WAAM technology (Wire + Arc Additive Manufacture) is a new method of additive manufacturing using wire as a construction material. The high productivity of the process, the ability to construct large-sized products without the need to use a controlled atmosphere chamber, and the low cost of equipment and construction materials allow using the WAAM technology to built products of simple and medium complexity with the highest economic efficiency. However, WAAM technologies in MIG-Pulse/CMT surfacing processes have a number of disadvantages, such as significant size of the heat-affected zone (HAZ) and large sizes of the build-up layer, which leads to undesirable temperature gradients and the accumulation of residual stresses. A further way to improve WAAM technology is to use metal-cored wires. For the research, metal-cored wire Cr20Mn5Ni4Mo2.5Cu3N0.3 Ø 1.6 mm was developed. It has been established that the use of metal-cored wire allows producing a defect-free surfaced metal with an austenite-ferritic structure (δF ≈ 1–3

Технология WAAM (Wire + Arc Additive Manufacture) – новый способ аддитивного производства с использованием проволоки в качестве материала построения. Высокая производительность процесса, возможность построения изделий больших габаритов без необходимости использования камеры с контролируемой атмосферой и невысокая стоимость оборудования и материалов построения позволяет использовать технологию WAAM для выращивания изделий простой и средней сложности с наибольшей экономической эффективностью. Однако WAAM технологии при процессах MIG-Pulse/CMT наплавки имеют ряд недостатков: значительный размер зоны термического влияния (ЗТВ), большие размеры наращиваемого слоя, что приводит к нежелательным температурным градиентам и накоплению остаточных напряжений. Дальнейшим путем совершенствования технологии WAAM является использование металлопорошковых проволок. Для проведения исследований разработана металлопорошковая проволока Cr20Mn5Ni4Mo2,5Cu3N0,3 Ø 1,6 мм. Установлено, что использование металлопорошковой проволоки позволяет получить бездефектный наплавленный металл с аустенитно-ферритной структурой (δF ≈ 1–3 %), обладающий высокими прочностными и пластическими характеристиками (σВ = 810 МПа, σ0,2 = 500 МПа, δ = 40 %). Предел текучести разработанного состава более чем в 2 раза больше, чем у широко распространенной аустенитной стали типа Х18Н10Т (σ0,2 = 206 МПа). Дальнейшие работы будут направлены на повышение показателей ударной вязкости наплавленного литого металла за счет оптимизации состава металлопорошковой проволоки. WAAM technology (Wire + Arc Additive Manufacture) is a new method of additive manufacturing using wire as a construction material. The high productivity of the process, the possibility of building large-sized products without the need to use a controlled atmosphere chamber, and the low cost of equipment and construction materials make it possible to use the WAAM technology to grow products of simple and medium complexity with the highest economic efficiency. However, WAAM technologies in MIG-Pulse/CMT surfacing processes have a number of disadvantages: a significant size of the heat-affected zone (HAZ), large sizes of the build-up layer, which leads to undesirable temperature gradients and accumulation of residual stresses. A further way to improve the WAAM technology is the use of metal-cored wires. For research, a metal-cored wire Cr20Mn5Ni4Mo2.5Cu3N0.3 Ø 1.6 mm was developed. It has been established that the use of metal-cored wire makes it possible to obtain a defect-free deposited metal with an austenitic-ferritic structure (δF ≈ 1–3%), which has high strength and plastic characteristics (σВ = 810 MPa, σ0.2 = 500 MPa, δ = 40%). The yield strength of the developed composition is more than 2 times greater than that of the widespread austenitic steel of the Kh18N10T type (σ0.2 = 206 MPa). Further work will be aimed at improving the impact strength of the deposited cast metal by optimizing the composition of the metal-cored wire.

An austenitic metal-cored wire (diameter – 1.6 mm) with additional nitrogen alloying (0.25–0.40 wt.

The use of copper and its alloys to create parts for metallurgical equipment is associated with an increase in abrasive wear and high-temperature corrosion. In this regard, there is a need to apply a protective coating. In particular, to prevent wear and premature chipping of the metal of copper tuyeres, the surface is hardened with a coating of zirconium dioxide stabilized with yttria oxide by thermal spraying in an air atmosphere. Due to the difference in the coefficient of thermal expansion of copper (at T = 300 K: 16.7 µm/m оС and at T = 750 K: 19.7 µm/m оС) and its low resistance to gas corrosion, the application of zirconium oxide (produced by a preapplied intermediate layer that plays a role in matching the coefficient of thermal expansion (CTE) between the copper base and the ceramic coating. In addition, the intermediate layer protects copper from gas corrosion. In this case, The use of copper and its alloys to create parts for metallurgical equipment is associated with an increase in abrasive wear and high-temperature corrosion. In this regard, there is a need to apply a protective coating. In particular, to prevent wear and premature chipping of the metal of copper tuyeres, the surface is hardened with a coating of zirconium dioxide stabilized with yttria oxide by thermal spraying in an air atmosphere. Due to the difference in the coefficient of thermal expansion of copper (at T = 300 K: 16.7 pm/m °G and at T = 750 K: 19.7 pm/m оG) and its low resistance to gas corrosion, the application of zirconium oxide (produced by a pre-applied intermediate layer that plays a role in matching the coefficient of thermal expansion (CTE) between the copper base and the ceramic coating. In addition, the intermediate layer protects copper from gas corrosion. In this case, nickel-based alloys were used as intermediate layers. The use of nickel as the basis of intermediate layers is due to the fact that copper and nickel form a continuous series of solid solutions, such as cupronickel or monel metal-like structures. This, in turn, assumes a smooth transition of thermophysical properties from copper to nickel alloy. To ensure increased adhesion of the transition layer to copper by increasing the area of mutual contact between copper and the sublayer (dagger penetration) and significantly increasing the homogeneity of the material of the intermediate layer made of a nickel alloy, laser melting of the intermediate sublayer (Ni–B–Si system) was used on a laser complex based on laser LS-5 with a power of 5 kW with a KUKA KR-60HA robot in an argon atmosphere. To test the modes, experiments were carried out on copper samples of a flat shape and a body of rotation. The optimal parameters for the process of melting flat samples were: processing speed 33 mm/s, power from 400 to 3900 W, focal length from 200 to 230 mm, pitch between tracks: 0.25, 0.5 and 1 mm. The optimal parameters for the process of melting rotating samples were: laser radiation power 400–450 W, processing step 0.125; 0.5, focal length from 200 to 210 mm.

The possibility of using diatomite from the Ilyinsky deposit as an unshaped thermal insulation for open risers of castings from aluminum alloys of different alloying systems: technical aluminum A5, AK7, AMg10, VAL10 has been studied. It was found that when the continuity of the oxide film on the surface of a diatomite particle is broken, an exchange reaction occurs with the formation of a silicon transition layer. Since silicon is wetted by aluminum, the diatomite particle sinks in the melt, forming a blockage. As a criterion for the continuity of the oxide film, it is proposed to use the Pilling‒Badworth factor of the alloy components. It has been shown that a high level of the Pilling‒Badworth factor, even at a low content of the component (~ 1 %), leads to the formation of blockages. Ill. 6. Ref. 12. Tab. 1.

The paper presents comparison of casting ‘Bearer’ for a heat-treatment furnace. The mentioned casting is produced by casting in the resin bonded sand and by centrifugal casting. High-temperature mechanical tests showed some defects in the resin bonded sand casting, the shrinkage nature whereof was identified in course of a metallographic study. Inevitability of the shrinkage effect formation was also conformed by modelling of pouring-in and solidification in the program LVMFlow. Study of the casting structure showed that a centrifugal casting possesses a directed axial anisotropic structure, with the grain size which is larger than that of a resin bonded sand casting. The totality of the obtained results speaks for the fact that to achieve an acceptable quality level of ‘Bearer’ casting, it should be produced with the use of centrifugal casting.

The technology of producing composite ceramic coating based on zirconium dioxide has been developed. The method includes applying a ceramic material to metal substrates with a specially prepared surface. The sample was dried, calcined and sintered at 1200 °C in vacuum.

Corrosion properties of type 625 alloys (Inconel 625 and Nicrofer 6020) in chloroaluminate melts were investigated in a wide range of temperatures and various exposure time intervals using gravimetric tests and energy- dispersive X-ray spectroscopy of corroded samples surface. It was shown that corrosion processes have electrochemical nature and the increase of temperature up to 650 °C leads to change of corrosion mechanism from gradual etching towards intergranular corrosion. Intergranular destruction is associated with the formation of secondary phases at the grain boundaries of alloys. "Time-temperature-precipitation" diagram was constructed to predict the possible conditions of type 625 alloys application. It was found that Inconel 625 and Nicrofer 6020 alloys can be used in contact with chloaluminate melts at temperatures less than 600 °C.

Carbide–boride coatings applied on both sides of V96Ts aluminum alloy samples by electric spark alloying (ESA) are metallographically studied. The coated samples are processed by laser on one side. Laser treatment of the surface decreases the pronounced roughness, pores, and cracks visible after ESA. Laboratory tests suggest combined (electric-spark–laser) hardening of the surface of V96Ts aluminum alloy samples to extend the service life of tools and machine parts.

The structure and wear resistance of Stellite 6 alloy were studied before and after laser heat treatment. A significant refinement of the microstructure after the heat treatment is noted, the hardness the alloy changed slightly. An increase of wear resistance in shock-abrasive wear at angles of attack of 60-90° as well as metal-to-metal wear with presence of an abrasive layer is shown.

A technology is proposed for producing heat-protective ZrO2 - Y2O3 - ceramic fiber coatings up to 3 mm thickness by pneumatic spraying of a slip, with additional reinforcement of the metal substrates with nichrome coils and the application of a sublayer composed of a mixture of nickel and aluminum powders.

The name of the first author should read V. V. Karpov.

The results of a comparative research into the corrosion resistance of an aluminum matrix composite material produced by the oxygen lancing of a prehydrogenated aluminum alloy melt based on Al–Si–Fe with an iron content of over 1.0% and Al–7% Si alloy with an iron content of up to 0.3% modified by ligature 5Al–Ti for 2% are shown. The aluminum-alloy corrosion was conditioned by the film discontinuity of the oxide on some phases, primarily Al 5 SiFe. The composite and reference alloy-sample couples with a diameter of 15 mm and a length of 50 mm were put to the test in a 7% solution of NaCl salt fog in SFC-1 chamber on suspension brackets at a temperature of 22°C for 300 h. The results show the mass loss close values of the samples, despite the significantly higher iron content in the composite, because particles 100–200 nm in size formed in the melt by lancing are deposited on the composite phase boundaries, reducing the interaction surface area with the corrosive environment. The researched composite material can be recommended as a corrosion-resistant alternative to alloys with elevated iron content, which are used for high pressure die casting (HPDC).

The structure of VDM ® Alloy C-4 (UNS 06455) in “as received” state was studied. The data on the kinetics of secondary phases formation for “sheet” and “tube” samples in the range from 550 to 1100 °С after exposure for various period of time (from 30 min to 1000 hours) are presented. The data concerning the resistance against intergranular corrosion of the material under various conditions were analyzed using ASTM G-28 and RD 24.200.15-90 techniques.