Arc sprayed coatings from Fe-Cr-B-Y cored wires additionally alloyed by Al, Si, C were studied. SEM and XRD analyses, microhardness characterized their morphology, microstructure, and phase composition. The coatings were also evaluated by two-body abrasive wear test, and heat resistance test in air, 700°C, 100 h. Among compared coatings, the Cr12B5Al5Y one with maximum Al and minimum C content showed better indicators of porosity, adhesion strength, wear- and heat resistance comparing to other coatings alloyed with Si or less content of Al. It is resulted from the largest quantity of the carbon enriched eutectic containing reinforcing carboboride phases (Fe, Cr)2B, Fe2(C, B), and a rational ratio of the alloying elements. As shown, Cr12B5Al5Y coating wear resistance is more than twice as high comparing to the coating from typical wear resistant 150Cr8Ti2Al cored wire. The latter one consists of martensite phase, forming from the metastable austenite during loading, and chromium carbides. Weight loss tests showed that coatings from studied Fe-Cr-B-Y cored wires are of the same heat resistance level as the austenite steels and 1-2 orders of magnitude higher as compared to the pearlite and ferrite-martensitic steels, which are widely used as boiler's materials.

Previous studies have shown that austenite-to-martensite transformations occur in certain ferrous materials under an applied load, along with synergistic improvements in hardness and wear resistance. The aim of this study is to investigate the effects of such transformations on the tribological properties of chromium steel (FeCCrTiAl) coatings and overlays. The coatings were produced by arc wire spraying and the overlays by arc surfacing. Microstructure and phase composition were analyzed and abrasive and adhesive wear tests were conducted. Strain-induced nucleation of martensite under external load was confirmed by structural changes and differences in the tribological properties of the coatings and overlays were attributed to the particular conditions of their formation.

This work evaluates the influence of yttrium on the heat and wear resistance of active arc sprayed (AAS) coatings produced using FeCrBAl cored wire. The AAS process differs from ordinary arc spraying in that it uses propane-air combustion products as a carrier gas instead of compressed air. This increases particle velocity and temperature and forms a reducing atmosphere that protects metal particles in flight and improves coating adhesion and porosity. Coating samples produced with different amounts of yttrium were characterized in terms of surface morphology, microstructure, phase composition, and hardness. They were also subjected to heat resistance, abrasive wear, and corrosion tests in which they performed better than typical wrought steels used in boilers.

A comparative study was done on the structure and tribological properties of arc sprayed coatings and arc surfaced layers of TRIP steel. An iron alloy feedstock was used due to its ability to form a metastable austenite structure in both sprayed and surfaced layers that can be transformed to hard martensite by an applied external load. Microstructural and phase analysis and adhesive and abrasive wear tests were conducted to evaluate the coatings and surfaced layers. Differences in properties are explained based on input energy parameters.

Simulation of oxygen intake into Fe-Cr-Al coating at arc spraying was done. Based on the study of structure and properties of these coatings, the reliability of the model was evaluated.

Analysis of melting mode of core wire at Arc Spraying helped to explain a possibility of incomplete fusion of a charge of a core wire. Influence of physicochemical parameters of feedstock and atomization modes was established. Analysis results helped to develop a metastable austenite type Core Wire for Arc Spraying of good wear resistance. Applications results are shown.

A significant group of steel-making process parts is exposed to high contact pressure, shock abrasive wear and elevated temperature. High productivity repair techniques are necessary because of the large size of the parts. Analysis of coating metallographic investigations, wear and corrosion test results, full-scale tests shows that restoration of base share of these parts is possible by High Velocity Oxygen Fuel / High Velocity Air Fuel (HVOF/HVAF) process. Comparison of manufacture's data has showed that HVAF excels HVOF alternatives noticeably at productivity. At the same time production costs are 2-2.5 times less. With regard to typical steel-making process parts some investigations results and examples of HVAF restoration at Joint Stock Company "Mashprom" are represented.