Method for producing a steel component having a metal coating protecting it against corrosion, and steel component

Patent metadata

Field	Value
Publication number	US-2016222484-A1
Application number	US-201414917899-A
Country	US
Kind code	A1
Filing date	Jul 15, 2014
Priority date	Sep 13, 2013
Publication date	Aug 4, 2016
Grant date	—

Abstract

Certain methods enable the production of steel components with well-adhering metallic coatings that protect against corrosion. In some examples, a flat steel product produced from a steel material having a yield point of 150-1100 MPa and a tensile strength of 300-1200 MPa may be coated with an anticorrosion coating of an alloy that comprises 35-70% by weight aluminum, 35-60% by weight zinc, 0.1-10% by weight magnesium, up to 10% by weight Si, and up to 5% by weight Fe. A blank obtained from the flat steel product may then be heated to at least 800° C. and formed into a steel component. Alternatively, the steel component may be formed into the steel component first and then heated to at least 800° C. Regardless, the steel component may then be hardened by sufficiently rapid cooling the steel component from a sufficiently high temperature.

First claim

1 .- 16 . (canceled)

17 . A method for producing steel components with metallic coatings that protect against corrosion, the method comprising:
providing a flat steel product made from steel material that has a yield point of 150-1100 MPa and a tensile strength of 300-1200 MPa; coating the flat steel product with an anticorrosion coating composed of an aluminum-zinc alloy that comprises 35-70% by weight aluminum, 35-60% by weight zinc, 0.1-10% by weight magnesium, up to 10% by weight silicon, and up to 5% by weight iron; heating a blank made of the coated flat steel product to a blank temperature of at least 800 degrees Celsius; forming a steel component from the blank in a forming die; and hardening the steel component by cooling the steel component from a temperature at which the steel component is in a state suitable for development of a tempered microstructure or a hardened microstructure at a cooling rate sufficient to develop the tempered microstructure or the hardened microstructure.

18 . The method of claim 17 wherein the aluminum-zinc alloy comprises up to 15% by weight of elements from the group encompassing calcium, nickel, manganese, and/or other alkaline earth metals.

19 . The method of claim 17 further comprising applying a nickel-containing coating to the flat steel product before the flat steel product is coated with the anticorrosion coating.

20 . The method of claim 17 further comprising subjecting the coated flat steel product or the blank to a heat treatment wherein the coated flat steel product or the blank of the coated flat steel product is heated to a temperature of 300-700 degrees Celsius to produce an accumulation of iron in the anticorrosion coating, the heat treatment occurring prior to forming the steel component from the blank in the forming die.

21 . The method of claim 17 further comprising subjecting the coated flat steel product or the blank to a heat treatment wherein the coated flat steel product or the blank of the coated flat steel product is heated to a temperature of 50-300 degrees Celsius, the heat treatment occurring prior to forming the steel component from the blank in the forming die.

22 . The method of claim 17 wherein after a temperature treatment in a range of 830-940 degrees Celsius the anticorrosion coating has a layered sequence from an outside inward:
an outer layer of aluminum-iron phases with zinc-rich phases;
an interlayer of an aluminum-rich aluminum-iron compound; and
a diffusion layer of an aluminum-rich iron solid solution.

23 . The method of claim 17 wherein prior to heating the blank to the blank temperature of at least 800 degrees Celsius the anticorrosion coating has a thickness of 5-50 μm.

24 . The method of claim 17 wherein the heating of the blank of the coated flat steel product to the blank temperature of at least 800 degrees Celsius is performed in an oven atmosphere comprising 5-25% by volume oxygen.

25 . The method of claim 17 wherein the heating of the blank of the coated flat steel product to the blank temperature of at least 800 degrees Celsius is performed in an oven atmosphere comprising dried air.

26 . A method for producing steel components with metallic coatings that protect against corrosion, the method comprising:
providing a flat steel product made from steel material that has a yield point of 150-1100 MPa and a tensile strength of 300-1200 MPa; coating the flat steel product with an anticorrosion coating composed of an aluminum-zinc alloy that comprises 35-70% by weight aluminum, 35-60% by weight zinc, 0.1-10% by weight magnesium, up to 10% by weight silicon, and up to 5% by weight iron; forming a steel component from a blank made of the coated flat steel product in a forming die; heating the steel component to a component temperature of at least 800 degrees Celsius; and hardening the steel component by cooling the steel component from a temperature at which the steel component is in a state suitable for development of a tempered microstructure or a hardened microstructure at a cooling rate sufficient to develop the tempered microstructure or the hardened microstructure.

27 . The method of claim 26 further comprising forming the steel component to a form-finished state after heating the steel component to the component temperature of at least 800 degrees Celsius.

28 . The method of claim 26 further comprising applying a nickel-containing coating to the flat steel product before the flat steel product is coated with the anticorrosion coating.

29 . The method of claim 26 further comprising subjecting the coated flat steel product or the blank to a heat treatment wherein the coated flat steel product or the blank of the coated flat steel product is heated to a temperature of 300-700 degrees Celsius to produce an accumulation of iron in the anticorrosion coating, the heat treatment occurring prior to forming the steel component from the blank in the forming die.

30 . The method of claim 26 further comprising subjecting the coated flat steel product or the blank to a heat treatment wherein the coated flat steel product or the blank of the coated flat steel product is heated to a temperature of 50-300 degrees Celsius, the heat treatment occurring prior to forming the steel component from the blank in the forming die.

31 . The method of claim 26 wherein the heating of the blank of the steel component to the component temperature of at least 800 degrees Celsius is performed in an oven atmosphere that comprises 5-25% by volume oxygen.

32 . The method of claim 26 wherein the coating of the flat steel product with the anticorrosion coating is applied to the flat steel product by way of hot dip coating.

33 . A steel component comprising:
a steel substrate comprised of steel material having a yield point of 150-1100 MPa and a tensile strength of 300-1200 MPa; an anticorrosion coating disposed on the steel substrate, the anticorrosion coating comprising an aluminum-zinc alloy that comprises 35-70% by weight aluminum, 35-60% by weight zinc, 0.1-10% by weight magnesium, up to 10% by weight silicon, and up to 5% by weight iron, wherein layers of the anticorrosion coating from an outside inward comprise:
an outer layer of aluminum-iron phases with zinc-rich phases,
an interlayer of an aluminum-rich aluminum-iron compound, and
a diffusion layer of an aluminum-rich iron solid solution.

34 . The steel component of claim 33 wherein the anticorrosion coating is more than 5 μm thick.

35 . The steel component of claim 33 wherein the anticorrosion coating comprises at least one of calcium, nickel, manganese, or other alkaline earth metals.

36 . The steel component of claim 33 further comprising a nickel-containing base layer disposed between the steel substrate and the diffusion layer.

Assignees

• Thyssenkrupp Steel Europe Ag

Inventors

• Köyer Maria
• Sikora Sascha
• Banik Janko
• Ruthenberg Manuela
• Schulz Jennifer

Classifications

• C21D8/00

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• Y10T428/24975

  No layer or component greater than 5 mils thick · CPC title

• C23C28/321

  with at least one metal alloy layer · CPC title

• B32B15/012

  one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy · CPC title

• Y10T428/12958

  Next to Fe-base component · CPC title