Non-magnetic austenitic stainless steel having improved strength and surface conductivity

Abstract

Disclosed is a non-magnetic austenitic stainless steel with improved strength and surface conductivity. An austenitic stainless steel according to an embodiment of the present disclosure includes, in percent (%) by weight of the entire composition, C: 0.07 to 0.2%, N: 0.15 to 0.4%, Si: 0.8 to 2%, Mn: 16 to 22%, S: 0.01% or less (excluding 0), Cr: 12.5 to 20%, Cu: 1 to 3%, the remainder of iron (Fe) and other inevitable impurities, and satisfies the following equation (1). Ni+0.65Cr+1.05Mn+0.35Si+12.6C+33.6N≥40  (1) Ni, Cr, Mn, Si, C, N are % by weight of each element.

1 . An austenitic stainless steel comprising, in percent (%) by weight of the entire composition, C: 0.07 to 0.2%, N: 0.15 to 0.4%, Si: 0.8 to 2%, Mn: 16 to 22%, S: 0.01% or less (excluding 0), Cr: 12.5 to 20%, Cu: 1 to 3%, the remainder of iron (Fe) and other inevitable impurities, and satisfying the following equation (1).
   Ni+0.65Cr+1.05Mn+0.35Si+12.6C+33.6N≥40  (1)
   (Ni, Cr, Mn, Si, C, N are % by weight of each element)   
     
     
         2 . The austenitic stainless steel of  claim 1 , wherein a yield strength represented by the following equation (2) is 450 MPa or more.
   yield strength(MPa)=185+1977C+605N+3.65Cu−3.63Mn  (2)
   (C, N, Cu, Mn are % by weight of each element)   
     
     
         3 . The austenitic stainless steel of  claim 1 , wherein a ferrite content measured after 70% cold working is less than 0.1%. 
     
     
         4 . The austenitic stainless steel of  claim 1 , wherein a permeability is 1.005 or less even at 70% cold working 
     
     
         5 . The austenitic stainless steel of  claim 1 , wherein a stacking fault energy (SFE) represented by the following equation (3) is 41 mJ/m 2  or more.
   SFE (mJ/m 2 )=25.7+1.59(Ni+Cu)−0.85Cr+0.001Cr 2 +38.2N 0.5 −2.8Si−1.34Mn+0.06Mn 2   (3)
   (Ni, Cu, Cr, N, Si, Mn are % by weight of each element)   
     
     
         6 . The austenitic stainless steel of  claim 1 , wherein a cold rolled material hardness (Hv) value is 215 or more. 
     
     
         7 . The austenitic stainless steel of  claim 1 , wherein a Cu+Mn content in the region within 2 nm of the passivation film is 0.2% or more. 
     
     
         8 . The austenitic stainless steel of  claim 7 , wherein a surface resistance is less than 10 mΩcm 2 .