Method for producing a component by hot forming a pre-product made of steel

Patent metadata

Field	Value
Publication number	US-2016130675-A1
Application number	US-201414890369-A
Country	US
Kind code	A1
Filing date	Apr 30, 2014
Priority date	May 28, 2013
Publication date	May 12, 2016
Grant date	—

Abstract

A method for producing a component by hot forming a pre-product made of steel is disclosed. The pre-product is heated to a forming temperature and is then reshaped, said component having a bainitic microstructure with a minimum tensile strength of 800 MPa after the forming process. In the process, the pre-product with the specified alloy composition is heated to a temperature below the A c1 transformation temperature, said pre-product already consisting of a steel with a microstructure made of at least 50% bainite.

First claim

What is claimed:

1 .- 15 . (canceled)

16 . A method for producing a component by hot forming a pre-product made of steel, comprising:
providing a pre-product made of steel having a microstructure of at least 50% bainite and having the following alloy composition in weight %:
C: 0.02 to 0.3
Si: 0.01 to 0.5
Mn: 1.0 to 3.0
P: max 0.02
S: max 0.01
N: max 0.01
Al: up to 0.1
Cu: up to 0.2
Cr: up to 3.0
Ni: up to 0.2
Mo: up to 0.2
Ti: up to 0.2
V: up to 0.2
Nb: up to 0.1
B: up to 0.01;
heating the pre-product to forming temperature below Ac1 transformation temperature; and
forming the pre-product into the component, wherein the component after the forming has a bainitic microstructure with a minimal tensile strength of 800 MPa.

17 . The method of claim 16 , wherein the microstructure of the pr-product is composed of at least 70% bainite and a content of residual austenite+martensite is<10% and the remainder is ferrite.

18 . The method of claim 16 , wherein the pre-product has the following alloy composition in weight %:
C: 0.02 to 0.11%
Si: 0.01 to 0.5%
Mn: 1.0 to 2.0%
P: max 0.02%
S: max 0.01%
N: max 0.01%
Al min : 0.015 to 0.1%
B: max. 0.004%
Nb+V+Ti: max 0.2%.

19 . The method of claim 16 , wherein the pre-product has the following alloy composition in weight %:
C: 0.05 to 0.11%
Si: 0.01 to 0.5%
Mn: 1.0 to 2.0%
P: max. 0.02%
S: max 0.01%
N: 0.003 to 0.01%
Al min : 0.03 to 0.1%
B: max 0.004%
Mo: 0.04 to 0.2
Ti: 0.04 to 0.2
Nb+V+Ti: 0.1 to 0.2%.

20 . The method of claim 16 , wherein during the heating step only portions of the pre-product are heated to forming temperature, and optionally above the Ac 1 transformation temperature.

21 . The method of claim 16 , wherein the pre-product is heated to a temperature below 720° C.

22 . The method of claim 21 , wherein the pre-product is heated to a temperature in a ranged from 400 to 720° C.

23 . The method of claim 22 , wherein the pre-product is heated to a temperature in a ranged from 500 to 700° C.

24 . The method of claim 16 , further comprising prior to the heating step, is providing the pre-product with a metallic or lacquer-like coating.

25 . The method of claim 24 , wherein the metallic coating contains Zn and/or Mn and/or Al and/or Si.

26 . The method of claim 16 , wherein the heating to forming temperature is accomplished inductively, conductively, or by means of radiation.

27 . The method of claim 16 , wherein the pre-product is a metal plate or a tube.

28 . The method of claim 27 , wherein the metal plate is made of hot strip or cold strip.

29 . The method of claim 27 , wherein the tube is a seamlessly hot rolled tube or a welded tube made of hot strip or cold strip.

30 . The method of claim 29 , wherein the tube is subjected to one or multiple further drawing and/or annealing processes.

Assignees

• Salzgitter Flachstahl Gmbh

Inventors

• Mütze Stefan
• Braun Michael
• Maikranz-Valentin Manuel

Classifications

• C21D8/10

  during manufacturing of tubular bodies · CPC title

• C21D8/02

  during manufacturing of plates or strips (C21D8/12 takes precedence) · CPC title

• C22C38/04

  containing manganese · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

• C23C2/06

  Zinc or cadmium or alloys based thereon · CPC title