Metallurgist, Vol. 46, Nos. 09–10, 2002
2002 Plenum Publishing Corporation
Electric steelmaking shop No. 3 at the factory of the company Mechel includes an electric steelmaking department
with 5-, 10-, 12-ton ac and dc arc furnaces, ESR, VAR, and IVR units, and forging and finishing departments. The shop was
originally built to make ingots, semifinished products, and finished products of high-alloy structural and tool steels and alloys.
Small arc furnaces make it possible to make a wide range of steels, and any additions or alloying elements (tung-
sten, niobium, molybdenum, nickel, chromium, etc.) are uniformly distributed in the bath of these units. However, as is
known, the steel is saturated with gases from the arc region during electro-refining and is contaminated by nonmetallic inclu-
sions from the lining and the slag during tapping. In addition, the oxidation losses of alloying elements – especially elements
that are readily oxidized - are substantial in electric-arc furnaces.
Metallurgists are quite familiar with the capabilities of ESR, VAR, and IVR with respect to degassing steel, remov-
ing nonmetallic inclusions, and improving the service properties of steels and alloys overall. However, when allowance is
made for the necessity of preparing the electrodes, remelting metal in these units becomes more than twice as expensive as
other steelmaking methods. The productivity of the units is not high, so that only a limited range of special steels and alloys
are remelted in ESR and VAR furnaces (orders for IVR-refined steels have declined sharply).
At the same time, the shop – which specializes in the production of high-alloy steels – still faces the important prob-
lem of improving the quality of its product mix as a whole. Taking into account the successful introduction of a ladle-fur-
nace unit (LFU) for the out-of-furnace treatment of steel made in the 10- and 12-ton electric furnaces, the company decided
to introduce a second refining facility – a vacuum-degassing unit.
In light of the small size of the available ladles, planners chose to use a chamber-type unit for vacuum degassing
(Table 1). The unit was installed in the auxiliary and pouring bays of the electric steelmaking department near the existing
LFU. The main components of the vacuum-degassing unit:
• steel-pouring ladle;
• vacuum chamber;
• chamber cover with a protective shield and batching hopper;
• power-driven transfer truck;
• mechanism to lift cover;
• pinch rollers to feed aluminum (cored) wire;
• vacuum system;
• gantry, working platforms, compartments;
• control post;
• system to supply energy carriers (steam, water, electricity, argon, compressed air).
DESIGN FEATURES OF A STEEL VACUUM-DEGASSING
UNIT FOR ELECTRIC STEELMAKING SHOPS WITH
N. I. Borob’ev, I. Yu. Zinurov,
I. V. Oleichik, S. E. Malkov,
A. L. Nikitin, D. M. Ulitin,
A. M. Shumakov, and V. K. Sarbaev
Open Joint-Stock Company Mechel, Close Joint-Stock Company Akont, and Limited Liability Company Ekvaks.
Translated from Metallurg, No. 10, pp. 41–43, October, 2002.