Research of structure and properties of boride hardening coatings

High strength aluminum alloys are particularly suitable as lightweight materials in vehicle and aircraft engineering. The wear resistance of materials can be improved by surface and coating technology. Strengthening of parts and units of machines, increased reliability and longer service life is an important task of modern industry. The aim of research was to apply boride coatings on surface of steel parts. Timeliness is subject to necessity to harden surface of steel used in high-load conditions. Samples of coatings on 65 G grade steel, applied by HFC-heating, were obtained. Research of samples with different coatings by means of metallurgical microscope was carried out. Data on samples with different coatings research by means of an eddy current measuring system was obtained and conclusion on electrical conductivity distribution along the sample surface depending on flux quantitative content during boriding was made

Investigation of the SHS process initiation in the base mixture during HFC heating and the dependence of the combustion rate on various factors

This work is devoted to the study of promising materials - liquid-phase systems aluminum-boron oxide. These materials after SHS process form a boride coating that provides high strength and wear resistance of steel parts. The article describes the features of the initiated SHS process and the nature of the mixture combustion, studies of the HFC heating effect for SHS process. At the first research stage, the dependence of initiation SHS in all investigated compositions on the characteristic size of the sample and the composition of the base mixture was determined. The combustion rate was estimated from the combustion time of the sample from one end of the sample to the other. The burning rate was also estimated SHS-compositions on the particle size of the reagents. At the second stage of the research, the composition of the base mixture was modified by the introduction of a flux P-0.66. The addition of flux made it possible to significantly reduce the burning rate and compare in time SHS process obtaining boron during combustion of a modified composition and the process of HFC boriding high-speed

Investigation of the steel parts’ hardsurfacing overlays properties

The article describes the studies’ results of steels with applied boron-based hardsurfacing overlays. The overlay was done in four different ways. The materials obtained differed in chemical composition, properties and wear resistance. A detailed technical process of surfacing and the surfacing charge composition, which makes it possible to obtain the necessary material, is given. Studies of hardness, macro- and microstructure, chemical and X-ray phase composition of the obtained materials have been carried out. The descriptions of the overlays’ characteristic phases are made and their properties are given. The chemical composition of the obtained overlays has been determined by the emission spectroscopy method. The X-ray phase analysis of the samples has also been carried out and the percentage of the additional modifier introduced into the overlays has been determined. Based on the results of the studies carried out, the conclusions about the optimal method of metal hardening have been drawn

Ultra-miniature eddy-current converter for small defects of deep occurrence search in the area of high-yield-stress steels weld joints

The presented study describes a diagram of an eddy-current measuring system built on the basis of a subminiature eddy-current converter, intended for the conducting materials’ study. The article describes the results of testing a designed measuring system for defects search in 6XB2S steel samples, connected by a weld joint. The technology for creating such materials permits the significant impact resistance of finished products and provides an optimal combination of hardness and toughness. However, the defects formed in the material near the weld joint become a serious problem in the operation of such materials. In this study, an assessment of the possibility of searching for model defects hidden by a weld in two steel plates was made. The defects had different linear dimensions (0.3 - 0.9 mm) and occurred at different depths (1 - 2 mm). The developed system showed high efficiency of scanning and searching for defects with linear dimensions up to 0.9 mm. The search for smaller defects required a significant modernization of the developed measuring system - the introduction of a second eddy-current converter. The article presents the data confirming the feasibility of this change in the measuring system and the possibility of using a measuring system with two eddy current converters to search for small defects occurring at a considerable depth

Chemical reactions at high-speed HFC-boriding

Strengthening of parts and units of machines, increased reliability and longer service life is an important task of modern industry. As an promising materials for protective-strengthening coatings, offered matrix composites based on the ternary system Fe-B-FenB. The article is proposed the complex heating of steel being borated and imbued medium by high frequency currents (HFC), and to combine the diffusion boriding from liquid and solid media and the transition of the diffusion boriding to chemical interaction between the elements of Fe and B. We determined the main components of the reaction-boronizing system, as well as their roles and possible processes that lead to the implementation of topochemical boriding initiated by HFC-heating. Confirmed the course of the reaction leading to the occurrence of reducing agents Ca, Si and active boron in the boronizing mixture

Research of high-speed HFC-boriding kinetics

The paper presents studies boride coatings, which were created using high-frequency treatment with currents. Chemical reactions characterized the boriding procedure at various temperatures are show. The choice of the main element, of the reaction-boriding scheme is characterize, their role is revealed, and the probable processes leading to the realization of topochemical boriding initiated by HFC-heating are established. The kinetic curves received during the test at different temperatures are showed. Anamorphoses of the kinetic curves are showed, and the values of activation energy and parameters of the boriding process using HFC-heating are calculated on the basis of linearization of the Arrhenius equation

Technology selection for cultivation of sunflower hybrids in Central Black Earth region

This study applies a number of technologies to cultivation of sunflower hybrids with variable soil properties, weather conditions and farm locations in Central Black Earth: Kursk, Orel and Voronezh regions. The three-year research identified reactions of sunflower hybrids from different manufacturers to cultivation technology and weather conditions; we made relevant observations; analysed yield structure, yield and seed quality parameters; forecast prospects of using CLEARFIELD and ExpressSun technologies for sunflower cultivation in Central Black Earth region. Overall, the experiment revealed the advantage of CLEARFIELD® (EURO-LIGHTNING®) technology in Kursk region. Hybrids from main producers had a superior average result compared to the standard hybrid SI Bacardi (Syngenta) over three years of research: this is an increase of 0.6 t/ha or 24% (hybrid P64LC108), 1.3 t/ha or 52% (hybrid EC Generalis), and 0.9 t/ha or 36% (hybrid MAS 89 IR).In Orel region hybrids cultivated with ExpressSun (Express® 75 v.y.) or Sumo showed better performance. The hybrid P62LE122 gave an increase of 0.4 t/ha or 20% and the hybrid EC Argentic - 0.3 t/ha or 15% compared to the standard hybrid Sumiko (Syngenta). In Voronezh region hybrids cultivated by ExpressSun (Express ® 75 v.y.) or Sumo technology had yield advantage. Increases were between 0.5 and 1.0 t/ha, or between 15 and 29%, depending on the sunflower hybrid cultivate

Scanning the welded joints of aluminium alloys using subminiature eddy-current transducers

Aluminium has a reputation for ease of use, strength and durability. In addition to its exceptional aesthetic properties, solid aluminium does not burn. As architects, contractors, consultants and real estate owners look to meet stringent safety requirements in the construction and refurbishment of high-rise constructions for both residential and commercial uses, aluminium cladding provides an alternative that is not only safe but that is also durable and attractive. One of the ways to connect elements into a aluminium construction is welding. friction stir welding is one of the most efficient. The authors developed a measuring system based on subminiaturized eddy-current transducers aimed at examining locally the defects of welded joints in aluminium-magnesium alloy plates connected by means of friction stir welding. The authors made a modification of the Delyann filter, which allowed them to increase considerably the signal-noise relations. The dependency of the eddy-current transducer response on defects was provided, i.e. concealed cuts and openings inside the welded joint, at the frequencies of 100-10000 Hz of the exciting winding

Experimental Studies of Conductive Paths of Printed Circuit Boards by Using Subminiature Eddy Current Transducers

This paper describes the development and experimental study of a software and hardware complex designed for studying the conductive tracks of printed circuit boards. In the course of this development, a subminiature eddy-current transducer and a measuring system capable of performing measurements using the newly developed transducer were created. The paper contains descriptions of the main parameters of the developed measuring system, and also presents the results of experiments conducted with various printed circuit boards, both with defect-free and those with artificial model defects. These experiments made it possible to confirm the possibility of using the developed measuring system and eddy-current transducer for controlling the conductive tracks on printed circuit boards and determining their quality