ABSTRACT

The objective of the project (RFS-CR-03049), partially supported by Research Fund for Coal and Steel, was to explore and quantify the benefits of Synchronised Tandem Wire Welding (STW) applied to structural steels as alternative technology to established arc welding technologies. T-joints and butt joints of 6 mm and 12 mm steel grade S355 plates have been investigated using two different types of welding gun configuration, i.e. fixed electrodes and variable electrodes configuration. The influence of electrodes distance, stick-out, arc types and welding speed has been examined. The optimised joints have been characterized in terms of structural integrity, microstructure, mechanical performance (impact fracture toughness, fatigue resistance), total deformation and compared to traditional arc welding joints. STW technology allowed to increase of about 50% both welding speed, at the same penetration, and deposited metal compared to GMAW with a not much greater heat input (1 kJ/mm) maintaining the same level of joint quality (EN ISO 5817qaulity level B) and structural integrity with a reduction of joint distortion. In addition fatigue resistance of STW joints was in compliance with the requirement (FAT Class 100 MPa). 5 The most significant benefits demonstrated for STW was an increase in productivity of generally between 50% and 100%, with no detrimental effects on mechanical performance or distortion.