Industrial tests of a new generation of cassette-type gates for metallurgical plants in Ukraine

Abstract

Results of industrial tests of a new generation of cassette-type gates for steel-teeming and tundish ladles are reported.The significantly shortened tap-to-tap period in updated and reconditioned electric steel-making furnaces and the ever-increasing capacity of ladle-furnaces operated in conjunction with high-productivity continuous casting machines have necessitated the refitting of steel ladles with cassette-type gates in place of the conventional block-type gates. This changeover allowed the pre-starting period for steel pouring facilities to be shortened from 2 -3 h to 20 -25 min, with a clear improvement in ladle turnover [1,2].The advanced cassette gates available from leading foreign manufacturers use special refractory plates enclosed within a metallic shell which is tightly held in position by means of disk or coil springs [3]. Domestic experience in the use of cassette gates purchased from foreign manufacturers has revealed, along with unquestionable advantages, some shortcomings inherent in them, in particular, continuous maintenance and close control of the spring elements and the necessary air cooling during the steel-teeming, which creates design and operational inconveniences [4]. Furthermore, the cost of cassette gates is rather high (US$10,000 -14,000 per item), likewise that of the refractory components used (US$70 -100 per item) [5]. An alternative might have been the development of domestic cassette gates and ceramic auxiliaries adapted to the actual conditions. In this connection, research teams were organized in Ukraine whose efforts should be aimed at developing a new generation of competitive slide gates [6 -8]. The research teams included specialists from the DonNTU, Doniks Research and Production Association, NKEP JSC, and IISWM JSC. Three major routes of initiative research were outlined:-elaboration of a clearly defined concept of design that would avoid shortcomings inherent in cassette-type pouring facilities currently available from foreign manufacturers;-comprehensive computer-assisted process analysis aimed at the reduction of materials consumption, design simplification, and cost cutting in the manufacture of critical assemblies of the innovative equipment;-laboratory and industrial-scale testing of the newly designed steel-teeming facilities aimed to save time and effort in the technological preparation for their large-scale production.In developing domestic components for the cassette gates of steel-teeming and tundish ladles, major attention was focused on the reduction of mass and cost of manufactured teeming facilities and enhancing the reliability of heavy-duty assemblies. In designing advanced gates we were guided by a rationality principle formulated by L. N. Reshetov according to which a mechanical system should have the potential to compensate for errors in linear dimensions of its elements associated with technical inaccuracy, technological loading, and operating temperature regime [8,9]. Accordingly, a rational slide gate system should provide for the following condi...

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