Vacuum diffusion welding

Vacuum diffusion welding refers to a welding method in which closely-fitting components are maintained at a certain temperature and pressure for a period of time in a vacuum environment, so that atoms between the contact surfaces are mutually diffused to form a connection. Although diffusion welding has a long history However, it has not been rapidly developed until recent years. The welding seam of this process is invisible to the naked eye, no solder is added, and no material is melted. Even under high magnification conditions, it is difficult to observe the crystal phase transition. The characteristics of the parts of diffusion welding also have the corresponding uniqueness of higher strength, best corrosion resistance, and no cross-contamination. Many new applications including energy engineering, semiconductors, tools and aerospace fields have begun to use because of its many advantages. This special process.

1. Characteristics of vacuum diffusion welding

(1)The joint strength is high. It is especially suitable for welding with materials that are prone to cracks in fusion welding. Since the properties of the base material are not changed, the chemical composition and structural properties of the joint are the same as or close to those of the base material, and the joint strength is high.

(2)There are many types of weldable materials. Diffusion welding can weld a variety of similar metals and alloys, as well as many dissimilar materials. If vacuum diffusion welding with a transition alloy layer is used, it is also possible to weld dissimilar or the same materials that have very different physical and chemical properties, and brittle compounds are easily formed at high temperatures.

(3)It can be used in the manufacture of parts that require large-area joints, laminated members, hollow members, porous or complicated internal channels, closed internal joints, and other parts with poor accessibility by welding methods.

(4)Diffusion welding is integral heating, with small component deformation and high dimensional accuracy

2. Main application of vacuum diffusion welding

Diffusion welding is mainly used for welding small, precise and complex weldments that are difficult to meet quality requirements by welding and brazing. In recent years, diffusion welding has solved the welding problems of various special materials in the technical fields such as atomic energy and aerospace missiles. For example, the connection of important components such as wings, doors, fuselage frames, engine rotor blades, guide blades, turbine disks, nozzle fairings, fan blades, etc. of advanced aircraft; thrust chambers and tail nozzles of rocket engines; aerospace Key components such as aircraft laminate injectors and honeycomb panels of aerospace aircraft. Diffusion welding is also widely used in the machinery manufacturing industry, such as inserting cemented carbide (or carbide) blades into heavy tools.

3. Main configuration of vacuum diffusion welding equipment

· Work area size: 500mm(length)×400mm(width)×400mm(height)

· Maximum temperature: 1100℃

· Temperature uniformity: ±3℃

· Temperature control accuracy≤±1℃

· Working vacuum degree≤4×10-3Pa

· Main cylinder pressure 500KN, head stroke 400mm