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Vacuum Heat Treatment Furnace

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Vacuum Brazing Furnace

Vacuum system of vacuum brazing

Titanium alloy materials are widely used in aerospace, navigation, chemical industry, metallurgy and medical fields due to their ultra-high specific strength, excellent heat resistance and good corrosion resistance. Among many workpieces made of titanium alloy materials, titanium alloy heat exchangers are core components of the power and environmental control systems of high-end marine and aerospace equipment.
Vacuum brazing is a welding method that heats the workpiece to the melting temperature of the filler metal without melting the base metal, and forms a permanent connection through the diffusion and dissolution of the filler metal and the base metal. It has small post-weld deformation and can weld multiple shapes at the same time. Due to its advantages such as complex welds, it is widely used in the production and manufacturing of plate-fin radiators. Vacuum brazing technology, vacuum brazing equipment and brazing materials are the three core factors affecting the brazing manufacturing of titanium alloy plate fin radiators.

Plate fin radiators are basically composed of fins, partitions, seals, deflectors and other parts. The fins are placed between the partitions, and the deflectors and seals are added to form a mezzanine. Different ways of fluid circulation are integrally brazed to form a plate bundle.
Compared with other radiators, the existence of fins gives the plate-fin radiator an expanded secondary heat transfer surface. During the heat conduction process, the primary heat conduction is performed by the partition. In addition, the heat will also flow along the fins. The heat conduction is transmitted in the height direction of the surface. Since the height of the fin is much greater than the thickness of the fin, a heat conduction type that is approximately a homogeneous slender guide rod is formed in the height direction of the fin. As the core component of the plate-fin radiator, the length, width, and height dimensions of the fins as well as the Reynolds number (Re number) and the type of fins have a great impact on the overall heat transfer rate and flow resistance.

Vacuum brazing process

The vacuum brazing method is a welding method in which the weldment assembled with solder is placed in a vacuum furnace for brazing. The oxides on the surface of the workpiece are removed under the combined action of high temperature and high vacuum. It is especially suitable for large brazing areas and many welds. of artifacts. The tools used in vacuum brazing are called vacuum brazing furnaces. Its main body is mainly composed of a furnace body, a vacuum system, a water cooling system, an air filling system, an electrical control system, etc. High-performance equipment is the prerequisite for ensuring the quality of brazing. Research on comprehensive performance will improve Excellent vacuum brazing equipment is of great significance for improving the brazing quality and size of titanium alloy plate fin radiators.
In vacuum brazing equipment, temperature control is a core element of its work. Scholars have conducted a lot of research on the changes in the temperature field of vacuum brazing equipment during the working process. The research content mainly focuses on the establishment and optimization of temperature conduction mathematical models, and the mathematical models are used to complete the simulation analysis, and the simulation results are fed back to In the actual production process, the optimization of parameters when using vacuum furnace brazing is completed, so as to ultimately achieve the purpose of improving brazing quality.
Vacuum brazing process conditions have a significant impact on the structure and properties of the brazing seam. As the brazing temperature and holding time change, the degree of interaction between the filler metal and the base metal during the brazing process also changes, resulting in significant changes in the microstructure and structure of the brazed joint, which in turn affects the joint performance. Especially in the welding of plate-fin titanium alloy heat exchangers, because the titanium alloy base material is thin and the number of welds is large, more attention must be paid to the design and optimization of the brazing process, so that the brazing filler metal and the brazing material can be used under the selected process conditions. The base metal is fully dissolved and diffused, forming a brazed joint with a clean appearance and reliable performance, without causing obvious coarsening of the microstructure of the brazing seam, resulting in damage to the mechanical properties of the joint. As a filler metal in the brazing process, brazing filler metal plays a very important role in the formation of brazed joints. A suitable brazing filler metal should have excellent wetting and filling capabilities and good mechanical properties.