The 'electron gun', the heart of the electron beam welder, which was over 99% dependent on imports, has been produced domestically, raising expectations that it will be possible to seek replacement of foreign products in the future and expansion into new technologies such as space launch vehicle joining and nuclear power.

The Korea Electrotechnology Research Institute (KERI) announced on the 4th that the team led by Dr. Han Seong-tae of the Electrical Application Research Center has localized the core technology of the ‘electron gun,’ which can be called the heart of the ‘electron beam welder.’

‘Welding’, which can be said to be the foundation of industry, is the process of melting and joining various metal materials together. While conventional welding utilizes heat from an arc (spark generated when electrical discharge occurs) or a laser, electron beam welding uses the kinetic energy of electrons to bond materials together.

That is, when an electron beam is fired, electrons accelerated by high voltage collide with the material to be welded, converting their kinetic energy into heat energy, and the high heat generated at this time joins the materials to be welded.

The advantage of electron beam welding is that it enables defect-free joining of thick materials that could not be achieved with conventional welding.

Recently, with the advent of the 4th industrial revolution, the production of cutting-edge equipment has become necessary in various fields, and in particular, a higher level of 'electron beam welder' is required for special purposes such as aerospace, defense, and nuclear power.

An electron beam welder was also used to flawlessly attach special steel materials and parts to the combustor of the Nuri launch vehicle launched in 2021.

Electron beam welding requires a very high level of technology, and Korea has been dependent on importing more than 99% of related equipment from Germany and Japan.

In addition, there is a risk that domestic cutting-edge technology will leak out during the process of maintaining imported welding machines.

The achievement of the KERI team led by Dr. Han Seong-tae, who solved this problem, was the localization of the ‘electron gun’ and ‘drive power system,’ which are the core elements of the electron beam welder.

The higher the acceleration energy of the electron gun in an electron beam welder, the greater the extent to which the heat source can penetrate into the material.

KERI's technological prowess boasts high output (60kW) and acceleration voltage (120kV) comparable to the world's best. It is at a level where it can be used for almost all processing of thick, large materials and parts.

The research team has put in a lot of effort, including optimizing the electric and magnetic field structures and minimizing voltage imbalance, based on the high-voltage technology accumulated for over 20 years to develop high-performance equipment, and the results have come to fruition.

Through this achievement, the path has been opened for Korea to be able to use electron beam welding without relying on foreign countries. Since most of the 12 national strategic technologies that will lead the future require electron beam welding, it is expected to have a significant impact on the development of related industries, the effect of substituting imports for equipment, and the prevention of technology leaks.

KERI’s Dr. Han Seong-tae said, “As industries move into high value-added fields, the demand for high-precision and high-quality welding will increase, and there will be many products that cannot be manufactured without electron beam welding.” He added, “It is also significant in that it opens a new path to manufacturing customized, cutting-edge original equipment capable of high-performance electron beam welding using domestic technology.”

KERI, which has completed patent applications and overseas paper publications related to its technology, plans to develop an ultra-large (over 176 kV) high-current (over 500 mA) electron gun that can be applied to the next-generation small modular reactor (SMR) field through continuous research.

In addition, the goal is to secure control technology that can perform various functions such as metal melting, material hardening, surface treatment, and coating for the use of electron beam welding in various fields such as 3D printing of complex metal structures that require high strength.

Meanwhile, KERI is a government-funded research institute under the National Research Council of Science and Technology, Ministry of Science and ICT. This research was conducted through the 'Industrial Technology Challenge Track of Advanced Equipment Project' project of the Ministry of Trade, Industry and Energy, and Hanlai Biotech Co., Ltd., Korea Institute of Machinery and Materials Busan Machinery Technology Research Center Laser Practical Application Research Lab, and Pukyung National University participated in the research.