METHOD OF INCREASING LIFE TIME AND WEAR RESISTANCE OF THE NEW AND RESTORED PLATES OF DRIVE LEAF CHAINS OF MECHANISMS OF WATER GATES AND GATE VALVES

摘要

FIELD: metallurgy.;SUBSTANCE: invention refers to method of increasing life-time and wear resistance of plates of drive leaf chains of mechanisms of water gate and gate valves of hydraulic structures, which are manufactured with specified thickness by die forming or plasma cutting from steel st45 or steel st65G, and can be used at manufacture of new chains and reconstruction of used ones. Method involves application of "Св"-08 steel layer to the surfaces of pre-ground or cleaned plates by plasma spraying. After that, in one hour maximum, the plates are subject to sulphocyaniding at temperature of 570-590°C during 3-4 hours with further cooling of plates together with furnace to indoor temperature. As sulphocyaniding medium, there used is gaseous medium containing gaseous carbon, sulphur and nitrogen, which is formed with pyrolysis products of sulphourea of carbamide with additional introduction of gaseous nitrogen and sulphur evaporation product to the environment of air-proof muffle of heat-treatment furnace.;EFFECT: increasing wear resistance of plates in friction couple 'plate material-bobbin material' at standard operation in river water in presence of suspended mud and sand under influence of tensile stresses, increasing corrosion resistance and strength limit of plate material at tension, relative elongation and hardness.;5 cl, 3 ex