U.S. patent application number 14/180106 was filed with the patent office on 2014-08-14 for heat treatment line and method for operating the heat treatment line.
This patent application is currently assigned to Benteler Automobiltechnik GmbH. The applicant listed for this patent is Benteler Automobiltechnik GmbH. Invention is credited to Georg Frost, Werner Morgenroth.
Application Number | 20140224388 14/180106 |
Document ID | / |
Family ID | 49274506 |
Filed Date | 2014-08-14 |
United States Patent
Application |
20140224388 |
Kind Code |
A1 |
Frost; Georg ; et
al. |
August 14, 2014 |
HEAT TREATMENT LINE AND METHOD FOR OPERATING THE HEAT TREATMENT
LINE
Abstract
A heat treatment line for producing a heat treated metal
component includes a heating station, which heats the metal
component to a component temperature above the austenizing
temperature, and a temperature treatment station, wherein the
temperature treatment station has an internal temperature which
essentially corresponds to the temperature of the metal
component.
Inventors: |
Frost; Georg; (Steinheim,
DE) ; Morgenroth; Werner; (Brilon, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Benteler Automobiltechnik GmbH |
Paderborn |
|
DE |
|
|
Assignee: |
Benteler Automobiltechnik
GmbH
Paderborn
DE
|
Family ID: |
49274506 |
Appl. No.: |
14/180106 |
Filed: |
February 13, 2014 |
Current U.S.
Class: |
148/579 ;
266/115; 266/160; 266/249 |
Current CPC
Class: |
C21D 9/0056 20130101;
C21D 9/0062 20130101; C21D 6/00 20130101; C21D 1/673 20130101 |
Class at
Publication: |
148/579 ;
266/249; 266/160; 266/115 |
International
Class: |
C21D 9/00 20060101
C21D009/00; C21D 6/00 20060101 C21D006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2013 |
DE |
10 2013 101 489.5 |
Oct 1, 2013 |
EP |
13 186 929.9 |
Claims
1. A heat treatment line for producing a heat treated, in
particular pre-coated metal component, comprising: a heating
station which heats at least regions of the metal component to a
component temperature above austenizing temperature; and a
temperature treatment station, said temperature treatment station
having at least in regions an internal temperature which
essentially corresponds to the component temperature of the metal
component.
2. The heat treatment line of claim 1, wherein the temperature
treatment station is constructed as continuous furnace, in
particular the continuous furnace has at least in regions the
internal temperature of the temperature treatment station.
3. The heat treatment line of claim 1, wherein the temperature
treatment station is constructed as chamber furnace.
4. The heat treatment line of claim 3, further comprising multiple
said multiple chamber furnace arranged on top of each other and/or
adjacent each other.
5. The heat treatment line of claim 3, wherein the chamber furnace
at least in regions has the internal temperature of the temperature
treatment station.
6. The heat treatment line of claim 1, wherein the temperature
treatment station is constructed as rotary kiln.
7. The heat treatment line of claim 1, further comprising a cooling
station arranged upstream of the temperature treatment station,
8. The heat treatment line of claim 7, wherein the cooling station
is constructed as hot forming and press hardening tool.
9. The heat treatment line of claim 8, wherein the cooling station
is constructed as dip bath.
10. The heat treatment line of claim 7, further comprising a
manipulator for transferring the metal component between the
heating station, the heat treatment station and the cooling
station.
11. The heat treatment line of claim 10, wherein the manipulator is
constructed as an industrial robot.
12. A method for operating the heat treatment line of claim 1,
comprising: establishing an internal temperature of the heating
station above the component temperature of the metal component;
introducing the metal component into the heating station; heating
at least regions of the metal component in the heating station to a
component temperature above austenizing temperature; and
introducing the metal component into the temperature treatment
station.
13. The method of claim 12, wherein the internal temperature of the
heating station is set between 1000.degree. C. and 1300.degree. C.
and the internal temperature of the temperature treatment station
is set between 800.degree. C. and 1000.degree. C.
14. The method of claim 12, wherein the internal temperature of the
heating station is set between 1100.degree. C. and 1200.degree. C.,
and the internal temperature of the temperature treatment station
is set between 850.degree. C. and 950.degree. C.
15. The method of claim 8, wherein the temperature treatment
station is used as buffer to compensate down times and/or
production halts at the heating station and/or the cooling
station.
16. The method of claim 8, wherein a pre-coated metal component
with a metallic pre-coating is heat treated for generating an at
least regional intermetallic phase.
17. The method of claim 12, wherein the metal component is removed
from the heating station when reaching an actual temperature of the
metal component of 700.degree. C. to 1100.degree. C. and
transferred into the temperature treatment station, and wherein at
least regions of the metal component are post heated in the
temperature treatment station to the component temperature, in
particular to at least 900.degree. C.
18. The method of claim 12, wherein the metal component is removed
from the heating station when reaching an actual temperature of the
metal component of 800.degree. C. to 1000.degree. C.
19. The method of claim 12, wherein the metal component is removed
from the heating station when reaching an actual temperature of the
metal component 850.degree. C. to 950.degree. C.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the priority of German Patent
Application, Ser. No. 10 2013 101 489.5, filed Feb. 14, 2013,
pursuant to 35 U.S.C. 119(a)-(d), the disclosure of which is
incorporated herein by reference.
[0002] This application claims the priority of European Patent
Application, Serial No. 13 186 929.9, filed Oct. 1, 2013, pursuant
to 35 U.S.C. 119(a)-(d), the disclosure of which is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to a heat treatment line and a
method for operating the heat treatment line.
[0004] The following discussion of related art is provided to
assist the reader in understanding the advantages of the invention,
and is not to be construed as an admission that this related art is
prior art to this invention.
[0005] In motor vehicle construction it is known for producing
vehicle body components and structural components of motor vehicles
to produce the components as formed sheet metal components from a
steel alloy. For this, a sheet metal blank is formed into a formed
sheet metal component in a forming press.
[0006] It is further known to produce these formed sheet metal
parts from high strength or ultra-high strength steel alloys,
wherein the mechanical resistance, in particular the strength and
the ductility properties, are significantly increased compared to
components made of conventional steel.
[0007] For producing hardened, formed sheet metal components, the
hot forming and press hardening technology has been standardized
for many years, wherein a sheet metal blank, which is heated to
austenizing temperature, is inserted into a forming tool, hot
formed in this forming tool and at the same time quenched in the
forming tool and thereby hardened.
[0008] For hardening components it is further possible to first
form the component, subsequently heat the component to above
austenzing temperature and thereafter take up the component again
and cool the component in a quenching station at such a fast rate
that the microstructure of the component is hardened. Such a device
is for example known from DE 102 009 051 157 B4.
[0009] From this, chamber furnaces are known which can be space
effectively arranged in a mounting hall. Such a chamber furnace has
however a limited capacity so that it can essentially only take up
one component at a time. When now the further processing is
interrupted, for example when a manipulator for loading the chamber
furnace has failed, this leads to halts in the production process
so that the components may remain in the chamber furnace for a
longer period of time. The chamber furnaces are heated to above
austenizing temperature and therefore require high energy
consumption for operating the furnace itself.
[0010] It would therefore be desirable and advantageous to provide
a possibility to heat treat metal components more efficiently,
while requiring a small space in an assembly hall, and wherein
fluctuations in production are compensated and energy consumption
is optimized.
SUMMARY OF THE INVENTION
[0011] According to one aspect of the present invention, a heat
treatment One for producing a heat treated, in particular
pre-coated metal component, includes a heating station which heats
at least regions of the metal component to a component temperature
above austenizing temperature; and a temperature treatment station,
the temperature treatment station having at least in regions an
internal temperature which essentially corresponds to the component
temperature of the metal component.
[0012] According to the invention a heating station is thus
provided in the heat treatment line, which may preferably be
configured as chamber furnace, alternatively also as rotary kiln or
continuous furnace. In the heating station the component is heated
to the desired component temperature. This component temperature is
particularly preferably above the austenizing temperature and is
thus between 800.degree. C. and 1000.degree. C., in particular
between 850.degree. C. and 950.degree. C. This austenizing
temperature is established at least in regions of the component
with the heat treatment line according to the invention. The
remaining regions of the component then remain at a temperature
below the austenizing temperature. The internal temperature of the
heating station is to be set above this temperature. When a
particularly fast heating time of the metal component is to be
achieved, the internal temperature of the heating station is to be
set significantly above the component temperature. The temperature
inside the heating station is thus preferably between 950.degree.
C. to 1300.degree. C., in particular 1100.degree. C. to
1200.degree. C.
[0013] Relative to the component temperature, the internal
temperature of the heating station is to be selected so as to be in
particular 5 to 30% above the component temperature, preferably 10
to 25% above the component temperature. The heating station can in
particular be configured as furnace with a burner.
[0014] The components thus heated to component temperature are then
removed from the heating station and according to the invention
transferred into a temperature treatment station. The temperature
treatment station is configured as intermediate station, in order
to maintain the temperature established in the component itself at
least in regions. Also in the temperature treatment station itself
the component temperature is then held at least in regions, whereas
the non-heated regions are correspondingly below the component
temperature. Here it is possible that an internal temperature which
corresponds to the component temperature itself is preferably
present in the temperature treatment station. As an alternative
thereto it is possible that an internal temperature exists in the
temperature treatment, which is set slightly above, in particular
between 0 and 10%, particularly preferably between 1 and 5%, above
the component temperature. It is thus possible to maintain the
component temperature inside the temperature treatment station for
a longer period of time. A component, which may not be fully
austenized inside the material due to production fluctuations is
further maintained at component temperature in the temperature
treatment station so that a complete austenization occurs as a
result of heat conduction inside the component itself. Due to the
fact that the internal temperature of the temperature treatment
station is selected so as to be not higher, in particular not
significantly higher, than the component temperature itself, the
temperature treatment station can be operated with lower energy
costs compared to the heating station.
[0015] When fluctuations in production occur during further
processing downstream of the temperature treatment station or
already at the heating station, for example as a result of failure
of a heating station or failure of a manipulator for transferring
the components between individual stations, it is possible to build
up a buffer of metal components to be heated with the temperature
treatment station according to the invention. This buffer makes it
possible that the entire production does not necessarily have to be
halted. Thus, maintenance work can be carried out, wherein the
metal components located inside the temperature treatment station
allow production to continue. For this, between 40 and 60% of the
possible components to be received are always located inside the
temperature treatment station during normal production. This
ensures that in case of a failure of the production line downstream
of the temperature treatment station, components can initially
still be transferred from the heating station into the temperature
treatment station. When the production line fails upstream of the
temperature treatments station, components are still initially
stored in the temperature treatment station for further
production.
[0016] For this, the temperature treatment station is particularly
preferably constructed as continuous furnace. The advantage
compared to the state-of-the-art is however that different from
conventional continuous furnaces, the temperature treatment station
does not have to have lengths of several dozen meters, so that the
component is heated to a temperature by the continuous furnace over
the time period in which it is to be transported, but is only held
at the temperature. It is thus possible to configure the
temperature treatment station to be only a few meters long. Within
the scope of the invention, it is also possible in the continuous
furnace to maintain the component temperature to be generated only
in regions in the temperature treatment station, for example by
means of sealing walls or the like. It is also possible within the
scope of the invention, for example by means of corresponding
covering elements, in particular in the form of cooling plates
and/or shielding plates, to prevent some regions to reach a
temperature above austenizing temperature. Within the scope of the
invention, the temperature treatment station and the heating
station are suited to subject only regions of the metal components
to temperature treatment.
[0017] Within the context of the invention a metal component means
a blank, wherein the metal component can be treated with the heat
treatment line according to the invention also as already
three-dimensionally formed metal component. Further particularly
preferably pre-coated materials for example a blank with a metallic
coating can also be used.
[0018] As an alternative thereto it is also possible within the
scope of the invention that the temperature treatment station
itself is constructed as chamber furnace, wherein multiple chamber
furnaces are arranged on top of each other and/or adjacent each
other. It is then possible by using a manipulator, in particular in
the form of an industrial robot, to load the multiple chamber
furnaces in the temperature treatment station or to remove the
components that are temperature treated in the multiple chamber
furnaces. Also in the chamber furnace or in the rotary kiln
described below it is again possible to bring only regions of the
component to the desired component temperature. Also in this case
it is again possible, for example by means of covering elements in
the form of cooling plates or by means of intermediate walls,
sealing walls or an insulation, to cool other regions or to keep
other regions colder than the component temperature.
[0019] Further preferably, the temperature treatment station is
constructed as rotary kiln. This again offers the advantage that
the rotary kiln can be loaded by means of only one manipulator. The
rotary kiln is in particular constructed so that it has multiple
receiving possibilities for receiving metal components on top of
each other and also radially circumferentially adjacent each other.
A respective empty chamber of the temperature treatment station can
then be loaded by the manipulator.
[0020] Further preferably, it is then provided in the heat
treatment according to the invention that a cooling station is
arranged downstream of the temperature treatment station. The
components heated to above austenizing temperature are removed from
the temperature treatments station and then quench hardened in the
cooling station. This can for example be realized by means of a
sprinkler or shower, so that the component is guided through a
sprayed-on cooling medium. As an alternative it is also possible
that the cooling station is configured as dip bath, wherein the
component is removed and dipped into the cooling station. In this
case the material of the microstructure of the component undergoes
such a change that the austenitic microstructure is transformed
into an essentially martensitic microstructure. Within the scope of
the invention, the cooling station can also be a hot forming and
press-hardening tool. The correspondingly heat treated component is
then transferred out of the temperature treatment station into the
hot forming tool where it is hot formed and subsequently press
hardened. In particular when only regions of the component are
austenized, press hardening also only occurs in the austenized
regions, wherein in contrast to this, the regions, which were not
temperature treated are not completely austenized and thus also not
completely hardened. These regions have a rather ductile component
property.
[0021] According to another advantageous aspect of the invention, a
method for operating the heat treatment line according to the
aforementioned features includes establishing an internal
temperature of the heat treatment station above the component
temperature of the metal component; introducing the metal component
into the heating station; heating at least regions of the metal
component in the heat treatment station to a component temperature
above austenizing temperature; and introducing the metal component
into the in the temperature treatment station.
[0022] Preferably an internal temperature is set in the heat
treatment station which is between 1000.degree. C. and 1300.degree.
C., in particular between 1100.degree. C. and 1200.degree. C. and
the internal temperature of the temperature treatment station is
between 800.degree. C. and 1000.degree. C., preferably between
850.degree. C. and 950.degree. C.
[0023] According to another advantageous aspect of the invention,
the temperature treatment station is used as a buffer in order to
compensate downtime and/or production halts at the heating station
and/or at the cooling station.
[0024] Within the scope of the invention it is in particular
possible to heat treat at least regions of a metal component with a
metallic pre-coating so that at least in regions an intermetallic
phase is generated.
[0025] According to the invention, a particularly advantageous
embodiment of the method is to remove the metal component from the
heating station at an actual temperature of the component of
700.degree. C. to 1100.degree. C., preferably 800.degree. C. to
1000.degree. C., in particular 850.degree. C. to 950.degree. C.,
and to subsequently post heat at least regions of the metal
component in the temperature treatment station to above austenizing
temperature, in particular to the component temperature,
particularly preferably to at least 900.degree. C. It is also
possible to then heat the entire component in the downstream
temperature treatment station to above 900.degree. C. This results
in an overall shortened run time to realize the pre-coated metal
component on the corresponding heat treatment line when producing
an at least regionally homogenous intermetallic alloy coating. For
example, an aluminum-silicone coating is used as metallic
pre-coating on the metal component to be heat treated, in
particular to be hot formed and press hardened. Within the scope of
the invention the time of the heating phase can further be
shortened when a metal component with a pre-alloyed metallic
pre-coating is produced. Pre-alloyed means that a heat treatment
with diffusion processes between steel substrate and the elements
of the metallic coating is already carried out prior to the heating
station, in particular at the steel producer.
BRIEF DESCRIPTION OF THE DRAWING
[0026] Other features and advantages of the present invention will
be more readily apparent upon reading the following description of
currently preferred exemplified embodiments of the invention with
reference to the accompanying drawing, in which:
[0027] FIG. 1 shows a heat treatment line according to the
invention with a temperature treatment station in the form of a
roller conveyor furnace and
[0028] FIG. 2 shows a heat treatment line according to the
invention with a temperature treatment station in the form of a
rotary kiln.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0029] Throughout all the Figures, same or corresponding elements
are generally indicated by same reference numerals. These depicted
embodiments are to be understood as illustrative of the invention
and not as limiting in any way. It should also be understood that
the drawings are not necessarily to scale and that the embodiments
are sometimes illustrated by graphic symbols, phantom lines,
diagrammatic representations and fragmentary views. In certain
instances, details which are not necessary for an understanding of
the present invention or which render other details difficult to
perceive may have been omitted.
[0030] Turning now to the drawing, and in particular to FIG. 1,
there is shown a heat treatment line 1 according to the invention
for producing heat treated metal components. The heat treatment
line 1 has a heating station 2 in the form of three adjacently
arranged chamber furnaces 3 and a temperature treatment station 4
arranged downstream of the heat treatment station 2. The
temperature treatment station 4 itself is constructed as roller
conveyor furnace 5, so that the roller conveyor furnace 5 has a
receiving side 6 with a not further shown receiving opening and a
retrieval side 7 with a not further shown retrieval opening.
Following the temperature treatment station 4 is a cooling station
8 for example in the form of a dip bath. Between the individual
stations a respective industrial robot 9 is used which transfers
the not further shown metal components between the individual
stations.
[0031] FIG. 2 shows an alternative embodiment wherein the heat
treatment line 1 again has a heating station 2 in which the chamber
furnaces are arranged adjacent one another. The temperature
treatment station 4 itself is constructed in the form of a rotary
kiln 10 which can be freely rotated in the rotation direction D in
order to transfer the individual components via an industrial robot
9 from the heating station 2 into the rotary kiln and after a
defined incubation time in the rotary kiln 10 to remove the
components from the rotary kiln 10 and feed the components to the
cooling station 8.
[0032] While the invention has been illustrated and described in
connection with currently preferred embodiments shown and described
in detail, it is not intended to be limited to the details shown
since various modifications and structural changes may be made
without departing in any way from the spirit of the present
invention, The embodiments were chosen and described in order to
best explain the principles of the invention and practical
application to thereby enable a person skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated.
[0033] What is claimed as new and desired to be protected by
Letters Patent is set forth in the appended claims and includes
equivalents of the elements recited therein:
* * * * *