Modifying the Steel Surface Layer by Compounds with High Melting Temperature Using Electric Slag Surfacing

• Published in: Steel in translation 2021-09, Vol.51 (9), p.616-620
• Main Authors: Saraev, Yu. N., Bezborodov, V. P., Perovskaya, M. V., Semenchuk, V. M.
• Format: Article
• Language: English
• Subjects: Abrasive wear; Alloying; Alloys; Arc welding; Base metal; Chemistry and Materials Science; Coating effects; Composition; Crystallization; Disilicides; Electrodes; Grains; High resistance; Inclusions; Intermetallic compounds; Iron silicide; Low alloy steels; Materials Science; Metal surfaces; Metallography; Microhardness; Protective coatings; Research facilities; Silicon nitride; Slag; Structural steels; Surface layers; Wear resistance
• ISSN: 0967-0912; 1935-0988
• DOI: 10.3103/S0967091221090102

The alloying effect on the structure, microhardness and abrasive wear resistance is studied for electric slag layers deposited on low-alloy 09G2S structural steel grade. The mixtures of Si 3 N 4 + FeSi 2 + Si powder obtained in the Department of Structural Macrokinetics of Tomsk Research Center (the Siberian Branch of RAS) using the method of SHS synthesis are used as modifiers. In addition, TiC-based powder compositions are applied as a modifying parameter. An electrode was made using low-alloy steel St3 to engage into arc welding. In the first experiment, the modifying compositions Si 3 N 4 + FeSi 2 + Si is covering the electrode whereas the modifying compositions Si3N 4 + FeSi 2 + Si is located under the electrode in the second case. The metallography and X-ray microanalysis techniques are used to determine the structure and compositions in deposited layers, in heat-affected areas and in base metal. The results are used to explain the hardness and wear-resistant coatings properties. It is shown that the main factor affecting wear-resistance deals with the structure of the metal to be deposited. A positive effect in modifying coatings using alloying materials containing Si 3 N 4 + FeSi 2 + Si and St3, TiC and St3 alloys was established. Molten layer features numerous crystallization centers represented by dispersed TiC particles. TiC dispersion particles have high melting temperature (3180°C). They are the first to fall out from the melt acting not only as multiple crystal grains, but also as a hurdle to grow austenite grains resulting in developing a dispersed structure. The coatings contain both TiC carbide particles and inclusions of other phases. An increase in hardness of the deposited layer containing inclusion of titanium carbide is observed in the direction of the base interface. The wear resistance of the layer is higher when the coating is made of TiC. The data obtained can be used to make deposited layers having high resistance to abrasive wear on the metal surface.