Non-vacuum electron beam welding employs essentially the same equipment as in-vacuum EBW but the beam is passed through a series of separately pumped pressure stages to allow the beam to be projected into the atmosphere without causing excessive gas leakage into the beam generator. Material thickness of up to 50mm in steel and 30mm in copper can be joined using this process. The process offers the following benefits:
- Single pass thick section welding at atmospheric pressure
- No vacuum chamber required
- Welding station process time minimal
- Cost of welding enclosure and pumping equipment greatly reduced compared with in-vacuum equipment
- Weld characteristics similar to those produced by in-vacuum EB welding, i.e. low distortion & high weld quality
- Joining rates in excess of 2m2 /hour possible in steel (e.g. 40m/hour for single pass welding of 50mm thick steel).
The European Eureka project EU86 culminated in the construction of a substantial 150kW non-vacuum facility at TWI which is expected to achieve single pass welding of 100mm thick steel with similar weld characteristics to in-vacuum electron beam welding. The equipment has already projected intense beams with power levels of up to 100kW into the atmosphere and initial welding trials, even at 60kW, have achieved over 50mm penetration in steel in the flat position. Ongoing development work, the use of pulsed beams and other equipment refinements are expected to improve substantially welding performance and weld quality.
Potential Application Areas:
- Nuclear/power generation
- Nuclear waste encapsulation
Based on preliminary results the following typical welding speeds are anticipated:
For further details please see Joining Technologies or contact us.