Low nickel containing chromium-nickel-maganese-copper austenitic stainless steel

Abstract

An austenitic stainless steel includes (a) 0.03 wt % to 0.12 wt % of C, (b) 0.2 wt % to 1.0 wt % of Si, (c) 7.5 wt % to 10.5 wt % of Mn, (d) 14.0 wt % to 16.0 wt % of Cr, (e) 1.0 wt % to 5.0 wt % of Ni, (f) 0.04 wt % to 0.25 wt % of N, (g) 1.0 wt % to 3.5 wt % of Cu, (h) trace amount of Mo, and the balance being Fe and incidental impurities. The austenitic stainless steel has a δ-ferrite content less than 8.5 and equal to 6.77[(d)+(h)+1.5(b)]−4.85[(e)+30(a)+30(f)+0.5(c)+0.3(g)]−52.75.

We claim:  
     
         1 . An austenitic stainless steel comprising: 
 (a) 0.03 wt % to 0.12 wt % of C;    (b) 0.2 wt % to 1.0 wt % of Si;    (c) 7.5 wt % to 10.5 wt % of Mn;    (d) 14.0 wt % to 16.0 wt % of Cr;    (e) 1.0 wt % to 5.0 wt % of Ni;    (f) 0.04 wt % to 0.25 wt % of N;    (g) 1.0 wt % to 3.5 wt % of Cu;    (h) trace amount of Mo; and    the balance being Fe and incidental impurities;    wherein said austenitic stainless steel has a δ-ferrite content that is less than 8.5 and that satisfies the following formula   δ-ferrite=6.77[( d )+( h )+1.5( b )]−4.85[( e )+30( a )+30( f )+0.5(c)+0.3( g )]−52.75.   
     
     
         2 . The austenitic stainless steel of  claim 1 , further comprising 5 to 30 ppm of B.  
     
     
         3 . The austenitic stainless steel of  claim 1 , further comprising no more than 150 ppm of S.  
     
     
         4 . The austenitic stainless steel of  claim 1 , further comprising no more than 0.06 wt % of P.