Vacuum Brazing Furnace

Vacuum brazing furnace

Application range

Product description:

Brazing in a vacuum furnace is a brazing process in which the workpiece after brazing is placed in a vacuum furnace. During the brazing process, the workpiece is in a vacuum state to avoid oxidation of the base metal, and under high-temperature vacuum conditions, the base material will volatilize at high temperature and be eliminated through the vacuum equipment system, and the residual brazing filler metal during the brazing process will also volatilize through the vacuum equipment. Brazing is performed in a vacuum furnace without adding brazing flux. The vacuum equipment consists of a mechanical vacuum pump, a diffusion pump, a vacuum connecting pipe, and a vacuum butterfly valve. It can improve the vacuum degree of the system and can have a positive effect on the quality of brazing. Generally, the vacuum degree of brazing in a vacuum furnace is within 1.33 * 10-1- 1.

Application:

Applicable to brazing stainless steel and high-temperature alloys with copper and nickel-based brazing fillers, especially suitable for high-temperature alloys containing titanium and aluminum. Copper, nickel, superalloys and silver-titanium alloys with silver brazing fillers, and cobalt alloys or titanium alloys with cobalt-based brazing fillers, etc.

Performance characteristics

The main advantages of vacuum furnace brazing are high brazing quality, no oxidation of the workpiece, small deformation, and can braze other materials that cannot be brazed by other brazing methods. However, since the metal is easy to evaporate under vacuum, the brazing should be properly controlled, that is, the melting point of the brazing, the melting temperature, the penetration time of the substrate, and the penetration time. Therefore, it is not recommended to use brazing filler metals with high content of elements such as zinc, cadmium, manganese, magnesium, and phosphorus when brazing, and it is not appropriate to use workpieces containing a large amount of these elements in the substrate. Materials brazed in a vacuum furnace.

Furnace structure:

The AE-VBF-600 vacuum brazing furnace consists of a furnace body, a heating chamber, a vacuum system, a gas filling system, a water cooling system, an electronic control and power supply system.

1. Furnace body: It consists of a furnace shell, a furnace door, a locking mechanism, a furnace support, etc. The furnace shell and the furnace door are both double-walled, made of SUS 304, and have an integral water cooling channel. The furnace door is welded by a double elliptical head and a circular flange, and there is an O-ring on the flange. The front door is a common working door. Load and unload workpieces from the front door. There are heating chambers, electrodes and exhaust ports for the main vacuum pump on the furnace body.

2. Heating chamber: It is a cylindrical chamber consisting of a heating element, a heat shield and a material table. The heating element is a high-strength molybdenum wire and is insulated by specially designed ceramic parts to avoid deformation of the shirt circuit due to welding volatilization. The heating zone can be disassembled separately and is easy to replace when damaged. The heating power supply is connected to the heating element through soft copper wire, copper strip, and copper electrode. The circuit and furnace body have good insulation performance and are easy to clean, disassemble and replace.

3. Vacuum system: including mechanical pump and diffusion pump. There are vacuum gauge sockets on each valve and pipeline. And each pipeline section is equipped with a vacuum measuring device to facilitate vacuum measurement in each pipeline.

4. Electric control system:

4.1 Including touch screen, PLC, thyristor voltage regulator, vacuum gauge, to realize power supply, control, recording, monitoring, alarm and protection functions.

4.2 A high temperature control accuracy is achieved by using German Siemens PLC and Japanese Shimaden temperature controller. At the same time, PLC comprehensively controls the operation of the furnace. According to the process requirements, sequential control signals are provided, and feedback signals from the field are collected to provide conversion, interlocking, indication and alarm signals. In addition to loading and unloading, the entire process can be automated and equipped with a manual operating system.

4.3 There are two thermocouples to measure the temperature in the furnace at any time and understand the temperature uniformity.

4.4 The furnace control interface is a touch screen control system. Through communication with PLC, temperature and vacuum curves can be established and recorded to develop and query the process. The running status of the furnace can be displayed in real time.

4.5 It has over-temperature and waterproof safety protection functions, and has an audible and visual alarm system. The furnace body is equipped with a safety valve device, and there are interlocking circuits such as air pressure, vacuum, water pressure, and heating.

4.6 The heating power supply uses a single-phase thyristor power supply, and is powered by low voltage and high current. Heating power 60KVA.

4.7 There is a fan cooling system in the control cabinet.

5. Water cooling system: The furnace body, furnace door, vacuum device, water-cooled electrode, and heat exchange system of the furnace require cooling water. The cooling water is distributed to each cooling component through a manifold, and it is a closed water circulation system. Each cooling pipe is equipped with a water flow observer and a water pressure alarm system. There is a branch connected to the tap water pipe for emergency use in case of power outage. The inlet and outlet pipes are made of stainless steel pipes.

6. Pneumatic system: It consists of a pneumatic three-piece set (water eliminator, pressure gauge, oil mist collector), a solenoid reversing valve, and a pipeline. Provide clean compressed air to pneumatic actuators such as cylinders, charging valves, vacuum valves, etc.

7. Inflatable pressure distribution system: It consists of a large-caliber pneumatic stop valve, a manual stop valve, a fine-tuning valve and a gas collecting pipe. There is a safety deflation valve when the furnace is deflated. And there is a pressure sensor to control the inflation pressure.

8. Workpiece conveying system: The material is loaded by a pallet or placed on a bearing platform.

9. Safety system: The safety system includes water stop, overheating, overheating, fault self-diagnosis, automatic protection and prevention of misoperation. And with sound and light alarm prompts and corresponding interlocking, interlocking protection functions.