EP1867738B2 - Hot forming line - Google Patents

Description

The invention relates to a hot forming line for producing a hardened sheet steel profile component.

Furnace systems for heating steel sheets or sheet steel components are known in a variety of designs. So-called continuous furnaces - electrically or gas-heated - are used for the continuous heat treatment of steel sheets or steel sheet components in large quantities. From the DE 1 010 547 B goes a continuous furnace for the heat treatment of elongated Wärmegut as rods or sheets with a heating channel, which is formed of two successively arranged, interchangeable construction sections. The use of a continuous furnace within a hot forming line for the production of hardened sheet steel profile components is for example in the DE 101 28 200 B4 or the DE 102 54 695 B3 described. Such furnaces can be designed up to a temperature range of 1,300 ° C. The heat treatment under a protective gas atmosphere is possible.

The US-A-5,923,699 discloses a furnace plant to bring steel to a stable temperature, particularly for use in conjunction with steel rolling processes. The furnace system has a modular structure consisting of oven modules which can be coupled together, with an initial module and an end module between which extension modules can be inserted.

From the above already mentioned DE 102 54 695 B3 For example, a method for producing a metallic mold component is known. Here, a component blank is first formed from a semi-finished by a cold forming process. The component blank is then trimmed on the edge side to an edge contour that corresponds approximately to the shaped component to be produced, and then the trimmed component blank is heated and finished in a hot-forming tool and at the same time press-hardened.

The FR-A-2 369 228 describes a tunnel kiln for ceramic goods, where the tunnel kiln are assembled in box construction with different modules can to achieve a higher throughput with reduced time and effort.

Also by the DE 1 433 840 A1 a tunnel kiln belongs to the state of the art, which is made up of individual furnace elements or tunnel sections. These are mounted on rails and connected by means of bolts yielding elastic.

"Integrated Channel Roller Hearth Furnace Line Technology", S.N. Banerjee, Aichelin-Steel Inc., 19th ASM Heat Treating Society Conference Proceedings, 1999, discloses a roller hearth furnace for mass parts with integrated quench system, wherein the roller hearth furnace is modular.

In practice, a hot forming line is designed for a specific power or production rate. This is also the basis of the capacity of the furnace within the hot forming line. Because of the large investment effort, it is understandable to try to avoid over-dimensioning the kiln plant. Also, one can sometimes at the beginning before commissioning a hot forming line the required

Do not calculate production rate reliably enough in later years. It happens that a kiln plant or a hot forming line meets its performance limit due to changed customer requirements and increased demand. It then comes before the decision to build a second hot forming line or to increase the existing hot forming line. Both are associated with high work and investment costs.

The invention is therefore an object of the invention to provide a thermoforming line for producing a hardened sheet steel profile component, which allows retrofitting to a higher throughput with reduced time, labor and investment costs.

The solution to this problem is characterized in claim 1.

Advantageous embodiments and further developments of the hot forming line according to the invention are the subject of the dependent claims 2 to 6.

The core of the invention is the measure that the heating zone of the furnace plant from at least two separable coupled furnace modules is formed as well as the use of such a furnace in the form of a continuous furnace in a hot forming line for producing a hardened sheet steel profile component.

The furnace system can be extended by installing further furnace modules in the manner of a modular system in their capacity, so as to take account of increased power requirements. For this purpose, the existing furnace modules are separated and installed corresponding expansion furnace modules.

By adjusting the kiln plant, consequently, the production capacity of a thermoforming line for the production of hardened steel sheet profiles can be increased. The necessary downtime and conversion times are clearly Lich lower than in the construction of a second production line or the conventional conversion of the existing kiln plant, because according to the invention, the replenishment of the furnace system with standardized furnace modules. These are equipped with all necessary heating devices, conveyors, insulation, air supply and / or air discharge as well as the necessary separation and coupling points.

Figur 1:

Technisch schematisiert eine Ofenanlage sowie ein Erweiterungs-Ofenmodul;

Figur 2:

die Ofenanlage mit eingebautem Erweiterungs-Ofenmodul;

Figur 3:

einen Ausschnitt aus dem Koppelbereich zwischen zwei Ofenmodulen;

Figur 4:

eine Ansicht auf die Darstellung von Figur 3 gemäß dem Pfeil IV;

Figur 5:

eine Warmformlinie und

Figur 6:

eine Warmformlinie gemäß der Figur 5 mit integrierter Vorformstation.

The invention is described in more detail below with reference to the accompanying drawings. Show it:

FIG. 1:

Technically schematized a furnace and an expansion furnace module;

FIG. 2:

the furnace with built-in expansion oven module;

FIG. 3:

a section of the coupling region between two furnace modules;

FIG. 4:

a view on the representation of FIG. 3 according to the arrow IV;

FIG. 5:

a thermoforming line and

FIG. 6:

a thermoforming line according to FIG. 5 with integrated preforming station.

Hardened sheet steel profile components are used in the automotive industry, for example, as A, B or C pillars, as door impact beams or bumpers. Side wall structures of a motor vehicle body are also produced by hot forming today and hardened in the press tool.

The FIGS. 5 and 6 show a schematic representation of a hot forming line.

First, a steel sheet 1 is separated from a unwound and straightened portion of a coil 2 made of a thermoformable sheet in a punching or cutting device 3. The optionally preformed steel sheet 1 is supplied with a first manipulator 4 of a furnace system 5 in the form of a continuous furnace.

For preforming the steel sheet 1 is in the hot forming line according to the FIG. 6 the continuous furnace 5 is preceded by a press 6, in which the steel sheet 1 is preformed and optionally trimmed. Otherwise, the representation of FIG. 6 the hot forming line as shown in FIG FIG. 5 ,

In the continuous furnace 5, the steel sheet 1 is heated to a temperature which is above the structural transformation temperature in the austenitic state. Depending on the grade of steel, this temperature is in a range between 700 ° C. and 1100 ° C. Advantageously, the atmosphere of the continuous furnace 5 is rendered inert by a targeted and sufficient addition of a protective gas to prevent scaling of the sheet steel surface. A second manipulator 7 picks up the heated steel sheet 1 and places it in a press tool 8. Here, the steel sheet 1 is finally formed into the steel sheet profile component 9 and rapidly cooled by means of a cooling device 10, whereby a fine-grained martensitic or bainitic material structure is set. In this case, hardening of the sheet steel profile component 9 takes place with a targeted adjustment of the material strength. Downstream of the press tool 8 is a third manipulator 11, which the finished molded and hardened sheet steel profile component 9 from the press tool 8 removes and transferred to a container.

The furnace 5 has in the basic design, as in FIG. 1 represented, an inlet zone E, a heating zone H and an outlet zone A on. The inlet zone E essentially comprises a feed table 12 with integrated transport rollers 13. Likewise, the outlet zone A has a take-off table 14 with transport rollers 15 arranged therein. The heating zone H consists here of two furnace modules 16, 17, namely an initial furnace module 16 and an end furnace module 17. These are coupled to each other separable.

To increase the throughput or the performance of the furnace 5 extension furnace modules 18 can be incorporated into the heating zone H. For this, the start oven module 16 and the end oven module 17 are separated and installed between them one or more extension oven modules 18. This is based on the Figures 1 and 2 clarified.

The furnace modules 16, 17, 18 are connected via end flanges 19, 20 by means of bolts 21 with inclusion of at least one heat-resistant seal 22 coupled together, as in the FIGS. 3 and 4 seen. The flanges 19, 20 may additionally be tightly welded. On the inside, the oven modules 16-18 are provided with an insulating lining 27.

Each oven module 16, 17, 18 is equipped with a heater 23. The heater 23 may be electrically or gas heated. Furthermore, in each furnace module 16, 17, 18, a conveyor 24 is integrated for transporting the steel sheets 1 through the furnace module 16-18. The conveyor means 24 each comprise a chain of oven rollers 25. The conveyor means 24 of adjacent oven modules 16-18 are closed together to provide a continuous transport path.

To generate a protective gas atmosphere within the furnace 5, at least one furnace module 16-18 is equipped with an inert gas supply 26.

The individual oven modules 16-18 have standardized dimensions, with the extension oven modules 18 being twice as long as a start oven module 16 or an end oven module 17. For example, a start oven module 16 and an end oven module 17 may together make up a 6m Unit result. Advantageously, the extension furnace modules 18 then have a total length of 6 m, so that a furnace installation 5 can be constructed modularly in each case from 6m units. Accordingly, the length L18 of an extension furnace module 18 corresponds to the total length of the start furnace module 16 and the end furnace module 17.

The construction of the furnace installation 5 of separable, standardized furnace modules 16-18 enables a capacity adaptation or conversion to a higher throughput with standardized building blocks. This has logistical and mounting advantages. In this way, the furnace 5 can be upgraded with relatively little time, labor and investment costs to increase throughput.

Reference numerals:

1 -

sheet steel

2 -

coil

3 -

cutter

4 -

1. manipulator

5 -

furnace

6 -

Press

7 -

2nd manipulator

8th -

Press tool

9 -

Steel profile component

10 -

cooling device

11 -

3. Manipulator

12 -

feed

13 -

transport wheels

14 -

delivery table

15 -

transport wheels

16 -

Initial oven module

17 -

End-oven module

18 -

Extension oven module

19 -

flange

20 -

flange

21 -

bolts

22 -

poetry

23 -

heater

24 -

funding

25 -

furnace roller

26 -

inert gas supply

27 -

insulating lining

E -

inlet zone

H -

heating zone

A -

run-off area

L ₁₆ -

Length of 16

L ₁₇ -

Length of 17

L ₁₈ -

Length of 18

Claims (6)

1. Hot forming line for the production of a hardened, steel sheet structure, from a possibly pre-formed steel sheet, with a 1.manipulator (4), wherein the steel sheet (1) is supplied to a continuous oven (5), in which the steel sheet(1) is heated to a temperature which is above the structural transformation temperature of austenite, and a 2.manipulator (7) which receives the heated steel sheet (1) and inserts it in a press tool (8) in which the steel sheet (1) is finally formed and cooled into a steel sheet structure (9), whereby a 3.manipulator is provided (11), wherein the steel sheet structure (9) is extracted from the press tool (8), is characterized in that the continuous oven (5) consists of at least two detachably linked oven modules (16-18) and an initial oven module (16) and an end oven module (17) is provided, between which can be inserted at least one oven extension module (18), whereby the length (L₁₈) of the oven extension module (18) corresponds to the overall length of the initial oven module(16) and the end-oven module (17).
2. Hot forming line according to claim 1, is characterized in that wherein the oven modules and the extension module (16-18) are coupled to one another via end flanges (19, 20), respectively, with a seal (22) being placed between the end flanges.
3. Hot forming line according to one of claims 1 or 2, is characterized in that each oven module (16-18) is equipped with a heating unit (23).
4. Hot forming line according to one of claims 1 to 3, is characterized in that in each oven module (16-18) a conveyor is incorporated (24), to transport the steel sheet (1) longitudinally through the oven modules (16-18).
5. Hot forming line according to claim 4, is characterized in that the conveyor (24) of adjacent oven modules (16-18) can be coupled to one another.
6. Hot forming line according to one of claims 1 to 5, is characterized in that at least one oven module (16-18) is equipped with an inert gas supply (26).

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