Longitudinal bendability of laser welded special steels in a butt joint configuration Available to Purchase

The Finnish steel-making company Ruukki Metals utilises the unique direct quench process in the production of special steels like ultra-high-strength, wear-resistant and protective steels. Raex® and Optim® are examples of Ruukki’s special steels. One of the steel service centres of Ruukki is specialised in CO2-laser welding, which has been found to be a reliable joining method for thin strip steels. In addition, for butt joints, superior weld quality is achieved together with excellent base material flatness. Normally, as a part of the welding procedure specification process, the transverse bendability of welded samples is tested. However, laser welded strips are used in applications like dump trailers, tipper bodies and waste containers, where the bending of welds in a longitudinal direction is encountered. Ruukki provides a guaranteed minimum bending radii R (90° bending), depending on the steel grade, thickness and bending direction. In this study, the longitudinal bendability of laser welds in 4 mm -thick steel sheets has been evaluated using visual examination and measurements. The steel grades studies were Raex 400 and 450 (wear-resistant steels), and Optim 700 MC (thermo-mechanically rolled structural steel). Comparative bend tests were carried out according to standard ISO 5173.