STRUCTURE AND PROPERTIES OF A CORUNDUM-CARBON
REFRACTORY MATERIAL SINTERED AT 1600°C
S. I. Kazakov,
A. M. Chuklai,
and O. F. Frolov
Translated from Novye Ogneupory, No. 10, pp. 91 – 92, October, 2004.
Original article submitted April 15, 2004.
The factors responsible for the failure of blow plugs for steel ladles used in extra furnace steelmaking techno
logy are considered. Results of a structural study of refractories based on electrofused corundum, crystalline
silicon, and artificial graphite are reported. To improve the properties of corundum-carbon refractories, the
sintering temperature should be increased to 1600°C.
Blow plugs for steel ladles used in extra furnace
steelmaking technology are fabricated from high-quality re-
fractory materials. Under service conditions, the plugs are
exposed to a number of factors that are capable of accelerat-
ing the wear of the plugs and finally lead to their failure.
These factors are:
inlet slit channels through which an inert gas is injected.
The ingress of molten metal may cause irreparable damage
to the blow facility;
high temperature gradients and, consequently, high ther
mal stresses in the refractory material because of the cooling
due to the injected gas;
enhanced risk of erosion failure of the gas channel walls
exposed to the gas jet and molten metal at the channel outlet
in the steel ladle.
In practice, blow facilities are subjected to a faster wear
than nozzle blocks or ladle bottom lining and therefore require
frequent replacement. Enhancing the service life of blow fa
cilities is a challenging task; for its satisfactory solution, one
will need innovative steps to be taken in both en
gineering design and advanced refractory materi
als. A step in this direction may be an adequate
assessment of the physical, chemical, and me
chanical properties of refractory materials poten
tially suitable for fabrication of blow facilities.
A problem of special concern here is that the
current methods for assessing refractory proper
ties are based on the use of specimens that have passed the
complete processing cycle for a particular material. For
oxide-carbon refractories, the final technological step is sin-
tering at 1200°C. Under service conditions, the blow facili-
ties come in direct contact with molten metal and, conse-
quently, can be exposed to temperatures as high as 1700°C.
A refractory material heated to 1200 – 1700°C may undergo
structural transformations capable of adversely affecting its
service durability. Most susceptible to damage are refractory
materials that compositionally contain reactive components.
In this paper, we report results of an x-ray phase and
petrographic study of a refractory material based on electro
fused corundum, crystalline silicon, and artificial graphite.
The auxiliary binder was aqueous orthophosphoric acid.
The technology used was conventional, involving mix
ing of dry crushed and milled components (homogenization)
and addition of the auxiliary binder. The mixture thus pre
pared was used to mold under pressure green performs with a
density of 2.80 – 2.90 g/cm
and porosity about 8 %. The
Refractories and Industrial Ceramics Vol. 46, No. 1, 2005
1083-4877/05/4601-0056 © 2005 Springer Science+Business Media, Inc.
Magnitogorsk Iron and Steel Works (MISW) Joint-
Stock Co., Magnitogorsk, Russia; Terg Joint-Stock
Co., Chelyabinsk, Russia.
TABLE 1. Interplanar Spacings in the Crystal Structure of Sintered Specimens
Interplanar spacing, 10
m; sintering temperature, °C
1200 1400 1600
3.49, 2.55, 2.38
2.08, 1.60, 1.40, 1.37
3.48, 2.55, 2.08
1.74, 1.60, 1.40
3.48, 2.55, 2.38, 2.08, 1.74
1.60, 1.51, 1.40, 1.37
Si 1.92, 3.19, 1.64, 1.35 3.14, 1.92, 1.64, 1.36 No
C 3.37 3.37 3.37
SiC No 2.51, 1.54, 1.31 2.51, 2.18, 1.55, 1.31