Patent ID: 8383034

Claim:
A ferritic stainless steel sheet for a water heater comprising, in terms of mass %, 0.020% or less of C, 0.30 to 0.82% of Si, 1.00% or less of Mn, 0.040% or less of P, 0.010% or less of S, 20.0 to 28.0% of Cr, 0.1 to 0.6% of Ni, 0.03 to 0.15% of Al, 0.020% or less of N, 0.0020 to 0.0150% of O, 0.3 to 1.5% of Mo, 0.25 to 0.60% of Nb, and 0.03% or less of Ti where Ti is present, the remainder being composed of Fe and unavoidable impurities, and the ferritic stainless steel sheet satisfying the following formulae (1) and (2): 25≦Cr+3.3Mo≦30 (1) 0.35≦Si+Al≦0.85 (2) wherein Cr, Mo, Si, and Al represent the contents (mass %) of Cr, Mo, Si, and Al, respectively.