Applications and properties of ferritic stainless steels with laser welding

This study evaluates the effects of laser welding on UNS S41003 stainless steel plates, which were pre-treated with a nickel-watts bath enriched with niobium. The plates, with an area of 0.36 dm², were subjected to this treatment for 10 minutes at 60°C, with a direct current of 3.2 A and pH 4, resulting in a thin coating. Subsequently, the plates were laser welded in a butt joint configuration, using a power of 1800 W, a welding speed of 2 cm/s, a focal distance of 3.8 cm, and argon as the shielding gas. The samples were categorized into three regions of interest: the fusion zone (FZ), the heat-affected zone (HAZ), and the base metal (BM). Twenty specimens were prepared by wire electrical discharge machining and were allocated for tensile testing, ferritoscopy, and Vickers microhardness testing. The aim is to determine whether the nickel-watts treatment combined with laser welding enhances the mechanical properties of the FZ and HAZ compared to the BM. Vickers microhardness testing will be used to assess hardness variations among the regions, while ferritoscopy will identify the presence of magnetic phases. Scanning electron microscopy (SEM) will provide three-dimensional images to characterize the microstructure and surface morphology. It is anticipated that the FZ and HAZ will exhibit improved tensile and impact resistance compared to the BM, due to the grain refinement induced by the nickel and niobium treatment.