Vacuum Tempering Furnace of Operation Process
Vacuum tempering furnace is a protective sintering furnace which uses induction heating to sinter heated articles. It can be divided into power frequency, intermediate frequency, high frequency and other types, and can be classified as a subcategory of vacuum sintering furnace. Vacuum induction sintering furnace is a complete set of equipment for sintering cemented carbide cutters and various metal powder compacts by using the principle of medium frequency induction heating under vacuum or protective atmosphere. It is designed for the industrial production of cemented carbide, dysprosium metal and ceramic materials.
1. Medium frequency power supply, vacuum furnace body and cooling water source of induction coil-water storage tank must be filled with water, and impurities must not be found in water.
2. Turn on the water pump to make the medium frequency power supply, the induction coil of the vacuum furnace and the cooling system of the furnace body circulate normally, and adjust the water pressure to control at the prescribed value.
3. Check the vacuum pump power supply system, the belt pulley is tight, and the vacuum pump oil is located in the middle line of the oil seal observation hole. After checking, manually turn the vacuum pump belt pulley. If there is no abnormality, start the vacuum pump with the butterfly valve closed.
4. Inspection of the inside of the vacuum furnace requires the first-level hygiene of the vacuum furnace, good insulation of the induction coil, elasticity of the sealing vacuum tape and qualified size.
5. Check whether the lever handle of the vacuum furnace body is flexible to start.
6. Check whether the rotary Maxwell vacuum gauge meets the requirements.
7. Check the graphite crucible and whether the furnace fittings are complete.
8. After the above preparations are completed, turn on the power supply, turn on the medium frequency power supply, try to start the frequency conversion according to the intermediate frequency start-up rule, and stop the frequency conversion after success before the furnace can be opened.
9. The observation and temperature measurement holes on the top of the vacuum furnace body should be cleaned every time the furnace is opened for observation and temperature measurement.
10. According to the different sintering products, the corresponding charging mode should be adopted. Packing according to relevant material charging rules shall not be changed at will.
11. In order to maintain constant temperature and prevent thermal radiation, two layers of carbon fibers are added to the heating crucible and then covered with a heat shield.
12. Pad the vacuum sealing tape.
13. Operate lever handle, rotate the top cover of vacuum furnace to coincide closely with the furnace body, lower the top cover, and lock the fixed nut.
14. Open the butterfly valve slowly and extract the air from the furnace body until the vacuum reaches the required value.
15. Start frequency conversion, adjust intermediate frequency power, operate in accordance with sintering regulations of related materials, heat up, heat preservation and cooling after the vacuum reaches the required requirements.
16. After sintering, stop the frequency conversion, press the stop frequency conversion switch, the inverters stop working, disconnect the intermediate frequency power supply and disconnect the main power supply.
17. After observing the blackening of the furnace from the observation hole of the furnace body, the butterfly valve of the vacuum pump is closed and the current of the vacuum pump is disconnected, then the tap water is added to continue cooling the induction coil and the furnace body, and finally the pump is stopped.
18. The medium frequency voltage 750 volts is dangerous of electric shock. In the whole operation and inspection process, attention should be paid to the safety of operation, do not touch the intermediate frequency cabinet by hand.
19. During the sintering process, the induction coil should be observed from the side hole of the furnace body at any time. If abnormal phenomena are found, the relevant personnel should be immediately reported to deal with them.
20. Start the vacuum butterfly valve slowly, otherwise oil will come out due to excessive pumping, resulting in adverse consequences.
21. Correct use of rotating Maxwell vacuum gauge will result in vacuum reading error or mercury spillover due to excessive operation, which will cause public hazards.
22. Pay attention to the safe operation of vacuum pump belt tray.
23. Pay attention to prevent pressing hands when cushioning vacuum sealing tape and capping the top of furnace body.
24. Workpieces or containers that are prone to volatilization and affect vacuum hygiene under vacuum conditions and cause pipeline blockage and dirty vacuum pumps shall not be put into the furnace.
25. When products are added with forming agents (such as oil or paraffin), they must be removed before they can be sintered into the furnace. Otherwise, they will cause adverse consequences.
26. During the whole sintering process, attention should be paid to the pressure range of the water meter and the circulation of cooling water in order to avoid accidents.