U.S. patent application number 11/126829 was filed with the patent office on 2005-12-22 for flexible rolling of light metals.
Invention is credited to Hauger, Andreas.
Application Number | 20050279433 11/126829 |
Document ID | / |
Family ID | 34936295 |
Filed Date | 2005-12-22 |
United States Patent
Application |
20050279433 |
Kind Code |
A1 |
Hauger, Andreas |
December 22, 2005 |
Flexible rolling of light metals
Abstract
A method of flexibly rolling a metal strip or a metal sheet bar,
wherein the metal strip or metal sheet bar is rolled in the
longitudinal direction of the rolling operation along its entire
length from a starting thickness to an end thickness which is
variable along its length. The strip or sheet bar material used is
in the form of light metals, more particularly aluminum or
magnesium.
Inventors: |
Hauger, Andreas; (Attendoro,
DE) |
Correspondence
Address: |
Wyatt, Gerber & O'Rourke, LLP
99 Park Avenue
New York
NY
10016
US
|
Family ID: |
34936295 |
Appl. No.: |
11/126829 |
Filed: |
May 11, 2005 |
Current U.S.
Class: |
148/667 ;
148/692; 428/585 |
Current CPC
Class: |
B21B 3/00 20130101; Y10T
428/12285 20150115; B21B 2003/001 20130101; B21B 37/26
20130101 |
Class at
Publication: |
148/667 ;
148/692; 428/585 |
International
Class: |
C22F 001/04; C22F
001/06 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2004 |
DE |
102004023885.5-14 |
Claims
1. A method of flexibly rolling a metal strip or a metal sheet bar
wherein the metal strip or metal sheet bar is rolled in the
longitudinal direction of the rolling operation along its entire
length from a starting thickness to an end thickness which is
variable along its length, and wherein the strip or sheet bar
material used is in the form of light metals, wherein said end
thickness comprises at least three different thickness stages.
2. A method according to claim 1, wherein the thickness of the
material is reduced along its entire length by at least 5% with
reference to the starting thickness of 100%.
3. A method according to claims 1 or 2, wherein differences in end
thickness of the material of different thickness stages are at
least 10%, which thickness stages adjoining one another in respect
of thickness, with reference to the starting thickness of 100%.
4. A method according to claims 1 or 2, wherein the thickness of
the greatest thickness stage ranges between 95% and 75% with
reference to the starting thickness of 100%.
5. A method according to claims 1 or 2, wherein the thickness of
the second greatest thickness stage ranges between 85% and 45%,
with reference to the starting thickness of 100%.
6. A method according to claims 1 or 2, wherein the thickness of
the second greatest thickness stage ranges between 85% and 45% with
reference to the starting thickness of 100% and wherein the
thickness of the third greatest thickness stage ranges between 75%
and 30% with reference to the starting thickness of 100%.
7. A method according to claim 6, wherein different thickness
stages alternate periodically, but in any optional sequence.
8. A method according to claim 6, wherein the changes in thickness
between the individual thickness stages are carried out with a
gradient .gamma. of at most 1:40 and of at least 1:4000.
9. A method according to claim 8, wherein the thickness of the
material is reduced by a maximum of 70% with reference to the
starting thickness of 100%.
10. A method according to claim 6, wherein if aluminum is used, the
material, prior to being rolled, is heated to a temperature of at
least 350.degree.-470.degree. C.
11. A method according to claim 6, wherein if magnesium is used,
the material, prior to being rolled, is heated to a temperature of
180.degree.-280.degree. C.
12. A method according to claim 6, wherein use is made of strip or
sheet bar with a width in excess of 1400 mm transversely to the
direction of rolling.
13. A metal strip or metal sheet bar which, by being flexibly
rolled in the longitudinal direction of the rolling operation, is
rolled along its entire length from a starting thickness to an end
thickness, which end thickness is variable along its length,
wherein the strip or sheet bar material is used in the form of
light metals, wherein the end thickness comprises at least three
different thickness stages.
14. A metal strip or metal sheet bar according to claim 13, wherein
there exists differences in end thickness of the materials between
thickness stages adjoining one another in respect of size of at
least 10% with reference to the starting thickness of 100%.
15. A metal strip or metal sheet bar according to any one of claims
13 or 14, wherein the thickness of the greatest thickness stage
ranges between 95% and 75% with reference to the starting thickness
of 100%.
16. A metal strip or metal sheet bar according to claim 15, wherein
the thickness of the second greatest thickness stage ranges between
85% and 45% with reference to the starting thickness of 100%.
17. A metal strip or metal sheet bar according to claim 16, wherein
the thickness of the third greatest thickness stage ranges between
75% and 30% with reference to the starting thickness of 100%.
18. A metal strip or metal sheet bar according to claim 17, wherein
the changes in thickness between the individual thickness stages
take place with a gradient .gamma. of at most 1:40 and of at least
1:4000.
19. A metal strip portion or a metal sheet bar according to claim
18 which produces a deformed planar element consisting of sheet
metal.
20. A metal strip portion or a metal sheet bar according to claim
19 which produces a hollow profile or tube consisting of sheet
metal.
Description
[0001] The invention relates to a method of flexibly rolling a
metal strip or metal sheet bar wherein the metal strip or metal
sheet bar is rolled in the longitudinal direction of the rolling
operation along its entire length from a starting thickness to an
end thickness which is variable along its length. This invention
also relates to products produced in accordance with this
method.
BACKGROUND OF THE INVENTION
[0002] A method of this type is known from German Publication DE
197 04 300 A1 wherein the starting material is first heated to a
temperature in excess of the crystallization temperature and then
rolled. After the hot rolling operation, the material structure is
re-crystallized. In view of the fact that there is mentioned a
re-crystallization temperature in excess of 700.degree. C. it is
clear that the starting material has to be assumed to be alloy
steels.
[0003] From German Publication DE 299 13 509 U1 there is known a
multi-roll stand which permits the so-called "flexible rolling"
process in that the rolling gap is controlled during the rolling
operation in accordance with a rolled strip thickness profile which
changes along the length of the strip. The rolled strip can consist
of steel or non-ferrous metals. German Publication DE 199 26 228 A1
proposes a method of rolling aluminum sheet or strip wherein the
latter is provided with a non-uniform thickness profile
transversely to the conveying direction and, additionally, in the
longitudinal direction. For this purpose, it is necessary to use a
stand with at least one working roll with different diameter
regions transversely to the conveying direction of the aluminum
sheet or strip.
OBJECT OF THE INVENTION
[0004] It is the object of the present invention to extend the
field of application of the initially mentioned method and, more
particularly, to especially adapt the method to selected light
metal materials.
SUMMARY OF THE INVENTION
[0005] The objective is achieved by a method wherein the strip or
sheet bar material used in the form of light metals and their
alloys, more particularly aluminum or magnesium, and which is
characterized in that the end thickness of the strip or sheet bar
material comprises at least three different thickness stages.
Between the individual thickness stages of constant thickness,
there are provided regions of transition with variable thicknesses,
more particularly with a gradient ranging between 1:40 and 1:4000
defined by thickness difference units over length units. The
inventive products can be used, for example, for further improving
the weight and strength optimization in motor vehicle construction.
For instance, while the greatest thickness stage can be used for
producing connections, several further thickness stages make it
possible to achieve specific adaptations to different load
application curves, which includes loads in the elastic deformation
range and loads in crash cases involving plastic deformation.
[0006] It is important that, when carrying out this method, the
thickness of the material be reduced by at least 5% along its
entire length with reference to the starting thickness which is
assumed to be 100%. In this way, there is achieved an intermediate
product with an improved quality and an increased dimensional
accuracy.
[0007] The differences in the end thickness of the material between
thickness stages adjoining one another in respect of thickness
should amount to at least 10%, preferably in excess of 20%, in
order to produce specifically usable strength differences of the
preliminary product for formed sheet metal parts to be produced
therefrom.
[0008] Preferred thickness ranges for the at least three thickness
ranges are mentioned below. The selection of concrete values
primarily depends on the strength requirements for the end product
to be produced from the inventive material.
[0009] The change in the different thickness stages can take place
in any sequence on the sheet bar or strip material, with the
sequence being periodically repeated in the strip material.
[0010] The maximum reduction in thickness of 70%, with reference to
the starting thickness of 100%, should not be exceeded. In
addition, a maximum gradient of the transition regions between the
individual adjoining thickness stages of approximately 1:40 has to
be observed. The proposed minimum gradient is 1:4000. In practice,
values near the maximum gradient will prevail.
[0011] If the strip or sheet bar material is used in the form of
aluminum, the material can be cold-rolled or, for hot-rolling
purposes, it can be heated to a temperature ranging between
350.degree. and 470.degree. C.
[0012] If the strip or sheet bar material is used in the form of
magnesium, the material can be cold-rolled or, for hot-rolling
purposes, it can be heated to a temperature ranging between
180.degree. to 280.degree. C.
[0013] In the case of hot-rolling, the strip material can be
preheated at the wound-up coil. However, it is also possible to
heat uncoiled strip in a continuous process, more particularly in
the case of induction heating.
[0014] Furthermore, the invention includes metal strip or metal
sheet bar produced in accordance with this process as well as
planar elements, tubes or profiles produced therefrom.
[0015] The flexibly rolled material can be cut to lengths or
trimmed and processed further in different ways and is suitable for
different uses. First, reference is made to German Publication DE
100 41 281 A1 according to which sheet bar of flexibly rolled metal
strip can be formed by deep-drawing or other forming processes into
profiles or dish-shaped elements. Furthermore, reference is made to
the earlier German Publication DE 103 23 694 A1 according to which
directly after the flexible rolling of continuous strip material
the latter is formed into a continuous tube or profile and cut into
individual tube or profile pieces. Furthermore, reference is made
to German Publication DE 103 23 693 A1 according to which flexibly
rolled material is formed into tube or profile members with
out-of-round cross-sections. In addition, reference is made to
German patent application 102004017343.5 dated Apr. 6, 2004
according to which, by deep drawing, flexibly rolled material is
formed into a tube or profile whose cross-section is variable in
the longitudinal direction. Finally, reference is made to German
patent application 102004019448.3 dated Apr. 19, 2004 according to
which hybrid metal plate elements of different parts are produced
by using flexibly rolled material. Reference is hereby expressly
made to the disclosure content of all the earlier patent
applications by the same applicant. In the latter case, provided
suitable joining technologies are used, it is also possible to
produce hybrid elements which partly consist of flexibly rolled
aluminum or magnesium and partly of steel plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Examples of the changes in strip or sheet bar material
occurring during the rolling operation are illustrated in the
drawings.
[0017] FIG. 1 illustrates a sheet bar or a strip portion prior to
being rolled.
[0018] FIG. 2 illustrates a sheet bar or a strip portion after
having been rolled.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIG. 1 shows a sheet bar or a strip portion 1 prior to being
rolled, with its thickness in the form of the starting thickness
being referred to as h0. From the starting thickness h0, the
material, by flexible rolling, is rolled in one single rolling pass
to three different thickness stages h1, h2, h3 with
h0>h1>h2>h3, so that the following relationship exists:
h1=h0-.DELTA.h.sub.1, h2=h0-.DELTA.h.sub.2 and
h3=h0-.DELTA.h.sub.3.
[0020] FIG. 2 shows a sheet bar or strip portion 2 after having
been rolled, with a first portion 3 having a thickness
h1=h0-Ah.sub.1, a second strip portion 4 having a thickness
h2=h0-.DELTA.h.sub.2 and a third strip portion 5 having a thickness
h3=h0-.DELTA.h.sub.3. A first transition portion 6 with the length
L.sub.1 forms the transition from thickness h1 to thickness h2,
with the idealized gradient having to be calculated to be
.sub..gamma.1=(h1-h2)/L.sub.1.
[0021] A second transition portion 7 with the length L.sub.2 forms
the transition from thickness h2 to thickness h3, with the
idealized gradient having to be calculated to be .gamma.
.sub..gamma.2=(h2-h3)/L.sub.2.
[0022] As the strip material is rolled along its entire length, the
relationship h1<h0 exists. As can also be seen, the relationship
h2<h1 and h3<h2 exists. The rolling direction can extend from
portion 3 to portion 4 or vice versa. By means of a third
transition portion (not illustrated), it is possible to change from
thickness h3 to thickness h1.
* * * * *