| 摘要 |
PROBLEM TO BE SOLVED: To provide: austenitic stainless steel which is applied for a steel pipe having an inner face subjected to shot peening treatment among heat exchanger pipes used in a thermal power generation facility and has improved scale exfoliation resistance of the inner face; and a stainless steel pipe comprising the stainless steel.SOLUTION: The heat-resistant austenitic stainless steel includes, by mass, 0.02-0.2% of C, 0.1-1.5% of Si, 0.1-3% of Mn, 7-13% of Ni, 16-20% of Cr, 0.4-4% of Cu, 0.05-0.6% of Nb, 0.05-0.6% of Ti, 0.05-0.35% of Zr, 0.005-0.1% of Ce, 0.0005-0.005% of B, 0.001-0.15% of N, 0.005% or less (excluding 0%) of S and 0.05% or less (excluding 0%) of P, respectively, with the balance of iron with inevitable impurities. In the heat-resistant austenitic stainless steel, a ratio (H/H) between an average hardness (H) of the area ranging from the surface to a depth of 50 μm in the thickness direction and an average hardness (H) of the center part in the thickness direction is 1.20 or more. |
