Determining the physical-chemical characteristics of the carbon-thermal reduction of scale of tungsten high-speed steels
Journal Title: Восточно-Европейский журнал передовых технологий - Year 2018, Vol 2, Issue 6
Abstract
<p>We determined that scale of the high-speed steel R18 is composed of the phases of Fe<sub>3</sub>O<sub>4</sub>, Fe<sub>2</sub>O<sub>3</sub>, FeO, with the presence of alloying elements as the replacement atoms. The microstructure is disordered and non-uniform. In the examined area, in addition to Fe, we revealed the presence of, % by weight: W – 16.34, Cr – 2.68, V – 1.82, and others. The content of O was 15.32 %. It was established that the reduction of scale at 1,523 K proceeds with the formation of α-Fe and carbides Fe<sub>3</sub>W<sub>3</sub>C, (Fe, Cr)<sub>7</sub>C<sub>3</sub>, W<sub>2</sub>C, V<sub>2</sub>C, Fe<sub>3</sub>C, Fe<sub>2</sub>C. Manifestation of carbides of alloying elements decreased with an increase in the degree of reduction. The microstructure of reduction products is heterogeneous, containing particles with a different content of alloying elements and has a spongy structure. The conditions are provided for the absence of phases subject to sublimation. We conducted experimental-industrial tests of using the metallized scale while smelting high-speed steel with a degree of disposal of alloying elements at the level of 92‒94 %. Improvement of environmental safety was implemented by the replacement of reduction melting with the newest methods of powder metallurgy employing the solid-phase reduction.</p>
Authors and Affiliations
Stanislav Hryhoriev, Artem Petryshchev, Karina Belokon’, Kristina Krupey, Mykhail Yamshinskij, Grigoriy Fedorov, Dmytro Stepanov, Andrii Semenchuk, Elena Matukhno, Alexander Savvin
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