Materials Science Forum Vol. 1037

Abstract: The paper presents the results of numerical experimental studies of cutting titanium blanks using mathematical modeling programs, which make it possible to completely repeat technological processes in a computer (digital twin). The LS-DYNA product was used as a program to simulate the process of stock removal from titanium blank. It has been established that the use of this method adequately describes the cutting processes, including with the introduction of the energy of an ultrasonic field into the processing zone, can significantly reduce the duration of experimental research and evaluate the influence of the elements of the cutting mode and design parameters of the tool on the thermal power aspects of the formation of new surfaces of machine parts.

Abstract: Abrasive processing remains one of most demanded for hardened steels parts. Grinding of end surfaces of machines parts has become widespread due to the fact that it allows processing heat-treated surfaces more efficiently than turning and also correcting the surface geometry. This processing type is used almost mainly for finish processing operations of shafts ends, bearing rings, gears, etc. However, there is still no mathematical model for this processing type, which would satisfy most of the main technological parameters. In this article a mathematical model of the cutting force when grinding the shaft end by the grinding wheel end on circular grinding machines is obtained. Processing schemes for this grinding type are given and the calculated graph of the cutting force according to the obtained mathematical model is shown.

Abstract: The article presents the results of the study of the quality parameters of the precise hole, depending on the size, spatial location and condition of the contacting surfaces, the parameters of the state of the contact zone, during finishing grinding. The correlation between the processing modes and the current parameters of the contact zone during internal grinding is established. Dependencies describe the flow cross-feed for the i-th turn increment of the depth of micro-cutting, compensation of radial material removal previous turn, deterioration of the wheel, the increment of the elastic and thermal strains. At the same time, the depth of micro-cutting and the increment of elastic and temperature deformations affect the values of the radial wear of the tool and the radial removal of the material. The equation of displacement balance is developed for discrete processes of hole processing with abrasive tools, during which the analyzed surface area comes into contact with the abrasive tool periodically.

Abstract: The paper describes some aspects of a scientific and research project dedicated to mechanical property prediction in plates for pipe production rolled at PJSC MMK 5000 Mill. The prediction is based on billet thermal state modelling by thermo-mechanical control process (TMCP) of rolling and subsequent cooling. The central focus of the modelling is the calculation of billet layer-by-layer cooling trajectory. The paper presents some results of model verification by test rolling.

Abstract: This article discusses the results of work on the creation of a flaw detection unit, which is focused on the study of high-strength steels. Welded joints of transformer tanks, which are made of steel grade 08G2B, were selected as the object of research. We chose this grade because of the ultra-low carbon content of this material. This opens up opportunities for the application of eddy current nondestructive testing methods. For practical measurements, a scanning device was designed and optimized. It includes a converter that uses the principles of eddy currents and includes three coils assembled on a ferrite core, grade 80NMZ. The device was tested on samples with model continuity defects (cracks and holes). Also, within the framework of the publication, modeling of corrosion defects in welded joints was carried out.

Abstract: It has been established that external uniaxial tensile stresses influence the character and kinetics of the g®a-transformation in cold-rolled martensite steel at sub-zero temperatures (down to -60 °C).

Abstract: The article presents a study of the characteristics of experimental samples with a chrome coating: the straightness and ovality of the inner surface of the cylinder, as well as the hardness and thickness of the chrome coating. The chrome coating is obtained on a previously developed installation for applying chrome coating on the inner surfaces of hydraulic cylinders of hydraulic drives with hydrostatic guides. The measurement of the geometric characteristics of the internal surface of the samples was carried out, the values ​​of deviations from roundness and deviations from straightness were obtained. A study of the chrome coating was carried out, for this we cut out sectors from the samples, carried out their sample preparation, measured the hardness and took pictures under a microscope, measured the hardness and thickness of the chrome coating. The obtained measurement results: deviation from roundness, deviation from straightness, coating hardness, coating thickness - correspond to the specified technical requirements, the proposed construction of the installation for applying chrome coating to the inner surfaces and the electrolyte composition, selected earlier, are applicable for chrome plating of the inner surfaces.

Abstract: The possibility of introduction of antifriction and wear-resistant modifying agents into the matrix of a composite nickel-phosphorus coating to obtain effective composite coatings, is considered. The analysis of the possible influence of modifying additives in the form of ultrafine powders on the tribological properties of the developed coatings, is carried out.

Abstract: The results of a study of the influence of shapes of samples, as well as the presence of internal cavities and their shapes, on the nature of wave strain hardening (WSH) are presented. The peculiarity of the method lies in the impact of a stream of pulses on the processed material, while instant wave states, which affect the microhardness maps in the workpiece are formed in the material. These studies were carried out for the first time on a specially designed stand. The studied grades of materials were: steel 45 and bronze BRAZH 9-4. As a result of the studies performed, the geometric shape of the samples and cavities in them was revealed, which contribute to an increase in microhardness.

Abstract: Investigations of metallographic and mechanical properties of local diffusion discrete oxide coating on high-speed steel Р6М5 have been carried out. It was found that the technology of discrete oxidation makes it possible to increase the hardness by 31% in relation to the uncoated material, and the wear resistance of the cutting tool with oxidation is 1.5-3 times higher than that of the tool hardened by the standard ion-plasma technology.