| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust system member having heat resistance equivalent to or higher than that of conventional steel and securing toughness in manufacturing processes. <P>SOLUTION: A low Cr stainless steel excellent in heat resistance and age hardening characteristics includes 0.08 mass% or less of C, 0.20 mass% to less than 0.80 mass% of Si, 0.30-1.50 mass% of Mn, 2.0 mass% or less of Ni, 11.0 mass% to 16.0 mass% of Cr, 0.08 mass% or less of N, 0.20-0.80 mass% of Nb, 0.60-2.50 mass% of Cu, and 0.01-0.20 mass% of V, with the balance being Fe and inevitable impurities. Furthermore, the low Cr stainless steel simultaneously satisfies that a value represented by the following formula (1) is 0 or more and 0.5 or less, a value represented by the formula (2) is 50 or more and 75 or less and a value represented by the formula (3) is 800 or less, and has a cast structure comprising 5% or more and 60% or less, in vol.%, of a martensitic phase with the balance being ferrite, while a structure after final annealing is a ferrite single-phase structure. The formulae (1) to (3) are represented: Nb≥8(C+N) (1); 420C-11.5Si+7Mn+47N-25(Nb+V)+9Cu+189 (2); and 35Cr+73Si+170Nb-250C-280N-115Ni-66Mn-18Cu-219V+310 (3), wherein, each chemical symbol represents a content (mass%) of the alloy element. <P>COPYRIGHT: (C)2012,JPO&INPIT |
