Improving the technology of steel pouring

Abstract

POURING UDC 669.18 : 621.746 At the Magnitogorsk Metallurgical Combine steel is poured from above into ingots weighing from 7 to 22.5 tons. Four or five ingot molds are placed on bogies with a load capacity of 60, 160, and 230 tons. The distance between the mold centers is 1850 mm for pouring steel in the No. 1 open-hearth shop and 1020 mm in the No. 2 and No. 3 shops. About 80% of the steel is poured simultaneously from a ladle with two stoppers. Nozzles with hole diameters of 30, 35, 40, 50, 60, and 80 mrn are used, and a diameter of 100 mm has also been tried.Ingots weighing 6.9-10 tons are poured through nozzles of various diameters: 30, 35, and 40 mm for killed steel; 30, 35, 40, and 50 rnm for rimming steel; and 40 and 50 mm for semikilled steel. Ingots weighing 16-22.5 tons are poured through 60-mm-diameter nozzles in the case of killed steel and 80-ram-diameter ones in the case of rimming and semikilled steel.As a result of the use of oxygen for speeding up open-hearth reciting and the conversion of the open-hearth furnaces into twin-bath ones, the casting bay has become the biggest bottleneck in the shop. At the Combine a great deal of work has been devoted to raising the throughput of the casting bay and to increasing the output of usable metal.The use of heat-insulating slabs for casting killed steel into molds which widen towards the bottom has resulted in a reduction in the amount of work involved in training workers, the elimination of bottlenecks and profitable extensions, a reduction in the consumption of refractory materials, and also a reduction in transport requirements. The surface quality of the ingots has thereby been improved, the number of transverse cracks has been reduced, and the number of mold sizes cut by half. In addition, mold life has been increased by 15-20o7o.It has been found by experiment that the quality of metal cast with heat-insulating linings satisfies all the GOST standards and technical recommendations for steels containing up to 0.35% carbon. An examination of the macrostructure of the metal revealed that ingots of kitled steel that have been cast into molds which widen towards the bottom and which are lined with heat-insulating slabs are characterized by the presence of a secondary shrinkage cavity situated at a depth up to 32% below the top of the ingot. As a rule, this cavity is wetded up during rolling.The top discard has fallen from 13-14~ to 11% for ingots weighing 7-10 tons and from 17-18% to 14~ for ingots weighing 16-20 tons.In 1972 and 1973, 1.9 and 3.3 million tons of steel, respectively, have been cast into molds lined with heat insulation, economies of metal of 1.24% and 1.96% respectively, being obtained in this way. The consumption of lining was 6.5-7.0 kg per ton of steel.The Chemical Sealing of Ingots of Rimming Steel. In the No. 1 open-hearth shop we have introduced the use of liquid and granulated aluminum for chemically sealing ingots of low-carbon structural rimming steel weighing from 16 to 20 tons. Trials were carried out with granulated and li...

Silicomanganese production from manganese rich slag

“…At the same time this variation will not be constant, but will change according to the recovery of silicon. 12 It was established by investigation that in order to obtain a fluid slag, ensuring normal production conditions for silicomanganese, the basicity of the waste slag, and consequently of the charge, must be taken 13 from the magnitude of the ratio b05(CaOzMgO)/(Al 2 O 3 ). In a recent study, the optimum slag basicity expressed as (CaOzMgO)/(Al 2 O 3 ) for silicomanganese production was found to be 1 .…”