Vacuum Tempering Furnace Maintenance
Re-calibration of heating power of vacuum tempering furnace is influenced by factors such as the prolongation of furnace service time, the decrease of thermal resistance of heat insulation screen, the volatilization of electric heating elements and the increase of resistance, etc., and power should be increased appropriately. In practical production, power is usually determined by empirical calculation, which is the relationship between the volume of graphite felt or refractory fiber felt insulating screen vacuum furnace and heating power. According to this figure, 1300 can be determined. C vacuum furnace heating power. If it is a vacuum furnace with a metal heat shield, the heating power needed to be increased by about 30%.
Maintenance and maintenance of heat shield plays the role of heat insulation and heat preservation in vacuum furnace, and sometimes serves as the structural basis of fixed heater. There are four types of heat shield structure: all-metal heat shield, sandwich heat shield, graphite felt heat shield and mixed felt heat shield. The main points of different heat shields should be mastered in maintenance.
Molybdenum and tungsten materials are usually used in the 1-2 layers of all-metal heat shield near the electric heating element, while stainless steel materials are used in the outer layers, and the thickness should be as thin as possible (medium and small furnaces are generally o.2). 0.5mm. The large furnace is o.5-1.Omm, and the surface of the heat shield should be polished before assembly to reduce blackness and enhance reflection effect. 1300. The number of heat shield layers of C furnace is generally 5-6 layers, and the distance between layers is 5-10 mm. The contact area of several radiation plates should not be too large to reduce thermal short circuit. The heat shield should be expanded and contracted, and made into a detachable type, so as to facilitate the next maintenance.
Vacuum tempering furnace operation and maintenance:
1. Furnace body, instrument and control cabinet should always be kept clean.
2. Flammable and explosive articles shall not be stored within 2 m around the furnace.
3. Furnace shell surface paint should be kept intact and painted regularly.
4. The furnace temperature is higher than 400. At 12 o'clock, the furnace door shall not be opened for a long time.
5. The service temperature shall not exceed the maximum rated temperature of the furnace.
6. Repair and improve the sealing measures of furnace mouth regularly.
7. Lubricate the mechanical transmission part regularly.
8. Check regularly whether the terminal of graphite heater is clamped and tighten in time.
9. Workpieces containing corrosive substances and moisture shall not be brought into the furnace for heating.
10. Once the graphite heaters are connected with each other, they should be separated in time after power failure.
11. Remove oxide scales and other impurities from bottom of furnace regularly.