National University of Science and Technology MISiS, Moscow, Russia:

O. V. Volkova, Researcher of a Chair of Steel Metallurgy, New Production Technologies and Metal Protection, e-mail: expertcorr@gmail.com
A. V. Dub, Professor of a Chair of Steel Metallurgy, New Production Technologies and Metal Protection, e-mail: AlVDub@rosatom.ru
A. G. Rakoch, Professor of a Chair of Steel Metallurgy, New Production Technologies and Metal Protection, e-mail: rakoch@mail.ru
I. A. Safonov, Assistant Professor of a Chair of Steel Metallurgy, New Production Technologies and Metal Protection, e-mail: iasafonov@cniitmash.com

The paper presents the results of a study on corrosion of a zinc coating, applied to the surface of carbon steel by the method of hot galvanizing, under conditions of moisture condensation on their surface in contact with heatinsulating materials with different characteristics: fiber types, and multicomponent binder composition. The influence of mineral wool heatinsulating materials of three types: stone and glass wool with binder based on plant components and phenol-formaldehyde resin, on the corrosion resistance of galvanized steel was investigated. These materials are widely used in building structures. Comparative corrosion tests were carried out under conditions of experimental modelling of the “dew-point” temperature for obtaining 100% relative humidity at the metal-insulator interface. It was established that in order to reduce the degree of aggressiveness with respect to galvanized steels, the heaters are arranged in the following order: quartzite with a binder based on phenol-formaldehyde resin; glass-fiber with a binder of a similar type and glass-fiber with a vegetable binder. Electrochemical studies confirmed the lowest aggressiveness of glass-fiber insulation with a vegetable binder compared to the corrosiveness of other heaters. It was proved that the longest period of operation without signs of corrosion of the steel base, even if moisture condenses, occurs in the case of galvanized profiles that are in contact with heaters with vegetable binders in comparison to phenolformaldehyde resin binders.

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