Process for producing steel components with highest stability and plasticity

1 . A process for manufacture of metal components or semi-finished products with high hardness and plasticity by the cold deforming of steel, wherein the degree of deformation lies at a total elongation in the range of 10 to 70%, comprising:

selecting a metal of which the deformation leads to a hardening by TWIP (Twinning Induced Plasticity) or SIP (Shearband Induced Plasticity) Effect, and

cold deforming following the last stage of annealing or crystallization annealing to the extent that a hardness increase of at least 30% of the start value is imparted and the residual tensile elongation of the metal is reduced by less than 20%.

2 . The process according to claim 1 , wherein the cold deforming is carried out in a first step with an elongation of 10 to 60% and with a final deformation in a subsequent step with an elongation of less than 10%.

3 . The process according to claim 1 , wherein the deforming is carried out as cold deforming with an elongation in at least one spatial direction of 10 to 35%.

4 . The process according to claim 1 , wherein the deforming is carried out to the extent until a hardness increase of at least 300 MPa is imparted.

5 . The process according to claim 1 , wherein the sum of the elongation of the deformation steps does not exceed 50%.

6 . The process according to claim 1 , wherein the metal is selected from steels with the following composition (amounts in wt. %):

1 to 6 Si,

1 to 8 Al, and

10 to 30 Mn,

or

2 to 3.5 Si,

2 to 3.5 Al, and

12 to 30 Mn,

or

0.1 to 6 Si,

8 to 12 Al, wherein Al+Si>12,

18 to 35 Mn,

0.5 to 2 C, and

at least one of the elements Mg, Ga, Be being up to 3,

or

3 to 6 Si,

8 to 12 Al, wherein Al+Si>12,

18 to 35 Mn,

0.5 to 2 C,

at most 0.05 B,

at most 3 Ti and at least one of the elements Mg, Ga, Be with a content of respectively 0.3 to 3,

or

0.1 to 0.25 Si,

0 to 0.01 Al,

18 to 25 Mn,

0.4 to 0.9 C,

0 to 0.01 N,

or

0.05 to 1 Si,

0 to 0.008 Al,

15 to 30 Mn,

0.4 to 0.7 C,

0.001 to 0.01 N,

besides iron and conventional minor components of steel.

7 . The process according to claim 1 or 2 , wherein the metal is steel with a duplex microstructure with austensitic and ferritic crystallites, or with a triplex microstructure with austensitic, ferritic and perovskite crystallites.

8 . A semi-finished product, or motor vehicle component produced by a process comprising:

selecting a metal of which deformation leads to a hardening by TWIP (Twinning Induced Plasticity) or SIP (Shearband Induced Plasticity) Effect, and

cold deforming following the last stage of annealing or crystallization annealing to the extent that a hardness increase of at least 30% of the start value is imparted and the residual tensile elongation of the metal is reduced by less than 20%,

wherein the semi-finished product exhibits a tensile strength of greater than 800 MPa and an elongation of greater than 35%.

9 . The semi-finished product or motor vehicle component according to claim 8 , wherein it exhibits a tensile strength of greater than 1000 MPa and a elongation in the range of 35 to 55%.

10 . The semi-finished product or motor vehicle component according to claim 8 , wherein the steel is pre-stretched by deforming in at least one spatial direction by 10 to 40%.