Ferritic-austenitic two-phase stainless steel

• Main Authors: Hineno, Makoto, Torigoe, Takeshi
• Format: Patent
• Language: English
• Published: 05.02.2002

The present invention relates to ferritic-austenitic two-phase stainless steel which is excellent particularly in thermal fatigue resistance and corrosion fatigue resistance and useful, for example, as a material for suction rolls for use in paper machines, and also to suction roll shell members prepared from the stainless steel. A ferritic-austenitic two-phase stainless steel consisting essentially of, 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]:The metal structure of the stainless steel is 45 to 80% in the area ratio % of a ferritic phase therein. Cr and N are further within the range defined by the following expression [ii]: