Precipitation hardenable austenitic steel

Abstract

The present invention relates to a stainless steel alloy, more precisely a highstrength stainless, precipitation hard-enable, austenitic, stainless alloy, containing a well adjusted amount of aluminium and a high silicon content and which has the following composition (in weight-%): C 0-0.07 Si 0.5-3.0 N 0-0.1 Cr 15.0-20.0 Ni 7.0-12.0 Al 0.25-1.5 Cu 0<Cu<4.0 Mn 0-3.0 Mo 0-2.0 Ti 0-1.0 and the balance Fe together with normally occuring impurities and additives and a product that is reduced by cold working, especially drawing, without intermediate heat treatment, the strength of which increases by final heat treatment at 300° C. to 500 ° C. by not less than 14%, that shows a M d30 -value of between −55 and −100, a loss of force that is smaller than 3.0% at 1 N during 24 h and which is very suitable for use in spring applications, such as springs of round wire and strip steel and in medical applications, such as surgical and dental instruments.

1 . Product, manufactured from a high-strength austenitic stainless alloy, in that it is precipitation hardenable and has the following composition (in weight-% ): 
 C more than 0 to 0.07    Si 0.5-3.0    N>0-0.1    Cr15.0-20.0    Ni 7.0-12.0    Al 0.25-1.5    Cu0sus4.0    Mn>0-3.0    Mo>0-2.0    Ti>0-1.0    and the balance Fe together with normally occurring impurities and additives, said alloy reducible by cold-working, without an intermediate heat treatment, and it's strength is increased by a final heat treatment at 300° C. to 500° C. with at least 14%.    
     
     
         2 . A product manufactured of a high-strength steel austenitic stainless precipitation hardenable alloy of  claim 1 , wherein the nickel at-a content of is between 8.0 and 11.0 weight-%.  
     
     
         3 . A product manufactured of a high-strength steel austenitic stainless precipitation hardenable alloy of  claim 1 , wherein the nickel content is between 9.0 and 10.0 weight-%.  
     
     
         4 . A product manufactured of a high-strength steel austenitic stainless precipitation hardenable alloy of  claim 1 , wherein the chromium content is between 16.0 and 19.0 weight-%.  
     
     
         5 . A product manufacture of a high-strength steel austenitic stainless precipitation hardenable alloy of  claim 1 , wherein the aluminium content is 0.4-1.0 weight-%.  
     
     
         6 . A Product manufactured of a high-strength steel austenitic stainless precipitation hardenable alloy of  claim 1 , wherein the silicon content is 0.5 to 2.5 weight-%.  
     
     
         7 . A product manufactured of a high-strength steel austenitic stainless precipitation hardenable alloy  claim 1 , wherein silicon content is 0.5 to 1.5 weight-%.  
     
     
         8 . A product of  claim 1 , which has loss of force which is smaller than 3.0% at 1400 N during 24 h.  
     
     
         9 . A product of  claim 1  in the form of wire, profiles and/or strip.  
     
     
         10 . A product of  claim 1  in the form of springs of round wire and strip steel.  
     
     
         11 . A product  claim 1  in the form of surgical and dental instruments.  
     
     
         12 . (canceled)  
     
     
         13 . (canceled)  
     
     
         14 . (canceled)  
     
     
         15 . (canceled)