Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:

Yu. S. Korobov, Head of a Chair of Welding Fabrication
M. A. Filippov, Professor of a Chair of Physical Metallurgy, e-mail: filma1936@mail.ru
A. A. Vopneruk, Assistant Professor of a Chair of Foundry and ReinforcingTechnologies
V. V. Legchilo, Post-Graduate Student of a Chair of Physical Metallurgy

Resource of continuous casting machine molds is limited by the wall resistance. Bronzes, microalloyed by silver or zirconium, are good as a wall material due to a high thermal conductivity combined with low loss of strength under cyclic heating. Various coatings of chromium and nickel alloys are used to improve the wear resistance of the wall. Experience has shown that the reliability of the coating is determined by its adhesive strength. In turn, the latter one is dependent on the degree of interaction of the coating with the substrate. Samples of such bronzes as (0.1 Ag, Cu bal). and (0.4–1.0 Cr, 0.03–0.08 Zr, Cu bal) with nickel-chromium type coating were subjected to metallographic and SEM analysis. The coating was made by high velocity air fuel spraying. The appreciable mutual diffusion of atoms between substrate and coating is revealed and the recrystallization in a border area of the substrate is shown. Transition zone extends to 20 μm deep as into coating and into substrate. It leads to increase the adhesion strength of the coating and its thermal cycling resistance. The mechanism of formation of the transition zone is proposed. It is associated with the impacting force of particles at flattening on the substrate during high velocity spraying. Results of investigation are applied to develop a technology of coating spraying on continuous casting machine mold plates.

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