2. Structural Introduction
The RT3-200-5 heat treatment furnace is mainly comprised of furnace
shell, lining, furnace door and door lifting mechanism, furnace door
compression mechanism, bogie and drawing mechanism, seal between
furnace body and bogie, heating element and fixed device, circulating
fan and furnace temperature automatic control system.
2.1 furnace shell
The electrical heat treatment furnace manufacturer surface steel structure is made
from 10-12# sectional steel and 4mm steel plates. The side pillar and back
pillars are made from sectional steel, and are reinforced with sectional steel
bracings. The external wall of the furnace is painted with 2 layers of primers,
and 2 layers of coating paint. The key part of the furnace is painted with heat
resistant paint.
2.2 lining
The wholesale bogie hearth furnace body is built with an all-fiber system.
The lining material used is hihg quality standard fibers fixed by round steel parts.
The aluminum fibers are pre-compressed into blocks (compression gravity:
≥230Kg/m3 ) and then fixed to the furnace body by round stainless steel parts.
This refractory lining structure has the advantages of low heat conductivity,
strong anti-shock capacity, and anti-erosion. The lining has a total thickness
of 260mm. The silicate aluminum fiber resists a maximum temperature of 950℃.
The refractory fiber is made from Luyang, Shandong.
2.3 furnace door and door up-down system, furnace door seal mechanism
The high temperature bogie hearth furnace door is comprised of all-fiber lining
and steel structure casing. The door frame is made of 10mm steel plate. The
door is built with high quality standard fiber blocks same as that for the furnace
body. The overall structure of the furnace maintains its shape while heated.
Driving method of door: The furnace door is electrically lifted upward and
downward by the hoist. And it is sealed by the furnace door self-weight.
2.4 bogie
The bogie is comprised of bogie frame, bogie surface plate, wheels, refractory
bricklaying body, bogie driving mechanism.
bogie structure: the bogie frame is made from 14# beam and 10mm steel plates.
The bogie could work for a long time without deformation at full load.
wheel: The wheels are made from ZG55# steel casting. The transmission shaft
is made from 45# steel, and it is heat treated. The transmission bearing is of the
heavy type pillar bearing to bear the weight. There are a total of 3 pairs of wheels,
and each wheel is of diameter 300mm.
bricklaying body: The bogie is built with a combination of heavy high alumina
refractory bricks, light refractory bricks, and heat preservation bricks. The impacted
parts and weight bearing area are bricked especially with heavy type high aluminum
refractory bricks. There is also free space left for the refractory lining expansion
when heated.
Bogie driving mechanism: The bogie moving mechanism adopts self-walking mode,
and it moves into and out of the furnace hearth by the reducer. The bogie movement
is stable and reliable.
Sealing: The sealing is a very important link in furnace design. It directly affects
the uniformity of temperature in the furnace and the service life of the furnace. At
the same time, the energy consumption and the heat treatment quality of the
workpiece are also greatly affected.
The seal between furnace door and furnace body and bogie is more important.
The seal between furnace door and furnace body adopts spring compression structure.
The seal between bogie and furnace body is seal of special-shaped brick and fiber
cotton block.
2.5 heating element
heating element: The 0Cr25AL5 resistance spiral-shape alloy resistance strips are
mounted in two side walls. The resistance strips are produced through special molds,
and are installed in the furnace wall by porcelain nails. And there is a porcelain gasket
between the fiber wall and the resistance strips to avoid short-circuit. There are 3 heating
zones. All lead-out conductor bars are made of φ16 0Cr25AL5 material.
2.6 electrical control system
Temperature control: the aging heat treatment furnace adopts intelligent temperature controller to control
the temperature which has self-tuning function to calculate the ideal PID parameter
and achieve a temperature stability. The temperature controller has the functions of
over-temperature alarm and thermal couple breakage protection.
The heat treat furnace for metal has 3 temperature control zones for controlling the linkage
between the temperature and the motor movements. Each zone is set with an over-temperature alarm.
The control actuation system is a large-power triggering one complete with a radiator and
an air cooling system. There is also an air switch. The heating loop is equipped with ammeter,
voltmeter, heating element on-off indicator, power-on interlock protection, and safe earthing
measures.
Movement control: The control system mainly controls the door up-down movement, door
compression, and door in-out movement. Also the movements are necessarily linked to
ensure the operation safety.
2.7 Hot air circulating system:
It is mainly comprised of three centrifugal fans and air guide plate in the furnace. The heat
emitted by the heating element is evenly blown to the effective working area by the circulating fan through the wind guide plate. The air guide plate is made of 1Cr18Ni9, and the fan and shaft are made of 1Cr18Ni9Ti. In order to ensure the normal use of bearings, the cooling method is air cooling.
2.8 Guiding device
It is mainly to effectively circulate the air generated by the circulating fan in the furnace along
the direction of the deflector in the furnace, so as to make the air in the furnace produce rapid convection, so as to achieve the purpose of uniform temperature. The materials of air deflector
and framework are all made of 304 stainless steel plate. The air deflector and framework are
movably connected to ensure the free expansion of air deflector under high temperature and
facilitate repair and maintenance.
