| 摘要 |
PROBLEM TO BE SOLVED: To provide a material having excellent crevice corrosion resistance in the weld zone even if Ar back gas seal is obviated when the shell plate and end plate of a hot water storage tank are joined by TIG welding or seam welding, relating to ferritic stainless steel used for a hot water storage tank used for a COrefrigerant heat pump hot water heater and an electric water heater.SOLUTION: The ferritic stainless steel having excellent corrosion resistance in the weld zone configures a COrefrigerant heat pump hot water heater, an electric water heater or the like, and has a composition containing, by mass, ≤0.02% C, ≤3.0% Si, ≤1.0% Mn, ≤0.04% P, ≤0.003% S, 0.2 to 3.0% Ni, 20 to 30% Cr, ≤3.0% Mo, ≤0.03% N, 0.05 to 0.4% Ti, 0.05 to 0.6% Nb, 0.02 to 0.5% Al and ≤0.0010% Ca, or further containing 0.1 to 3.0% Cu and one or more selected from 0.0003 to 0.005% B and 0.01 to 0.5% W, and the balance Fe with inevitable impurities. |
