The key discharge parameters forming the anomalous growth are determined and the mechanism of vapor-air shell growth is proposed