Steel 12X18H10T Research Articles

ОБРАБОТКА ТОРЦОВ ЗАГОТОВОК ДЕТАЛЕЙ

The study objective is to increase turn process efficiency of corrosion-resistant stainless hard-to-machine steel 12X18H10T. The task is to reduce tool costs. Research methods are the following: full-field testing and simulation in deform software environment. The novelty of the work: a new approach is formed to increase the durability of a metal-cutting tool for turning the ends of workpieces. This made it possible to find out the most rational coatings for different operating conditions. Research results: recommendations are developed to choose a rational coating for hard alloy of VK8 grade.

Особенности моделирования шероховатости поверхности при фрезеровании нержавеющих сталей c применением различных сред

Modeling characteristics for surface finish when milling stainless steels using various media (grade steel 12X18H10T) using IOL-20A (industrial oil lubricant), CM-99 (cooling mixture), rapeseed and castor oils and on dry treatment, using the algorithms of the group method of data handling are viewed. The use of various lubricating and cooling technological mixtures (LCTM) is thought of as the theory of metal cutting factor reducing surface undulation. However, the degree of influence of various LCTM, including vegetable oils, when milling steel 12X18H10T has not been determined. The study case of various effects interaction on the milling process has shown that these studies were conducted on the basis of single-phase experiments that do not allow specifying mutual influence of the studied factors on the value of the parameters of the cutting process for various types of treatment. The research methodology provides for modeling surface finish under milling of 12X18H10T steel according to experimental data using various process liquids in the accepted range of cutting modes. At the same time, modern modeling methods allow us to determine these mutual effects. To obtain models, it is urgent, first of all, to be aware of break-in process criterion and dulling tool criterion as well. As a result of processing experimental data for each of processing media, surface finish models in the form of dependencies Ra = f (v, sz, t) were constructed, adequately describing the milling process with various media. It is indicated that the influence of regime parameters on the formation of micro-dimensions take the form of their close interrelation. Their interplay has various effects, depending on the LCTM used for the specified work stock and tool material.

ALKALINE WATER ELECTROLYSIS WITH ANION EXCHANGE MEMBRANES AND DIFFERENT TYPES OF ELECTRODES

The article is devoted to the creation of a new generation element base for aqueous alkaline electrolyzers with anion-exchange membranes. As a result of the research, two new membranes and various types of electrodes have been proposed, which significantly increase the purity of the generated electrolysis gases and the operating outlet pressure directly at the outlet of the electrolysis module while maintaining low values of specific energy consumption. In this case, the electrolysis module consists entirely of electrode-membrane blocks. Their composition includes components tested in industrial alkaline electrolysis, which distinguishes them from known analogues in chemical resistance. Various types of catalysts that can be used as part of membrane-electrode blocks are considered separately. The results of express tests of electrodes made of stainless steel 12X18H10T are presented, the oxidation process of chromium, which is part of the alloy, is shown, which leads to a decrease in its corrosion resistance. When testing electrodes based on a steel mesh coated with a protective layer of nickel, extensive pitting corrosion was detected on the anode during its operation at high current densities. As an alternative, electrodes made of nickel mesh are proposed. These samples showed excellent corrosion resistance and high adhesion to electrodeposited catalysts. Catalytic coatings consisting of nickel or nickel-cobalt powder with additionally chemically precipitated phosphorus were investigated as catalysts.

EMPIRICAL FORMULA FOR THE DEPENDENCE OF HPGe-DETECTOR EFFICIENCY ON ENERGY AND DISTANCE FOR SHIELDED GAMMA-RAY SOURCES

The accuracy of gamma-spectrometric measurements in the isotopic analysis of shielded nuclear materials depends on the accuracy of the detector calibration in terms of energy efficiency, which should take into account corrections related to the measurement geometry and the absorption of γ-radiation by the shield material. The results of experimental studies of the energy efficiency of the HPGe-detector measured at fixed distances between the calibration source and the detector (50 and 100 mm) in the presence and absence of an absorbing shield made of stainless steel 12X18H10T (thickness ‒ 9.6 mm) are presented. On the basis of experimental data, an empirical description of the efficiency dependence for fixed distances between the gamma radiation source and the detector in the presence of a stainless steel absorbing shield was obtained.

Structure and properties of multilayer coatings based on CoCrAlY/Al2O3 obtained by detonation spraying

Ceramic coatings are used to protect against high-temperature oxidation of metal products. The efficiency of the technology of detonation spraying of two-layer coatings of aluminum oxide ( Al2O3 ) and a heat-resistant alloy (CoCrAlY) on the surface of a sample made of steel 12X18H10T was studied. A multi-chamber detonation unit was used in the work, providing high speed (up to 1000 m/s) and a 60–80% utilization rate of the sprayed material. We used an oxygen-neutral combustible mixture based on propane-butane. The coating material has a smooth gradient of properties from ceramic to sample substrate The complex of the obtained structural and physical-mechanical properties of the coating material makes it possible to predict its high performance under conditions of high-temperature oxidation.

EVALUATION OF THE INFLUENCE OF VARIOUS FACTORS ON THE CORROSION OF STEELS DURING MOISTURE CONDENSATION UNDER THE CONDITIONS OF TRANSPORTATION OF A CORROSIVE GAS

The problem of internal corrosion is an urgent problem in the transportation of produced products with the presence of corrosive-aggressive components through gas pipelines. The presence of CO2 or H2S in the produced gas in combination with the presence of condensation water, as well as a number of other factors, stimulates the intensive development of carbon dioxide or hydrogen sulfide corrosion of a local nature. To determine the limiting rates of local corrosion, corrosion tests were performed under conditions of moisture condensation, which occurs when a temperature gradient occurs and the transported gas is rapidly cooled. A study was carried out to assess the influence of the main operational factors on corrosion processes during moisture condensation on the inner surface of the gas pipeline: humidity, temperature, type of steel, the presence of a weld and the presence of alcohol, monoethylene glycol and acidic environments. It has been established that many of the above corrosion parameters accelerate local corrosion of carbon and low alloy steels, thedevelopment rate of which reaches up to several mm/year. It has been determined that the rate of development of corrosion processes during the condensation of water-glycol and water-alcohol solutions depends on the amount and composition of the liquid condensing on the metal surface. High-alloy steel 12X18H10T (with 18% Cr) showed resistance to corrosion conditions during moisture condensation.

К ВОПРОСУ О МОДЕЛИРОВАНИИ ОПЕРЕЖАЮЩЕЙ ТРЕЩИНЫ ПРИ ВИБРОТОЧЕНИИ

The work objective is to consider the possibility of creating conditions for appearing a leading crack by adjusting the modes of vibratory turning, regardless of the properties of the machined materials.
 The problem to which the paper is devoted. The paper is devoted to modeling vibration turning for developing stresses in the machined material to create conditions for appearing and maintaining a leading crack and in the cutting area during vibratory turning, the search for optimal modes to create conditions for its existence. 
 Research methods. Modeling was carried out by the finite element method in Deform software application. The starting point for modeling was the results of field experiments on vibratory turning of corrosion-resistant austenitic steel 12X18H10T.
 The novelty of the work lies in the application of the finite element method to define the modes of vibratory turning in order to create a certain area of internal stresses in the processed material in a given direction for forming a leading crack. 
 Study results. As a result of modeling, optimal turning modes are defined during vibration cutting, which will create conditions for appearing a leading crack and exhausting the plasticity margin of the machined material. 
 Conclusions: The creation of a leading crack and the exhaustion of the plasticity margin of the machined material contributes to the chip control, the formation of microgeometry of the machined surface during vibratory turning, the reduction of cutting forces when turning hard-to-machine materials and built-up surfaces.

Investigation of the Parameters of the Surface Layer of Steel 12X18H10T after Plastic Deformation

The paper presents the results of metallographic and electrophysical studies of the structure of 12X18H10T steel after plastic deformation. Studies allow us to determine the optimal modes of plastic deformation of corrosion-resistant steels.

Effect of multilayer coatings based on zirconium and titanium on wear resistance of carbide tools during turning of stainless steel

In this article, the influence of coatings of the type (Ti—Zr)N—TiN, TiN—ZrN and ZrN—(Ti—Zr)N—TiN obtained by physical vapor deposition on the wear resistance of T15K6 cemented carbides plates during longitudinal turning blanks from stainless steel 12X18H10T is considered. It has been experimentally established that the presence and composition of the coating on the working surfaces of the tool in all cases contributes to a significant decrease in the wear rate of cemented carbides inserts. According to the research results, the composition ZrN—(Ti—Zr)N—TiN should be considered the best option. During the cutting process, for a tool with this type of coating, the minimum wear along the flank surface and the length of chip contact with the rake surface, as well as the smallest values of the shear angle in the zone of primary plastic deformations, were recorded.

A new method for restoring worn surfaces of steel parts of pumping equipment, nuclear power plants

The paper proposes a new method of restoring worn surfaces of steel parts of pumping equipment used at nuclear power plants and subjected to radiation irradiation. The method belongs to the field of electrophysical and electrochemical treatment, in particular to electrospark alloying (ESA), and is applicable to repair parts of machines of nuclear power plants. The EBS method has a number of specific features: the anode material (alloyed material) can form a coating layer on the cathode surface (alloyed surface) that is extremely strongly bonded to the surface; the alloying can be performed in strictly specified places without protecting the rest of the part surface; the ESA technology for metal surfaces is very simple, and the necessary equipment is compact and transportable. The method includes coating of the worn surface of the part by electroplating with the same metal electrode - an instrument made of material (steel 12X18H10T or nickel) without special additives of cobalt and other elements that form long-lived isotopes in the active working environment. The electrodeposition is carried out in two stages. Before the first stage of coating with metallic electrode-tool a layer of coating with graphite electrode-tool with discharge energy Wp = 0.02 J and capacity 0.3 cm2/min is applied to the worn-out steel surface by ESA method, Then the first stage of coating layer application by ESA method by the metal electrode/tool at discharge energy 0.20-0.55 J and productivity 1.6-2.5 cm2/min ensuring surface thickness 0.09-0.16 mm and its continuity 100% , after that the surface obtained is subjected to the second stage of coating layer application by ESA method by the same metal electrode/tool with discharge energy 0.55-0.90 J and productivity 2.5-3.4 cm2/min.

Possibilities of Additive Technologies for the Manufacturing of Tooling from Corrosion-Resistant Steels in Order to Protect Parts Surfaces from Thermochemical Treatment

The structure and physical–mechanical properties of products made from powders of corrosion-resistant steel 12X18H10T by the laser-beam powder bed fusion (LB-PBF) and subsequent ion-plasma nitriding in the work were investigated. Comparative studies of the physical mechanical properties of specimens made by the LB-PBF and conventional method from steel of the same grade were carried out. The density of the specimens and the coefficient of linear thermal expansion (CLTE) after the LB-PBF are almost the same as those of the conventionally manufactured specimens. Our analysis of the obtained dilatograms in the temperature range from 20 to 600 °C showed that the CLTE of steel after the LB-PBF is within acceptable limits (18.6 × 10−6 1/°C). Their hardness, tensile strength, yield strength and elongation are higher than those of a conventionally manufactured specimen. The phase composition and structure of specimens of steel 12X18H10T made by the LB-PBF after the process of ion-plasma nitriding were investigated. The obtained results show that the mode of ion-plasma nitriding used in this case (stage 1—570 °C for 36 h; stage 2—540 °C for 12 h) does not lead to deterioration of the characteristics of the selected steel. A technological process for the manufacture of modified tooling from 12X18H10T steel by the LB-PBF was developed. It protects the surfaces that are not subject to nitriding and makes it possible to obtain a uniform high-quality nitrided layer on the working surface of the part made from spheroidal graphite iron.

Formation of resistance of welded seams against forming of hot cracks when welding is performed with an increased speed

ABSTRACT The results of experimental studies of some features of non-consumable electrode welding in argon steel 12X18H10T with increased speed are presented. The possibility of improving the quality of formation and resistance of seams against the formation of hot cracks by exposing the arc and metal of the weld pool by controlling the magnetic field of the current flowing through the contact conductor located above the tail section of the weld pool, perpendicular to the electrode is shown.

ИССЛЕДОВАНИЕ ВЗАИМОДЕЙСТВИЯ СОЛЕЙ РАДИЯ С КОНСТРУКЦИОННЫМИ МАТЕРИАЛАМИ

Through calcination of barium salts (as a simulant of radium) on metal substrates interaction of barium nitrate and barium carbonate with some structural materials was examined: steel grade St3, stainless steel 12X18H10T, tantalum, nickel, zirconium and silver. The experiments were performed again for nickel and stainless steel using milligramme quantities of radium.

Machinability investigation and optimizing process parameters in ECM of stainless steel −12X18H10T for minimizing surface roughness

The tool and die applications are preferred the unconventional machining processes as they are popular in machining the difficult to cut type complex contour/ profile. The complex profile machined on hard material. Some special materials like Stainless Steel 12X18H10T withstand its inherent properties even it exposes at higher temperature. This investigation aims to expand its application by investigating its machinability in Electro Chemical machining process for surface finish. The process parameters like gap between work material and tool, discharge current, concentration of electrolyte and applied voltage at three levels. The Taguchi approach is used for optimizing the process parameters and confirmation runs also conducted for developing the mathematical modelling. For optimizing number of experiment the Taguchi L9 is utilized for this investigation.

VACUUM-PLASMA PROPERTIES OF STAINLESS STEEL AFTER IMPACT OF COMBINED GLOW-MICROWAVE DISCHARGES IN ARGON ATMOSPHERE

The experiments were carried out to determine the vacuum-plasma characteristics (mainly erosion and outgassing rate in a vacuum) of the stainless steel 12X18H10T before and after processing the walls of the vacuum chamber with the glow discharge and combined, glow-microwave plasma discharges in argon atmosphere. The current-voltage characteristics, the electron density and electron temperature were measured. It was observed that the discharge voltage in the combined regime is significantly lower than in glow discharges. In some modes, this voltage decrease can be up to 200 V. It was shown that erosion of stainless steel 12X18H10T in the combined discharges is 70 %, less than in the glow discharges. Measurements were made of the outgassing rate of 12X18H10T stainless steel with the thermal desorption probe in situ in the DSM-1 vacuum chamber. It was shown that cleaning the chamber wall by the glow discharge during 5 h leads to a decrease in the outgassing rate from 5.5·10-5 to 1·10-5 (Torr.l)/(s.cm2) . When the chamber wall is treated with GM discharge starting from nearly the same initial conditions the outgassing rate decreased to 3·10-6 (Torr.l)/(s.cm2). Spectral measurements of the plasma radiation of a glow and combined discharges show a decrease in the ratio of the peaks of argon ions and neutrals during the transition from a glow discharge to a combined one.

The main parameters of the cutting process and technological factors affecting the reliability of the axial tool

This article discusses the main parameters of the cutting process that affect the reliability of the axial tool. The stability of the technological process of machining is largely determined by the quality characteristics of the tool used: its design, tool materials and modes of its operation, which are determined at the design stage of the technological process. A drill with MNP (multi-faceted non-resurfacing plates) of a new design was developed at the Department of Engineering Technology of the Tashkent State Technical University named after I.A.Karimov, and the study was carried out on the same drill. According to the research carried out: when processing steel 12X18H10T, the specific energy consumption of the cutting process with a drill with MNP is more than 5.0 times lower than that when processing with a twist drill, and when drilling steel 45, it is almost 2 times lower.

EXPERIENCE IN MANUFACTURING OF THE OUTER CASING OF AN IMMOVABLE AMPOULE NA-228 OF THE IGR RESEARCH REACTOR

The article presents the technological cycle of manufacturing the outer casing of an immovable ampoule NA-228 of the Pulsed Graphite Reactor (IGR) made of stainless steel 12X18H10T. The results of strength analysis of structural elements and casing manufacturing technology are presented. By welding control samples, the optimal welding parameters of the casing segments were determined, as well as the number of tacks and layers, order and number of passes ensuring high product quality.

Assessment of Hydroabrasive Wear Resistance of Construction Materials with Functional Coatings, which are Formed by Resource-Saving and Environmentally Friendly Technologies

The work presented in this paper is devoted to the formation of thick-layer wear-resistant coatings by technologies based on electrospark alloying, an example of essential components hardening for the heavy-duty processing equipment operating under hydroabrasive wear conditions. The aim of the paper is to improve the manufacturing and repairing technologies for the helical surfaces of the screws made of 65Г, 30X13 and 40X steels and corrosion-resistant stainless steel 12X18H10T. The above aim has been achieved owing to applying the new environmentally friendly technologies for the formation of the surface layers, and also due to the choice of the surface layers that are most resistant against hydroabrasive wear, which choice being provided for by conducting the comparative tests on the samples made of the above said steel grades and strengthened in various ways. The analysis results of the hydroabrasive wear resistance of the samples made of steel and provided with protective coatings is presented.

Structural regularities of welded seam between Ti-TiB and vanadium with 12X18H10T interlayer by using electron beam welding

Possibilities of obtaining and using an intermediate layer for joining of Ti-TiB and austenitic steel 12X18H10T (analog of AISI 321; 1.4541; X10CrNiTi18-10) were studied. An alloyed interlayer with TiB reinforcing fibers and the main alloying elements of 12X18H10T steel was formed on the surface of the Ti-TiB sample. Such interlayer was formed during electron beam welding of Ti-TiB with vanadium using foil made of 12X18H10T steel. The microstructure of the interlayer consists of a metal matrix reinforced with microfibers. It’s composition corresponds to vanadium-alloyed titanium boride. In comparison to the initial Ti-TiB alloy, significant grinding of reinforcing boride microfibers in the interlayer microstructure was observed. Besides, the phase formations close to Ti2B in zone of primary titanium borides decomposition in the interlayer, initiated by electron beam were determined. As a result, application of Ti (63-68 at.%) and V (18-25 at.%) based interlayer with alloying additives (Fe, Cr, Ni, B, C) has great potential for utilization in electron-beam welding of 12Х18Н10Т steel with Ti-TiB alloy.

ТЕХНОЛОГІЧНІ АСПЕКТИ ЗАБЕЗПЕЧЕННЯ ЯКОСТІ ДЕТАЛЕЙ ПРИ ПНЕВМОУДАРНОМУ ШТАМПУВАННІ ВИРУБУВАННЯМ-ПРОБИВАННЯМ

The paper considers the issues related with technological capabilities and features of the process of cutting-punching of sheet-metal parts with an elastic medium of pneumatic impact stamping, taking into account the indicators of their quality and accuracy, and also suggests effective ways to improve them. One of the promising methods for producing high-precision parts, including those with a complex profile, is a shaping method based on the technology and equipment of pneumatic shock stamping with an elastic medium on the TA-1324 in-stallations. The advantages of this method are environmental cleanliness, safe operation, wide technological capabilities, mobility and versatility, low labour and energy costs. At these installations it is advisable to perform formative operations of separation (cutting-punching) and shallow shaping both as a separate operation and together with cutting-punching. As a workpiece for the study the sheet material of the following grades was used: steel 08kp, aluminium alloy AMG-M, steel 12X18H10T. The thickness varied within the range from 0.5 to 2.5 mm. Dies and copier punches were made of U8A steel, followed by heat treatment to a hardness of HRC 56-62. An analysis of the experimental studies of punching-cutting processes allows us to conclude that with an increase in the number of stamped parts, there is an increase in size deviations from their nominal values. This increase is due to the wear of operating elements (copier punches and dies). At the same time, the sizes of the copier punches are reduced, and the sizes of the matrices are increased. The absolute values of deviations do not depend on the type of operations; their values, both during cutting and punching, are almost the same in each of the samples taken. The process of pneumatic impact stamping, where a hammer with a bevelled end was used, has a similar character. The paper also proposed and tested ways to improve pneumatic impact stamping, providing cutting, punching of parts from sheet copper, aluminium alloys with a thickness of 0.3 to 3 mm and mild steel up to 3 mm thick. The roughness of the cutting surface is in the range Ra = 0.3 to 0.6 μm, and in the case of high-strength materials up to 2.5 mm thick, the roughness of the cutting surface is Ra = 0.6 to 1.0 μm, depending on the contour configuration that is cut down or punched.