Product Code: PIC06_502

Economic Edge Preparation for Laser-MAG Hybrid Welding of High Strength Steel
Authors:
Ben Boese, Laser Zentrum Hannover E.V.; Hannover Germany
Gerd Kuscher, Schweitechniche Lehr- und Versuchsanstalt Hannover gGmbH; Hannover Germany
Presented at PICALO 2006

In the crane and freight vehicle manufacturing industry, lightweight construction is a strong issue. A reduction of material thickness in extension arms of cranes or mobile concrete pumps leads to an increase of the number of segments possible and therefore to a longer reach and a higher payload. For these applications, a wide range of high strength fine grain steels for coarse plates has been developed. While these steels have excellent material properties with high yield strengths, special care has to be taken while welding. Therefore, the thermal cycle implemented by Laser-GMA hybrid welding has to be fitted to the metallurgical needs of the steel. Laser welding and laser hybrid welding usually requires an exact edge preparation, often with milled edges which are expensive in manufacturing. In order to make hybrid welding more economic, specimens using laser nitrogen cut, laser oxygen cut and plasma cut edge preparations were welded with various gap widths and tested in accordance to european approval standards for welding procedures, including tensile testing, charpy testing and metallographical and X-ray testing. In the paper, economic methods of preparing and laser hybrid welding of high strength steel will be shown.