U.S. patent application number 12/745360 was filed with the patent office on 2010-12-02 for method for producing a shaped component having at least two structural regions of different ductility.
This patent application is currently assigned to Benteler Automobiltechnik GmbH. Invention is credited to Stefan Adelbert, Johannes Boke, Otto Buschsieweke, Jurgen Krogmeier, Markus Pellmann.
Application Number | 20100300584 12/745360 |
Document ID | / |
Family ID | 39777859 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100300584 |
Kind Code |
A1 |
Buschsieweke; Otto ; et
al. |
December 2, 2010 |
METHOD FOR PRODUCING A SHAPED COMPONENT HAVING AT LEAST TWO
STRUCTURAL REGIONS OF DIFFERENT DUCTILITY
Abstract
According to the method, a blank (7) that is severed from strip
material (4) of coated, high-strength boron steel is homogeneously
heated in a furnace (11) having a plurality of temperature zones
(8, 9, 10) first in a 1.sup.st zone (8) to a temperature of
approximately 830.degree. C. to 950.degree. C. and maintained at
this temperature level for a defined time (t). Thereafter, a region
(12) of first kind of the blank (7) is cooled down in a 2.sup.nd
zone (9) of the furnace (11) to a temperature of approximately
550.degree. C. to 700.degree. C. and maintained at this lowered
temperature level for a defined time (t.sub.1). At the same time, a
region (13) of second kind of the blank (7) is maintained in a
3.sup.rd zone (10) of the furnace (11) at a temperature level of
approximately 830.degree. C. to 950.degree. C. during a time
(t.sub.2). After this heat treatment, a blank (7) is formed into a
shaped component (1) in a thermoforming process.
Inventors: |
Buschsieweke; Otto;
(Paderborn, DE) ; Adelbert; Stefan; (Delbruck,
DE) ; Boke; Johannes; (Blomberg, DE) ;
Pellmann; Markus; (Sassenberg, DE) ; Krogmeier;
Jurgen; (Hovelhof, DE) |
Correspondence
Address: |
HENRY M FEIEREISEN, LLC;HENRY M FEIEREISEN
708 THIRD AVENUE, SUITE 1501
NEW YORK
NY
10017
US
|
Assignee: |
Benteler Automobiltechnik
GmbH
Paderborn
DE
|
Family ID: |
39777859 |
Appl. No.: |
12/745360 |
Filed: |
November 3, 2008 |
PCT Filed: |
November 3, 2008 |
PCT NO: |
PCT/DE08/01799 |
371 Date: |
May 28, 2010 |
Current U.S.
Class: |
148/530 |
Current CPC
Class: |
F27B 9/028 20130101;
C21D 9/0068 20130101; C21D 9/46 20130101; C21D 2221/00 20130101;
C21D 1/673 20130101 |
Class at
Publication: |
148/530 |
International
Class: |
C21D 8/00 20060101
C21D008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2007 |
DE |
10 2007 057 855.7 |
Claims
1.-6. (canceled)
7. A method of producing a shaped component with at least two
structural regions of different ductility, comprising the steps of:
cutting a blank from a strip material of high-strength boron steel
provided with an Al/Si coating; heating the blank in a first
temperature zone of a furnace to a first temperature of about
830.degree. C.-950.degree. C.; maintaining the blank at the first
temperature for a defined time; allowing a first region of the
blank to cool down in a second temperature zone of the furnace to a
second temperature of about 550.degree. C.-700.degree. C.;
maintaining the first region of the blank at the second temperature
for a defined time, while maintaining a second region of the blank
in a third temperature zone of the furnace at the first
temperature; and forming the blank into the shaped component in a
thermoforming process.
8. The method of claim 7, wherein the first region of the blank is
brought momentarily in contact with cooling jaws to cool down to
the second temperature.
9. The method of claim 7, wherein the first region of the blank
cooled down to the second temperature by blowing cooled gas onto
the first region.
10. The method of claim 7, wherein the cooled gas is nitrogen.
11. A method of producing a shaped component with at least two
structural regions of different ductility, comprising the steps of:
heating a strip material of high-strength boron steel provided with
an Al/Si coating in a pre-furnace to a first temperature of about
830.degree. C.-950.degree. C.; maintaining the strip material at
the first temperature for a defined time; cooling down the strip
material; cutting blanks from the strip material; transferring each
blank into a two-zone furnace; heating a first region of each blank
in a first zone of the furnace to a second temperature of about
550.degree. C.-700.degree. C., while heating a second region in a
second zone of the furnace to the first temperature; and forming
the blanks into the shaped component in a thermoforming
process.
12. The method of claim 11, wherein the first region of the blank
is brought momentarily in contact with cooling jaws to cool down to
the second temperature.
13. The method of claim 11, wherein the first region of the blank
cooled down to the second temperature by blowing cooled gas onto
the first region.
14. The method of claim 13, wherein the cooled gas is nitrogen.
15. A method of producing a shaped component with at least two
structural regions of different ductility, comprising the steps of:
cutting blanks from a strip material of high-strength boron steel
provided with an Al/Si coating; heating each blank to a first
temperature of about 830.degree. C.-950.degree. C. in a
pre-furnace; maintaining the blanks at the first temperature for a
defined time; cooling down the blanks; transferring each blank into
a two-zone furnace; heating a first region of each blank in a first
zone of the furnace to a second temperature of about 550.degree.
C.-700.degree. C., while heating a second region in a second zone
of the furnace to the first temperature; and maintaining the first
and second regions of each blanks at the first and second
temperatures, respectively; forming the blanks into the shaped
component in a thermoforming process.
16. The method of claim 15, wherein the first region of the blank
is brought momentarily in contact with cooling jaws to cool down to
the second temperature.
17. The method of claim 15, wherein the first region of the blank
cooled down to the second temperature by blowing cooled gas onto
the first region.
18. The method of claim 17, wherein the cooled gas is nitrogen.
Description
[0001] The invention relates to a method for producing a shaped
component with at least two structural regions of different
ductility from a metallic blank that has been cut from strip
material, whereby the blank has differently heated regions and then
undergoes a thermoforming process to form it into the shaped
component (preamble of claims 1, 2, 3).
[0002] DE 102 56 621 B3 describes a method for producing a shaped
component with at least two structural regions of different
ductility, and a continuous furnace for this method. According to
this proposal, a semi-finished product of hardenable steel moves
through a continuous furnace with at least two zones having
different temperature levels and arranged side-by-side in movement
direction. The semi-finished product is hereby heated to different
temperatures so as to establish two structural regions of different
ductility during a subsequent thermoforming process.
[0003] DE 102 08 216 C1 also discloses a method for producing a
shaped component with at least two structural regions of different
ductility. A semi-finished product of hardenable steel moves hereby
through a heating device with homogenous temperature distribution
and is heated completely to an austenitization temperature. A
partial region of first kind of the semi-finished product is then
cooled down during its further transport that the base material can
convert from austenite to ferrite and/or perlite. Thus, a
subsequent thermoforming process does not cause any or causes only
little martensitic formation. As a result, the partial region of
first kind has a high ductility. At the same time, the other
partial region of second kind of the semi-finished product is
subjected during the transport to a temperature which is held at a
level to allow the formation of just enough martensitic structures
during the subsequent thermoforming process. Thus, compared to the
partial region of first kind, the partial region of second kind has
a smaller ductility but greater strength.
[0004] Even though heating is carried out in a furnace under a
nitrogen atmosphere in both afore-described methods, scaling cannot
be avoided of the respective semi-finished product during transfer
from the furnace to a forming press and also during the forming
process.
[0005] Starting from the state of the art, the invention is based
on the object to provide a method for the production of a shaped
component with at least two structural regions of different
ductility, which method obviates problems associated with
scaling.
[0006] The first solution of the object which the invention is
based upon is set forth by the features of claim 1.
[0007] Accordingly, when applied for a shaped component of
high-strength boron steel coated with an Al/Si coating, a blank cut
from strip material of such a substance is completely homogenously
heated first to such a temperature and maintained at this
temperature level for a defined time that a diffusion layer as
corrosive or scale protective layer is formed, wherein material
from the coating diffuses into the base substance. The heating
temperature is about 830.degree. C. to 950.degree. C., preferably
about 920.degree. C. This homogenous heating is carried out
advantageously in a 1.sup.st zone of a continuous furnace which has
several temperature zones. Following this method step, a region of
first kind of the blank is cooled down in a 2.sup.nd zone of the
furnace to a temperature which causes austenite to break down. This
takes place at about 550.degree. C. to 700.degree. C., preferably
at about 625.degree. C. This lowered temperature level is
maintained for a defined time so that the break down of austenite
is reliably implemented.
[0008] Simultaneous with the local cool down of the region of first
kind of the blank, the temperature in a region of second kind is
maintained in a 3.sup.rd zone just enough to allow formation of
martensitic structures during the subsequent thermoforming in a
respective press. This temperature is at 830.degree. C. to
950.degree. C., preferably at about 900.degree. C.
[0009] In this way, the regions of first and second kinds of the
shaped component have different ductility properties, with the
region of second kind, compared to the region of first kind, having
a smaller ductility but yet higher strength properties.
[0010] Such shaped components manufactured in this way, can have
concrete sections that can be best suited to the demands at hand in
order to meet its characteristic as structural component, for
example as component of a vehicle body.
[0011] A second solution of the object which the invention is based
upon is set forth by the features of claim 2.
[0012] The formation of a diffusion layer as corrosive or scale
protective layer is hereby realized by alloying strip material from
high-strength boron steel, coated with an Al/Si coating, in a first
operating step during continuous advance through a pre-furnace and
then cooling it down. The temperature is 830.degree. C. to
950.degree. C., preferably about 920.degree. C.
[0013] Blanks are then severed in a further operating step from
this alloyed strip material. Subsequently, each severed blank is
transferred into a two-zone furnace. A region of second kind of the
blank is hereby austenitized at a temperature of 830.degree. C. to
950.degree. C., preferably about 930.degree. C. The region of first
kind is heated to a temperature which at a maximum is below the
austenitization temperature which is about 550.degree. C. to
700.degree. C., preferably about 680.degree. C.
[0014] This type of heat treatment causes the regions of second
kind of the shaped components ultimately manufactured in a
thermoforming process from the blanks to have smaller ductility
properties, compared to the regions of first kind, but, yet have
higher strength properties.
[0015] A third solution of the object which the invention is based
upon is set forth by the features of claim 3.
[0016] Accordingly, when applied for a shaped component of
high-strength boron steel coated with an Al/Si coating, blanks are
cut from strip material of such a substance. Thereafter, each blank
is homogenously heated in a second operating step in a pre-furnace
to a temperature of about 830.degree. C. to 950.degree. C.,
preferably about 920.degree. C., maintained at this temperature
level for a defined time, and then cooled down again. Formation of
a diffusion layer as corrosive or scale protective layer is hereby
realized from the Al/Si coating of the strip material. In a third
operating step, each blank is then transferred to a two-zone
furnace and a region of first kind is again heated in a 1.sup.st
zone of the furnace to a temperature of about 550.degree. C. to
700.degree. C., preferably about 680.degree. C. At the same time, a
region of second kind is heated in a 2.sup.nd zone of the furnace
to a temperature of 830.degree. C. to 950.degree. C., preferably
about 920.degree. C. Finally, the blank is formed by a
thermoforming process into a shaped component. The shaped component
has then a region of second kind which, compared to the region of
first kind, has smaller ductility properties but higher strength
properties.
[0017] To accelerate cooling down to the transformation
temperature, at which austenite breaks down to ferrite and perlite,
according to the features of claim 4, the local cool down of the
region of first kind of the blank can be realized after heating by
contacting the region of first kind momentarily with cooling
jaws.
[0018] According to the features of claim 5, it is, however, also
possible to blow cooled gas onto the region of first kind of the
blank after heating.
[0019] This can be preferably implemented by using nitrogen as gas,
as set forth in claim 6. Exemplified embodiments of the invention
will now be described in greater detail with reference to the
drawings, which show in:
[0020] FIG. 1 a schematic illustration of the production of a
shaped component with two structural regions having different
ductility;
[0021] FIG. 2 a schematic illustration of a further method for the
production of a shaped component with two structural regions having
different ductility; and
[0022] FIG. 3 a schematic illustration of a third method for the
production of a shaped component with two structural regions having
different ductility.
[0023] 1 designates in FIGS. 1 to 3 a shaped component with two
structural regions 2, 3 of different ductility. The shaped
component 1 involves a B column of an otherwise unillustrated
vehicle body.
[0024] The manufacture of the shaped component 1 is based on
high-strength boron steel which is provided with an Al/Si
coating.
[0025] A strip material 4 from such steel is wound according to
FIG. 1 to a coil 5. The strip material 4 is then drawn continuously
from this coil 5 and guided through a punch 6. Blanks 7 are cut
from the strip material 4 in the punch 6 and then fed to a
continuous furnace 11 having three temperature zones 8, 9, 10.
[0026] In a 1.sup.st zone 8 of the continuous furnace 11, each
blank 7 is completely homogenously heated to a temperature of about
830.degree. C. to 950.degree. C., preferably 920.degree. C., and
maintained at this temperature level over a defined time t (FIG.
2).
[0027] Subsequently, a region 12 of first kind of the blank 7 is
cooled down in a 2.sup.nd zone 9 of the continuous furnace 11 to a
temperature of about 550.degree. C. to 700.degree. C., preferably
about 680.degree. C., cooled down and maintained at this lowered
temperature level over a defined time t.sub.1. At the same time, a
region 13 of second kind of the blank 7 is maintained in a 3.sup.rd
zone 10 of the continuous furnace 11 at a temperature level of
about 830.degree. C. to 950.degree. C., preferably about
900.degree. C.
[0028] After exiting the continuous furnace 11, the heat-treated
blank 7 is thermoformed into the shaped component 1 in a press not
shown in greater detail.
[0029] Illustrated below and above the continuous furnace 11 is the
temperature profile as a function of the time during passage of the
blank 7 through the continuous furnace 11 with respect to the
region 12 of first kind and the region 13 of second kind of the
blank 7, with the lower graph 14 depicting the heat treatment of
the region 12 of first kind, i.e. the temperature profile of the
"soft" section of a blank 7, and the upper graph 15 depicting the
heat treatment of the region 13 of second kind, that is the
temperature profile of the "hardened" section of a blank 7.
[0030] FIG. 2 shows a method for the production of a shaped
component 1 with two structural regions 2, 3 of different
ductility, whereby strip material 4 of boron steel provided with an
Al/Si coating is first drawn from a coil 5 and guided through a
pre-furnace 16. The strip material 4 is homogenously heated in the
pre-furnace 16 to a temperature of about 830.degree. C. to
950.degree. C., preferably about 920.degree. C., and maintained at
this temperature level over a defined time. The thus heat-treated
strip material 4 is then wound to a coil 17. The heat-treated strip
material 4 is fed from this coil 17 to a punch 18 for cutting
blanks 7 from the strip material 4. The strip material 4 may also
be cooled down directly after exiting the pre-furnace 16 and then
fed to the punch 18. These blanks 7 from the pre-treated strip
material 4 are then transferred to a two-zone furnace 19 and a
region 12 of first kind is heated therein in a 1.sup.st zone 20 of
the furnace 19 to a temperature of about 550.degree. C. to
700.degree. C., preferably about 680.degree. C., and a region 13 of
second kind is heated simultaneously in a 2.sup.nd zone 21 of the
furnace 19 to a temperature of about 830.degree. C. to 950.degree.
C.
[0031] The blanks 7 heat-treated in this manner are ultimately
formed into shaped components 1 with two different structural
regions 2, 3 by way of a thermoforming process not shown in greater
detail.
[0032] The lower graph 22 in the temperature-time diagram 23 of
FIG. 2 shows in this context the temperature profile in the region
12 of first kind of the blank 7, and the upper graph 24 shows the
temperature profile in the region 13 of second kind of each blank
7.
[0033] FIG. 3 illustrates the manner in which the strip material 4
of boron steel provided with an Al/Si coating is drawn from a coil
5 and directly fed to a punch 18. Blanks 7 are cut from the strip
material 4 in the punch 18 and then fed to a pre-furnace 16 for
homogenously heating the blanks 7 to a temperature of about
830.degree. C. to 950.degree. C., preferably about 920.degree. C.,
and maintained at this temperature level over a defined time
t.sub.2.
[0034] Blanks 7 heat-treated in this way are then transferred to
the afore-mentioned two-zone furnace 19 and a region 12 of first
kind is heated here, as described, in the 1.sup.st zone 20 to a
temperature of about 550.degree. C. to 700.degree. C., preferably
about 680.degree. C., and a region 13 of second kind is heated at
the same time in the 2.sup.nd zone 21 of the furnace 19 to a
temperature of about 830.degree. C. to 950.degree. C.
[0035] The temperature-time diagram 23 corresponds to the one of
FIG. 2.
[0036] Also the thus heat-treated blanks 7 are finally formed into
shaped components 1 with two different structural regions 2, 3 by
way of a thermoforming process.
REFERENCE SYMBOLS
[0037] 1--shaped component
[0038] 2--structural region of 1
[0039] 3--structural region of 1
[0040] 4--strip material
[0041] 5--coil
[0042] 6--punch
[0043] 7--blank
[0044] 8--1.sup.st zone of 11
[0045] 9--2.sup.nd zone of 11
[0046] 10--3.sup.rd zone of 11
[0047] 11--continuous furnace
[0048] 12--region of first kind of 7
[0049] 13--region of second kind of 7
[0050] 14--lower graph
[0051] 15--upper graph
[0052] 16--pre-furnace
[0053] 17--coil
[0054] 18--punch
[0055] 19--two-zone furnace
[0056] 20--1.sup.st zone of 19
[0057] 21--2.sup.nd zone of 19
[0058] 22--lower graph in 23
[0059] 23--diagram
[0060] 24--upper graph in 23
[0061] t--time
[0062] t.sub.1--time
[0063] t.sub.2--time
* * * * *