Historically, for butt welding of sheets, Anderson has made use of double tungsten inert gas (TIG) welding which requires two skilled artisans to work simultaneously to achieve one weld. This process allows us to achieve a one pass weld on material up to a thickness of 4 mm. These welds are achieved while the job is in a vertical plane. For any material thicker than this, several passes with back grinding, are required. This process is still used for the smaller welds and for once-off applications.

However, most of the sheet butt welds and circular strake welds are now done on the new plasma welding machine as it can achieve a one pass weld on material up to 8 mm thick. The machine requires two semiskilled operators. The machine has a 3 metre seam welding bench upon which sheets of material are welded together in a horizontal plane. The column and boom have been designed to allow the welding head to rotate and weld on the seam bench as well as on the rotating table. Cylindrical vessel shell strakes with diameters of up to 4 metres can be joined together. This machine can weld up to 3 metre lengths at a speed of 3 minutes 20 seconds per metre. The PLC control system uses camera technology allowing the operator to see the weld pool and make fine control adjustments to ensure consistent, quality welds.

A TIG weld

A plasma weld