Vacuum Sintering Furnace: Essential Professional Knowledge

2025-05-07 11:23:50

A vacuum sintering furnace is a protective sintering furnace used to heat materials in a vacuum environment. Heating methods include resistance heating, induction heating, and microwave heating. A vacuum induction furnace is a type of furnace that utilizes induction heating to protect the heated materials. It can be classified into power frequency, intermediate frequency, and high frequency types, making it a subclass of vacuum sintering furnaces. A Vacuum Induction Sintering Furnace employs the principle of medium-frequency induction heating under vacuum or protective atmospheres to sinter cemented carbide tools and various metal powder compacts. It is widely used in industrial production of cemented carbides, dysprosium metals, and ceramic materials.

Principle and Applications

A Vacuum Induction Tungsten Sintering Furnace operates by evacuating the chamber and introducing hydrogen protection. A tungsten crucible within the induction coil is heated via medium-frequency induction to generate high temperatures, transferring heat to the workpiece through thermal radiation. This system is suitable for sintering refractory alloys such as tungsten, molybdenum, and their derivatives in research and military applications.

Main Structure and Components

the furnace is typically designed with a vertical drainage structure. Key components include:

● Furnace body

● Vacuum system

● Water cooling system

● Pneumatic system

● Hydraulic system

● Loading/unloading mechanisms

● Base and worktable

● Induction heating assembly (tungsten heaters and advanced insulating materials)

● Power supply system (medium-frequency power supply and electrical gas control system).

Primary Functions

After evacuation, hydrogen is introduced to control pressure and atmosphere during sintering. Temperature measurement (0–2500°C) is achieved via fiber-optic infrared radiation thermometers or sheathed thermocouples. By comparing real-time data with preset programs in an intelligent temperature controller, feedback is sent to the medium-frequency power supply to automatically regulate temperature and insulation processes.

Safety Operating Procedures：

1 Cooling System Preparation: Ensure the medium-frequency power supply, induction coil water tank, and furnace cooling system are filled with impurity-free water.

2 Water Circulation: Activate the water pump to establish normal circulation. Adjust water pressure to specified values.

3 Vacuum Pump Checks: Verify power supply, belt tension, and oil level (at the midpoint of the oil seal observation window). Manually rotate the vacuum pump pulley to confirm smooth operation before starting the pump with the butterfly valve closed.

4 Furnace Inspection: Ensure the chamber is clean, induction coils are insulated, and vacuum seals are elastic and properly sized.

5 Mechanical Checks: Test the flexibility of the furnace handle and confirm the rotary Maxwell vacuum gauge meets specifications.

6 Material Setup: Verify the integrity of graphite crucibles and furnace tools.

7 Power Activation: After completing the above steps, power on the medium-frequency supply and test-start the inverter per regulations. Proceed only if successful.

8 Observation and Measurement: Clean observation and ports on the furnace top before each use.

9 Loading Protocol: Follow material-specific loading rules; do not alter arrangements arbitrarily.

10 Thermal Protection: Add two layers of carbon fiber around the heated crucible and cover with insulation boards to maintain temperature and block radiation.

11 Sealing: Install a vacuum sealing belt.

12 Chamber Closure: Align and secure the furnace lid using the handle, then lock it with fastening nuts.

13 Evacuation: Gradually open the butterfly valve to evacuate the chamber until the required vacuum level is achieved.

14 Sintering Process: Activate the inverter, adjust medium-frequency power, and execute sintering according to material-specific protocols (heating, insulation, cooling) under vacuum.