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Ikromjon Rakhmonov, Bakhriddin Kholikhmatov, Makhzuna Korjobova

    Bu səhifədəki naviqasiya:
  • Table 1
 
2 Experimental research 
Electrodes used in the steel industry are divided into 
several types based on their application and the types of 
manufactured products. They are selected for durability 
and thermal stability of the electrodes [5-10].Their names 
are indicated in the following diagram, 
Fig.1.
 
Fig.1.
Types of electrodes 
The electrodes of an arc steelmaking furnace work in 
extremely difficult conditions. Therefore, a number of 
specific requirements are imposed on the material for the 
manufacture of electrodes. They must have sufficient 
mechanical strength at low and high temperatures; have 
high electrical conductivity; be resistant to oxidation in 
the working space of the furnace and outside it, provide 
reliable contact in the heads of the electrode holders and 
the junction points of the electrode sections, have a low 
cost. Currently, only electrodes made of carbonaceous 
material meet such requirements.
Graphite electrodes are used in electric arc furnaces 
for several reasons. Because the temperature of the 
furnace is very high (1600-1800°C), electrodes that can 
withstand this temperature are graphite electrodes. The 1 
table has types of graphite electrodes. 


Title of the conference 
Types of graphite electrodes 
Table 1
 
RP 
A conventional power graphite electrode is 
also called a graphite molded column to allow 
a current density through a graphite electrode 
of less than 17 A/cm 2, Mainly used in 
steelmaking, yellow phosphorus, silicon and 
other ordinary power electric furnaces. 
HP 
The high-current HP electrode is appropriate 
for casting operations or occasionally in arc 
furnaces.
High power graphite electrode wire 
material for steelmaking of an electric arc 
furnace, which is made of petroleum coke, 
needle coke, coal asphalt, and high-
temperature wire material produced by a 
series of strict process processes. In order to 
allow the current density through the graphite 
electrode to 18 ~ 25A / km 2, mainly used in 
a high-power steelmaking arc furnace. 
UHP 
Ultrahigh graphite electrodes are used to 
recycle steel in the arc furnace industry. The 
main ingredient is high-quality needle coke 
made from oil or coal tar. In order to allow the 
current density through the graphite electrode 
to be larger than 25A/cm 2. Mainly used for 
ultra-high power steelmaking electric arc 
furnace. 
Above are the types and classification of electrodes, of 
which the most widely used in the steel melting process 
are UHP graphite electrodes. Take as an example of 
graphite electrodes, due to improper use of graphite 
electrodes in technological processes and operation, 
electrodes can be broken and damaged. As a result, the 
metal melting time increases and the cost of the product 
increases. If broken graphite electrodes fall into the 
furnace, carbon content will be added to the slag and stop 
the melting process in the furnace. This leads to the 
deterioration of the properties of steel and the decrease in 
the price of the product by the purchasing companies, and 
in some cases cases of non-purchase occur.
In addition, broken or damaged electrodes cause an 
increase in the consumption of electrodes and an increase 
in the price of the product. As a result, the amount of profit 
metallurgical plants receive from the sale of these 
products will decrease significantly. Therefore, it is 
necessary to reduce the consumption of electrodes in 
order to increase technical and economic indicators in 
steel production. In many countries (in particular, in 
Uzbekistan) steel melting furnaces of large and medium 
capacity are used.
Take a graphite electrodes as an example, the 
production technology of high-quality graphite electrodes 
for heavy-duty arc furnaces is quite complex. The high 
cost of charge materials and high power consumption 
determine the very high cost of special graphite electrodes 
for heavy-duty furnaces ($1500-2000 per 1 ton). Because 
of the high cost of graphite electrodes, the cost of 
electrodes during the operation of furnaces of ordinary 
power for smelting carbon steels is 8% of the cost of steel; 
when operating heavy-duty furnaces, such costs can 
exceed 15% of the cost of steel, in some cases reaching 
30%. The consumption of graphite electrodes fluctuates 
within a significant range, which during normal operation 
of furnaces is 4–8 kg/t (in a well-functioning heavy-duty 
steel-smelting furnace, the total consumption of 
electrodes was 4 kg/t of steel).
According to the above points, we can say that the 
consumption of graphite electrodes in EAF steelmaking 
depends not only on the quality of the electrodes, but also 
on the level of operation and management of steelmaking.
So what factors influence electrode breakage or 
failure? When these factors were analyzed, it was studied 
that there was too much factor dependence. The below in 
fig. 2 follows the main 3 factors, which are:
Fig.2.
Factors causing breakage and damage of 
graphite electrodes 
To minimize electrode consumption and prevent 
breakage and failure in steel melting furnaces, it is crucial 
to employ proper electrode usage techniques. Fig.3. 
illustrates key solution factors that mitigate electrode 
damage.
Fig.3.
Strategies for preventing electrode breakage in 
steel production.
Preparations 
break the 
graphite 
electrodes
When smelting,
after the bottom
of
preparations
gradually melt, it
is like a main
shaft, the space
under
it
is
empty, the un-
melted
scrap
steel on furnace
wall
will
fall
down
to
the
electrodes,
causing
cracks.
Generally,
the
broken part is the
electrode holder.
Vibration 
break
The electrode is
subjected
to
electromagnetic
force
during
smelting, and it
will
definitely
vibrate,
which
will easily cause
the electrode to
fatigue
and
break.
These
breaks have no
disciplines,
mostly
occurs
near the middle
of the electrode
nipples.
Inappropriate 
operation of 
electrode holder
It
is
not
allowed to have
foreign
matter
between
the
electrode
and
holder,
both
should be always
vertical,
holder
cannot be held out
of the safety line
of the electrode.
These
irregular
operations
will
cause
the
electrode to break.
The electrode gripper should avoid clamping at the 
electrode joint and the hole of the electrode joint. 
Keep the tilting system in good condition and keep the 
tilting stable. 
The electrode pillar is aligned with the furnace top hole, 
and the electrode pillar is parallel. 
Avoid the existence of non-conductive materials in scrap 
steel.
The scrap is evenly distributed in the furnace, and the 
large scrap is placed at the bottom of the furnace as far as 
possible.
Correct electrode phase sequence, counterclockwise 
direction.


Title of the conference 
Preserving the integrity of graphite electrodes during 
the steel melting process positively impacts both 
economic efficiency and metal quality.
Another problem is that during steel production in 
electric arc furnaces, there are high energy losses. Firstly, 
they are associated with the unsatisfactory quality of 
carbon-graphite electrodes and their improper operation. 
Also, in below other reasons that reduce the efficiency of 
the furnace installation are given:
Fig. 4.
Factors causing energy waste in steel smelting 
technology. 
Based on the above-mentioned issues, there are 
concerns regarding energy inefficiency, increased 
electrode consumption, and the adequacy of electrode 
strength and durability in the steel production process 
when using electrodes. Addressing these challenges 
through the provision of solutions enhances the 
technological process quality.

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