Austenitic Lightweight Steel and Use Thereof

Abstract

Austenitic lightweight steel with a characteristic value of the cold formability higher than 30,000 MPa %, with tensile strengths between 600 and 800 MPa, and fracture strains over 50% has a chromium content of >2.0%<18%, a silicon content of >1.0%<4%, a manganese content of >2.0%<20%, an aluminum content of >0.05%<4%, wherein the steel is within an alloying range determined by (Cr equ =14; Ni equ =14.5); (Cr equ =14; Ni equ =17.5) (Cr equ =20; Ni equ =10) (Cr equ =20; Ni equ =13), wherein the chromium and nickel equivalents are calculated based on the following relations (1) and (2): Cr equ =% Cr+% Mo+1.5% Si+0.5% W+0.9% Nb+4% Al+4% Ti+1.5% V  (1) Ni equ =% Ni+30% C+18% N+0.5% Mn+0.3% Co+0.2% Cu−0.2% Al  (2) from the chemical composition of the steel, wherein the values represent wt. % and the balance is largely iron and other steel accompanying elements.

1 - 11 . (canceled) 
     
     
         12 . Austenitic lightweight steel with good cold formability and a characteristic value of the cold formability higher than 30,000 MPa %, with tensile strengths between 600 and 800 MPa and fracture strains over 50%, the steel comprising:
 a chromium content of more than 2.0% but less than 18%;   a silicon content of more than 1.0% but less than 4%;   a manganese content of more than 2.0% but less than 20%;   an aluminum content of more than 0.05% but less than 4%,   wherein the steel is within an alloying range determined by coordinates of four points:
   (Cr equ =14; Ni equ =14.5) 
   (Cr equ =14; Ni equ =17.5) 
   (Cr equ =20; Ni equ =10) 
   (Cr equ =20; Ni equ =13), 
   
       wherein the chromium and nickel equivalents are calculated based on the following relations (1) and (2):
   Cr equ =% Cr+% Mo+1.5% Si+0.5% W+0.9% Nb+4% Al+4% Ti+1.5% V  (1) 
   Ni equ =% Ni+30% C+18% N+0.5% Mn+0.3% Co+0.2% Cu−0.2% Al  (2) 
 
       from the chemical composition of the steel, wherein the values represent wt. % and the balance is largely iron and other steel accompanying elements (O, P, S). 
     
     
         13 . Lightweight steel according to claim  11 , wherein
 the nickel content is 0 to 10%,   the niobium content is 0 to 1.2%,   the carbon content is 0.01 to 0.15%,   the nitrogen content is 0 to 0.1%,   the copper content is 0 to 4%,   the cobalt content is 0 to 1%,   the molybdenum content is 0 to 4%,   the tungsten content is 0 to 3%,   the titanium content is 0 to 1%, and   the vanadium content is 0 to 0.15%.   
     
     
         14 . Lightweight steel according to claim  11 , wherein
 the carbon content is 0.04%,   the chromium content is 13%,   the silicon content is 1.5%,   the niobium content is 0.15%,   the nickel content is 7.9%,   the manganese content is 8.1%,   the aluminum content is 0.11%, and   the nitrogen content is 0.02%.   
     
     
         15 . Lightweight steel according to claim  11 , wherein
 the carbon content is 0.03%,   the chromium content is 15.82%,   the silicon content is 1.22%,   the nickel content is 7.5%,   the manganese content is 5.8%, and   the aluminium content is 0.11%.   
     
     
         16 . Lightweight steel according to  claim 12  as material for hot-rolled sheet metal and strips. 
     
     
         17 . Lightweight steel according to  claim 12  as material for cold-rolled sheet metal and strips. 
     
     
         18 . Lightweight steel according to  claim 12  as material for crash-loaded components and strengthening structural components. 
     
     
         19 . Lightweight steel according to  claim 12  for non-flat products and fastening components. 
     
     
         20 . Lightweight steel according to  claim 12  wherein the steel is heat-treated. 
     
     
         21 . Lightweight steel according to  claim 12  as material for weather-resistant and slow-corroding parts. 
     
     
         22 . Lightweight steel according to  claim 12  as material for stainless parts.