WELDED STRUCTURE OBTAINED BY TIG WELDING FERRITE STAINLESS STEEL EXHIBITING EXCELLENT CORROSION RESISTANCE AND STRENGTH IN WELD ZONES

Ferritic stainless steel excellent in corrosion resistance of the weld zone, in particular the corrosion resistance to crevice corrosion, even if eliminating the Ar gas shield at the time of TIG welding and, furthermore, excellent in weld zone strength and a structure of the same are provided. By making the ingredient system one satisfying the following formula (1) in ferritic stainless steel which has predetermined contents of ingredients by mass% under a usual corrosive environment, it is possible to raise the corrosion resistance. Furthermore, under a severely corrosive environment, by making the relationship between the back surface exposed width of the weld bead and the steel sheet thickness satisfy the formula (2) in addition to the relationship of the ingredients prescribed in formula (1), it is possible to obtain a welded structure strong in crevice corrosion. Furthermore, by improving the weld strength by making the contents of Nb and V satisfy formula 3, it is possible to obtain a welded structure with a high weld strength: Si + 2.5 ¢ Al + 3 ¢ Ti ‰¤ 1.50 0 < Wb / 2 ¢ t ‰¤ 1.50 (t: sheet thickness of welded metal, Wb: length of bead width exposed at back surface) Nb × V ‰¥ 0.01