JP3502939B2 - Al-Mg-Si aluminum alloy extruded shape with excellent impact energy absorption - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
When received, it has the effect of absorbing the impact load, for example
Impact energy suitable as a structural member for automobiles and railway vehicles
Al-Mg-Si-based aluminum with excellent energy absorption
The present invention relates to an extruded alloy shape. [0002] 2. Description of the Related Art Weight reduction in automobile frame structure
For this reason, the application of aluminum alloy hollow extruded materials has been studied.
Yes. Automobile frame materials are subject to shocking deformation during a collision.
In this case, however, the impact energy does not break brittlely.
It is necessary to absorb For example, side members and bumpers
-In stays, etc., a compression impact load is applied in the direction of the extrusion axis.
The entire shape is Euler buckled (the entire shape is
No buckling) and crushing cracks.
Stable and high energy that contracts and deforms like a bellows
It is necessary to obtain absorption. Or the railway vehicle
Aluminum alloy extruded material is applied in part to the film structure
However, the frame material is subject to shocking deformation at the time of collision.
It is necessary to absorb the impact energy when
At the same time, it may cause crushing and shards
Must not be. In addition, aluminum alloy extruded materials are used in automobiles and
For use in structural members such as railcar frames,
150N / mm at least²Above, preferably 200N /
mm ²It is required to have the above proof stress. Al-M
This strength is achieved in the extruded material of g-Si aluminum alloy.
In general, online press hardening or
After solution treatment and quenching treatment by fly, aging treatment
I am doing it. Aging treatment improves the strength of the extruded material
At the same time, the tissue is stabilized and natural aging progresses during use.
Thus, the strength can be prevented from changing. Up to now, it can be used as an impact absorbing member.
High-strength aluminum can be used as an aluminum alloy extrusion.
Among all alloys, it has relatively good corrosion resistance and is recyclable.
But Al-M is superior to other aluminum alloys
Many g-Si aluminum alloy extruded shapes have been studied.
(For example, JP-A-6-25783, JP-A-7-
Japanese Patent No. 54090, Japanese Patent Laid-Open No. 7-118782,
(Kaihei 9-256096). However,
The energy absorption evaluation is usually also described in the publication.
As shown in the figure, the extruded profile is cut to a predetermined length and several tens of meters
Compressed in the axial direction at a compression speed of m / min to buckle and deform
Obtain the amount of energy absorption from the load-displacement diagram at
It is also done by visually observing for cracks.
The Therefore, the conventional Al-Mg-Si based aluminum alloy
As the gold extruded shape showed excellent energy absorption
But it is only energy under quasi-static compression conditions
It is only absorbable. [0005] On the other hand, during an actual collision,
Deformation occurs at a very high deformation rate. And Al-
Common materials for Mg-Si-based aluminum alloy extrusions
As with materials, when deformed at high speed, deformed at low speed
The strength changes compared to. Therefore, as mentioned above, quasi-static
Excellent energy absorption when mechanically deformed
Even if they are compressed and deformed at high speed, they are brittle
Cracks occur and energy absorption changes
There are many. Also, if brittle crushing cracks go badly
There is also the danger of debris scattering. In fact, the conventional Al-M
For g-Si based aluminum alloy extruded profiles, quenching and
When the strength is increased by aging treatment, the compression impact load
When it receives heavy, it breaks brittlely and has good energy absorption
It did not show sex. In view of the above problems, the present inventors have yield strength ≧ 1.
50 N / mm²And compressive impact load at the time of collision
Excellent energy absorption when received, especially in automobiles
Al-Mg-Si suitable for structural members such as railway cars
An aluminum alloy extruded profile
The [0007] The present inventors have provided a compression impulse.
Al- with excellent energy absorption when subjected to impact load
Seed to develop Mg-Si aluminum alloy extrusions
Obtained by instrumented Charpy test in the course of conducting experimental research.
Load (load) -displacement diagram is a compression impact load
There is a close relationship with energy absorption when receiving
And based on that, the present invention can be obtained.
It was. That is, it is excellent in impact energy absorption according to the present invention.
Al-Mg-Si-based aluminum alloy extruded shape
Yield strength is 150 N / mm²Above, preferably 200N / m
m²Above, and in the instrumented Charpy test, maximum load
Absorption after the maximum load point with respect to absorbed energy up to the emphasis
The collected energy is 60% or more. [0008] DETAILED DESCRIPTION OF THE INVENTION Instrumented Charpy test is a test material.
JIS No. 3 test taken from parallel to the extrusion direction
Use specimen (however, the width of the specimen shall be the thickness of the extruded material)
Compliant with JISB7722 and JISB7755
The test is performed in accordance with JISZ2242.
FIG. 1 shows the test apparatus, and the impact blade of the hammer 1
Attach the strain gauge 2 to the support base 3 and support the test piece 4
The test piece 4 was broken by the impact of the hammer 1 and
The signal of the strain gauge 2 when the amplifier 5 oscilloscope
6 and PC 7 and load as shown in FIG.
(Load) -Displacement diagram is obtained and the maximum load point in FIG.
The amount of energy absorbed (area A) up to (see arrow),
Compare the amount of absorbed energy (area B) after the maximum load point
(B area / A area) × 100 (%) (hereinafter,
Energy ratio). The power of hammer 1
The moment is 49 N · m. Al-Mg-Si aluminum alloy extrusion
When the profile is subjected to a compressive impact load, its displacement-load line
Looking at the figure, after showing the maximum load at the beginning of the impact,
The load decreases with progress. Absorbed energy at that time
-The amount is determined by how viscous the material is, i.e. brittle after maximum load.
How long to maintain a high load without sexual destruction
Therefore, it is greatly affected. The degree of stickiness and instrumentation
There is a correlation between the results of the Calpy test and the energy ratio is low.
In the case where it is low, the material is less sticky and easily brittle. one
On the other hand, if the energy ratio is high, the material is good and brittle
It is difficult to destroy and the amount of energy absorption increases. And energy
-When the ratio is 60% or more, Al-Mg-Si-based aluminum
The proof stress of the extruded aluminum alloy is 150 N / mm²That's it
Even brittle when subjected to a compressive impact load in the direction of the extrusion axis
Without damaging it, it deforms like a bellows and has excellent energy absorption
Showing gender. Also, compression in the lateral direction (perpendicular to the extrusion axis direction)
Even when subjected to an impact load, it does not break brittlely and absorbs the impact
can do. Al-Mg-Si based aluminum alloy
In extruded profiles, the crystal structure is a fibrous structure (fiber
Organization). Where fiber tissue
Is a hot-worked structure found in extruded materials and is long in the extrusion direction.
It is the extended grain structure. The material is deformed
The strain in the material when guided by the movement of dislocations
However, the part where the arrangement of metal crystals such as grain boundaries is irregular is dislocation.
Displacement of the lattice due to the accumulation accumulates and distortion concentrates.
Therefore, the distribution of dislocations in the material, that is, the strain distribution is
Smaller grain size tends to be uniform in the whole material
Yes. And to suppress the occurrence of cracks during high-speed collisions
It is necessary to make the deformation strain uniform within the material. Reunion
Suppression of crystal and fine structure of fiber structure, that is, grain boundary
By holding in a state, deformation strain is evenly distributed in the material.
Can be made of cloth, with high strength and compressive impact load
Improves pressure cracking resistance when received and absorbs energy
The amount can be increased. The Al-Mg-Si based aluminum alloy
Is a precipitation hardening alloy mainly composed of Mg and Si.
As a preferred composition, Mg: 0.2 to 1.6%, Si:
0.2 to 1.8%, desirably Mg: 0.3 to 1.1
%, Si: 0.5 to 1.3%, if necessary, Cu:
0.05-0.7%, Ti: 0.005% -0.2
%, Zr: 0.05 to 0.2%, Mn: 0.05 to
Any one of 0.5%, Cr: 0.001 to 0.2%
Or two or more, or any one of
It consists of the balance Al and inevitable impurities.
Among these, a particularly desirable composition is Mg, S in the above range.
Contains i, Cu, Ti, Zr, plus Mn or Cr
Or a composition comprising both. Next, the Al—Mg—Si based alloy according to the present invention will be described.
The composition of the extruded aluminum alloy will be described. Mg, Si Mg and Si combine to form Mg₂Si is formed and the alloy strength is increased.
Improve. Necessary for structural members such as automobiles and railway vehicles
In order to obtain the required strength, addition of 0.2% or more of each
is required. However, Mg is 1.6% or Si is 1.
If added over 8%, the grain boundary precipitates increase,
Even if the absorbed energy ratio of
When subjected to brittle crushing cracks. Follow
The Mg content is 0.2 to 1.6%, and the Si content is 0.8.
2 to 1.8%. More desirably, Mg: 0.3 to
1.1%, Si: 0.5 to 1.3%, more desirable
Mg: 0.3-0.8%, Si: 0.5-1.0
%, More desirably, Mg: 0.4 to 0.7%, S
i: 0.5 to 0.7%. Cu Cu reduces the strength of Al-Mg-Si based aluminum alloys.
There is an effect of increasing the amount depending on the amount of addition, and it is added as appropriate. Shi
However, if it is less than 0.05%, the action is insufficient, and 0.7%
If it exceeds 50%, corrosion resistance, stress corrosion cracking resistance and weldability are low.
Therefore, the content is made 0.05 to 0.70%. Yo
More preferably, it is 0.1-0.6%, More preferably, it is 0.8.
1 to 0.4%. Ti Ti is nucleated during melt casting to refine the ingot structure.
Are added as appropriate. However, from 0.005%
If it is less, the effect of miniaturization is not sufficient, and more than 0.2%
Saturated and a huge compound is generated, causing crushing cracking deterioration
It becomes. Therefore, the Ti content is 0.005 to 0.2.
%. A more desirable range is 0.01 to 0.1%.
A more desirable range is 0.01 to 0.05%. Zr, Mn, Cr Zr, Mn, and Cr stabilize the fiber structure of the extruded material
Of these, one or more of these are
0.05-0.2%, 0.05-0.5%, 0.
001-0.2%, added as needed. Respectively
If it is less than the lower limit, the effect of stabilizing the fiber structure is obtained.
On the other hand, when Zr exceeds 0.2%, the action is saturated.
If Mn exceeds 0.5%, Mg diffusion during heat treatment
Suppressed, heat treatment deteriorates and coarse compounds
Which causes crushing cracks and Cr exceeds 0.2%
Then, extrudability deteriorates. In addition, when Zr is added,
The effect of improving the crushing cracking effect when treated effectively is great. Ma
Zr, Mn, and Cr all increase the sensitivity to quenching.
Zr is an element that reduces press hardenability.
Since the decrease in press hardenability is small compared to n and Cr,
Of these three elements, first add Zr,
It is desirable to add Mn or / and Cr. More desired
New ranges are: Zr: 0.05 to 0.15%, Mn: 0.00.
1 to 0.2%, Cr: 0.001 to 0.1%. By the way, after manufacturing cost reduction and quenching
The required strength and excellent pressure fracture for improving the dimensional accuracy of
It is desired to obtain this by press quenching by air cooling.
The As mentioned above, Mn, Cr and Zr are fiber structures
To improve strength and pressure cracking resistance
However, this fiber assembly is air-cooled by press quenching.
In order to obtain a weave, a total content of 0.1% or more is necessary.
At the same time, these elements are Al-Mg-Si based aluminum
In order to sharpen the quenching sensitivity of the alloy, the total content is 0.
If it exceeds 4%, the cooling rate is slow (usually 100 to 400).
° C / min) Press quenching with air cooling
It does not enter, and high strength (particularly yield strength) cannot be obtained. Therefore,
Aging treatment is performed after press quenching by air cooling.
In this case, the total content of Mn, Cr and Zr is 0.1-0.
It needs to be 4%. Inevitable impurities Of the inevitable impurities, Fe is the most in aluminum ingots
Impurities contained in the alloy exceeding 0.35%
If present, coarse intermetallic compounds crystallize during casting,
Impairs mechanical properties. Therefore, the Fe content is 0.35.
% Or less. Desirably, it is 0.30% or less,
Furthermore, 0.25% or less is desirable. Also aluminum
When casting an alloy, various kinds of metal, intermediate alloy of additive elements, etc.
Impurities are mixed in from a complicated route. Various elements are mixed
However, impurities other than Fe alone are 0.05% or less, and the total amount
If it is 0.15% or less, it will have almost no effect on the alloy properties
Does not reach. Therefore, these impurities are 0.05% alone.
% Or less, and the total amount is 0.15% or less. In addition, impurity
About B, Ti content in the alloy with the addition of Ti
1/5 of the amount, but more desirable range is
It is preferably 0.02% or less, more preferably 0.01% or less. [0017] Examples of the present invention will be described below. D
By C casting, Al—Mg—Si having the composition shown in Table 1
-Based aluminum alloy billet, 470 ° C x 4h
r soaking was performed. Subsequently, the extrusion temperature was 500 ° C.
Extrusion is performed at a speed of 5 m / min.
Air cooling or water cooling (No. 7 and 9 are water cooling, others are all empty)
(Cold) press quenching and hollow as shown in Fig. 3
Cross-section extruded material (long side 70mm, short side 54mm, wall thickness
Was 2 mm). Next, this extruded material is shown in Table 1.
An aging treatment was performed under the conditions described above to obtain a test material. Air cooling is
Fan cooling with air cooling rate of about 190 ° C / min, water cooling
The rejection rate was about 12000 ° C./min. [0018] [Table 1] Using these specimens, the following tests were conducted.
It was. The results are shown in Table 2. ・ Tensile test: JIS No. 5 test piece was collected from each test material,
A tensile test was performed according to JISZ2241. ・ Crush test; high speed for each specimen (length: 200 mm)
The crush test was conducted. Fig. 4 is a conceptual diagram showing the crush test method
It is. Shaft of specimen 9 with falling weight 8 (mass 200kg)
A load was applied in the direction, and the load was measured with the load cell 10.
The speed of the falling weight 8 at that time is about 50 km / h. And
Based on this test result, create a displacement-load diagram,
From this displacement-load diagram, the range of displacement up to 100 mm is shown.
The amount of energy absorbed was measured in the range. Test that was crushed at the same time
The crushing cracking property of the material is judged visually, and opening cracks are generated.
Evaluate that there are no cracks, and evaluate that there are cracks in the opening
It was. ・ Instrumented Charpy test; test as above (test
The width of the specimen: 2 mm) and the energy ratio were determined. In addition, as a comprehensive evaluation, proof stress (σ_0.2) 150N /
mm²In the above case, absorbed energy is 1500J or more
(However, 200 N / mm²In the above case, absorbed energy
-Amount of 2500J or more) and excellent crushing cracking
○, one of which was inferior was evaluated as x. [0020] [Table 2]As shown in Table 2, the energy ratio is 60%.
No. above. 1 to 6 are high energy and excellent energy
As a structural member for automobiles, railway vehicles, etc.
There is aptitude. All the test materials are compressed into a bellows shape,
There were no opening cracks. On the other hand, the proof stress satisfies the provisions of the present invention.
No. whose energy ratio is less than 60%. 8 and 9 are open
A mouth crack occurred. No. 7 is an open crack
However, the yield strength is low and the energy absorption is low. Follow
Both are suitable as structural members for automobiles and railway vehicles.
There is no sex. [0022] According to the present invention, high-speed and shock-induced deformation is achieved.
Have excellent energy absorption characteristics, for example
(Side members, cross members, bumper stays,
Side frames, pillars, etc.), bumpers, door beams, etc.
In addition to structural parts for automobiles, structural parts such as railway vehicles and ships
An aluminum alloy extruded shape suitable for the material
be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram of an instrumented Charpy test apparatus. FIG. 2 is a load-displacement diagram obtained by an instrumented Charpy test apparatus. FIG. 3 is a view showing a cross-sectional shape of an extruded profile used in an example. FIG. 4 is a conceptual diagram of a high-speed crush test performed in an example. [Explanation of symbols] 1 Hammer 2 Strain gauge 3 Support base 4 Test piece 8 Drop weight 9 Test material 10 Load cell

─────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C22C 21/06 C22C 21/06 // C22F 1/05 C22F 1/05 (56) Reference Japanese Patent Laid-Open No. 5-171328 (JP, A) JP 2000-54051 (JP, A) JP 2000-54050 (JP, A) JP 2000-54048 (JP, A) JP 9-256096 (JP, A) JP 7-54090 ( JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) C22C 21/00-21/18 C22F 1/04-1/057

Claims (1)

(57) [Claims] [Claim 1] Mg: 0.3 to 0.7% (mass%, the same shall apply hereinafter), Si: 0.5 to 1.0%, Cu: 0.1 to 0 .
4%, Ti: 0.005 to 0.2%, and Zr:
0.05 to 0.2%, Mn: 0.05 to 0.4% , C
r: Al—Mg—Si-based aluminum alloy extruded material containing 0.1 to 0.4% in total of any one or more of 0.001 to 0.2%, the balance being Al and inevitable impurities T5 tempered material subjected to press quenching by air cooling and artificial aging treatment, a fibrous structure is formed, the proof stress is 150 N / mm ² or more, and in the instrumented Charpy test, up to the maximum load point The absorption energy after the maximum load point with respect to the absorption energy is 60% or more.
l-Mg-Si-based aluminum alloy extruded shape.