What is a vacuum furnace? A vacuum furnace is a device that heats in a vacuum environment. In a specific space of the furnace cavity, a vacuum system (a vacuum pump, a vacuum measuring device, a vacuum valve and other components are carefully assembled) is used to discharge part of the material in the furnace cavity, so that the pressure in the furnace cavity is less than a standard atmospheric pressure The space thus achieves a vacuum state, mainly used for ceramic firing, vacuum smelting, degassing of electrical vacuum parts, annealing, brazing of metal parts, and ceramic and metal sealing.
Vacuum furnace classification:
Vacuum furnaces can be divided into vacuum quenching furnaces, vacuum brazing furnaces, vacuum annealing furnaces, vacuum magnetizing furnaces, vacuum tempering furnaces, vacuum sintering furnaces, vacuum diffusion welding furnaces, and vacuum carburizing furnaces.
According to the heating method, it is divided into vacuum resistance furnace, vacuum induction furnace, vacuum arc furnace, vacuum consumable arc furnace, electron beam furnace (also known as electron bombardment furnace) and plasma furnace.
Vacuum furnace product structure:
A vacuum furnace is generally composed of a host, a furnace, an electric heating device, a sealed furnace shell, a vacuum system, a power supply system, a temperature control system, and an outside furnace transport vehicle. The sealed furnace shell is welded with carbon steel or stainless steel, and the joint surface of the removable parts is sealed with a vacuum sealing material. In order to prevent the furnace shell from being deformed after heating and the sealing material to be deteriorated by heating, the furnace shell is generally cooled by water or air. The hearth 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 coils, electrodes and electron guns.
Vacuum furnace function:
Vacuum quenching (tempering, annealing) is a treatment method that achieves the desired performance by heating or cooling materials or parts in a vacuum state according to the process regulations.
Vacuum sintering furnace A method for heating metal powder products under vacuum to sinter adjacent metal powder crystal grains into parts through adhesion and diffusion.
Vacuum atmosphere furnace is also known as oxygen-free annealing furnace. Vacuum atmosphere furnace is commonly used in various atmospheres such as vacuum, hydrogen, oxygen, nitrogen and inert gas (such as argon). Selecting a suitable atmosphere for sintering different materials can help the sintering process, improve the degree of product densification, and obtain products with good performance.
A vacuum brazing furnace is a welding process in which a group of welding parts is heated to a temperature above the melting point of the filler metal, but lower than the melting point of the base metal. The welding process is performed by using the filler metal to wet and flow the base metal ( (The brazing temperature varies depending on the material).
Vacuum furnace use precautions:
1. Pickling, cleaning and drying the workpieces to be quenched to ensure that there is no dirt and water on the surface of the workpieces and baskets.
2. Check whether water, electricity and gas are unblocked, and alarm devices and interlock protection such as water pressure, over-temperature, and over-current should be intact.
3. Check that the insulation resistance of the furnace door should be greater than 22Kw, and that the furnace door is well sealed.
4. Adjust the air-cooling pressure: adjust the upper limit of the electric vacuum pressure gauge to the range required by the process.
5. During the furnace loading process, the workpieces should be placed uniformly to make the heating process more uniform and ensure the uniformity of the furnace temperature. Long workpieces should be erected as much as possible to reduce the deformation caused by gravity under high temperature.
6. During the operation of the vacuum furnace, the control cabinet of the distribution cabinet uses low voltage to control high voltage. Generally, the operator will not directly contact the high voltage, which is generally 24V or 36V. However, the power supply voltage is still 380V, and the electrical components in the power distribution cabinet also have 380V voltage, so it is still necessary to pay attention to the safe use of electricity.
7. In the production process of the vacuum furnace, air tightness must be strictly ensured. This is the prerequisite to ensure the vacuum state. The circulating water in the furnace must also ensure that there is no water leakage. When the furnace body and other components are connected, the seal ring must be used for connection. And to ensure the cleanliness of the connection surface and apply vacuum grease, during maintenance, after each repair, wipe each contact surface with a volatile liquid such as acetone.
