TWI Industrial Member Report Summary 202/1983
By C J Dawes, M N Watson and J D Sharman
Laser welding trials have been conducted on T joints made from 2, 3 and 4mm thick low carbon steels. The trials have established practical process application data with respect to laser beam impingement angle, laser beam/workpiece alignment and workpiece fitup. The data are based on results obtained from visual, macrosection and radiographic examinations. A 10° laser beam impingement angle is most suitable for welding T joints in 2mm material, whereas 7° is better for thicker materials. A beam angle of 5° is unsatisfactory as it is difficult to set up and maintain without the beam clipping the workpiece. Laser beam/workpiece alignment requires special care and has little tolerance to variation. A gap of 0.15mm at the joint face can be tolerated when welding 2 and 3mm thick materials and a gap of 0.25mm for 4mm materials. A surface mismatch of more or less 40% of the sheet thickness can be tolerated when making welds in 2 and 3mm materials and more or less 50% for 4mm materials.