Plasma Powder Surfacing Research Articles

АНАЛИЗ МАТЕРИАЛОВ ДЕТАЛЕЙ, РАБОТАЮЩИХ В АГРЕССИВНЫХ СРЕДАХ ПЕРЕРАБАТЫВАЮЩИХ ПРОИЗВОДСТВ

Processing and food industries, as well as animal husbandry, play a significant role in the structure of the agro-industrial complex of Russia. The specifics of working in these industries imply constant contact of equipment parts with aggressive environments, due to which mechanical wear is enhanced by corrosion wear. In processing, food production and animal husbandry, the task is further complicated by the fact that special sanitary and hygienic requirements are imposed on materials in contact with products. (Research purpose) The research purpose is studying the materials used for the manufacture of parts operating in aggressive environments in animal husbandry and processing production; identifying the most characteristic defects during operation; offering analogues of materials for repair and restoration. (Materials and methods) Used literary and patent sources, studied the principle and working conditions of milking machines and packaging machines. (Results and discussion) It was pointed out that the use of materials from which equipment parts are made in processing and food production is determined by such factors as the neutrality of the material to the product, the neutrality of the product to the material, the operability within the technological process. It was noted that the most versatile materials in terms of strength, rigidity, heat resistance, corrosion resistance, low cost, high hygienic properties are corrosion-resistant steels. However, such materials also wear out over time as a result of mechanical wear, which is enhanced by corrosion. Most often, guides, drive rollers and discs suffer, which experience loads in the form of friction. (Conclusions) In the equipment of processing and food production, as well as in animal husbandry, parts made of corrosion-resistant steels are most often used. It is advisable to restore such parts using laser technologies or plasma-powder surfacing, since alloyed steels are difficult to weld.

IMPROVING THE EFFICIENCY OF RESTORATION AND HARDENING OF THE WORKING BODIES OF TILLAGE MACHINES BY PLASMA-POWDER SURFACING OF CARBIDE ELECTROEROSIVE MATERIALS

The use of powders obtained from solid alloy waste as a highly solid dispersed component of the composition for plasma-powder surfacing will improve the quality, reliability and durability of plasma coatings of working bodies of tillage machines with a minimum of costs for powder materials. However, the properties of these plasma coatings have not been studied enough, so it is necessary to conduct comprehensive studies. (Research purpose) The research purpose is improving the technology of restoration and hardening of the working bodies of tillage machines by plasma-powder surfacing of powder materials obtained by electroerosive dispersion of solid alloy waste T30K4. (Materials and methods) Carbide powders made by electrodispersing solid alloy waste T30K4 in kerosene were used to obtain plasma coatings. We chose for the renovation object a pointed cultivator paw made of 40XC rolled steel. The obtained plasma coatings were studied using modern equipment and complementary methods of physical materials science. (Results and discussion) We have developed, tested and investigated a new technology for restoring and strengthening the working bodies of tillage machines using the example of a pointed cultivator paw by plasma-powder surfacing of carbide electroerosive powder materials. The effectiveness of the development was confirmed by the properties of plasma coatings: the microstructure of the coating has a fine-grained structure, without inclusions, uniform phase distribution and the absence of pores, cracks and discontinuities; elements W, Ti and Co in the coating are evenly distributed; phases of carbides WC and TiC are present; the grain size of the coatings is about 0.3 micrometers; the microhardness of the coatings is about 14245 megapascals. (Conclusions) The results of field tests showed that the resource of the working bodies of tillage machines, restored and strengthened with carbide electroerosion materials, is 1.25 times higher than the resource of new parts.

WEAR-RESISTANT POWDER MATERIALS FOR PLASMA-POWDER SURFACING

Among powder surfacing materials with high hardness and resistance to abrasive wear, powders based on WC-TiC-Co systems, which are the basis of hard alloys, are among the most promising. (Research purpose) The research purpose is investigating wear-resistant powder materials for plasma-powder surfacing by electrodispersing solid alloy waste of the T30K4 brand in kerosene. (Materials and methods) We chose substandard carbide plates of the T30K4 brand as the starting material; lighting kerosene as the working fluid. We solved the tasks set in the work on the study of the composition, structure and properties of the obtained carbide powders using modern equipment and complementary methods of physical materials science. Electrodispersion of solid alloy waste was carried out on the original installation; the shape and morphology of the particle surface were studied on an electron-ion scanning microscope with field emission of electrons QUANTA 600 FEG; particle size composition ‒ on a laser particle size analyzer Analysette 22 NanoTec; X-ray spectral microanalysis of particles was carried out on an energy dispersive X-ray analyzer of EDAX company, integrated into a scanning electron microscope QUANTA 200 3D; phase analysis of particles was performed on an X-ray diffractometer Rigaku Ultima IV. (Results and discussion) A new technology for producing a carbide electroerosive powder suitable for plasma-powder surfacing has been developed and investigated, the effectiveness of which is confirmed by the properties of the proposed powder material: the spherical shape of powder particles; the average size of powder particles is 58.4 micrometers; powder particles with a uniform distribution of alloying elements: C, Co, Ti and W; powder particles include phases of carbides WC and TiC. (Conclusions) The conducted studies have shown that it is possible to obtain a wear-resistant powder alloy with a uniform distribution of alloying elements by the method of electroerosive dispersion of solid alloy waste of the T30K4 brand.

Plasma-Powder Surfacing of Alloys Based on Nickel and Cobalt on Copper

Plasma-Powder Surfacing of Alloys Based on Nickel and Cobalt on Copper

Application of secondary carbide powders for restoration and hardening of parts

Attention in this work is paid to the technology of obtaining powder materials from waste metals and alloys by the method of electroerosive dispersion and subsequent deposition of wear-resistant coatings. At present, it is important to look for new materials for the repair and restoration of parts of various equipment. Recycling of metal waste using electroerosive dispersion will reduce the cost of such materials. The most common way to restore parts is plasma-powder surfacing. In this case, the physical and technological parameters of the metal powders used are of particular importance. In the presented work, the expediency and relevance of the use of recycled powder materials in the technologies for the restoration and hardening of parts by the method of plasma-powder surfacing is proved. (Research purpose) Increasing the resource of parts of various equipment, restored and hardened with hard-alloy powder materials obtained by recycling waste from machinebuilding industries by the method of electroerosive dispersion. (Materials and methods) The work was carried out at the laboratory-experimental base of the Central Collective Use Center "Nano-Center" FGBNU FNATS VIM. To conduct research, a powder of the T15K6 brand was obtained from the waste of hard-alloy plates by the method of electroerosive dispersion. The following equipment was used: a pulse generator for electrospark processing of modes. Elitron-52B, Niton XL3t GOLDD + X-ray fluorescence spectrometer, set of sieves, ShS-80-01 SPU drying cabinet, Acculab ALC-210d4 analytical balance. (Results and discussions) Investigations were carried out on the elemental composition of the powders used, as well as the physical and mechanical properties of the coatings obtained on their basis by plasma-powder surfacing. (Conclusions) Studies have shown the rationality of using secondary hard-alloy powder materials in the technologies of plasma-powder surfacing in the restoration and hardening of parts. The hardness of the resulting coatings is much higher than the initial hardness of worn parts.

Robotic Center for Plasma–Powder Surfacing of Shafts

Robotic Center for Plasma–Powder Surfacing of Shafts

Ultrasonic testing of hardfacing babbit metal porosity

A step-by-step report on the results of ultrasonic testing of the antifriction surfacing of plain bearing shells in the scope of technology development for plasma-powder surfacing of babbitt alloys is presented. The revealed correlation between wear resistance and porosity of the antifriction surfacing structure is described. The analysis of modern methods and means of porosity testing is carried out. A hypothesis is put forward about the need for ultrasonic testing of the antifriction surfacing porosity in order to increase the service life of the plain bearing shells.

Technological Methods of Increasing the Resource and Efficiency of Fast-Wearing Working Bodies

The working bodies of tillage machines are operated in a soil abrasive environment and, due to wear, they change their shapes and sizes, which negatively affects tillage agrotechnical and energy indicators. The problem of increasing the durability and operability of the working bodies of tillage machines remains relevant. In particular, this is reflected in the reduced resource of serial tillage working bodies. (Research purpose) The research purpose is to ensure the increased durability and efficiency of agricultural machines. (Materials and methods) The downtime of agricultural machinery due to the failure of tillage working bodies negatively affect the efficiency of agricultural operations and entail up to 15-20 percent reduction in subsequent yields. The cost of purchasing and reinstalling spare parts is up to 18 percent in the structure of the cost of agricultural products. The most technological method of plasma-powder surfacing (hardening) has been used, which is up to two times more productive and 2.2-2.7 times more economical in comparison with the known technology of plasma surfacing in argon medium. The most high-strength (σВ at least 1600 megapascals) steels of the type 25XGTYUR, 30XGSA, 27XGR were selected for the manufacture of the developed tillage working bodies. (Results and discussion) Parts made of high-quality materials according to the created technology are not inferior in resource and wear resistance to the best foreign surfaced analogues, and non-melted imported products are 1.5-1.7 times superior. New materials and technological surfacing methods for strengthening domestic and import-substituting working bodies of agricultural machines allow, in terms of resource and operational indicators, to achieve a level of competitiveness with leading foreign manufacturers. (Conclusions) According to the «quality-price» criterion, new working bodies with reasonable materials, structural and technological parameters have a 1.5-2.5 times advantage over the best foreign analogues.

The influence of nitrogen on the formation of the structure and properties of plasma coatings of the 10P6M5 type

The effect of nitrogen doping from an additive material on the formation of the structure and properties of a coating of type 10P6M5 obtained by plasma-powder surfacing is investigated. The microstructure and phase composition of the deposited layers, as well as the transition coefficients of alloying elements during surfacing, are studied. The influence of the additive powder composition and the surfacing mode on the hardness and abrasive wear resistance of coatings is determined. The positive effect of nitrogen on increasing the abrasive wear resistance of coatings is shown.

The influence of hardening on the operational properties of soil-cutting tools

Today, soil cutting tools are mainly made from carbon steels, which are heat treated to provide high hardness and strength. However, at present, the durability of such a hardened soil-cutting tool of both domestic and foreign manufacturers is far from perfect. One of the reasons for the insufficient resistance to abrasive wear of a soil-cutting tool subjected to hardening by heat treatment may be its heating by frictional force in contact with the soil. As a result of such heating, the steel undergoes additional tempering, which leads to a decrease in the surface hardness of the cutting edge of the tool by almost 2 times - 49-50 HRC to 22-34 HRC, depending on the intensity of metal heating. This circumstance was established during metallographic studies of samples cut from the shares of the KB-01 body of the PBS-4 plow. One of the ways to solve this problem is to obtain a wear-resistant layer on the surface of the soil-cutting tool, which is not subject to the negative effects of reheating during operation, for example, from alloyed white cast iron by the method of plasma-powder surfacing. Metallographic studies showed that the deposited layer has a hardness of more than 62 HRC. At the same time, such types of heat treatment as hardening, normalization or annealing do not have a noticeable effect on the hardness of the deposited layer. Metallographic studies of the deposited metal after operation also showed the absence of noticeable changes in its microstructure and hardness. This indicates that reheating from the action of friction forces does not have a significant effect on the properties of a soil-cutting tool strengthened by plasma-powder surfacing, which contributes to an increase in its duration of operation.

Дугове та плазмово-порошкове наплавлення ущільнювальних поверхонь робочих коліс насосів

Дугове та плазмово-порошкове наплавлення ущільнювальних поверхонь робочих коліс насосів

Arc and plasma-powder surfacing of sealing surfaces of pump impellers

Arc and plasma-powder surfacing of sealing surfaces of pump impellers

Structural-technological model of wear for surfacing materials based on Fe–Cr–Ni–Мо and Fe–Co–Ni–Мо

The paper presents the results obtained when studying the structure of surfacing materials based on martensitic-aging Fe–Cr– Ni–Мо и Fe–Co–Ni–Мо alloys obtained by plasma powder surfacing. Silicon was chosen as an alloying element, which made it possible to significantly improve the technical and economic performance of martensitic-aging materials. A comparison of martensitic-aging steels with high-carbon steels showed that the former provide an advantage as a wear-resistant material due to their increased resistance to crack propagation. Microscopic analysis, X-ray diffraction analysis and electron microprobe analysis were used for the research. Surfacing materials were tested for wear and internal friction. Silicon oxide particles and chromium and molybdene silicides involved in the process of alloying material strengthening were found during the experiments. Silicide particle density was determined that varies depending on the amount of silicon in the material. The effect of the silicon content on the material hardness was considered. The data obtained on the structure and phase composition of Fe–Cr–Ni–Мо и Fe–Co–Ni–Мо compounds doped with silicon in both the initial and aged states made it possible to suggest a structural-physical model of their hardening in the course of aging. Results of the experiments showed that the heat treatment process actively influences the wear rate and weight wear reducing their values that is typical for both Fe–Cr–Ni–Мо and Fe–Co–Ni–Мо alloys. Based on these data, a structural-technological model of wear was obtained for the surfacing materials studied.

Comparison of three surface treatment methods for preparing WC-containing coatings

ABSTRACT A coating containing WC was prepared by induction cladding, laser cladding and plasma powder surfacing. The microstructure, chemical composition, hardness and corrosion resistance were analysed by optical microscope, scanning electron microscope, EDS, X-ray diffraction, micro hardness tester and electrochemical workstation. The results show that the forming quality of the samples deposited by induction cladding is very poor. The microstructures of LC and PS are mainly composed of dendrites, cellular crystals and interdendritic eutectic structure. Both of them contain Fe3C and Cr3C2 phase, as well as W2C phase. In addition, the PS alloy layer also contains other complex alloy phases and hard phases. The hardness decreases with the increase of current, while the hardness of laser cladding alloy layer is similar to that of plasma sample with 150A current. The best corrosion resistance is plasma sample with 125A current. The corrosion resistance of laser cladding sample is between 150A and 175A plasma sample.

Сorrection сalculation of the heat source power during plasma-powder surfacing of the necks of stepped shafts

A mathematical model is proposed for calculating temperature fields during arc surfacing of limited cylinders, eliminating the need for dimensionless parameters, when solving the differential heat equation, which facilitates the practical application of the developed calculation method. It is proposed that the penetration depth be calculated using the Lambert function. The obtained dependences make it possible to quantify the required correction of the heat source power in the process of surfacing the necks of stepped shafts.

Elevation of the Wear Resistance of Low-Alloy Structural Steel by Plasma-Powder Surfacing with Alloys Based on Iron, Chromium, and Nickel

We study the chemical and structural inhomogeneities and the parameters of wear resistance of the coatings obtained by the arc-welding method. The coatings were obtained from PR-KhN80SSR3, PN-AN-34, and Kh17N8S6G powders based on nickel, cobalt, and iron, respectively, and from an experimental powder based on Ni and Fe. The tribological properties of iron-based alloys are better than for the cobalt- and nickel-based alloys. In the course of friction, the austenitic component of the coating undergoes plastic deformation as a result of which it covers the surface as a lubricant, which decreases the friction coefficient and wear.

Plasma Powder Surfacing of Toughened Steel S690Q Performed Using the NiBSi Powder with a Tungsten Carbide Addition

Plasma Powder Surfacing of Toughened Steel S690Q Performed Using the NiBSi Powder with a Tungsten Carbide Addition

Features of Wear-Resistant Cast Iron Coating Formation During Plasma-Powder Surfacing

The structure of coatings deposited on steel 45 by plasma-powder surfacing of white wear-resistant cast iron is studied. The effects of surfacing regime and additional production effects on the welding bath during surfacing produced by current modulation, accelerated cooling of the deposited beads by blowing with air, and accelerated cooling of the substrate with running water on the structure, are determined. A new composition is suggested for powder material for depositing wear-resistant and corrosion-resistant coatings on a carbon steel by the plasma-powder process.

Experience in Restoring Hydraulic Cylinder Rods by Plasma Powder Surfacing

Development of technology for restoring worn hydraulic cylinders by plasma-powder surfacing providing new operating properties is of current interest. The possibility is studied of restoring rods by surfacing with a coating of the Fe–C–Cr–V system.

Evaluation of the effect of heat input in superduplex stainless steel deposition by the plasma powder process

Plasma powder surfacing is one of the latest processes for application of coatings, with control of dilution as its main feature. Surfacing with superduplex stainless steels is an interesting option for the construction and repair of equipment for applications in a highly corrosive environment, allowing the desired characteristics to be achieved: corrosion resistance and good mechanical properties. The aim of this work is to assess the ferrite content in the weld metal and the mechanical characteristics via microhardness profiles in surfacing of C-Mn steel pipes with deposition of UNS S32760 by plasma powder surfacing. Welding operations were carried out on pipes with deposition of SDSS, employing three welding heat input levels, varying the welding speed or the welding current. Then the geometry was analysed, the ferrite content in the weld metal was quantified and the microhardness profile was recorded. Variation in welding heat input caused changes in weld bead geometry, with variation in the welding current producing the most significant changes. Increase in heat input caused decrease in ferrite content of the weld metal. Regarding microhardness, only the condition with a higher level of welding current gave sufficiently high levels of microhardness in the weld metal.