U.S. patent application number 14/618724 was filed with the patent office on 2016-04-21 for alloy for die-cast vehicle parts and method for manufacturing the same.
The applicant listed for this patent is Hyundai Motor Company. Invention is credited to Hee Sam Kang.
Application Number | 20160108500 14/618724 |
Document ID | / |
Family ID | 55638170 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160108500 |
Kind Code |
A1 |
Kang; Hee Sam |
April 21, 2016 |
ALLOY FOR DIE-CAST VEHICLE PARTS AND METHOD FOR MANUFACTURING THE
SAME
Abstract
An alloy for die-cast vehicle parts and a method for
manufacturing the alloy are provided. The alloy includes aluminum
as a main component; magnesium in an amount of about 8.0 to 10.5 wt
% based on the total weight of the alloy composition; silicon in an
amount of about 1.9 to 3.4 wt % based on the total weight of the
alloy composition; copper in an amount of about 0.4 to 2.0 wt %
based on the total weight of the alloy composition; manganese in an
amount of about 0.3 to 1.0 wt % based on the total weight of the
alloy composition; beryllium (Be) at a maximum of about 50 ppm, and
other essential impurities. Further, during the manufacturing
process, a molten metal is heated to a temperature of about 670 to
730.degree. C. and is injected into a die at a speed of about 3.0
m/s or greater.
Inventors: |
Kang; Hee Sam; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hyundai Motor Company |
Seoul |
|
KR |
|
|
Family ID: |
55638170 |
Appl. No.: |
14/618724 |
Filed: |
February 10, 2015 |
Current U.S.
Class: |
420/534 ;
164/113 |
Current CPC
Class: |
C22C 21/08 20130101;
B22D 17/00 20130101; B22D 21/04 20130101 |
International
Class: |
C22C 21/08 20060101
C22C021/08; B22D 21/04 20060101 B22D021/04; B22D 17/00 20060101
B22D017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 15, 2014 |
KR |
10-2014-0138797 |
Claims
1. An alloy for die-cast vehicle parts, comprising: aluminum (Al)
as a main component; magnesium (Mg) in an amount of about 8.0 to
10.5 wt % based on the total weight of the alloy composition;
silicon (Si) in an amount of about 1.9 to 3.4 wt % based on the
total weight of the alloy composition; copper (Cu) in an amount of
about 0.4 to 2.0 wt % based on the total weight of the alloy
composition; manganese (Mn) in an amount of about 0.3 to 1.0 wt %
based on the total weight of the alloy composition; a maximum of
about 50 ppm of beryllium (Be); and other essential impurities,
wherein a weight ratio of Mg to Si (Mg/Si) ranges from about 3.1 to
about 4.3.
2. The alloy of claim 1, wherein a generation amount of
Al--Mg--Cu-based intermetallic compound is equal to or greater than
about 7.0%.
3. The alloy of claim 1, wherein a tensile strength is equal to or
greater than about 300 MPa and a yield strength is equal to or
greater than about 170 MPa.
4. The alloy of claim 1, wherein an Al--Mg--Cu-based intermetallic
compound which is a main strengthening phase is dispersedly
distributed in an aluminum matrix, along with Mg.sub.2Si
particles.
5. The alloy of claim 4, wherein a size of the Mg.sub.2Si particle
is from about 10 to about 30 .mu.m.
6. The alloy of claim 1, consisting essentially of: aluminum (Al)
as a main component; magnesium (Mg) in an amount of about 8.0 to
10.5 wt % based on the total weight of the alloy composition;
silicon (Si) in an amount of about 1.9 to 3.4 wt % based on the
total weight of the alloy composition; copper (Cu) in an amount of
about 0.4 to 2.0 wt % based on the total weight of the alloy
composition; manganese (Mn) in an amount of about 0.3 to 1.0 wt %
based on the total weight of the alloy composition; and a maximum
of about 50 ppm of beryllium (Be).
7. A method for manufacturing an alloy for die-cast vehicle parts,
wherein the alloy comprises: aluminum (Al) as a main component;
magnesium (Mg) in an amount of about 8.0 to 10.5 wt % based on the
total weight of the alloy composition; silicon (Si) in an amount of
about 1.9 to 3.4 wt % based on the total weight of the alloy
composition; copper (Cu) in an amount of about 0.4 to 2.0 wt %
based on the total weight of the alloy composition; manganese (Mn)
in an amount of about 0.3 to 1.0 wt % based on the total weight of
the alloy composition; beryllium (Be) at a maximum of about 50 ppm,
and other essential impurities, and a molten metal in which Mg/Si
ranges from about 3.1 to about 4.3 is heated to a temperature of
about 670 to 730.degree. C. and is injected into a die at a speed
of about 3.0 m/s or greater.
8. A die-cast vehicle part that comprises an alloy of claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2014-0138797, filed Oct. 15, 2014, the entire
contents of which is incorporated herein for all purposes by this
reference.
TECHNICAL FIELD
[0002] The present invention relates to an alloy for die-cast
vehicle parts and a method for manufacturing the alloy.
Accordingly, a high corrosion resistant light aluminum alloy may be
manufactured and applied to the die-cast vehicle parts.
BACKGROUND
[0003] Typically, an ADC10/12 alloy used for die-cast vehicle parts
costs less and has excellent castability, and thus, it has been
widely used. As a driving environment of a vehicle becomes more
severe, the ADC10/12 alloy has gradually shown limitations. For
example, damage may be caused by a lack of durability, a white rust
may occur due to salinity of sea water or a snow removal material,
and the like, which have not been addressed in the vehicle parts
until recently. Therefore, a necessity of a new alloy for
supplementing the ADC 10/12 alloy has emerged.
[0004] Moreover, environmental regulations have recently been
strengthened to make efforts to suppress environmental pollution,
and therefore, the environmental regulations have become stricter.
Accordingly, vehicle industries have continuously conducted
research to reduce a weight of vehicle parts to improve fuel
efficiency, but have still had difficulty in determining an
alternative alloy having essential performance and price
competitiveness that can replace the currently used commercial
alloys.
[0005] The contents described as the related art have been provided
only for assisting in the understanding for the background of the
present invention and should not be considered as corresponding to
the related art known to those skilled in the art.
SUMMARY
[0006] Thus, in preferred aspects, the present invention provides
an alloy for die-cast vehicle parts and a method for manufacturing
the vehicle parts that are capable of increasing durability greater
than about 40% compared to those manufactured from the conventional
alloy. In addition, white rust appearing in various aluminum parts
may be prevented. When the new aluminum alloy having improved
strength and corrosion resistant is applied to the die-case vehicle
part, weight thereof may be reduced by about 7% for the same shape
by reducing a density of the alloy. Accordingly, weight and cost of
aluminum die-cast vehicle parts may be reduced and durability of
the aluminum die-cast vehicle parts may be improved.
[0007] According to an exemplary embodiment of the present
invention, provided is an alloy for die-cast vehicle parts. The
alloy may include: aluminum (Al) as a main component; magnesium
(Mg) in an amount of about 8.0 to 10.5 wt % based on the total
weight of the alloy composition; silicon (Si) in an amount of about
1.9 to 3.4 wt % based on the total weight of the alloy composition;
copper (Cu) in an amount of about 0.4 to 2.0 wt % based on the
total weight of the alloy composition; manganese (Mn) in an amount
of about 0.3 to 1.0 wt % based on the total weight of the alloy
composition; beryllium (Be) at a maximum of about 50 ppm; and other
essential impurities. In particular, a weight ratio of Mg to Si
(Mg/Si) ranges from about 3.1 to about 4.3.
[0008] A generation amount of Al--Mg--Cu-based intermetallic
compound may be equal to or greater than about 7.0%. A tensile
strength may be equal to or greater than about 300 MPa and a yield
strength may be equal to or greater than about 170 MPa. The
Al--Mg--Cu-based intermetallic compound, as a main strengthening
phase, may be dispersedly distributed in an aluminum matrix,
together with Mg.sub.2Si particles. A size of the Mg.sub.2Si
particle may be in a range from about 10 to about 30 pm.
[0009] It is also provided that the alloy of the invention may
consist of, or consist essentially of the above-mentioned
components in its composition. For example, the alloy for die-cast
vehicle parts as described herein may consist or consist
essentially of: aluminum (Al) as a main component; magnesium (Mg)
in an amount of about 8.0 to 10.5 wt % based on the total weight of
the alloy composition; silicon (Si) in an amount of about 1.9 to
3.4 wt % based on the total weight of the alloy composition; copper
(Cu) in an amount of about 0.4 to 2.0 wt % based on the total
weight of the alloy composition; manganese (Mn) in an amount of
about 0.3 to 1.0 wt % based on the total weight of the alloy
composition; beryllium (Be) at a maximum of about 50 ppm.
[0010] According to another exemplary embodiment of the present
invention, provided is a method for manufacturing an alloy for
die-cast vehicle parts. In particular, the alloy may include:
aluminum (Al) as a main component; magnesium (Mg) in an amount of
about 8.0 to 10.5 wt % based on the total weight of the alloy
composition; silicon (Si) in an amount of about 1.9 to 3.4 wt %
based on the total weight of the alloy composition; copper (Cu) in
an amount of about 0.4 to 2.0 wt % based on the total weight of the
alloy composition; manganese (Mn) in an amount of about 0.3 to 1.0
wt % based on the total weight of the alloy composition; beryllium
(Be) at a maximum of about 50 ppm; and other essential impurities.
Further, a molten metal in which a weight ratio of Mg to Si (Mg/Si)
may range from about 3.1 to about 4.3 may be heated to a
temperature of about 670 to 730.degree. C. The molten metal may be
injected into a die at a speed of about 3.0 m/s or greater.
[0011] Further provided are die-cast vehicle parts that may
comprise the alloy having composition as described herein.
[0012] Other detailed matters of the present invention are included
in the detailed description and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other objects, features and advantages of the
present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0014] FIG. 1 shows a photograph that includes exemplary micro
structures from an exemplary embodiment of the present invention
and from the related art;
[0015] FIG. 2 illustrates exemplary parts where a hot crack occurs
due to a high injection velocity; and
[0016] FIG. 3 shows exemplary fluidity evaluation results depending
on a melt temperature.
DETAILED DESCRIPTION
[0017] It is understood that the term "vehicle" or "vehicular" or
other similar term as used herein is inclusive of motor vehicles in
general such as passenger automobiles including sports utility
vehicles (SUV), buses, trucks, various commercial vehicles,
watercraft including a variety of boats and ships, aircraft, and
the like, and includes hybrid vehicles, electric vehicles, plug-in
hybrid electric vehicles, hydrogen-powered vehicles and other
alternative fuel vehicles (e.g. fuels derived from resources other
than petroleum). As referred to herein, a hybrid vehicle is a
vehicle that has two or more sources of power, for example both
gasoline-powered and electric-powered vehicles.
[0018] The terminology used herein is for the purpose of describing
particular exemplary embodiments only and is not intended to be
limiting of the invention. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof As used herein, the term "and/or" includes any and
all combinations of one or more of the associated listed items.
[0019] Unless specifically stated or obvious from context, as used
herein, the term "about" is understood as within a range of normal
tolerance in the art, for example within 2 standard deviations of
the mean. "About" can be understood as within 10%, 9%, 8%, 7%, 6%,
5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated
value. Unless otherwise clear from the context, all numerical
values provided herein are modified by the term "about."
[0020] Hereinafter, an alloy for die-cast vehicle parts and a
method for manufacturing the same according to various exemplary
embodiments of the present invention will be described with
reference to the accompanying drawings.
[0021] An alloy for die-cast vehicle parts according to an
exemplary embodiment of the present invention may include aluminum
(Al) as a main component to implement reduced weight, improved
strength, and improved corrosion resistant properties compared to
the current alloy for die-cast vehicle parts. The alloy for
die-cast vehicle parts may further include: magnesium (Mg) in an
amount of about 8.0 to 10.5 wt % based on the total weight of the
alloy composition; silicon (Si) in an amount of about 1.9 to 3.4 wt
% based on the total weight of the alloy composition; copper (Cu)
in an amount of about 0.4 to 2.0 wt % based on the total weight of
the alloy composition; manganese (Mn) in an amount of about 0.3 to
1.0 wt % based on the total weight of the alloy composition;
beryllium (Be) at a maximum of about 50 ppm; and other essential
impurities. In particular, a weight ratio of Mg to Si (Mg/Si) may
be in a range from about 3.1 to about 4.3 for generation and
appropriate distribution of Al--Mg--Cu-based intermetallic compound
thereby improving strength and corrosion resistance.
[0022] Further, the generation of the intermetallic compound may be
suppressed by adding Mg, Si, and Cu during various researches and
experiments. For example, the Mg/Si ratio may be set to about 1.98
to 2.5 to obtain a micro structure, and then ultrasonic treatment
and the like may be performed, thereby obtaining an alloy having a
pseudo-binary system process structure of Al--Mg.sub.2Si. However,
as contents of the alloy are increased, the process conditions
which may obtain the targeted pseudo-binary system process
structure of the alloy may be limited, and therefore, may have a
problem such that a quality deviation may increase.
[0023] Therefore, according to the exemplary embodiment of the
present invention, the Mg/Si ratio may be increased to implement a
complex micro structure in which a substantial amount of
Al--Mg--Cu-based intermetallic compound and primary crystal
Mg.sub.2Si are generated, thereby providing improved strength,
reduced density, improved corrosion resistant alloy compared to the
conventional alloy during a general casting process.
[0024] FIG. 1 shows a photograph that includes an exemplary micro
structure of an exemplary alloy prepared according to an exemplary
embodiment of the present invention and a photograph of an
exemplary pseudo-binary system process structure according to the
related art. As shown in FIG. 1, compared to the micro structure
with the pseudo-binary system process structure in which eutectic
Mg.sub.2Si particles are finely distributed in a typical aluminum
matrix (Al matrix), the alloy according to the exemplary embodiment
of the present invention may include the Al--Mg--Cu-based (white)
intermetallic compound. In particular, the Al--Mg--Cu-based (white)
intermetallic compound may be a major strengthening phase,
uniformly distributed therein. Further, the exemplary alloy may
include the primary crystal Mg.sub.2Si particles (black) having a
size in a range from about 10 to about 30 .mu.m distributed
therein.
[0025] When the size of the Mg.sub.2Si particle is greater than
about 30 .mu.m, an alloy of the present invention may not be
prepared to have a sufficient tensile strength of about 300 MPa and
a sufficient yield strength of about 170 MPa or greater as used for
the die-case vehicle parts. When the size of the Mg.sub.2Si
particle is less than about 10 .mu.m, the alloy may have a
structure similar to the pseudo-binary system process structure in
the related art as shown in FIG. 1. Particularly, the alloy of the
present invention may be differentiated from the conventional
alloys by reducing a ratio of other alloy elements except Mg and
increasing a micro structure mainly based on a primary crystal
aluminum resin, thereby maximizing elongation.
[0026] Hereinafter, the reason for limiting a numerical value of a
composition of the alloy for die-cast vehicle parts according to
the exemplary embodiment of the present invention will be
described.
[0027] Magnesium (Mg), as used herein, may be one of the most
important element that implements improved strength, improved
corrosion resistant, and reduced density properties. The amount of
Mg may be of about 8.0 to 10.5 wt %. When the Mg is added less than
about 8.0 wt %, an amount of Al--Mg--Cu-based intermetallic
compound may be insufficiently generated and thus a desired amount
of Al--Mg--Cu-based intermetallic compound when adding Si may not
be obtained. Accordingly, the amount of intermetallic compound
which implements the improved strength, improved corrosion
resistant properties may be reduced and thus the desired physical
properties may not be obtained. When the Mg is added in an amount
greater than about 10.5 wt %, coarsening and generation of hot
crack of the Al--Mg--Cu-based intermetallic compound may occur and
thus castability and mechanical physical properties may
deteriorate.
[0028] Silicon (Si), as used herein, may be a component to improve
the castability of the alloy and an amount of Si may be of about
1.9 to 3.4 wt %. When the Si is added in an amount less than about
1.9%, castability may not be improved sufficiently, and when the Si
is added in an amount greater than about 3.4%, a substantial amount
of Mg.sub.2Si particles may be generated instead of the
Al--Mg--Cu-based intermetallic compound which is a main
strengthening particle, and thus, corrosion resistance and the
strength may be reduced.
[0029] Further, to obtain substantially improved strength and
corrosion resistant properties, the weight ratio of Mg to Si
(Mg/Si) may be adjusted within a range of about 3.1 to 4.3. When
the ratio of Mg/Si is less than about 3.1, a size of Si may be
coarsened. When the ratio of Mg/Si is greater than about 4.3, the
Mg.sub.2Si particle may not be generated.
[0030] Copper (Cu), as used herein, may form the Al--Mg--Cu-based
intermetallic compound as of a strengthening phase together with
the Mg. When the Cu is added in an amount less than about 0.4%, the
strengthening effect may not be sufficient, and when the Cu is
added in an amount greater than about 2.0%, an intermetallic
compound which causes galvanic corrosion from the Al matrix may be
generated and thus the corrosion resistance may be reduced.
[0031] Manganese (Mn), as used herein, may be added to reduce a die
soldering problem that may occur during the die casting. When the
Mn is added in an amount less than about 0.3%, the soldering
reducing effect may be insufficient, and when the Mn is added in an
amount greater than about 1%, an intermetallic compound having a
coarse bar shape may be generated and thus strength may be
reduced.
[0032] Beryllium (Be), as used herein, may be a finite element to
prevent generation of oxide inclusion in a product by suppressing
surface oxidation when melting the alloy including a substantial
amount of Mg. The Be may be added at a maximum of about 50 ppm
according to the die casting process conditions.
[0033] A method for manufacturing an alloy for die-cast vehicle
parts is also provided according to an exemplary embodiment of the
present invention. The alloy for die-cast vehicle parts may have
the composition as described above. Accordingly, a filling defect
problem due to the reduction in castability which may occur when
preparing the alloy (ADC10/12) which is used for the typical die
casting product and the casting defect problem due to the
occurrence of hot cracks and the shrinkage cavity may be prevented.
In particular, the method for manufacturing an alloy for die-cast
vehicle parts according to the exemplary embodiment of the present
invention may apply casting process conditions such as molten metal
temperature, injection velocity, cooling time, and the like, and
such process conditions may be differentiated from the conventional
die casting process conditions to prevent the hot crack, the
non-filling, the shrinkage defect, and the like, thereby providing
mass production. As a result, such problems, for example, lack of
durability and the white rust, which are caused during the
conventional die-cast parts, may be prevented and weight reduction
effect may be obtained.
[0034] In an exemplary method for manufacturing an alloy for
die-cast vehicle parts, the molten metal temperature may be
elevated to a temperature at least of about 670.degree. C. or
greater since reduced fluidity compared to the ADC10/12 alloy.
Further, since a content of Mg is relatively greater than that of
other elements, the molten metal temperature may be limited to a
temperature at maximum of about 730.degree. C. to prevent a molten
metal oxidation problem.
[0035] Further, since the alloy according to the exemplary
embodiment of the present invention may have a greater mushy zone
than that of the ADC10/12 alloy, a filling time may be reduced.
Accordingly, the high injection velocity may be at least of about
3.0 m/s or greater and a switching position may be limited to a
maximum of 8/10 point of a sleeve length. As shown in Table 1, the
generated amount of the Al--Mg--Cu-based intermetallic compound in
each example is shown as the content of Mg in each example varies.
In addition, effects of the generation amount of the
Al--Mg--Cu-based intermetallic compound on improving strength and
corrosion resistant properties in the Al--Mg--Si-based alloy are
compared.
TABLE-US-00001 TABLE 1 Generation amount of Mg Si Al-Mg-Cu-based
intermetallic Division Al (wt %) (wt %) compound (%) Comparative
Balance 7.5 3.0 4.0 Example 1 Comparative Balance 8.0 3.0 5.0
Example 2 Example 1 Balance 8.5 3.0 7.0 Example 2 Balance 9.0 3.0
8.0 Example 3 Balance 9.5 3.0 9.5 Example 4 Balance 10.0 3.0 10.5
Example 5 Balance 10.5 3.0 12.0
[0036] As shown in Table 1, sufficient amounts of intermetallic
compound are generated when the Mg is added in an amount of about
8.0 wt % or greater. The amount of intermetallic compound is
increased in proportion to the content of Mg, but when the Mg is
added greater than about 10.5 wt %, the hot crack occurs and thus
it is highly likely to increase the defective rate during the
casting process.
[0037] The mechanical natures of the alloys were tested while
changing a content of Cu in an Al-10 Mg-3Si-based alloy to confirm
improvement in strength properties of an Al--Mg--Si--Cu-based
alloy. The results are shown in the following Table 2.
TABLE-US-00002 TABLE 1 Tensile Yield Division Al Mg(wt %) Si(wt %)
Cu(wt %) strength(MPa) strength(MPa) Comparative Balance 10 3.0 0.3
280 160 Example 3 Example 6 Balance 10 3.0 0.4 310 175 Example 7
Balance 10 3.0 0.5 325 185 Example 8 Balance 10 3.0 0.7 325 210
Example 9 Balance 10 3.0 0.9 335 220
[0038] As shown in Table 2, as the content of Cu is increased, the
mechanical properties of the Al--Mg--Si-based alloy are
improved.
[0039] To obtain the targeted improvement in strength of 300 MPa or
greater, it may be appreciated that Cu may be added in an amount
greater than about 0.4 wt %. Similar to the Mg, the Cu has the
improved mechanical natures in proportion to the increase in the
content of Cu, but when the Cu is added in an amount greater than
about 2.0 wt %, the corrosion resistance is reduced due to the
galvanic corrosion, and thus, the amount of Cu needs to be
limited.
[0040] FIG. 2 illustrates exemplary die-cast vehicle parts where
the hot crack may occur due to the change in the molten metal high
injection velocity. As illustrated in FIG. 2, as the result of an
experiment, when the same molten metal satisfying the composition
of the alloy according to the exemplary embodiment of the present
invention is used but the high injection velocity is different, the
hot cracks occur, for example, when the high injection velocity is
about 2.4, about 2.6, and about 2.8 m/s. Meanwhile, the hot cracks
disappear when the high injection velocity is about 3.0 m/s and
therefore an improved quality of product may be obtained.
[0041] FIG. 3 illustrates the result of an experiment of fluidity
evaluation of the molten melt. As the result of an experiment using
the same molten metal satisfying the composition of the alloy
according to the exemplary embodiment of the present invention, the
molten metal may secure the sufficient fluidity at a temperature of
about 670.degree. C. or greater.
[0042] As described above, according to the alloy for die-cast
vehicle parts and the method for manufacturing the same according
to the present invention, the durability may be increased by
greater than 40% compared to the conventional alloy and the white
rust appearing in various aluminum parts may be prevented by
developing the die-cast vehicle parts to which the high-strength,
high corrosion resistant new aluminum alloy is applied. Further,
weight of the parts may be reduced by about 7% in the same shape by
reducing the density to reduce the weight, and cost of the aluminum
die-cast vehicle parts may be reduced, while the durability of the
aluminum die-cast vehicle parts may be improved.
[0043] It will be understood by those skilled in the art that the
present invention may be practiced in other detailed forms without
changing the technical idea or the essential features. Therefore,
it should be understood that the above-mentioned embodiments are
not restrictive, but are exemplary in all aspects. It should be
interpreted that the scope of the present invention is defined by
the following claims rather than the above-mentioned detailed
description and all modifications or alterations deduced from the
meaning, the scope, and equivalences of the claims are included in
the scope of the present invention.
* * * * *