High-tensile steel containing manganese, use of said steel for flexibly-rolled sheet-products, and production method and associated steel sheet-product

Abstract

A high-strength, manganese-containing steel, in particular for producing a flexibly rolled flat steel product in the form of a hot or cold strip, includes the following chemical composition (in wt. %): C: 0.005 to 0.6; Mn: 4 to 10; Al: 0.005 to 4; Si: 0.005 to 2; P: 0.001 to 0.2; S: up to 0.05; N: 0.001 to 0.3; with the remainder being iron including unavoidable steel-associated elements, with optional alloying of one or more of the following elements (in wt. %): Sn: 0 to 0.5; Ni: 0 to 2; Cu: 0.005 to 3; Cr: 0.1 to 4; V: 0.005 to 0.9; Nb: 0.005 to 0.9; Ti: 0.005 to 0.9; Mo: 0.01 to 3; W: 0.1 to 3; Co: 0.1 to 3; B: 0.0001 to 0.05; Zr: 0.005 to 0.5; Ca: 0.0002 to 0.1 which has a good combination of strength, expansion and deformation properties.

1 .- 15 . (canceled) 
     
     
         16 . A high-strength, manganese-containing steel, in particular for producing a flexibly rolled flat steel product, said steel comprising a following chemical composition in wt. %:
 C: 0.005 to 0.6   Mn: 4 to 10   Al: 0.005 to 4   Si: 0.005 to 2   P: 0.001 to 0.2   S: up to 0.05   N: 0.001 to 0.3   with the remainder being iron including unavoidable steel-associated elements.   
     
     
         17 . The steel of  claim 16 , further comprising at least one alloying element, in wt. %, selected from the group consisting of:
 Sn: 0 to 0.5   Ni: 0 to 2   Cu: 0.05 to 3   Cr: 0.1 to 4   V: 0.005 to 0.9   Nb: 0.005 to 0.9   Ti: 0.005 to 0.9   Mo: 0.01 to 3   W: 0.1 to 3   Co: 0.1 to 3   B: 0.0001 to 0.05   Zr: 0.005 to 0.5   Ca: 0.0002 to 0.1.   
     
     
         18 . The steel of  claim 16 , wherein a content of Al is >0.1 to 4. 
     
     
         19 . The steel of  claim 16 , wherein a content of Si is >0.5 to 2. 
     
     
         20 . The steel of  claim 16 , wherein a sum of contents in wt. % of Al and Si is >0.8. 
     
     
         21 . The steel of  claim 16 , wherein a content of Al is >0.5 to 4, with a content of dissolved nitrogen in the steel being limited to <300 ppm. 
     
     
         22 . The steel of  claim 16 , further comprising, in wt. %, Sn: 0.005 to 0.5. 
     
     
         23 . The steel of  claim 16 , further comprising, in wt. %, Ni: 0.1 to 2. 
     
     
         24 . The steel of  claim 16 , further comprising, in wt. %, Cu: 0.1 to 3. 
     
     
         25 . The steel of  claim 16 , further comprising, in wt. %, B: 0.0005 to 0.05. 
     
     
         26 . The steel of  claim 16 , further comprising, in wt. %, Zr: 0.01 to 0.5. 
     
     
         27 . The steel of  claim 16 , wherein the steel has a tensile strength Rm of at least 700 MPa, and an elongation at fracture A50 of 6% to 45%. 
     
     
         28 . The steel of  claim 16 , wherein the steel has a tensile strength Rm of >800 to 1600 MPa. 
     
     
         29 . The steel of  claim 16  for use in the production of a flexibly rolled flat steel product, in particular for use in the automotive industry, agricultural engineering, rail vehicle construction, traffic engineering or in household appliances. 
     
     
         30 . A method for producing a flat steel product, comprising:
 smelting a steel melt with a following composition in wt. %:   C: 0.005 to 0.6   Mn: 4 to 10   Al: 0.005 to 4   Si: 0.005 to 2   P: 0.001 to 0.2   S: up to 0.05   N: 0.001 to 0.3,   with the remainder being iron including unavoidable steel-associated elements;   casting the steel melt to form a pre-strip by a horizontal or vertical strip casting process approximating a final dimension or casting the steel melt to form a slab or thin slab by a horizontal or vertical slab or thin slab casting process;   flexibly hot rolling the pre-strip, or the slab or thin slab to form a flexibly rolled flat steel product, or hot rolling the pre-strip, or the slab or thin slab to form a hot strip with a unitary thickness;   optionally annealing the hot strip,   flexibly cold rolling the hot strip rolled to a unitary thickness or the cast pre-strip approximating the final dimension having a thickness of less than or equal to 3 mm utilising the TRIP and/or TWIP effect to form a flexibly rolled flat steel product, or cold rolling the hot strip rolled to a unitary thickness or the cast pre-strip approximating the final dimension having a thickness of less than or equal to 3 mm to form a cold strip having a unitary thickness, optionally annealing the cold strip and then flexibly cold rolling the cold strip rolled to a unitary thickness utilising the TRIP and/or TWIP effect to form a flexibly rolled flat steel product;   annealing the flexibly rolled flat steel product at an annealing temperature of 600 to 750° C. and annealing duration of 1 minute to 48 hours.   
     
     
         31 . The method of  claim 30 , wherein the steel melt contains at least one alloying element in wt. % selected from the group consisting of:
 Sn: 0 to 05   Ni: 0 to 2   Cu: 0.05 to 3   Cr: 0.1 to 4   V: 0.005 to 0.9   Nb: 0.005 to 0.9   Ti: 0.005 to 0.9   Mo: 0.01 to 3   W: 0.1 to 3   Co: 0.1 to 3   B: 0.0001 to 0.05   Zr: 0.005 to 0.5   Ca: 0.0002 to 0.1.   
     
     
         32 . The method of  claim 30 , wherein the pre-strip has a thickness of greater than 3 mm. 
     
     
         33 . A flat steel product produced by a method as set forth in  claim 30 , said steel product comprising a tensile strength Rm of at least 700 MPa, and an elongation at fracture A50 of 6% to 45%. 
     
     
         34 . The steel product of  claim 33 , wherein the tensile strength of the steel product is 800 to 1600 MPa. 
     
     
         35 . The steel product of  claim 33 , wherein the steel product is galvanised by hot-dipping or electrolytically or is coated metallically, inorganically or organically.