摘要:
A ferritic stainless steel for automobile exhaust gas passage components comprises, in mass percent, C: not more than 0.03%, Si: not more than 1 %, Mn: not more than 1.5%, Ni: not more than 0.6%, Cr: 10-20%, Nb: not more than 0.5%, Ti: 0.05-0.3%, Al: more than 0.03% to 0.12%, Cu: more than 1% to 2%, V: not more than 0.2%, N: not more than 0.03%, B: 0.0005-0.02%, 0: not more than 0.01%, and the balance of Fe and unavoidable impurities, whose composition satisfies the relationships Nb ≥ 8 (C + N) and 0.02 ≤ Al - (54/48) O ≤ 0.1. The steel enables fabrication of automobile exhaust gas passage components that are excellent in high-temperature strength and weld toughness, and offers a wide range of freedom in selecting suitable pipe-making conditions.
摘要:
To provide a ferritic stainless steel material for automobile exhaust gas passage components usable in a high-temperature range over 900°C and even over 950°C. The ferritic stainless steel material has excellent heat resistance and low-temperature toughness and has a composition comprising, in terms of % by mass, at most 0.03 % of C, at most 1 % of Si, from 0.6 to 2 % of Mn, at most 3 % of Ni, from 10 to 25 % of Cr, from 0.3 to 0.7 % of Nb, from more than 1 to 2 % of Cu, from 1 to 2.5 % of Mo, from 1 to 2.5 % of W, at most 0.15 % of Al, from 0.03 to 0.2 % of V, and at most 0.03 % of N, and optionally containing any of B, Co, W, Ti, Zr, REM and Ca with a balance of Fe and inevitable impurities, and the composition satisfies restrictive formulae 1.2Nb + 5Mo + 6Cu ≥ 11.5 and 15Nb + 2Mo + 0.5Cu ≥ 10.5. The steel material has a texture where the total amount of Nb and Mo existing as a precipitation phase is at most 0.2 % by mass.