Use of plasma spraying in the production of slide gate plates

This article presents the results of investigations of the production of slide gate plates with the use of plasma spraying. The determination of the possibility in principle of application of protective coatings on the plates and development of the spraying conditions were done on a unit that includes the plasmotron (PVK-50) connected through the manifold with the electrical, gas, and water supply systems and also the feeder for supplying the powder. Specimens of refractory parts of various compositions were used as the bases, and electro-corundum with a grain size of 40-60 ..mu..m both in pure form and in mixtures based on it as the powder for spraying. An analysis of the results obtained shows that the specimens with the coatings have a gas permeability 0.5-1.5 orders of magnitude less than the original bases, and coatings on bases (corundum and high-alumina) close in chemical composition to the sprayed powders are more effective in this respect. An experimental lot of composite plates were tested from the specimens with coatings. The plates were assembled using the normal method and the plates were tested in bottom teeming of steel from 200-ton ladles. Types St45 and St40Kh steel were teemed. The successful results of production more » tests showed that the use of the plasma method makes less expensive use of the plates and provides more available materials protected from direct contact with the molten metal by a coating not more than 3mm thick. « less