U.S. patent application number 10/333555 was filed with the patent office on 2005-02-10 for method for producing half-finished products made of aluminium alloys and an article manufactured with the aid of said method.
Invention is credited to Budanov, Viktor Mikhailovich, Igumenov, Alexander Alexandrovich, Valkov, Viktor Yakovlevich.
Application Number | 20050028899 10/333555 |
Document ID | / |
Family ID | 20238588 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050028899 |
Kind Code |
A1 |
Igumenov, Alexander Alexandrovich ;
et al. |
February 10, 2005 |
Method for producing half-finished products made of aluminium
alloys and an article manufactured with the aid of said method
Abstract
The present invention relates to the method of fabrication of
wrought semiproducts from high strength aluminium-based alloys, and
fabrication of articles from such semiproducts e.g frames,
fittings, beams, etc. used in aerospace engineering and
transportation facilities. The suggested method comprises: casting
an ingot, homogenization, forging the ingot, extrusion of the
wrought billet, solution heat treatment, cold working in two steps:
1. stretching with 1-5% permanent set, 2. multi-axial shaping of
the billet by bending while simultaneously performing the local
plastic deformation of the billet by compressing (1-20%) the joint
places of the blank parts being disposed at an angle of
45-135.degree. to each other; two stage ageing: 1.sup.st
stage=heating to 90-120.degree. C. for 5-24 hours; 2.sup.nd
stage=heating to 160-190.degree. C. for 5-20 hours. The suggested
method allows to fabricate long, irregular-shaped semiproducts from
wrought aluminium-based alloys having high strength and fracture
toughness and low level of residual stresses, thereby providing the
fabrication of products without any distortion or buckling upon
machining.
Inventors: |
Igumenov, Alexander
Alexandrovich; (Samara, RU) ; Valkov, Viktor
Yakovlevich; (Samara, RU) ; Budanov, Viktor
Mikhailovich; (Samara, RU) |
Correspondence
Address: |
LADAS & PARRY
26 WEST 61ST STREET
NEW YORK
NY
10023
US
|
Family ID: |
20238588 |
Appl. No.: |
10/333555 |
Filed: |
June 20, 2003 |
PCT Filed: |
July 30, 2001 |
PCT NO: |
PCT/RU01/00319 |
Current U.S.
Class: |
148/552 |
Current CPC
Class: |
C22F 1/053 20130101;
C22F 1/04 20130101 |
Class at
Publication: |
148/552 |
International
Class: |
C22F 001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2000 |
RU |
2000120275 |
Claims
1. Method of fabrication of semiproducts from aluminium-based
alloy, which method comprising casting an ingot, homogenization,
forging an ingot, extrusion of the forged billet, solution heat
treatment and quenching, cold working and ageing of the billet,
wherein cold working after solution heat treatment and quenching is
performed in two steps, the first step of which comprises
stretching of the as-quenched extruded billet, the second step
comprises multi-axial shaping of the billet by bending while
simultaneously performing the local plastic deformation of the
billet by compressing the joint places of the blank parts, said
parts being disposed at a predetermined angle to each other.
2. Method of claim 1, characterized in that stretching is performed
with 1-5% permanent set without heating.
3. Method of claim 1, characterized in that multi-axial shaping of
the billet by bending is performed in a die without heating, but
providing local compression with 1-20% permanent set.
4. Method of claim 1, characterized in that ageing is performed in
two stages: the first stage comprises heating to temperature
90-120.degree. C. for 5-24 hours, the second stage comprises
heating to temperature 160-190.degree. C. for 5-20 hours.
5. Method of claim 1, characterized in that the blank parts are: a
longitudinal rib and a plate disposed at the angle 45-135.degree.
to each other.
6. The article made of aluminium-based alloy, characterized in that
said article is fabricated by the method according to claims 1-5.
Description
FIELD OF THE INVENTION
[0001] The present Invention relates to metallurgy, and more
particularly it relates to the method of fabrication of wrought
semiproducts from aluminium-based alloys and the articles made from
said semiproducts. Such articles may be used in aerospace
engineering, ship building, automotive and machine-building as
frames, fittings, beams and other irregular-shaped long elements
preferably having longitudinal and transverse ribs. In such
articles the most important are: the low level of residual stresses
and the related distortion and buckling during subsequent machining
of semiproducts.
BACKGROUND OF THE INVENTION
[0002] Well-known is the method of fabrication of semiproducts from
high strength aluminium-based alloy, which method comprising
casting an ingot, homogenization, preferably extrusion of the
billet, forging and hardening (solution heat treatment
+quenching+aging) (U.S. Pat. No. 3.791.876 U.S. Cl. 148/2 (publ.
24.10.72)) [1]. By this method it is possible to produce
irregular-shaped semiproducts having high strength but their
distortion is rather great. It leads to reduction (up to 40-50%) of
articles'output after machining. When producing long regular-shaped
semiproducts (e.g. sheets, plates), there is widely used stretching
with 1-10% permanent set in order to relieve residual stresses and
to prevent distortion (Kozlovskaya V. P., Kudryashov V. G.,
Bunnistrov V. I. et al,. <<Technologiya Lyogkikh
Splavov>>, 1976, .No. 11, pp. 16-18) [2]; (Vladimirov S. A.,
Vishnyakov Ya. D., Shadsky A. A. <<Technologiya Lyogkikh
Splavov>>, 1977, No. 11, pp. 18-21) [3]. But this method is
not applicable to complex-shaped semiproducts because stretching of
such products doesn't reduce distortion to required degree owing to
uncontrollable non-uniformity of deformation along stretching
axis.
[0003] To relieve residual stresses and to reduce distortion of
irregular-shaped semiproducts it is known to use compressing with
1-6% permanent set (Bykov L. N., Vladimirov S. A., Shadsky A. A.
<<Technologiya Lyogkikh Splavov>>, 1982, No. 1, pp.
25-29) [4]. But this method also has essential restrictions because
of the irregular shape of the product. In particular, the scheme of
deformation by compressing is maximum effective when regular-shaped
products having axial symmetry (cylindrical, circular, rectangular)
are straightened.
[0004] When long articles having complex geometry (having ribs,
curved elements, different thicknesses) e.g. fittings, frames, etc,
are to be straightened, one can't use the method of compressing
because it is not possible to provide uniformity of plastic
deformation and to eliminate distortion and buckling during
subsequent machining.
[0005] Well-known is the method of production of semiproducts from
wrought aluminium-based alloys, which method comprising:
[0006] casting a billet,
[0007] homogenization of as-cast billet,
[0008] forging of as-cast billet,
[0009] extrusion of the forged billet,
[0010] solution heat treatment and quenching from 470.degree.
C.,
[0011] cold working by compressing in one direction with 1.5-5.0%
set and then in another direction normal to the first one with the
same-set,
[0012] aging 108.degree. C., 7 hours+163.degree. C., 7 hours (Japan
Application No 04187747 (publ. 22.11.90) Int. Cl. C22F 1/04)
[5].
[0013] The shortcoming of this method is the impossibility to
produce long, irregular-shaped semiproducts with length-to-width
ratio>2:1, free from quenching stresses, that means it is
impossible to produce long products of high quality. Besides that,
in said method relieving of residual stresses is achieved by
compression with 1.5-5.0% set in one direction and then in another
direction normal to the first one, with the same set, but the
required change in billet shaping is not achieved. Therefore in
order to provide the required shape, the subsequent step is needed
which causes the additional residual stresses which in turn lead to
distortion and to quality reduction during the subsequent
machining.
DESCRIPTION OF INVENTION
[0014] The object of the present invention is to provide the method
of fabrication of long, irregular-shaped semiproducts from wrought
aluminium-based alloys with enhanced strength properties and crack
resistance, and reduced level of residual stresses, which method
allows to fabricate distortion free products during machining.
Accordingly, there is provided method comprising:
[0015] casting an ingot,
[0016] homogenization of as-cast billet,
[0017] forging the as-cast billet,
[0018] extrusion of the forged billet,
[0019] solution heat treatment and quenching,
[0020] cold working in two steps:
[0021] the first step comprises stretching of the as-quenched
extruded billet;
[0022] the second step comprises multi-axial shaping of the billet
by bending while simultaneously performing the local plastic
deformation of the billet by compressing the joint places of the
blank parts, said parts being disposed at a predetermined angle to
each other,
[0023] ageing. Stretching is performed with 1.0-5.0% permanent set
without heating.
[0024] Multi-axial shaping of the billet by bending is performed in
a die without heating, but providing local compression with 1-20%
permanent set of the joint places of the blank parts (e.g. ribs and
plates). Ageing of the resulted blank is performed in two
stages:
[0025] 1.sup.st stage--heating to 90-120.degree. C. for 5-24
hours;
[0026] 2.sup.nd stage--heating to 160-190.degree. C. for 5-20
hours. More preferably, method of the invention is applicable to
semiproducts consisting of the following parts: a longitudinal rib
and a plate which are disposed at an angle of 45-135.degree. to
each other.
[0027] By suggested method it is possible to fabricate such long
products as fittings, frames, beams, etc., which products have
enhanced strength and crack resistance and have no distortion or
buckling after machining.
[0028] The suggested method differs from prior art methods in
possibility to change the blank shape after solution heat treatment
and quenching by multi-axial shaping by bending in a die without
heating while simultaneously relieving the residual stresses by
performing the local plastic deformation by compressing (with 1-20%
permanent set ) the joint places of the blank parts being disposed
at an angle to each other, that is why it becomes possible to
eliminate distortion and buckling during subsequent machining.
Besides that, in the suggested method the blank parts, namely ribs
and plates, are disposed at an angle of 45-135.degree. to each
other, and length-to-width ratio is >2:1. The above-said angle
range embraces all possible structural designs of semiproducts.
[0029] Embodiments of the present invention will now be described
by way of example.
EXAMPLE 1
[0030] A long fitting blank having an irregular shape: cross-shaped
section of variable thickness (40-100 mm), asymmetric deflection of
blank parts relative to longitudinal axis, and angle between ribs
and a plate changing from 75 to 105.degree., was fabricated from
high-strength alloy of Al--Zn--Mg--Cu system by the following
method: casting of an ingot .O slashed. 870 mm, homogenization of
as-cast billet at 460.degree. C. for 24 hours, forging the ingot at
all sides at 410.degree. C., extrusion of the cross-shaped blank at
400.degree. C. with reduction ratio 1:10. Solution heat treatment
of the extruded blank from 470.degree. C. and water quenching at
20.degree. C. Stretching the quenched blank with 1.9% permanent set
for residual stress relieving, multi-axial shaping of the blank by
bending without heating in a die while simultaneously performing
the local plastic deformation by compressing (with 2% permanent
set) the joint places of longitudinal ribs and plate thus finally
shaping the blank, and ageing at 120.degree. C. for 5
hours+160.degree. C. for 15 hours.
EXAMPLE 2
[0031] From the same alloy as in Example 1, a long blank having
cross-shaped section of variable thickness (30-80 mm), was
fabricated. The blank had more asymmetric deflection of axis and
plate as compared with Example 1, and angle between ribs and a
plate changed from 45 to 135.degree..
[0032] In this example the following method was used: casting and
homogenization of an ingot 0 650 at 460.degree. C. for 12 hours;
forging an ingot at all sides at 450.degree. C.; extrusion of the
cross-shaped blank at 390.degree. C. with reduction ratio 1:10.
Solution heat treatment of the extruded blank was performed at
470.degree. C. with subsequent water quenching at 20.degree. C.
After quenching the blank was stretched with 2.8% permanent set.
Then it was performed multi-axial shaping of the blank by bending
combined with simultaneous local plastic deformation by compressing
(with 20% permanent set) the joint places of blank's ribs and a
plate, without heating, in a die. Ageing was performed as follows:
120.degree. C. 24 hours+190.degree. C. 5 hours.
EXAMPLE 3
[0033] A long beam blank with T-shaped cross-section and of
variable thickness (30-65 nun), with asymmetric deflection relative
to longitudinal axis, the angle between a rib and a plate changing
from 60 to 110.degree., was fabricated from the alloy B93.PI.(of
AL-Zn--Mg--Cu systems) according to the following schedule:
[0034] casting and homogenization of an ingot 0 650 at 450.degree.
C. for 5 hours; forging an ingot at all sides at 410.degree. C.;
extrusion of the forged blank at 390.degree. C. with reduction
ratio 1:12. Solution heat treatment of the extruded blank at
475.degree. C., water quenching at 20.degree. C. After quenching
the blank was stretched with 5% permanent set. Then it was
performed multi-axial shaping of the blank by bending combined with
simultaneous local plastic deformation by compressing (with 10%
permanent set) the joint places of the blank's ribs and a plate, in
a die without heating. Ageing was performed as follows: 110.degree.
C. 8 hours+165.degree. C. 12 hours.
EXAMPLE 4
[0035] From the alloy of Al--Zn--Mg--Cu system, a long cross-shaped
fitting blank identical to that of Example 1, having variable
(55-110 mm) cross-section thickness, was fabricated according to
the method described in Japan Application No 04187747:
[0036] casting and homogenization of an ingot 0 870 at 460.degree.
C. for 24 hours; forging the as cast ingot at all sides at
390.degree. C. with reduction ratio 1:8. The hardening of the
wrought billet included solution heat treatment at 475.degree. C.,
water quenching at 20.degree. C. Straightening of the billet was
performed by compressive deformation with 5% permanent set in one
direction and then in another one normal to the first, with the
same set.
[0037] Shaping of the final blank was performed by bending in a die
without heating. Ageing was performed as follows: 110.degree. C. 8
hours +165.degree. C. 12 hours.
[0038] The samples for mechanical properties' and crack resistance
determination were cut from final semiproducts. The rest
semiproducts were machined, and the deviations of the blank's
dimensions as compared to drawings' requirements, were determined.
The material utilization index (MUI) was also determined.
[0039] The Table below shows the comparative properties of
semiproducts obtained by the practices of the present invention and
disclosed in Japan Application No 04187747.
[0040] The data given in the Table evidently show that practice of
the present invention allows to fabricate long, complex-shaped
semiproducts and articles from aluminium-based alloy having a
pronounced high level of strength and fracture toughness (K
.sub.1c) combined with a reduced level of residual stresses thereby
providing the fabrication of products without any distortion or
buckling upon machining, increase of the material utilization index
by 1.5 times and avoiding of faulty production related to
impermissible deviations from the dimensions pointed out in the
drawing.
[0041] The described method of the invention allows to fabricate
long, irregular-shaped products such as fittings, frames, beams,
etc. used in aerospace engineering and transportation
facilities.
1TABLE 1 Mechanical properties and data of efficiency of
semiproducts fabrication from high strength alloy of Al--Zn--Mg--Cu
system Faulty production Max. through UTS, YTS, E1, K.sub.1c,
distortion, MUI*, distortion, Example MPa MPa % MPa{square root}m
mm % % 1 550 490 13 46 3.0 40 0 2 510 460 14 49 2.0 48 0 3 540 470
14 47 1.8 60 0 4 prior art 520 460 13 39 18.3 25 46
* * * * *