Klas Nilsson

Influence of joint geometry and fit-up gaps on hybrid laser-metal active gas (MAG) welding

This article presents the results of an experimental program to investigate the sensitivity of the hybrid laser-MAG welding process to gaps between the work pieces being welded. It was concluded that the minimum throat depth of the welds remained surprisingly stable for fillet welds as long as the metal active gas (MAG) parameters were set high enough to fill the gaps involved (up to a gap size of approximately 3 mm). If the MAG parameters were insufficient then the welding process collapsed with increasing gap widths.This article presents the results of an experimental program to investigate the sensitivity of the hybrid laser-MAG welding process to gaps between the work pieces being welded. It was concluded that the minimum throat depth of the welds remained surprisingly stable for fillet welds as long as the metal active gas (MAG) parameters were set high enough to fill the gaps involved (up to a gap size of approximately 3 mm). If the MAG parameters were insufficient then the welding process collapsed with increasing gap widths.

Laser hybrid welding of high strength steels

This paper presents results from an ongoing investigation into laser-arc-hybrid welding of thick, high strength steels used in the heavy mechanical and heavy automotive industries. The results include welding parameters for a 6 and 12 kW laser combined with conventional MIG/MAG equipment.In this work, the laser-arc-hybrid welding technique has been further developed and applied to thick steel plate welding, giving high quality welds at high speeds. Successful welds were obtained on 6-12 mm plate thickness with laser, plasma or sheared edges as received from the blanking process. Thereby any costly, additional joint preparation is avoided, giving the hybrid welding technique an enhanced potential for use in the heavy automotive and mechanical industries.This paper presents results from an ongoing investigation into laser-arc-hybrid welding of thick, high strength steels used in the heavy mechanical and heavy automotive industries. The results include welding parameters for a 6 and 12 kW laser combined with conventional MIG/MAG equipment.In this work, the laser-arc-hybrid welding technique has been further developed and applied to thick steel plate welding, giving high quality welds at high speeds. Successful welds were obtained on 6-12 mm plate thickness with laser, plasma or sheared edges as received from the blanking process. Thereby any costly, additional joint preparation is avoided, giving the hybrid welding technique an enhanced potential for use in the heavy automotive and mechanical industries.

Fatigue strength of Nd:YAG-laser welded stainless steel lap joints

Fatigue tests were carried out on thin section stainless steel lap welds produced by Nd:YAG-laser. Analysis of the fatigue tests results and the fracture surfaces identified sheet thickness and inter sheet gaps as having considerable effect on fatigue life. Weld width has a more moderate influence on fatigue life and weld porosity has a negligible effect at low concentrations.