Develop improved beam focusing and projection technology for deployment of high power (up to 80kW) beams in gas a pressure of from 1 to 1000mbar.
Assess to effect of gas pressure on beam intensity.
Establish a prototype small scale welding facility to assess welding performance.
Map out the penetration thickness, working distance range and weld quality capability for the pressure range 1 to 100mbar.
Identify and align welding performance to appropriate large scale fabrication needs.
Current TWI NVEB equipment is capable of projecting beams of over 70kW into gas at 1000mbar. This will be used as an initial test vehicle to assess the effect of gas pressure on beam intensity. A suitable gun column will be mounted on a vacuum chamber and visual and beam probing techniques use to assess beam profile and intensity in a range of gas environments. Electron-gas scattering calculations will be carried out including the effect of gas pressure, species and temperature. Means of enhancing beam quality will be applied; this may include special beam extraction, plasma control and beam pulsing technology. The effect of beam convergence angle and projection distance will be studied. The test facility will include a traverse mechanism to allow appropriate thick section materials to be welded for investigation of penetration depth and weld quality.
Emphasis will be placed on the welding of ferritic and austenitic steels but other metals will be considered as industrial applications emerge. The most favourable EBW pressure/beam power regimes will be identified.
Following this existing equipment will be modified to operate at the elevated pressure. Ultimately this may include an add-on pressure stage to the sliding seal Reduced Pressure equipment recently established at the TWI Technology Centre (North East) to allow large scale components to be welded at pressures in excess of 50mbar.
The programme will also include a watching brief on thick section, large scale, industrial fabrication needs and the programme will be geared to match these to the most appropriate high power, thick section, EBW pressure regime.
Relevant Industry Sectors
Power Generation, Nuclear, Construction and Engineering, Chemical Plant, Marine
Technical and Economic Benefits
Increased productivity, single pass penetration, weld quality and welding speed for thick section alloys.
Reduced weld distortion.
Reduced completion time for large scale fabrications.
Industrial Member Report
Access the Industrial Member Report resulting from this programme:
Reduced-pressure, local-vacuum electron beam welding system commisision and initial welding trials