Microstructural evolution and properties of tungsten inert gas and fiber laser welded SUS445 ferritic stainless steel

To determine the weldability of SUS445 ferritic stainless steel, two welding approaches, tungsten inert gas and fiber laser welding processes, were used and compared. After the welding processes, the microstructure, mechanical properties, and corrosion resistance of the welds were investigated. In the weld fusion zones of these two welding approaches, different morphologies of the grains were obtained. No obvious precipitation formed in these zones. In the heat affected zone of the tungsten inert gas welds, more volume fraction and larger grain sizes of the Laves phase and larger matrix grains were observed, which significantly affected its corrosion resistance and mechanical properties. However, in the heat affected zone of the fiber laser welds, only small amounts Laves phases and a relatively narrow matrix grain growth area were observed, which offers better corrosion resistance and mechanical properties.