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Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Why Switch to Brazing in the Vacuum Furnace

The so-called brazing refers to a welding method that uses a metal material with a lower melting point than the base metal (material to be welded) as a solder, and uses the solder that melts into a liquid state to infiltrate the base metal and fill the interface gap between the workpiece and diffuse it with the base metal. The brazing deformation is small and the joints are smooth and beautiful. It is suitable for welding precision, complex and components composed of different materials, such as carbide cutting tools and printed circuit boards. The vacuum brazing furnace is a high-temperature furnace that can meet the requirements of brazing. The temperature in the furnace is controlled in an environment where the brazing material can melt but the base material does not melt, and is isolated from oxygen. It is processed through a vacuum brazing furnace (rather than manual welding). ) heat exchanger enables the water pipes and cylinders, water pipes and heat-absorbing fins to be more closely and evenly combined, and has the advantages of high heat exchange efficiency and long service life.

1. Selection of solder material
The main components of the brazing material should be the same as the base metal, and the liquidus temperature of the brazing material should be at least 30°C lower than the solidus temperature of the base metal. The smaller the temperature difference, the higher the temperature control accuracy and furnace temperature uniformity requirements of the vacuum brazing furnace; the temperature difference between the solidus line and the liquidus line of the brazing material should be as small as possible; at the brazing temperature, the brazing material The main components of the brazing material should have high chemical stability, that is, low oxidation and low vapor pressure; the main components of the brazing material should be as close as possible to the main components of the base metal in the periodic table of elements, so that the brazing joint has good corrosion resistance.

2. Vacuum brazing process
Due to the aluminum alloy and brazing brands, part shape and size, brazing quality requirements, surface oxide film removal alkali composition, concentration, corrosion temperature and corrosion time, vacuum brazing vacuum degree, heating rate, holding time, cooling rate and other processes The parameters are slightly different, and experimental screening and optimization should be carried out according to different situations to finally determine a good combination of process parameters.
Vacuum brazing is the overall heating of the workpiece. It can accurately control the temperature and heat evenly, with small deformation of the workpiece. It can braze difficult-to-weld high-temperature alloy materials without flux. The brazing quality is good, and it is widely used in the welding of important workpieces.
The vacuum brazing furnace consists of a vacuum system and a heating system. The vacuum system is used to meet the vacuum degree required by the vacuum brazing process; the heating system heats the parts and melts the brazing material to complete the brazing of the parts. The process is automatically controlled by a temperature controller. .
The main working process of vacuum brazing is: first put the assembled workpiece into the vacuum chamber, start the mechanical vacuum pump, wait until the system reaches a certain degree of vacuum, turn on the diffusion pump, pump the vacuum chamber to the required vacuum degree and then start pressing Requires heating. The vacuum system should be continuously pumped throughout the heating process to maintain the required vacuum degree. The heating speed should not be too fast to avoid a sharp drop in vacuum. After the heating process is completed, it is cooled. When the temperature in the furnace drops to the discharge temperature, it is discharged from the furnace and the brazing work of the parts is completed. After brazing, it is generally cooled to below 1500°C before being allowed to be released from the furnace to avoid oxidation of the workpiece.