| 摘要 |
PROBLEM TO BE SOLVED: To provide a ferrite steel which can suppress decrease in the creep strength of a welded part.SOLUTION: A ferrite steel has a structure of a chemical composition comprising, in mass%, C: 0.05% or less, Si: 1.00% or less, Mn: 0.30-0.70%, Ti: 0.010-0.10%, N: 0.010-0.050%, Co: 5.00-12.00%, W: 0.50-5.00%, B: 0.0025-0.020%, P: 0.03% or less, S: 0.015% or less, Al: 0.03% or less, Cu: 0.01% or less, Ni: 0.01% or less, Cr: 0-11.50%, Mo: 0-2.00%, V: 0-0.50%, Nb: 0-1.00%, Ta: 0-1.00%, Zr: 0-0.10%, with the balance being Fe and impurities, where an area ratio of a ferrite phase is 95% or more and a ferrite particle diameter of the ferrite phase is less than 50 μm.SELECTED DRAWING: None |
