scholarly journals Regulation of powder particles shape and size at plasma spraying

2021 ◽  
pp. 7-15
Author(s):  
S. B. Ermakov ◽  
Keyword(s):  
Spherical Shape ◽  
Plasma Generator ◽  
Current Strength ◽  
Additive Technologies ◽  
Chemical Compositions ◽  
Metal Powders ◽  
Gas Velocity ◽  
Technological Parameters ◽  
Powder Particles ◽  
Protective Gas

Additive technologies are among the most rapidly developing areas of modern production. To ensure the progressive movement of additive technologies development in the Russian Federation, it is necessary to provide maximum availability of additive raw materials – spherical metal powders for the domestic enterprises; however, the absence of domestic assemblies to produce such powders hampers the solution of this issue. Peter the Great St. Petersburg Polytechnic University has developed and successfully carried out industrial tests of a plasma atomization system for solid metal feedstocks of various chemical compositions. The paper presents the results of the study of the influence of some technological parameters on the granulometric size, shape, and defect structure of 12H18N9 steel and VG98 alloy powders. The paper includes the results of the research of the influence of such spraying parameters as the current strength and the plasma-forming gas velocity supplied to the plasma generator and the volume of protective gas supplied to the spray torch through the fluidized bed system nozzles located in the midsection of the atomizer spraying chamber. The study showed that by increasing the current strength and the plasma-forming gas velocity, it is possible to reduce the average size of the powder particles; and by changing the volume of the protective gas supply, it is possible to control the particle shape. The analysis of the chemical composition of the obtained powders shows that during the spraying process, there is no loss of alloying elements and the powder composition is the same as the original feedstock compositions. The paper gives the developed modes for the alloy feedstocks spraying, shows the possibility to produce metal powders with the level of the spherical shape factor of 92–96 % and minimal – not exceeding 0.5 % of powder aggregate weight – number of particles with nonmetallic inclusions, external and internal defects.

scholarly journals Influence of temperature and time factor on process of spraying of metallic powders in a plasma atomizer

2020 ◽  
Vol 221 ◽  
pp. 02003
Author(s):  
Sergey Ermakov ◽  
Evgeny Gyulikhandanov ◽  
Evgeny Petukhov
Keyword(s):  
Mathematical Modelling ◽  
Industrial Production ◽  
Additive Technologies ◽  
Time Factor ◽  
Chemical Compositions ◽  
Metal Powders ◽  
Spray Chamber ◽  
Commercial Products ◽  
Influence Of Temperature

The development of additive technologies is hampered by the almost complete absence of domestic systems for the production of metal powders. A prototype installation of a plasma atomizer was developed and manufactured, which makes it possible to obtain low-tonnage batches of metal powders of various chemical compositions. However, when the technology was transferred from the laboratory to production, a number of additional issues arose associated with a decrease in the quality of commercial products as the time of continuous spraying increases. It was found that the reason for this is the formation of powder deposits on the walls of the spray chamber and the increase in its temperature. Using the method of mathematical modelling, the maximum permissible temperature of the walls of the spraying chamber was determined, ways of stabilizing the quality of the powder during industrial production were shown.

Study of mechanical spheroidization of powders obtained from waste metal shavings

2021 ◽  
pp. 41-46
Author(s):  
A. D. Samukov ◽  
M. V. Cherkasova ◽  
M. P. Kuksov ◽  
S. V. Dmitriev
Keyword(s):  
Energy Consumption ◽  
3D Printing ◽  
Spherical Shape ◽  
Spherical Particles ◽  
High Tech ◽  
Metal Powders ◽  
Powder Preparation ◽  
Russian Science ◽  
Additional Energy ◽  
Powder Particles

This paper covers the search for a new method for generating metal powders for additive manufacturing. Raw materials for 3D printing are subject to certain requirements regarding the spherical shape of the powder particles, which are not easily met. The powder preparation methods used in the powder metallurgy may not be directly used for 3D printing without additional energy consumption for the spheroidization operation. More high-tech principles of melt dispersion shall be used for the spheroidization (atomization) of powder particles. Metal waste grinding in ball or vibrating mills generally yields plate-like particles, also requiring the use of energy-intensive atomization technologies. However, an analysis of related foreign research provided an alternative that is to use two-stage grinding to obtain spherical metal powder particles. Continued research in mechanical spheroidization enables the simultaneous manufacture and grinding of the required spherical particles while maintaining practically the same energy consumption that had been previously required for the grinding process. In order to form a research program and establish the optimal grinding size in terms of energy consumption and the dependence between the ball diameter and the grinding and spheroidization results for metal particles, respective preliminary experiments were carried out. The results of these experiments were then used to formulate the conclusions required to develop a method for establishing the optimal grinding ball charge level and composition. The study was carried out under the grant issued by the Russian Science Foundation (project No. 20-79-10125).

Installation for producing of spherical metal powders for additive technologies

2020 ◽  
pp. 77-78
Author(s):  
K.V. Lebedinskiy ◽  
N.E. Kurnosov
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Spherical Shape ◽  
Additive Technologies ◽  
Metal Powders ◽  
Powder Metal ◽  
Metal Spraying

A unit was developed for the production of powders of various metals with a dispersion of 0.5÷100 mm of a spherical shape and a given particle size distribution. Keywords powder, metal, spraying, sphere, dispersion. [email protected]

Gas Atomization of the Liquid 82N7HSR Nickel Base Alloy to Produce Micropowder for Additive and Coating Technologies

2016 ◽  
Vol 870 ◽  
pp. 309-313 ◽  
Author(s):  
P.A. Lykov ◽  
R.M. Baitimerov ◽  
D.A. Zherebtsov
Keyword(s):  
Base Alloy ◽  
Additive Technologies ◽  
Gas Jet ◽  
Gas Atomization ◽  
Spray Nozzle ◽  
Nickel Base Alloy ◽  
Technological Parameters ◽  
Powder Particles ◽  
Series Of Experiments ◽  
Nickel Base

In this paper an atomization of the Ni-based alloy 82N7HSR in a gas jet was studied. During the series of experiments different combinations of 3 main technological parameters (melting temperature, type of spraying gas, gas pressure in the spray nozzle) were considered. The size and shape of powder particles were studied by scanning electron microscopy and the optical granulomorphometer Occhio 500nano. The suitability of obtained powders 82N7HSR for usage in additive technologies and coating technologies was estimated.

scholarly journals Structural features of metal powders obtained by plasma spraying

2021 ◽  
Vol 248 ◽  
pp. 04025
Author(s):  
Evgeny Gulikhandanov ◽  
Sergey Ermakov
Keyword(s):  
Structural Features ◽  
Chemical Compositions ◽  
Metal Powders ◽  
Technological Parameters ◽  
Heat Treated ◽  
Minimum Number ◽  
The Russian Federation ◽  
Properties Of Materials ◽  
High Level ◽  
Number Of Particles

The development of additive technologies in the Russian Federation is constrained by the lack of indigenous base for the production of metal powders. SPbPU has developed, manufactured and introduced a plasma atomizer. It provides atomization of metal powders and alloys of various chemical compositions. The data on the main technological parameters of atomization of nickel alloy Inconel 718 and titanium alloy Ti-6A1-4V are presented in the paper. It is shown that by optimizing the spraying mode the possibility to obtain alloy powders with a high level of sphericity and a minimum number of particles with surface and internal defects. The chemical compositions of the obtained particles are almost identical to the composition of the initial atomized materials. Samples for the mechanical testing were made from the obtained powders by the SLM method. The results of mechanical properties tests show that the properties of samples made by 3D printing methods from powders sprayed by plasma atomization methods are identical to the properties of materials made and heat-treated by traditional methods.

scholarly journals Thermodynamic Behavior of Fe-Mn and Fe-Mn-Ag Powder Mixtures during Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 234
Author(s):  
Jakob Kraner ◽  
Jožef Medved ◽  
Matjaž Godec ◽  
Irena Paulin
Keyword(s):  
Selective Laser Melting ◽  
Manganese Oxides ◽  
Elevated Temperatures ◽  
Manganese Content ◽  
Chemical Compositions ◽  
Metal Powders ◽  
Laser Melting ◽  
Powder Mixtures ◽  
Ε Martensite ◽  
The Impact

Additive manufacturing is a form of powder metallurgy, which means the properties of the initial metal powders (chemical composition, powder morphology and size) impact the final properties of the resulting parts. A complete characterization, including thermodynamic effects and the behavior of the metal powders at elevated temperatures, is crucial when planning the manufacturing process. The analysis of the Fe-Mn and Fe-Mn-Ag powder mixtures, made from pure elemental powders, shows a high susceptibility to sintering in the temperature interval from 700 to 1000 °C. Here, numerous changes to the manganese oxides and the αMn to βMn transformation occurred. The problems of mechanically mixed powders, when using selective laser melting, were highlighted by the low flowability, which led to a less controllable process, an uncontrolled arrangement of the powder and a large percentage of burnt manganese. All this was determined from the altered chemical compositions of the produced parts. The impact of the increased manganese content on the decreased probability of the transformation from γ-austenite to ε-martensite was confirmed. The ε-martensite in the microstructure increased the hardness of the material, but at the same time, its magnetic properties reduce the usefulness for medical applications. However, the produced parts had comparable elongations to human bone.

DETERMINATION OF TECHNOLOGICAL PARAMETERS OF CULINARY PRODUCTS PRODUCTION USING MIXTURES AND EMULSIONS FOR ADDITIVE TECHNOLOGIES

2020 ◽  
pp. 189-198
Author(s):  
A. Meliaschenya ◽  
I. Kaltovich ◽  
G. Pinchuk
Keyword(s):  
Broiler Chicken ◽  
Raw Materials ◽  
Chicken Meat ◽  
Additive Technologies ◽  
Technological Parameters ◽  
Optimal Length ◽  
Layer Width ◽  
Degree Of Hydration ◽  
Rational Sequence

The article presents the results of research on the determination of rational technological parameters for the production of culinary products using dry mixtures and emulsions based on animal raw materials for additive technologies. It was found that when making products using mixtures and emulsions based on broiler chicken meat, as well as a combination of broiler chicken meat and pork, pork and beef (ratio 1:1) rational height of the layer, which makes it possible to ensure stability and safety of the product shape (with a fixed diameter of the opening of the culinary syringe – 7 mm and the optimal length of the layer - 100 mm), is from 14–21 mm (with a layer width of 7 mm) and up to 133–154 mm (with a layer width of 98 mm), which allows for improved structural and mechanical (SSL – 1090.7–1099.9 Pa) and functional and technological indicators of these products (WHC – 92.7–97.5%). The rational sequence of application and the duration of chopping of the main and auxiliary raw materials for the manufacture of emulsions, the duration of preparation (3 minutes), the degree of hydration (1:2 – 1:3) and the temperature of water for the reduction of dry mixtures (60±1° C) were established, which made it possible to develop technological schemes for the production of culinary products using additive technologies.

The Effect of Annealing to the Hardness of Oxide Dispersion Strengthened (ODS) Fe-15Cr-0.3Y2O3 Alloy

2017 ◽  
Vol 888 ◽  
pp. 428-431
Author(s):  
Farha Mizana Shamsudin ◽  
Yusof Abdullah ◽  
Shahidan Radiman ◽  
Nasri A. Hamid
Keyword(s):  
Vickers Hardness ◽  
Spherical Shape ◽  
Hardness Test ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Alloy Matrix ◽  
Hardness Tester ◽  
Powder Particles ◽  
Average Size ◽  
Vickers Hardness Test

The objective of this study is to investigate the microstructure and effect of annealing to the hardness properties of oxide dispersion strengthened (ODS) Fe-15Cr-0.3Y2O3 alloy. This type of alloy was prepared by mechanical alloying (MA) method followed by compacting and sintering. The microstructure of milled Fe-15Cr-0.3Y2O3 alloy powders and pellet was examined by using field emission scanning electron microscope (FESEM). The milled alloy powders consist of nearly spherical shape of powder particles with average size of 10 µm. For the alloy pellet microstructure, the formations of Y2O3 nanoparticles with average size of 5 nm were observed indicating the dispersion and incorporation of this nano-scale dispersoids into the alloy matrix. Fe-15Cr-0.3Y2O3 alloy pellet was annealed at temperature of 600°C, 800°C and 1000°C, respectively for the Vickers hardness test. The Vickers hardness test was performed by using a micro-Vickers hardness tester with a load of 200 gf. The hardness value (HV) of this alloy pellet started to decrease at temperature of 600°C indicating the grain growth of this material at high temperature

scholarly journals RESULTS OF FIELD RESEARCHES OF PELLETED BUCKWHEAT SEEDS WITH ORGANIC FERTILIZERS BASED ON HUMIC ACIDS WITH SUBSTANTIATION OF CONSTRUCTIVE AND TECHNOLOGICAL PARAMETERS OF CENTRIFUGAL PELLETER WITH BLADE REFLECTOR

2018 ◽  
Vol 56 (3) ◽  
pp. 357-365
Author(s):  
V. R. Petrovets ◽  
D. A. Mikheev
Keyword(s):  
Humic Acids ◽  
Crop Production ◽  
Seed Quality ◽  
Experimental Studies ◽  
Spherical Shape ◽  
Organic Fertilizers ◽  
Technological Parameters ◽  
Seeding Rate ◽  
Presowing Treatment ◽  
Seed Crops

One can obtain high yields of crops only when seeds with high varietal and sowing qualities are used for sowing. Various methods of presowing processing are used to improve the seed quality. Presowing seed treatment not only improves germination, but also eliminates seeds from pathogens, significantly increases their viability and improves young crops yield. One of the most promising ways of presowing treatment of small and irregular shape seeds is pelleting. This method helps to increase the seeds size and acquire a spherical shape, which greatly simplifies their sowing and allows to accurately observe the seeding rate. The paper presents design of a centrifugal pelleter with blade reflector, the results of studying the process of buckwheat seeds pelleting, and its best design and technological parameters are determined based on those when organic fertilizers based on humic acids were used as material for pelleting. Factors significantly affecting seed pelleting in a centrifugal pelleter with blade reflector were determined, the choice of objective function and criterion for improving the process are substantiated. A dependence describing the process of seed pelleting in a pelleter was obtained as a result of the regression analysis of the obtained results of experimental studies. The obtained results can be used in the field of crop production in agricultural production during presowing treatment of small seed crops and agricultural engineering during development of centrifugal pelleters with blade reflectors.

scholarly journals MONITORING OF AUTOMATED TECHNOLOGICAL ENVIRONMENT FOR TOOL WORKING IN PLASMA-GENERATOR OF GLOW DISCHARGE BASED ON NEURONET APPROACH

2020 ◽  
Vol 2020 (12) ◽  
pp. 31-37
Author(s):  
Vladimir Logvin ◽  
Tatyana Karlova
Keyword(s):  
Glow Discharge ◽  
Plasma Generator ◽  
Current Strength ◽  
Engineering Process ◽  
Pumping Rate ◽  
Working Volume ◽  
Investigation Methods ◽  
Considerable Impact ◽  
Gas Environment ◽  
The Stability

The work purpose is to increase effectiveness and quality of engineering process control of tool working in a plasma-generator of a glow discharge based on a neuronet approach. Investigation methods: use of computer technologies based on an artificial neuronet system for the creation of control systems as an investigation method consisting in computer imitation of the process of plasma-generator operation at separate stages of processing. It will allow developing an optimum system for quality control and management of engineering processes performed for tool working in the plasma-generator of a glow discharge. The essence of the modeling method when using an artificial neuronet approach consists in the development of such algorithms and programs which imitate the behavior of the plasma-generator, its properties and characteristics in the composition essential for investigations, volume and field of technical parameter changes. Investigation results: the operation sequence of the engineering process for product working in the plasma-generator of a glow discharge ensures the formation of the specified structure and micro-hardness on the surface of products worked. A considerable impact upon working quality is made by the structure of technological gas environment and a rate of its pumping at constant pressure in a vacuum chamber for the formation of the essential flux of bombarding ions with the specified value of kinetic energy before a hit on a surface. During the development of working stage sequence there is taken into account a state and magnitude of the defected layer formed at the stages of previous working and ageing. The effectiveness of force impact is defined with the stability of current strength in the discharge and electrode voltage in the plasma-generator of a glow discharge. The fluctuations of current strength and voltage at discharge burning depends upon the stability of structure, pressure and a pumping rate of technological gas environment through a working volume of the plasma-generator.

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