Refractory
materials for sliding nozzles: nozzle block bricks; upper and lower slide
plates; upper nozzles; lower nozzles; drainage sand for nozzles. I shared the
skateboard with you in the front, and now I have sorted out the physical and
chemical indicators and usage methods of the water inlet and the water outlet,
cleaning methods and the factors that affect the water outlet and the water
outlet. In addition, there is drainage sand for the nozzle.
Refractory material for sliding nozzle-upper nozzle
The upper nozzle brick
is directly installed in the ladle nozzle seat brick. When the molten steel
flows through the upper nozzle under high temperature, the chemical erosion and
erosion of molten steel and molten slag and the mechanical damage caused during
installation make the upper nozzle require long life, resistance to molten
steel and slag erosion. , Scouring. Aluminum and carbon are commonly used in
domestic water outlet bricks, and their service life is related to factors such
as steel grade, amount of steel passing and casting time. There are many CaO-C
nozzle bricks used abroad. The bricks are formed by isostatic pressing, and the
apparent porosity of CaO sand is required to be <5%. Compared with the
original Al2O3-C quality nozzle, the CaO-C quality nozzle is characterized by
no blockage, no cracks, and 30% melting loss rate in use, while the Al2O3-C
quality nozzle has no cracks but The blockage is more serious, and the melting
loss rate is 3.3%.
Advantages of CaO-C upper nozzle
(1) The reactivity
of CaO sand and C in a high-temperature vacuum reduction atmosphere is small,
maintaining the structural strength of the nozzle and improving the corrosion
resistance of the nozzle;
(2) CaO sand
reacts with Al2O3 in molten steel to produce CaO·Al2O3 and 3CaO·Al2O3 and other
low-melting substances flowing down with molten steel, effectively preventing
the clogging of the nozzle;
(3) CaO sand has
the function of adsorbing sulfur, phosphorus, oxygen and other non-metallic
inclusions in molten steel, and has the function of purifying molten steel.
Clean the water
inlet during use
Analysis of the factors affecting the water inlet
1. The performance of the water inlet material itself
2. Water inlet
size and wall thickness
3. The user's
judgment and understanding of the safety of the water inlet
4. Self-opening
rate of drainage sand, maintaining the level of oxygen burning, etc.
5. Other factors
that affect the life of the ladle, such as slag line, breathable bricks, nozzle
block bricks, etc., will also limit the further use of the upper nozzle
Refractory material for sliding nozzle-drain
The drain is mainly
used to control the flow and injection rate of molten steel, and it is required
to have good erosion resistance at high temperatures, good volume stability at
high temperatures, and a certain degree of self-melting. The damage factors of
the spout include: corrosion and erosion of molten steel and molten slag;
cracking or fracture caused by sudden temperature changes; melting loss caused
by oxygen burning. The material requires good corrosion resistance. For
example, high-aluminum and fused silica can be used for casting ordinary carbon
steel; when casting steel with higher manganese content, aluminum-carbon,
magnesia and other drains can be selected. In order to improve the thermal
shock resistance of the drain, the drain is installed in the iron sleeve to
prevent cracking. Should try to avoid burning oxygen to start pouring. The
drain uses high-aluminum, aluminum-carbon and aluminum-zirconium-carbon, and
its service life is 1 time and 2~3 times respectively.
Analysis of
Factors Affecting the Sewage
1. The performance
and quality of the drain material itself
2. The level of
installation and operation of the drain
3. Self-opening
rate of drainage sand
4. Maintain the
level of oxygen burning, etc.
5. Other factors
that affect the life of the ladle, such as ladle slag line, breathable bricks,
nozzle block bricks, etc., will also limit the further use of the drain
Refractory material for sliding nozzle-drainage sand for nozzle
Before the ladle is officially filled with steel, after closing the sliding nozzle, use a long funnel to put drainage sand into the upper nozzle to prevent the molten steel from entering the upper nozzle and condensing. When the skateboard is turned on, the molten steel will drop immediately after the drainage sand drops to achieve the purpose of automatic pouring. Whether the ladle drainage sand can be self-opened is greatly related to factors such as the material of the drainage sand, the particle size ratio, and the length of the refining time. Drainage sand includes sea sand, river sand, refractory bricks and chrome ore in materials.
Drainage sand for nozzle:
(1) Drainage sand
has high density and high melting point. The particles are not easy to sinter,
and the volume is stable at high temperatures;
(2) The shape of
the drainage sand is spherical, without obvious edges and corners, with
moderate particle size, the smaller the fine powder content, the better, and
the particle size should be consistent;
(3) The smaller
the natural pile angle, the better, the flow performance is good, and the
surface is smooth for filling and scattering;
(4) In order to
prevent molten steel from penetrating into the drainage sand, it is required
that the molten steel has a greater interfacial tension on the drainage sand;
(5) Drainage sand
has good corrosion resistance to molten steel and molten slag at high
temperatures, and it is required that the drainage sand does not chemically
react with the sliding nozzle near the bottom nozzle, and has good
high-temperature physical properties;
6) Drainage sand
must be dried before use, so that the moisture content is <0.5%
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