EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The aim of this work is the study of the weldability of high strength steel used as tendons for strand anchors with the friction welding process. The motivation of this study is to provide extensions for strand anchors which are widely used (e.g. slope stabilization, retaining structures, bridge abutments) in civil engineering. These extensions are necessary to extend the lifespan of such anchors, which otherwise have to be replaced which is a costly and resourceful action. The friction welding process has been chosen because it has proven in the past that is a very capable process for welding of hard to weld materials like high strength steel. The strand, which has an outer diameter of 15.3 mm, consist of 7 single wires with a diameter of 5 mm. Additionally to the welding parameters, several weld preparation measures have been investigated to investigate their effects on the joint strength. SEM investigations of the fracture surface of tensile tested specimens have shown that, although the weldability is given, only a limited contact area of the strand (or the single wires) is contributing to the joint and therefore, the joint strength is quite low compared to the material strength. Further measures have been taken to increase the joining area. Microstructural examinations and supplementary hardness measurements are used to characterize the joint.