Under of high-temperature oxidation environment of 200 - the 400 is superior corrosion-resistant the ferritic stainless steel

摘要

PROBLEM TO BE SOLVED: To produce a ferritic stainless steel small in deterioration in corrosion resistance in a high temp. environment by specifying the componental compsn. of a steel and forming concentrated layers of Cr, Si and B as surface oxidized coating. ;SOLUTION: Finish annealing for a cold rolled sheet of a steel composed of, by weight, ≤0.02% C, 0.1 to 1.5% Si, ≤1.0% Mn, ≤0.05% P, ≤0.01 S, 10 to 25% Cr, ≤0.02% N, 0.002 to 0.02% Nb, 0.0003 to 0.0025% B, 6×(C%+N%) to 0.5% Ti, and the balance Fe is executed at 750 to 1000°C for ≤10min in a reducing atmosphere in which the dew point is regulated to -5 to 60°C, the volume of the componental H₂ is regulated to 1 to 20%, and the balance N₂. Then, a steel sheet in which the oxidized coating on the surface has concentrated layers of Cr, Si and B, and the concn. of the most concentrated part compared to the concn. of the base material is regulated to ≥ two times as to Cr and ≥ five times as to Si, and deterioration in corrosion resistance in a high temp. environment at 200 to 400°C is small is obtd. Moreover, the above steel may be incorporated with prescribed amounts of one or more kinds among Ni, Mo, Cu and Ca.;COPYRIGHT: (C)1997,JPO