The converter shop at the Severstal’ Metallurgical Combine has developed and introduced a unit for the
chemical preheating of steel in pouring ladles. When the filled ladle arrives at the steel-finishing unit,
the steel is blown with argon in accordance with existing procedures. Measurements of temperature are
then used to evaluate the need for chemical heating of the steel. The mass of aluminum to be used for this
purpose and the total consumption of oxygen are calculated based on the steel’s temperature and aluminum
content. The chemical heating technology can be used in the production of ordinary steels, automobile
sheet 08Yu, and tube steel 22GYu. When IF-type automobile sheet is being made, the amount of oxygen
used for chemical preheating should be limited to 100 m
One of the most important factors that affects the quality of steel is the temperature regime used in the casting oper-
ation. For example, maintaining a narrower range of temperatures to which steel is preheated in the tundish (15–25°C above
the liquidus temperature) improves the macrostructure of cast slabs while stabilizing the casting operation and improving the
quality of the slab’s surface.
The temperature of steel can usually be controlled most accurately in a ladle-furnace unit. However, this approach
has several shortcomings: large capital investment and high operating costs, as well as the difficulty of obtaining a low mass
content of nitrogen in the steel (no more than 0.008% for tubes steels and no more than 0.006% for automobile sheet) due to
the effect of the electric arc (when the steel is made in electric furnaces).
For steelmaking in oxygen converters, the Severstal’ Metallurgical Combine has developed and introduced a unit
designed for chemically preheating the steel in the pouring ladle (Fig. 1).
Physicochemical and heat-engineering calculations that were performed showed that, assuming 100% use of the heat
that is generated, 1 ton of steel is heated 35.4°C through the combustion of 1 kg of aluminum. Assuming a heat assimilation
of 75–80%, it is necessary to add 0.04 kg of aluminum and 0.022 m
of oxygen to 1 ton of steel steel in order to raise its tem-
perature by 1°C.
The process of chemical preheating consists of the following. When the pouring ladle arrives at the steel-finishing
unit, the steel is blown with argon in accordance with existing specifications. Temperature measurements are made to deter-
mine the need for preheating of the steel. The amount of aluminum and the total consumption of oxygen are calculated based
on the steel’s aluminum content and temperature.
The oxygen feed through the main line is established so as to ensure an oxygen discharge of 3000–6000 m
through the lance. The lance is lined with high-alumina refractory concrete and has a cast-iron nozzle. The exact duration
of the oxygen blow (within the range 4–10 min) is determined by the total amount of oxygen to be used and blowing rate.
To develop a suitable technology, we subjected heats of steels 3sp, 08Yu, 08ps, 10, and SAE 1006 and tube steel
22GYu to chemical preheating in a ladle. Oxygen blowing rate was kept within the range 2000–3600 m
/h, blowing time
Metallurgist, Vol. 51, Nos. 1–2, 2007
TECHNOLOGY FOR CHEMICAL PREHEATING
OF AUTOMOTIVE-GRADE AND TUBE STEELS
IN THE LADLE
M. V. Filatov, A. V. Kuklev, and V. V. Tinyakov UDC 621.746.589
Korad Corporation and the Severstal’ Metallurgical Combine. Translated from Metallurg, No. 2, pp. 45-47,
2007 Springer Science+Business Media, Inc.