TY - JOUR

T1 - Investigations on the Specifics of Laser Power Modulation in Laser Beam Welding of Round Bars

AU - Grajczak, J.

AU - Nowroth, C.

AU - Coors, T.

AU - Twiefel, J.

AU - Wallaschek, J.

AU - Saure, F.

AU - Pape, F.

AU - Poll, G.

AU - Nothdurft, S.

AU - Hermsdorf, J.

AU - Kaierle, S.

N1 - Funding Information: Open Access funding enabled and organized by Projekt DEAL. Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - CRC 1153, subproject A3–252662854. The authors would like to thank the DFG for the financial and organisational support of this project.

PY - 2022/12

Y1 - 2022/12

N2 - Welding round bars of large diameters in a rotational laser beam welding process corresponds with weld pool bulging and the risk of weld defects. Power modulation is a promising approach for bulge reduction and for keyhole stabilisation to achieve superior weld quality. The following investigations are about the specific effects of power modulation for round bars with a diameter of 30 mm. The welding speed is 0.95 m/min and argon is used as shielding and process gas. Triangle shaped power modulation at 8 kW average laser beam power, 0/2/4/6 kW amplitude power and 2/10/50 Hz modulation frequency is used for the round bar welding of a 1.4301 steel alloy. The welds are evaluated by visual inspection, metallographic cross sections and scanning acoustic microscopy. The amount of weld defects increases at medium and high power modulation, but weld pool bulging is already reduced at low power modulation. Weld pool bulging can be impeded by a low normalised power modulation frequency of 0.05 and a high modulation depth of 0.86. The power modulation’s advantages of weld mixing and degassing do not apply to rotational round bar welding because of the linear welding speed’s gradient from the specimen surface to the centre.

AB - Welding round bars of large diameters in a rotational laser beam welding process corresponds with weld pool bulging and the risk of weld defects. Power modulation is a promising approach for bulge reduction and for keyhole stabilisation to achieve superior weld quality. The following investigations are about the specific effects of power modulation for round bars with a diameter of 30 mm. The welding speed is 0.95 m/min and argon is used as shielding and process gas. Triangle shaped power modulation at 8 kW average laser beam power, 0/2/4/6 kW amplitude power and 2/10/50 Hz modulation frequency is used for the round bar welding of a 1.4301 steel alloy. The welds are evaluated by visual inspection, metallographic cross sections and scanning acoustic microscopy. The amount of weld defects increases at medium and high power modulation, but weld pool bulging is already reduced at low power modulation. Weld pool bulging can be impeded by a low normalised power modulation frequency of 0.05 and a high modulation depth of 0.86. The power modulation’s advantages of weld mixing and degassing do not apply to rotational round bar welding because of the linear welding speed’s gradient from the specimen surface to the centre.

KW - Keyhole stability

KW - Laser beam welding

KW - Power modulation

KW - Round bars

KW - Steel alloy 1.4301

KW - Weld pool bulging

UR - http://www.scopus.com/inward/record.url?scp=85135502703&partnerID=8YFLogxK

U2 - 10.1007/s40516-022-00183-5

DO - 10.1007/s40516-022-00183-5

M3 - Article

AN - SCOPUS:85135502703

VL - 9

SP - 469

EP - 480

JO - Lasers in Manufacturing and Materials Processing

JF - Lasers in Manufacturing and Materials Processing

SN - 2196-7229

IS - 4

ER -