Large trolley annealing furnace
Main technical description
The large trolley type annealing furnace is a periodic operation furnace, which is mainly used for heat treatment (normalizing, annealing, and quenching) of general large and medium-sized metal ring or alloy parts, castings, and stainless steel solid solution at a temperature lower than the rated temperature.
2. Technical parameters;
(1) Rated power: according to the volume of the furnace body
(2) Rated voltage: 380V
(3) Number of phases: 3P
(4) Frequency: 50HZ
(5) Maximum working temperature: 1200 ° C
(6) Number of heating zones:
(7) Furnace temperature uniformity: ≤ ± 10 ℃
(8) Empty furnace heating time: ≤2h
(9) Empty furnace loss: ≤15%
(10) Effective working area size
(11) Temperature control accuracy: ≤2 ℃
(12) Temperature control mode: PID control
3. Structure introduction:
(1) This trolley furnace consists of a furnace body and a movable trolley.
(2) The furnace shell and trolley are welded from high-quality steel and section steel.
(3) The heating element adopts the high resistance alloy 0Cr27AL7Mo2 resistance strip made by Shougang, which is arranged on the furnace door, furnace side, furnace rear wall and trolley.
(4) The furnace lining is made of high-aluminum fiber cotton. This material has high temperature resistance and good thermal insulation, which is not a substitute for ordinary fiber cotton. The load-bearing part is built with heavy refractory bricks to enhance the structural strength of the furnace lining. In order to ensure that the heat transfer at the bottom of the trolley is not very high, the thermal insulation layer of the trolley adopts a composite structure of aluminum silicate refractory fiber and diatomite thermal insulation brick to improve Furnace body thermal insulation performance.
Second, the main technical characteristics
The electric furnace is mainly composed of a furnace body (including a furnace door), a furnace lining, a furnace door lifting, a furnace car, a furnace car transmission mechanism, an electric heating device, a temperature control and recording system, and the like.
1, furnace body
(1) Furnace lining:
This furnace lining adopts all-aluminum silicate refractory fiber blanket with excellent heat insulation performance, which is combined into a large plate after special processing, and finally combined into a furnace lining.
The furnace body adopting the refractory all-fiber large plate structure has excellent heat insulation performance. The all-fiber furnace lining weighs only 1 / 30th of the refractory brick furnace body, not only has excellent thermal insulation performance, but also saves about 30% of energy compared to brick-type resistance furnaces of the same specification, and the heating rate is faster.
The all-fiber refractory structure has good thermal shock stability, resistance to rapid cold and heat, and a longer service life than a brick furnace. This kind of furnace body is very convenient to repair. If it is damaged due to mechanical collision, only partial repair can be used. This kind of furnace lining also has the characteristics of easy installation and short construction time.
(2) Steel structure: All-fiber large plate furnace lining is hung on the steel skeleton. The steel skeleton is welded by section steel and steel plate, which is light and reliable. The furnace uses a full-fiber large-plate structure lining, so its steel structure is much lighter than a traditional refractory brick furnace.
2.Electric heating device
Adopt advanced hanging structure, high radiation efficiency, strengthen the heat exchange in the furnace, improve the thermal efficiency of the furnace, and extend the service life of the electric heating element. The electric heating element adopts 0Cr27AL7MO2 resistance band, which is processed into a wave structure by a special mold, and is suspended in a group on the furnace wall fixing (ceramic screw), which is very convenient for installation and maintenance and has a long service life.
The trolley heating element adopts the same material spiral structure.
The trolley is a platform for carrying workpieces and running. The loading plane size of the furnace trolley is:
(1) Refractory insulation material:
The surface of the trolley is a heavy-duty brick to ensure the compressive strength. The heat insulation layer is divided into two parts, the first part is diatomite brick, and the second part is light clay brick to ensure the heat insulation effect.
Around the trolley, heavy shaped refractory bricks are used to increase the strength.
(2) Furnace car steel structure:
The frame is composed of section steel and channel steel, and its rigidity is guaranteed to not deform under full load and heavy load. The lower part of the trolley is equipped with a wheel device, and a reducer is used as the transmission mechanism. There are steel sand seals around the frame. Both sides of the car are provided with sealing devices matching the side seals.
(3) Safety interlocking devices:
There is a double insurance limit mechanism and a chain mechanism with the furnace door to ensure safe operation. The trolley is flexible in and out, and accurate in positioning.
(4) Furnace floor:
The bottom of the trolley is equipped with a pressure-resistant and high-temperature cast NI7N furnace floor to carry the workpiece. In order to prevent the scale generated after the workpiece is heated from falling through the gap between the furnace floor and surrounding the heating element and causing damage to the heating element, the contact place of the furnace floor and the furnace body is inserted.
4. Furnace door:
(1) Furnace door structure;
The furnace door adopts light steel structure skeleton and refractory fiber as heat insulation material
(2) Furnace door lifting power:
The furnace door adopts electric lifting, and the electric hoist is installed above the furnace door frame.
(3) Security protection:
The furnace door is provided with an upper and lower stroke double insurance limit mechanism and an interlocking device with the furnace car, and the furnace car is provided with an entrance and exit double insurance limit mechanism. As soon as the furnace door is opened, the power supply of the electric heating element is automatically cut off. When the furnace door is closed, the trolley cannot enter or exit.
The sealing condition of a furnace directly affects the temperature uniformity and power consumption in the furnace. The furnace has adopted sealing facilities at each joint of the furnace, as described below:
(1) Joint of furnace door, furnace body and furnace car:
This joint is the most difficult to seal the trolley furnace, and the largest leakage of the furnace. The furnace uses the weight of the door and the domestic advanced spring compression device. Can effectively seal this part.
(2) The joint between the furnace body and the furnace car on both sides:
Because the furnace body and the furnace car are relatively in and out, considering the expansion after heating, there should be a considerable gap in this part, so this part is sealed by soft contact with refractory fiber and refractory brick, and there are two seals with sand seal groove. Good sealing effect.
(3) The joint between the furnace car and the furnace body:
It adopts plug-in soft edge seal and is compacted by the power of the furnace car.
6. Temperature control and recording system of resistance furnace:
The resistance furnace is controlled by a PID zero-crossing trigger. The power is adjusted by Shanghai Guolong intelligent instrument. The size and power can be adjusted. The three-phase current imbalance can also be adjusted. control.