Hybrid laser welding of single sided fully penetrated fillet welds

Abstract

Fillet welds are inherent part of large structures in the shipbuilding industry, where distortion is a major issue. Hybrid laser welding enables fully penetrated fillet welds to be achieved with a lower energy than arc-based welding processes. This provides an increase in productivity, decrease in distortion and reduction of weight. To achieve defect-free welds with good fatigue life it is necessary to control the weld profile, particularly in fully penetrated welds. In this work a detailed study of the key forces determining the profile and the fatigue life of hybrid fillet welds has been carried out. The effect of laser and Metal Inert Gas (MIG) parameters, such as the laser power density, MIG current and voltage and processing angles of both sources on the weld bead profile has been investigated. The results indicate that the weld profile in fully penetrated fillet joints is a net result of the amount of deposited material by the MIG source, the energy distribution of the laser and the pressure of the laser- induced vapour and the electromagnetic force of the MIG. By changing the balance between the deposited material and the net pressure that transports it to the back side, the weld profile can be tailored to a particular application.Fillet welds are inherent part of large structures in the shipbuilding industry, where distortion is a major issue. Hybrid laser welding enables fully penetrated fillet welds to be achieved with a lower energy than arc-based welding processes. This provides an increase in productivity, decrease in distortion and reduction of weight. To achieve defect-free welds with good fatigue life it is necessary to control the weld profile, particularly in fully penetrated welds. In this work a detailed study of the key forces determining the profile and the fatigue life of hybrid fillet welds has been carried out. The effect of laser and Metal Inert Gas (MIG) parameters, such as the laser power density, MIG current and voltage and processing angles of both sources on the weld bead profile has been investigated. The results indicate that the weld profile in fully penetrated fillet joints is a net result of the amount of deposited material by the MIG source, the energy distribution of the laser and the pressure of the ...