Fatigue properties of the fillet welded joint for non-load carrying type using hot-wire laser welding process

Abstract

In order to investigate the fatigue properties of the fillet welded joint for non-load carrying type using hot-wire laser welding process, fatigue tests were carried out in comparison with the fillet welded joint using CO₂ arc welding process to be widely used as a conventional welding method. Furthermore, the welding method to achieve the hot-wire laser welded joints with superior fatigue properties was suggested based on the experimental knowledge on the fatigue properties. It is clear that hot-wire laser welding process can remove the primer coating at steel plate surface during the welding process. From the results of the fatigue tests, CO₂ arc welded joints indicated the higher fatigue strength compared with hot-wire laser welded joints because the hardness of HAZ was higher than that of the welded metal in hot-wire laser welded joints whereas the hardness of the welded metal and HAZ indicated the same value in CO₂ arc welded joints in the case of using the same welding wire JIS:Z3312YGW11. Therefore, it can be improved the difference of the fatigue strength by selecting the welding wire as to achieve the same hardness in both of the welded metal and HAZ. Furthermore, it can be possible to achieve the hot-wire laser welded joints with higher fatigue strength compared with the CO₂ arc welded joints by adjusting the wire feed speed and controlling the weld toe shape. From the experimental results, it was concluded that hot-wire laser welding process can be applied with high safety and reliability as alternative welding process to CO₂ arc welding process.