INTRODUCING AN ARGON BOTTOM BLOW TECHNOLOGY
FOR USE IN STEEL LADLES AT THE MAGNITOGORSK
IRON AND STEEL WORKS JOINT-STOCK Co.
V. G. Ovsyannikov,
Yu. A. Bodyaev,
and V. P. Andreev
Translated from Novye Ogneupory, No. 4, pp. 103 – 106, April, 2004.
Modernization of the oxygen converter shop (OCS) at
the Magnitogorsk Iron and Steel Works Joint-Stock Co. —
primarily involving putting into service a ladle furnace unit
and extending the range of steel products — has necessitated
the use of high-performance refractory materials capable of
meeting the ever-increasing requirements placed on the qua
lity of commercial end products. One of the major technolog
ical operations in a ladle furnace unit is the blow of argon
through the molten metal using bottom blowing tuyeres. The
bottom blow technology allows one to control the molten
metal temperature in the steel ladle, to achieve the required
metal purity by floating nonmetallic inclusions into the slag,
and to assure uniform distribution of the alloying additives.
The argon blow at different metal processing steps is effected
at different flow rates, which places high requirements on the
reliable performance of blowing units.
The bottom blow technology for 385-ton steel ladles
used in ladle furnace units at the MISW JSC was started in
June 2000, and until the present, work continnues, aimed at
improving the design and performance of the blowing units,
in cooperation with domestic and foreign manufacturers. The
blowing units that are supplied to the MISW are composed of
a nozzle block and a tuyere. In a 385-ton ladle, two blowing
units are mounted on the guard plates on the left trunnion
side opposite to the tap hole. Before mounting in the ladle,
the blowing units are tested for blow efficiency and leak
tightness. The working argon pressure in the ladle furnace
unit is maintained at 0.8 – 1.2 MPa. With steel-teeming ope
rations completed, the tuyere was cleaned of molten slag and
metal by means of oxygen fed through a metal tube while
through the tuyere itself, natural gas was passed which, for a
tuyere with normal blow, had to form a burning torch. All ar
gon supply pipelines were equipped with easily detachable
connection pipes and check valves which were used to con
trol residual pressure and to prevent the tuyere channels from
clogging. Blowing tuyeres of three types were tested:
(i) tuyeres assembled from ceramic plates; (ii) tuyeres with
ring channels; and (iii) tuyeres with vertical guiding channels.
Tuyeres assembled from ceramic plates. Tuyeres of
this type are assembled from plates of Al
composite; they look like a stack of plates separated by
slit-like channels. Typically, a tuyere thus designed has 6 – 8
channels. Initially, HAS-25-grade tuyeres (available from
Mayerton, China) were used for the ladle furnace technology
at the MISW JSC. The HAS-25 tuyeres were assembled
either of four plates (6-channel) or five plates (8-channel).
The tuyere body was made up from a thixotropic corundum
castable. In 2000 – 2001, three types of HAS-25 tuyeres
were available for use; their characteristics are given in Ta-
ble 1. Best results for argon-blown technology were achieved
using tuyeres of types 1 and 2 (Table 2).
During service, the tuyeres were inspected visually for
wear and free blow (channel passability). As was estab-
Refractories and Industrial Ceramics Vol. 45, No. 4, 2004
1083-4877/04/4504-0279 © 2004 Springer Science+Business Media, Inc.
Magnitogorsk Iron and Steel Works Joint-Stock Co. (MISW
JSC), Magnitogorsk, Russia.
TABLE 1. Characterization of HAS-25-type Blowing Tuyeres
HAS 25 B1/R
360 Zr – Al
HAS 25 D/R
360 Zr – Al
HAS 25 D/R1 420
420 Zr – Al
Eight slit-like channels 0.2 – 0.3 mm wide for each tuyere type.
TABLE 2. Test Results for HAS-25-type Blowing Tuyeres
HAS 25 B1/R
710 58.2 17.8 515 29.0
HAS 25 D/R
568 68.5 19.0 692 36.4
HAS 25 D/R1
Shown in brackets are average values.