Rolled ferritic stainless steel sheet, method for producing the same, and flange part

Abstract

The present invention provides a rolled ferritic stainless steel material excellent in corrosion resistance and toughness, in particular suitable as a material for a flange and a method for producing the same and flange part. The rolled ferritic stainless steel material contains, by mass %, C: 0.001 to 0.08%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.01 to 0.05%, S: 0.0002 to 0.01%, Cr: 10.0 to 25.0%, and N: 0.001 to 0.05%, has a balance of Fe and unavoidable impurities, has a thickness of 5 mm or more, and has an area ratio of crystal grains with a <011> direction within 15° from the rolling direction of 20% or more in a cross-section parallel to the rolling direction at any location between the left and right ends of the steel sheet.

1 . A hot rolled annealed steel sheet or a hot rolled annealed steel strip comprised of ferritic stainless steel material containing, by mass %, C: 0.001 to 0.08%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.01 to 0.05%, S: 0.0002 to 0.01%, Cr: 10.0 to 25.0%, and N: 0.001 to 0.05%, having a balance of Fe and unavoidable impurities, having a thickness of 5 mm or more, and having an area ratio of crystal grains with a <011> direction within 15° from the rolling direction of 20% or more in a cross-section parallel to the rolling direction at any location between the left and right ends of the steel sheet. 
     
     
         2 . The hot rolled annealed steel sheet or the hot rolled annealed steel strip comprised of ferritic stainless steel material according to  claim 1 , wherein in a cross-section parallel to the rolling direction at any location between the left and right ends of the steel sheet, a sum of the lengths of low-angle grain boundaries with a crystal misorientation of less than 15° is 10% or more with respect to a sum of lengths of the crystal grain boundaries. 
     
     
         3 . The hot rolled annealed steel sheet or hot rolled annealed steel strip comprised of ferritic stainless steel material according to  claim 1  or  2 , further containing, by mass %, one type or two types or more of Ti: 0.01 to 0.4%, Nb: 0.01 to 0.6%, B: 0.0002 to 0.0030%, A1: 0.005 to 0.3%, Ni: 0.1 to 1%, Mo: 0.1 to 2.0%, Cu: 0.1 to 3.0%, V: 0.05 to 1.0%, Mg: 0.0002 to 0.0030%, Sn: 0.01 to 0.3%, Sb: 0.01 to 0.3%, Zr: 0.01 to 0.1%, Ta: 0.01 to 0.1%, Hf: 0.01 to 0.1%, W: 0.01 to 2.0%, Co: 0.01 to 0.2%, Ca: 0.0001 to 0.0030%, REM: 0.001 to 0.05%, and Ga: 0.0002 to 0.1%. 
     
     
         4 . The hot rolled annealed steel sheet or hot rolled annealed steel strip comprised of ferritic stainless steel according to  claim 1  or  2 , used as a flange part.