Patent ID: 11866814
Assignee: NIPPON STEEL CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  F | IPC C  F

Claim 2:
3. A facility comprising power plant boilers, or petroleum refining or petrochemical plants, the power plant boilers, or petroleum refining or petrochemical plants including components, each component exposed to polythionic acid made from an austenitic stainless steel, which consists of by mass percent, C: not more than 0.02%, Si: not more than 1.5%, Mn: not more than 2%, Cr: 17 to 25%, Ni: 9 to 13%, Cu: more than 0.26% to less than 2.95%, N: 0.06 to 0.35%, sol. Al: 0.008 to 0.03%, an amount of Co, the Co amount 0.03 to 1.0%, an amount of Ta, the Ta amount not more than 0.2%, an amount of Nb, the Nb amount not more than 0.5%, an amount of V, the amount of V not more than 0.4%, an amount of Ti, the amount of Ti not more than 0.4%, and further contains one or more elements selected from Hf: not more than 0.2% and Zr: not more than 0.2%, with the balance being Fe and impurities, in which the contents of P, S, Sn, As, Zn, Pb and Sb among the impurities are P: up to 0.04%, S: up to 0.03%, Sn: up to 0.1%, As: not more than 0.01%, Zn: not more than 0.01%, Pb: not more than 0.01% and Sb: not more than 0.01%, and the values of F1 and F2 defined respectively by the following formula (1) and formula (2) satisfy the conditions F1≤0.075 and 0.05≤F2≤1.7-9×F1;

F1=S+{(P+Sn)/2}+{(As+Zn+Pb+Sb)/5}  (1),

F2=Nb+Ta+Zr+Hf+2Ti+(V/10)  (2);, wherein each element symbol in the formulas (1) and (2) represents the content by mass percent of the element concerned.