Scope of application of box furnace:
Box type furnaces are mainly suitable for quenching, normalizing, annealing, and tempering heating of workpieces such as carbon steel and alloy steel. Suitable for heat treatment of various small parts, springs, and molds. Adopting a new type of energy-saving furnace lining, it heats up quickly, reduces losses from empty furnaces, and saves more than 20% energy compared to old products.
The structural characteristics of the box furnace:
1. The appearance of this series of resistance furnaces is rectangular, and the furnace shell is made of angle steel and high-quality steel plate folded and welded. The studio is a furnace made of refractory materials, with heating elements placed inside. The furnace and shell are insulated with insulation materials.
2. The furnace door is fixed to the electric furnace panel through multi-level hinges. The furnace door is closed by the self weight of the furnace door handle. When the furnace door and the furnace mouth are tightly closed and opened through the lever principle, simply lift the handle upwards, pull the limb hook outward, and place the furnace door on the left side. In addition, the lower end of the furnace mouth is equipped with a safety switch that is interlocked with the furnace door. When the furnace door is opened, the power supply of the electric furnace is automatically cut off to ensure safe operation.
Characteristics of Box Furnace:
1. Electric furnaces have a large loading capacity and high productivity, especially suitable for heat treatment and heating of small and medium-sized machinery, with energy savings of up to 20%, uniform furnace temperature, automatic control of furnace temperature by digital displays, and high precision;
2. The electric furnace is convenient for loading materials and has good operating conditions;
3. The sealing between the furnace door and the furnace body is automatic and does not require manual sealing
4. The electric furnace is equipped with a chain protection device to prevent malfunctions and accidents caused by misoperation;
Box furnace temperature control
Due to the poor sealing of the furnace mouth and door, the heat dissipation of the box furnace is large, and its temperature is lower than the center temperature of the furnace. If the temperature difference range of the heated workpiece is required to be controlled within a small range, the heating area of the parts will inevitably be reduced, and the corresponding effective area of the furnace will also be reduced. The furnace cannot work at full load, resulting in energy and labor waste, and the unit consumption of products will also increase. Therefore, it is necessary to expand the temperature equalization zone of the box furnace as much as possible.
The specific methods include:
1. Installing electric heating elements on the furnace door can increase the temperature at the entrance and improve the temperature uniformity of the furnace. High temperature box furnace is a resistance wire heating method. During the temperature uniformity test, it is analyzed from the test data that a certain test point has a low temperature. By adjusting the heating current of the resistance wire, the temperature uniformity of the furnace can meet the process requirements.
2. Reasonably arrange the power (resistance wire) along the length direction of the furnace, and increase some power at the furnace mouth, or use grouping and zoning control methods.
3. Setting up fans to force gas convection in the furnace can greatly improve the uniformity of furnace temperature.
4. Improving the paint color of the furnace shell, the radiation coefficient varies depending on the color of the object. Spraying silver gray or black paint on the outer shell of the experimental furnace can reduce the heat dissipation of the outer space of the furnace.
5. Improve the temperature control system and adopt appropriate furnace temperature adjustment methods. By using PXR type temperature control instrument and changing the control mode to PID continuous control mode instead of analog instrument, the uniformity of furnace temperature can meet the production process requirements.