Effect of rewinding on flux-cored welding wires

Rewinding of welding flux-cored wires can be a practical way to reduce the waste of welding consumables. However, changing the winding on the spool carries the risk of disrupting the welding process. The study presents the results of research on the impact of controlled rewinding on different types of flux-cored wires, conducted by examining the stability of the welding process and the diffusible hydrogen content in deposited metal. It was found that after rewinding, both seamless and seamed wires showed greater variation in the recorded arc voltage and welding current data. Rewinding also caused an increase in diffusible hydrogen content from 9.14 to 10.35 ml/100 g. Using a full factorial design, the influence of rewinding was evaluated under various welding parameters and wire surface conditions. The lowest stability indexes were observed at lower arc voltage and with worse wire surface condition. Rewinding of flux-cored wire caused a deterioration in process stability, manifested, among other things, by as many as 41 and 35 exceedances of current fluctuation thresholds for seamed and seamless wires, respectively. However, selecting appropriate welding parameters, positioned near the upper limits recommended by the wire manufacturers, can enable stable welding after rewinding, even for wires with partially degraded surface conditions.