Root formation and mechanical properties in laser keyhole welding of 15 mm thick HSLA steel
Bunaziv, Ivan; Dørum, Cato; Nielsen, Steen Erik; Suikkanen, Pasi; Ren, Xiaobo; Nyhus, Bård; Eriksson, Magnus Carl Fredrik; Akselsen, Odd Magne
Peer reviewed, Journal article
Published version
Permanent lenke
https://hdl.handle.net/11250/2987267Utgivelsesdato
2021Metadata
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Originalversjon
IOP Conference Series: Materials Science and Engineering. 2021, 1135 . 10.1088/1757-899x/1135/1/012011Sammendrag
Deep penetration laser welding is promising in joining thick (> 10 mm) steel sections. Focused laser beam by drilling vapour cavity, the keyhole, generates deep and narrow welds. Full penetration single-pass joining has a persistent problem with root quality where humping is one of the most frequent imperfection. This strongly hampers the use of high-power laser for thick plate welding. A 16 kW disk laser was used for single-pass welding of 15 mm thick plates in a butt joint configuration. Root humping occurred within a wide range of welding parameters. This provides narrow processing window. By adding an arc source to the laser beam process, the tendency of root humping increases. To achieve humping-free welds and consistent root quality over length, a delicate balance of process parameters is required. High heat input (> 0.50 kJ/mm) was positive to achieve a combination of low hardness (< 325 HV) and good Charpy toughness at -50 °C (> 50 J).