Laser-arc hybrid welding of 12- and 15-mm thick structural steel

• Published in: International journal of advanced manufacturing technology Vol. 107; no. 5-6; pp. 2649 - 2669
• Main Authors: Bunaziv, Ivan, Dørum, Cato, Nielsen, Steen Erik, Suikkanen, Pasi, Ren, Xiaobo, Nyhus, Bård, Eriksson, Magnus, Akselsen, Odd M.
• Format: Journal Article
• Language: English
• Published: London Springer London 01-03-2020; Springer Nature B.V
• Subjects: Arc welding; Butt joints; Butt welding; CAE) and Design; Computer-Aided Engineering (CAD; Engineering; Hardness; High power lasers; Impact strength; Industrial and Production Engineering; Laser beam welding; Lasers; Mechanical Engineering; Media Management; Original Article; Penetration depth; Process parameters; Structural steels; Tensile strength; Thick plates; Weld defects; Welded joints; Hybrid welding; Mechanical properties; Toughness; Laser welding; High strength steel; Thick steel
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-020-05192-2

High-power lasers are very effective in welding of plates thicker than 10 mm due to the keyhole mode. High-power intensity generates a vapor-filled cavity which provides substantial penetration depth. Due to the narrow and deep weld geometry, there is susceptibility to high hardness and weld defects. Imperfections occur due to keyhole instability. A 16-kW disk laser was used for single-pass welding of 12- to 15-mm thick plates in a butt joint configuration. Root humping was the main imperfection and persisted within a wide range of process parameters. Added arc source to the laser beam process may cause increased root humping and sagging due to accelerated melt flow. Humping was mitigated by balancing certain arc and other process parameters. It was also found that lower welding speeds (< 1.2 m/min) combined with lower laser beam power (< 13 kW) can be more positive for suppression of humping. Machined edges provided more consistent root quality and integrity compared with plasma cut welded specimens. Higher heat input (> 0.80 kJ/mm) welds provided hardness level below 325 HV. The welded joints had good Charpy toughness at − 50 °C (> 50 J) and high tensile strength.