Flat steel product having improved processing properties
AssigneeThyssenKrupp Steel Europe AG
InventorsMaria Köyer, Fred Jindra, Dirk Czupryna
Life of this patent
Estimating the term…
Abstract
A flat steel product for production of a sheet metal component by hot forming includes a steel substrate consisting of a steel including 0.1-3% by weight of Mn and optionally up to 0.01% by weight of B, an aluminium-based coating disposed on at least one side of the steel substrate. A coating here has an applied layer weight of 15-30 g/m2. In addition, the coating has an Al base layer consisting of 1.0-15% by weight of Si, optionally 2-4% by weight of Fe, 0.1-5.0% by weight of alkali metals or alkaline earth metals, and optional further constituents, the contents of which are limited to a total of not more than 2.0% by weight, and aluminium as the balance.
Claims8
A shaped sheet metal article, formed from a flat steel product made by a process comprising the following steps:
- a) providing a slab or a thin slab consisting of a steel having 0.1-3% by weight of Mn and up to 0.01% by weight of B;
- b) through-heating the slab or thin slab at a temperature (T1) of 1000-1400° C.;
- c) pre-rolling the through-heated slab or thin slab to give an intermediate product having an intermediate product temperature (T2) of 1000-1200° C.;
- d) hot rolling to give a hot-rolled flat steel product, where a final rolling temperature (T3) is 750-1000° C.;
- e) winding the hot-rolled flat steel product, wherein a winding temperature (T4) is not more than 700° C.;
- f) descaling the hot-rolled flat steel product;
- g) cold rolling the flat steel product, wherein a degree of cold rolling is at least 30%;
- h) annealing the flat steel product at an annealing temperature (T5) of 650-900° C.;
- i) cooling the flat steel product to a dipping temperature (T6) of 650-800° C.;
- j) coating the flat steel product that has been cooled to the dipping temperature with a coating having an applied layer weight of 15-30 g/m2 by
- i. dipping it into a melt bath having a melting temperature (T7) of 670-710° C.;
- ii. blowing the flat steel product dry after it has exited from the melt bath by means of a gas stream with a flow pressure of 200-750 mbar;
- k) cooling the coated flat steel product to room temperature including cooling through a first cooling time tmT and a second cooling time tnT, where the first cooling time tmT in a temperature range between 600° C. and 450° C. is more than 14 s, and the second cooling time tnT in a temperature range between 400° C. and 300° C. is more than 12 s;
- l) skin pass rolling the coated flat steel product;
- wherein the shaped sheet metal article comprises:
- A) steel substrate consisting of a steel having 0.1-3% by weight of Mn and up to 0.01% by weight of B and
- B) an aluminium-based coating disposed on at least one side of the steel substrate, wherein the coating has an applied layer weight of 15-30 g/m2 and consists of 1-15% by weight of Si, 15-35% by weight of Fe, 0.1-5% by weight of alkali metals or alkaline earth metals, and further constituents, the contents of which are limited to a total of not more than 2.0% by weight, and aluminium as the balance.
A shaped sheet metal article, comprising:
- A) steel substrate consisting of a steel having 0.1-3% by weight of Mn and up to 0.01% by weight of B;
- and
- B) an aluminium-based coating disposed on at least one side of the steel substrate, wherein the coating has an applied layer weight of 15-30 g/m2 and consists of 1-15% by weight of Si, 15-35% by weight of Fe, 0.1-5% by weight of alkali metals or alkaline earth metals, and further constituents, the contents of which are limited to a total of not more than 2.0% by weight, and aluminium as the balance.
Dependencies are inferred from the claim text.