The sealed shell of vacuum furnace is welded with carbon steel or stainless steel

The sealed shell of vacuum furnace is welded with carbon steel or stainless steel

The vacuum furnace appeared around the 1930s. In 1927, the vacuum annealing furnace for electrical materials was made in the United States. In 1953, the vacuum consumable arc furnace was used in industry to smelt titanium sponge. The vacuum induction furnace was widely used in industry around the 1950s. In 1960, the United States developed the oil quenching vacuum furnace.

Vacuum furnace is generally composed of furnace, electric heating device, sealed furnace shell, vacuum system, power supply system and temperature control system. The sealed furnace shell is welded with carbon steel or stainless steel, and the joint surface of removable parts is sealed with vacuum sealing materials. In order to prevent the furnace shell from deformation and sealing material from deterioration after heating, the furnace shell is generally cooled by water or air cooling. The furnace is located in a sealed furnace shell. According to the purpose of the furnace, different types of heating elements are installed inside the furnace, such as resistance, induction coil, electrode and electron gun. Crucibles are installed in the furnace of vacuum furnaces for metal smelting, and some are also equipped with automatic pouring devices and manipulator for loading and unloading materials. The vacuum system is mainly composed of vacuum pump, vacuum valve and vacuum gauge.

As there are many types and types of vacuum furnaces, the maintenance and overhaul items are different. The maintenance and inspection contents shall be divided into items for each furnace, every day, every month, every half a year and every year according to the furnace technical documents and actual needs.

For the air pump with gas ballast function, check it every day before the furnace is opened and open it for 30min as required to remove the water in the pump oil.

Frequently check the pressure of cooling water, compressed air, hydraulic system and the flow of cooling water.

The pressure in the furnace of vacuum furnace can be pumped into an industrial furnace lower than atmospheric pressure. The vacuum furnace is electrically heated. The surface of the heated workpiece is free from oxidation and decarburization, with small deformation and good mechanical properties. Melting metal in vacuum furnace is beneficial to removing impurities. The finished product has fewer pinholes, small segregation and good quality. The vacuum furnace is applicable to the smelting and heating of high-quality, high-purity and refractory metals, such as the smelting of tungsten, molybdenum, tantalum, niobium, titanium, heat-resistant alloy steel and the heat treatment of magnetic materials, electrical materials, high-strength steel, stainless steel, tool steel, die steel, etc.

Check the rubber seal and flange surface of the furnace door before closing the guard door. There shall be no sand and sundries. Wipe the rubber seal ring and flange surface with a clean cloth, and then apply vacuum grease evenly before closing the furnace door.

The workpiece must be cleaned before being put into the furnace for treatment. After oil quenching, all the oil on the oiled material frame and carrier parts shall be cleaned.

Air cooled motor is generally a common motor. If it cannot be started under vacuum, it can only be started after inflation and shall be protected by electrical interlocking protection device.

Roots pump can only be started when the vacuum degree is above 133Pa, and it shall also be protected by electrical interlocking protection device.