Structure and properties of hybrid laser arc welded T-Joints (laser beam - MAG) in thermo-mechanical control processed steel S700MC of 10 mm thickness

In this article examinations of hybrid welding technology (laser beam + MAG) of T-joints from thermomechanically worked high strength steel S700MC 10 mm thick were presented. Joints welded from one side and both sides were made. Carried examinations enabled to classify joints in quality level B according to ISO 12932 (Welding. Laser-arc hybrid welding of steels, nickel and nickel alloys. Quality levels for imperfections). In case of one sided welding with partial penetration with beam power of 8.5 kW 8 mm of penetration was achieved without noticeable distortion of web. Double sided joints were characterized with correct geometry. Joint metal is bainitic-ferritic in structure and its hardness rises about 40 HV1 in comparison to base metal hardness (280 HV1). In HAZ a slight softening of material in comparison to base metal is present.