Non-vacuum electron beam welding
Even with the introduction of reduced pressure EB welding the necessity of a vacuum chamber is still seen by many as a major obstacle in terms of the cost of providing one big enough to handle large components. Also loading, evacuation and unloading operations can slow down component throughput and increase costs.
The concept of launching an electron beam into the atmosphere is almost as old as high vacuum EB welding, but electrons are easily scattered by shielding gas atoms and dense metal vapour. As a consequence, industrial application of Non-Vacuum Electron Beam (NVEB) has, with few exceptions, been limited to the welding of simple thin section products.
At TWI R&D into NVEB has been going on for over 10 years and we have been able to improve the equipment, and hence the process, to enable better welding of thicker sections at atmospheric pressures.
The current capability of our experimental machine has been the transmission of electron beams of up to 270mA at 150kV (40.5kW) and 300mA at 175kV (52.5kW) into the atmosphere. These produced welds with round roots and high depth to width ratios.
More detailed information is available to TWI's Industrial Members:
Contact: electronbeam@twi.co.uk
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