TECHNOLOGY OF REPAIR AND WAYS OF IMPROVING THE DURABILITY
OF THE LINING OF A VACUUM DEGASSING CHAMBER
A. A. Metelkin,
D. V. Koryukov,
and V. N. Sergeev
Translated from Novye Ogneupory, No. 3, pp. 10 – 11, March, 2006.
Original article submitted August 24, 2005.
A technology for repair of the lining of a vacuum degassing chamber is presented. Ways of improving the ser
vice life of submersible snorkels by hot repair and strengthening the metallic structure of snorkels are pro
The technology for making automobile steel actually in
service at the Nizhny Tagil Iron and Steel Works (NTISW)
Joint-Stock Co. involves treatment of steel on a circulating
vacuum degasser intended for degassing the metal and im-
proving the metal’s properties. Reliable operation of the va-
cuum chamber (whose service life is determined by the con-
ditions of the lining) is of exceptional importance for an effi-
cient degassing technology.
The lining of the degasser undergoes nonuniform wear.
Durability of the upper wall section in 2004 was more than
1500 heats, that of the middle wall section 800 heats, of the
lower wall section 180 heats, and that of the snorkel —
90 heats (Fig. 1) The difference in durability is primarily ex
plained by the different operating conditions of a particular
section. During service, the lining of the upper section is ex
posed to hot gases, and the temperature fluctuations in this
section are minimum. The lining of the middle section is ex
posed, apart from hot gases, to thermal shocks and molted
slag and metal; borne upwards in the form of droplets, they
are deposited on the middle-section lining to form a
slag-metal scull. The lining in the lower section is exposed to
the most severe operating conditions: temperature drop from
1600 to 700°C and aggressive attack by molten slag from the
ladle furnace. Furthermore, the refractory lining suffers from
mechanical and chemical erosion.
To repair the lining of a vacuum chamber, one typically
proceeds in the following manner. A new chamber, on its
passing through a campaign (> 90 heats), is laid up for mid-
life (or reconditioning) repair; this decision is made from the
results of a visual inspection of the state of snorkels. The
chamber is allowed to cool to enable partial replacement of
the periclase refractory components in the linings of the bot-
tom and lower wall section. The inlet and outlet snorkels are
exchanged places considering that the wall wear in the for-
mer was higher (by a factor of 1.5 – 2.0) than in the latter; on
the average, the wear rates were 1.0 and 0.6 mm/heat. The
mid-life repair being completed, the vacuum chamber is put
back in service. In a chamber taken off for repair, the lining
in the lower wall section, bottom, and snorkels is completely
replaced. Decision on the eventual repair of the upper and
middle sections is made after the lining has been inspected
for damage. Schematically, the technology for lining repair is
given in Table 1. As shown in Table 1, the major functional
Refractories and Industrial Ceramics Vol. 47, No. 2, 2006
1083-4877/06/4702-0083 © 2006 Springer Science+Business Media, Inc.
Nizhny Tagil Iron and Steel Works (NTISW) Joint-Stock Co.,
Nizhny Tagil, Russia.
Fig. 1. The lining of a vacuum degasser: I – III ) upper, middle, and
lower wall sections; IV ) snorkel.