TO THE QUESTION OF STRUCTURAL FEATURES OF IRON COATINGS OF HIGH THICKNESS OBTAINED BY THE ELECTROGALVANIC METHOD WITH MECHANICAL LAYER-LAYER HARDENING

The process of electrogalvanic production of coatings of increased thickness with layer-by-layer mechanical hardening is considered. The mode of deposition and the scheme of coating deposition, the research technique and the results of the X-ray analysis of internal stresses are presented.

Influence of the Structure of Iron Coatings on their Physical and Mechanical Properties

The influence of electrolysis parameters on the structure and properties of iron coatings is shown. The dependencies of hardness of iron coatings upon the parameters of metal microstructure characterized by dilatation are established. It is shown that dilatation can be used as a checkup parameter for iron strength properties. The influence of some factors on the properties of iron deposits obtained under non-stationary deposition regimes is analyzed.

Electroplating of iron and its alloys

Analytical review of information on electrodeposition of iron and its alloys from aqueous solutions is carried out. Processes of electroplating of iron and its alloys from aqueous solutions and the principal fields of application of these galvanic coatings are discussed. The principal technological advantages of using iron coatings in the reconditioning of steel parts are considered. Compositions of electrolytes and conditions for plating of iron coatings are provided. Technological parameters of electroplating of iron from industrial electrolytes are considered. Data are presented on the effect of some organic additives on the iron plating process. The effect of the concentration of Fe3+ ions in iron plating electrolytes on electroplating of iron coatings and their physic-mechanical properties is discussed. The data are presented on physic-mechanical properties of iron coatings obtained in different electrolysis modes. Nonsteady-state electrolysis modes are discussed that are used in industry for application of iron coatings. The effect of coating plating conditions on their mechanical properties is studied. Technological parameters of electroplating of iron alloys are considered. Co-deposition of iron with nickel, chromium, titanium, phosphorus, molybdenum, vanadium and tungsten is described. Data are provided on compositions of electrolytes and conditions of electroplating of these alloys. Main fields of application of electroplated iron alloys are discussed. Information is provided.

Intensification of the recovery of hydraulic equipment parts by iron in the electrolyte flow

The technology of bath-free ironing of parts in an electrolyte flow with simultaneous hydrome-chanical activation of the growing surface is proposed. Its advantages over the traditional type of coating are introduced. The structure, some physicomechanical and operational properties of iron coatings were studied depending on the electrolysis regimes and the composition of electrolytes. The possibility of high-speed electrodeposition of iron with a wide range of physical and mechanical properties is shown. There were shown the electrolysis modes, which make it possible to obtain high-quality strong-adhered pure-iron coatings with a wear resistance several times higher than hardened alloy steels and a precipitation growth rate tens of times higher than with traditional iron-ing. A typical technological process of parts ironing was developed. It was tested on the example of restoration of hydraulic valve spools of agricultural machinery. The design of an installation and an electrochemical cell for ironing the valve hydraulic distributors, providing optimal hydrodynamic conditions when applying coatings to worn surfaces, was proposed. Recommendations for the post-electrolysis treatment of restored parts by iron are given. Bench and field tests of hydraulic valves with remanufactured valves were carried out. They confirmed the results of laboratory studies, and showed that no malfunctions were identified during the operation period. Technical and economic calculations have shown the high efficiency of the proposed technology in comparison with tradi-tional ironing. The introduction of the technology in production will reduce the production area and the time spent on restoring parts by increasing the productivity of the iron process and reducing the number of operations, reducing the cost of materials for preparing electrolytes by reducing the op-eration of anodic treatment and washing, and increasing the reliability of the technology by improv-ing its structural scheme.

ВОССТАНОВЛЕНИЕ СЕЛЬСКОХОЗЯЙСТВЕННОЙ ТЕХНИКИ И ОБОРУДОВАНИЯ ГАЛЬВАНИЧЕСКИМИ ПОКРЫТИЯМИ НА ОСНОВЕ ЖЕЛЕЗА

В процессе ремонта изношенных деталей сельскохозяйственных машин необходимо обеспечить требуемый комплекс физикомеханических и эксплуатационных характеристик восстановленных поверхностных слоев. Износ деталей можно значительно уменьшить, используя для восстановления геометрических размеров гальванические покрытия, легированные металлами или неметаллами. Такие покрытия имеют большую износостойкость, коррозионную стойкость и высокие антифрикционные свойства. В работе рассмотрено использование Ni и Cr в качестве легирующих добавок в железные покрытия для упрочнения поверхностных слоев изношенных деталей, т.к. они повышают прочностные характеристики покрытий из электроосажденного железа. Хром имеет низкий коэффициент трения в паре с контролем, высокую тепло и коррозионную стойкость, что позволяет прогнозировать повышение эксплуатационных свойств в условиях использования сельскохозяйственных машин (окружающей среды, абразивномеханического износа и т.п.). Использование асимметричного переменного тока позволяет повысить скорость осаждения, увеличить твердость железных покрытий с легирующими компонентами (Ni и Cr) и применить их для восстановления деталей с высокими износами, эксплуатируемыми в жестких условиях. На асимметричном переменном токе значительно повышается производительность, технологичность, экономичность технологического процесса восстановления деталей, в частности, гальваническими покрытиями. Покрытия FeNiCr оказались эффективными при повышении долговечности восстановленных лемехов почвообрабатывающих машин и самотечных зернопроводов, поскольку обладают более высокой абразивномеханической, коррозионной стойкостью в сравнении с серийными лемехами, упрочненными сормайтом, и зернопроводов, изготовленных из листовой стали.During the repair of worn parts of agricultural machines it is necessary to provide the required complex of physical, mechanical and operational characteristics of the restored surface layers. Wear parts can be significantly reduced, using to restore the geometric dimensions of the galvanic coating, alloyed metals or nonmetals. Such coatings have high wear resistance, corrosion resistance and high antifriction properties. The paper considers the use of Ni and Cr as alloying additives in iron coatings to strengthen the surface layers of worn parts, as they increase the strength characteristics of coatings of electrodeposited iron. Chromium has a low coefficient of friction in conjunction with the counterbody, high heat and corrosion resistance, which makes it possible to predict an increase in operational properties in the conditions of use of agricultural machines (the environment, abrasive and mechanical wear, etc.). The use of asymmetric alternating current can increase the deposition rate, increase the hardness of iron coatings with alloying components (Ni and Cr) and apply them to restore parts with high wear, operated in harsh conditions. The asymmetric alternating current significantly increases the productivity, processability, and costeffectiveness of the process of restoring parts, in particular, galvanic coatings. Coating FeNiCr was effective in increasing the longevity of the restored plowshares tillage machines and gravitational grain pipelines because they have a higher abrasivemechanical, corrosion resistance in comparison with the serial shares, reinforced sorbitol and grain pipelines made of sheet steel.