REFRACTORIES IN HEATING UNITS
EXPERIENCE FROM THE USE OF MODERN UNMOLDED REFRACTORY
MATERIALS IN THE LINING OF THE HEATING FURNACES OF ROLLING
K. G. Zemlyanoi,
A. A. Kurovskii,
T. P. Ryzhova,
and A. N. Musikhin
Translated from Novye Ogneupory,No.3,pp.3–5,March, 2012.
Original article submitted February 17, 2012.
Joint development and industrial tests of a new generation of Termoset exothermic unmolded materials and
MMTF gunning bodies are conducted. It is established that with the use of the general-purpose Termoset exo
thermic refractory compound the time needed for repairs to heating units may be reduced and the quality of the
repairs improved, durability increased, the service stability of the lining of heating furnaces guaranteed
throughout the entire scheduled period and, ultimately, expenditures for servicing of the heating furnaces of
rolling mills reduced.
Keywords: heating furnaces, thermal stability, strength, exothermic compound, corrosion-resistant material,
The heating furnaces of rolling mills, which are designed
to heat billets prior to rolling, are the basic thermal units of
rolling factories as well as the most capital-intensive equip-
ment of rolling mills, which is a basic consumer of expensive
energy resources, such as natural gas and electricity. A de
crease in the expenditures spent on repairs and operation of
heating furnaces is one of the most effective means of in
creasing the profitability of rolling factories.
Heating furnaces operate at comparative low tempera
tures (1200 – 1350°C), though their operating regime is com
plicated by the intensive chemical and corrosive action of
scale on the surface of the lining, high amplitude and fre
quency of temperature fluctuations in the workspace, and the
mechanical and vibratory action of the moving billet. Natural
gas is used as the fuel in the furnaces; it is burned in burners
with excess-air coefficient a ~ 1.1±0.2, which is responsible
for the variable reduction-oxidation nature of the gaseous
medium in the work space. This also leads to a decrease in
the service life of lining.
Thermally stable refractories with high resistance to the
chemical and corrosive action of metallic scale, such as
periclase-chromite and chromite-periclase, and high-alumina
(mullite, mullite-corundum) substances are generally used as
the materials for the lining of heating furnaces, while cha
motte and semi-acidic materials are used in the reinforcing
layers of the lining and in low-temperature zones. Some frac
tion of the total number of thermal units in use are lined with
energy-efficient fibrous, thermally insulating materials, but
their introduction is limited by the need to increase the level
of technological culture and redesign of the mechanical
equipment of the furnaces.
The basic mechanisms responsible for deterioration of a
refractory lining in the heating furnaces of rolling mills are
– wear of the working layer of the lining of the walls at
the level of the moving billet induced by the mechanical ef
fect produced by the tubular billet;
– complex chemical and thermal wear of the lining of
the walls and crown of the furnace produced by spalling
throughout the zone of impregnation induced by variations in
the thermophysical properties of the refractory material
(temperature coefficient of linear expansion) upon impregna
tion with metallic scale and as a consequence of recurrent
Refractories and Industrial Ceramics Vol. 53, No. 2, July, 2012
1083-4877/12/05302-0075 © 2012 Springer Science+Business Media, Inc.
FGAOUVPO Ural Federal University, Yekaterinburg, Russia.
OOO Granit-resurs, Yekaterinburg, Russia.
OAO Pervoural’sk New Pipe Factory, Pervoural’sk (Sverdlovsk