Ferritic-austenitic two-phase stainless steel

• Main Authors: HINENO, MAKOTO, TORIGOE, TAKESHI
• Format: Patent
• Language: English; French; German
• Published: 02.05.2003
• Edition: 7
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; METHODS OF PRODUCING PAPER THEREON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PAPER-MAKING; PAPER-MAKING MACHINES; PRODUCTION OF CELLULOSE; TEXTILES; TREATMENT OF ALLOYS OR NON-FERROUS METALS

A ferritic-austenitic two-phase stainless steel comprising, in wt. %, over 0% to not more than 0.05% of C, 0.1 to 2.0% of Si, 0.1 to 2.0% of Mn, 20.0 to 23.0% of Cr, 3.0 to 3.9% of Ni, 0.5 to 1.4% of Mo, over 0% to not more than 2.0% of Cu and 0.05 to 0.2% of N, the steel further containing, when desired, at least one element selected from the group consisting of over 0% to not more than 0.5% of Ti, over 0% to not more than 0.5% of Nb, over 0% to not more than 1.0% of V, over 0% to not more than 0.5% of Al, over 0% to not more than 0.5% of Zr, over 0% to not more than 0.5% of B, over 0% to not more than 0.2% of a rare-earth element, over 0% to not more than 1.0% of Co, over 0% to not more than 1.0% of Ta and over 0% to not more than 1.0% of Bi, the balance being substantially Fe. Cr, Mo and N are within the range defined by the following expression i­: Cr + 3.3 x Mo + 16 x N ≤ 28% The metal structure of the stainless steel is 45 to 80% in the area ratio alpha % of a ferritic phase therein. Cr and N are further within the range defined by the following expression ii­: 0.2 x Cr/N) + 25 ≤ alpha