Austenitic stainless steel with improved deep drawing

Abstract

Disclosed is an austenitic stainless steel with improved deep drawability. The austenitic stainless steel with improved deep drawability according to the present disclosure includes, in percent by weight (wt %), 0.01 to 0.05% of C, 0.01 to 0.25% of N, 1.5% or less of Si (excluding 0), 0.3 to 3.5% of Mn, 17.0 to 22.0% of Cr, 9.0 to 14.0% of Ni, 2.0% or less of Mo (excluding 0), 0.2 to 2.5% of Cu, and the balance of Fe and inevitable impurities and satisfies Expression (1) below. Cr+Si+2*Mo+3*(Ni+Cu)+50*(C+N)≥63  Expression (1): Here, Cr, Si, Mo, Ni, Cu, C, and N represent the content (wt %) of each element.

1 . An austenitic stainless steel with improved deep drawability comprising, in percent by weight (wt %), 0.01 to 0.05% of C, 0.01 to 0.25% of N, 1.5% or less of Si (excluding 0), 0.3 to 3.5% of Mn, 17.0 to 22.0% of Cr, 9.0 to 14.0% of Ni, 2.0% or less of Mo (excluding 0), 0.2 to 2.5% of Cu, and the balance of Fe and inevitable impurities, and
 satisfying Expression (1) below:
   Cr+Si+2*Mo+3*(Ni+Cu)+50*(C+N)≥63  Expression (1):
 
   wherein Cr, Si, Mo, Ni, Cu, C, and N represent the content (wt %) of each element.   
     
     
         2 . The austenitic stainless steel according to  claim 1 , wherein the austenitic stainless steel satisfies Expression (2) below:
   0<2.4*Cr+1.7*Mo+3.9*Si−2.1*Ni−Mn−0.4*Cu−58*C−64*N−13<5.5  Expression (2):
   wherein Cr, Mo, Si, Ni, Mn, Cu, C, and N represent the content (wt %) of each element.   
     
     
         3 . The austenitic stainless steel according to  claim 1 , further comprising at least one of 0.04% or less of Al (excluding 0), 0.003% or less of Ti (excluding 0), 0.0025% or less of B (excluding 0), 0.035% or less of P, and 0.0035% or less of S. 
     
     
         4 . The austenitic stainless steel according to  claim 1 , wherein a true strain value is 0.2 or less at a maximum work-hardening exponent in Expression (3) below:
   σ= Kε   n   Expression (3):
   wherein σ is a stress, K is a strength coefficient, ε is a strain, and n is a work-hardening exponent.   
     
     
         5 . The austenitic stainless steel according to  claim 4 , wherein a difference between a true strain value at the maximum work-hardening exponent and a true strain value at a work-hardening exponent of 0 is 0.11 or more. 
     
     
         6 . The austenitic stainless steel according to  claim 1 , wherein an elongation is 35% or more. 
     
     
         7 . The austenitic stainless steel according to  claim 1 , wherein a tensile strength is 360 MPa or more. 
     
     
         8 . The austenitic stainless steel according to  claim 1 , wherein cracks do not occur until a fifth stage in the case of multi-stage formation at a drawing ratio of 1.7 to 4.3.