What Is Electron Beam Welding?

Electron beam welding technology uses high-energy electron beam as the processing heat source, and uses high-energy-density electron beams to bombard the metal at the joint of the weldment to make it melt quickly and then quickly cool to achieve the purpose of welding.

Electron beam welding is widely used in aerospace, because it has the advantages of no electrode, not easy to oxidize, good process repeatability and small thermal deformation.

According to the basic principle of electron beam welding, in the late 1970s, western countries researched and developed a new production line for electron beam welding of bimetal saw bands, replacing the traditional ordinary high-speed steel saw band production process, thereby saving a lot of high-speed steel and improving sawing. Belt life.

Electrons are one of the basic particles of matter, and usually they orbit the nucleus at high speed. When electrons are given a certain amount of energy, they can jump out of orbit. A cathode is heated so that it releases and forms a free electron cloud. When the voltage is increased to 30 to 200kv, the electrons will be accelerated and move toward the anode.

1) Electron beam welding has high energy density and can weld welds that are difficult to achieve in general arc welding;

2) Electron beam welding is performed in a vacuum, the chemical composition of the weld is stable and pure, the strength of the joint is high, and the quality of the weld is high;

3) The electron beam welding speed is fast, the heat affected zone is small, and the welding thermal deformation is small;

4) Electron beam welding is suitable for welding almost all metal materials, especially for aluminum welding;

5) Electron beam welding can obtain a weld with a large aspect ratio (20: 1 50: 1), which can be formed at one time without opening the groove when welding thick parts;

6) Electron beam welding combined with computer technology achieves precise control of process parameters and completely automates the welding process.

Electron beam welding technology is currently the fastest growing and most widely used electron beam technology.

Due to the above characteristics of electron beam, it has been widely used in micro-drilling of high hardness, easily oxidizable or tough materials, milling of complex shapes, welding, melting and segmentation of metal materials, surface hardening, Lithography and polishing, as well as precision microfabrication of micro integrated circuits and ultra-large-scale integrated circuits in the electronics industry. With the continuous deepening of research, electron beam processing has become one of the special processing methods indispensable for the development of high technology.

Electron beam surface modification

Electron beam surface modification is to modify the surface of materials by using the high energy and high heat characteristics of the electron beam. The main modification methods are: electron beam surface alloying, electron beam surface quenching, electron beam surface cladding, electron beam surface fusion, and manufacturing of amorphous layers on the surface. After modification, the surface structure of the material is improved, the strength and hardness are greatly improved, and the corrosion resistance and water resistance are correspondingly enhanced.

Electron beam physical vapor deposition

Electron beam physical vapor deposition (EB-PVD) is an organic combination of electron beam technology and physical vapor deposition technology. It is a surface processing technology that uses high-energy electrons to bombard the deposited material, cause it to rapidly heat up and vaporize, and condense on the surface of the substrate. According to the nature of the deposited material, the coating can have excellent thermal insulation, abrasion resistance, corrosion resistance and erosion resistance, and can have a certain protective effect on the base material.

This technology is currently mainly used in the following areas.

1) Wear-resistant coating: The wear-resistant coating material with high hardness is deposited on the surface of tools and molds, which can greatly improve the service life of tools and molds.

2) Anticorrosive coating: due to EB. The coating prepared by PVD technology has a high degree of compactness, and its anticorrosive effect is very good for parts working in corrosive environments. In addition, EB. The morphology of the coating obtained by PVD is good, and the residual stress also significantly improves the corrosion resistance of the base material.

3) Thermal barrier coatings: Thermal barrier coatings (TBCs) are made of ceramic materials with good thermal insulation properties, which are deposited on the surface of high-temperature resistant metals or superalloys. Thermal barrier coatings provide thermal insulation to the base material and reduce the The temperature enables the devices (such as engine turbine blades) made of them to operate at high temperatures, and the thermal efficiency of the devices (engines, etc.) can reach more than 60%. At the same time, TBCs also have anti-corrosive and anti-oxidative effects ^[1] .