Modern hybrid welding process for structural steelwork engineering-laser submerged arc hybrid welding

Abstract

The welding of steel with large plate thicknesses gains more and more in importance for the structural steelwork engineering (e.g. pipe- or crane building). Nowadays those welding tasks are performed by a time-consuming conventionally submerged-arc welding process. A large number of welding passes are necessary which are accompanied by thermally induced distortion. So there is a high demand for a welding process which allows the economical welding of thick steel plates with high plate thicknesses. By the development of a laser beam submerged-arc hybrid welding process (LB-SAW) a technique is created which combines the high penetration depth of the laser with the high thermal efficiency of the submerged-arc process. This leads to synergy effects which predestine LB-SAW for the given welding task. Further projects have shown the general feasibility of LB-SAW. Steel plates with thicknesses up to 36 mm have been joined without any welding errors with the double-sided single pass technique. As conspicuous prove the differing results of the notch impact test in the laser beam-dominated and the submerged-arc-dominated welding areas.This paper presents the latest welding results which are performed by LB-SAW. It was possible to increase the weldable plate thickness up to 50 mm by a simultaneous gain of process stability. Also the influence of different process distances in relation to synergy effects is shown.The welding of steel with large plate thicknesses gains more and more in importance for the structural steelwork engineering (e.g. pipe- or crane building). Nowadays those welding tasks are performed by a time-consuming conventionally submerged-arc welding process. A large number of welding passes are necessary which are accompanied by thermally induced distortion. So there is a high demand for a welding process which allows the economical welding of thick steel plates with high plate thicknesses. By the development of a laser beam submerged-arc hybrid welding process (LB-SAW) a technique is created which combines the high penetration depth of the laser with the high thermal efficiency of the submerged-arc process. This leads to synergy effects which predestine LB-SAW for the given welding task. Further projects have shown the general feasibility of LB-SAW. Steel plates with thicknesses up to 36 mm have been joined without any welding errors with the double-sided single pass technique. As conspicuous prov...