Vacuum annealing furnace is mainly composed of electrical control system, motor system, high vacuum system, furnace system and system. The high vacuum system is mainly composed of high vacuum units, which are mainly used to evacuate the furnace body and maintain vacuum. Its advantages are as follows: First, annealing changes the crystal structure, eliminates internal stress and softens the material. Second, it prevents oxidative decarburization and degreasing, thereby improving the brightness and mechanical properties of the surface. Third, the volume of the furnace is large, the temperature control accuracy is high, the temperature difference in the temperature zone is small, and the system is stable. Fourth, the furnace temperature control system is complex, and the data has the characteristics of time-varying, nonlinear and hysteresis. Therefore, as the heating time increases, the heating temperature increases and the vacuum degree increases, different annealing effects will be produced. Fifth, the programmable controller has a simple structure, strong anti-interference ability, and good versatility, which can improve the stability and accuracy of the system, thereby improving production efficiency. The vacuum annealing furnace is designed as follows.
Vacuum annealing furnace is a fast-cooling horizontal resistance furnace using external circulation and single-chamber heating. The vacuum annealing furnace is composed of a furnace body system, a transmission system, a high vacuum system, a heating system and a cooling system.
The furnace system is composed of furnace door, furnace shell, heating chamber and resistance band. The opening and closing of the furnace door is controlled automatically, which is controlled by the transmission device of the pressing cylinder. The shell of the vacuum annealing furnace adopts a cylindrical structure and is made of stainless steel. The furnace body has multiple heating temperature zones, and each temperature zone is heated by a resistance band.
The transmission device refers to the control of the material rack, flatbed car and electric motor. Put the workpiece on the material rack, and place the material carts of the workpiece on the flatbed cart. Put it into the furnace door, and it will be conveyed by the motor control. When it is sent to the furnace mouth, the limit switch is closed, and then it is sent to the heating zone in the furnace, which is also driven by the motor control device.
It is composed of vacuum units, all of which are located on one side of the furnace body. Each set of vacuum units is composed of diffusion pump, Roots pump, maintenance pump, circuit breaker, contactor and corresponding pipelines. The main function is to control the start and stop of the drive pump and Solenoid valve switch. The control program of the vacuum system is the sequential control of the unit, and its sequence is: first, the control of the preheating of the diffusion pump. Second, the control of the rough pumping valve and high vacuum valve of the furnace body.
The heating method of the vacuum annealing furnace heating system is electric heating, which uses resistance bands for heating. Different temperature zones are distributed in the furnace, and corresponding temperature control equipment is also set up. The furnace heating program is the control of the heater, which is controlled according to the temperature curve in the furnace. When the vacuum degree in the furnace is lower than the set value, heating is carried out.
The cooling method of the cooling system is to use water cooling to cool down the furnace and vacuum pump. The body of the vacuum annealing furnace utilizes water circulation in the shell interlayer, and the shell is wound with water pipes. The vacuum pump is also piped.