JPH11279723A - Production of structural member made of heat resistant aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a sound structural member having excellent heat resistance. SOLUTION: As the stock, the one composed of a heat resistant Al alloy in which the average grains size d1 of Al crystals composing the matrix is regulated to d1 <=1,000 nm, and furthermore, the average grains size d2 of intermetallic compds. dispersed into the matrix is regulated to d2 <=500 nm is prepd. The stock is subjected to forging in such a manner that, respectively, the forging temp. T1 is set to 200 deg.C<=T1 <=400 deg.C, and the die temp. T2 is set to 0.5T1 <=T2 <=0.9T1 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a heat-resistant aluminum alloy structural member.

[0002]

2. Description of the Related Art Generally, a heat-resistant Al alloy has a high deformation resistance. Therefore, when forging a material made of the alloy, the forging temperature T _{1 of the} material is set to 450 ° C. ≦ T ₁ ≦ 60.
It must be increased to 0 ° C.

[0003]

However [0007], when the forging temperatures T ₁ is set higher as the, or impaired properties such as heat resistance of the Al alloy, easy material to occur troubles baking Ku such as the mold Therefore, the condition management for avoiding them becomes very complicated, and as a result, there arises a problem that productivity is reduced.

[0004]

The present invention SUMMARY OF], the forging temperature T ₁ of the mold temperature T ₂ while realizing the reduction of the forging temperatures T ₁ by selecting the heat-resistant Al alloy material having a specific metal structure It is an object of the present invention to provide the above-mentioned manufacturing method capable of achieving a plastic working by correlating with the above, thereby efficiently obtaining a sound structural member having excellent heat resistance. According to the present invention, in order to achieve the above object, according to the present invention, as a raw material, the average particle diameter d ₁ of Al crystals constituting the matrix is d ₁ ≦ 1000 nm, and the average particle diameter d ₂ of the intermetallic compound dispersed in the matrix is Is d ₂
A material composed of a heat-resistant Al alloy having a temperature of ≦ 500 nm is prepared, and the forging temperature T _{1 is set} to 200 ° C. ≦ T ₁ ≦
Manufacture of a heat-resistant Al alloy structural member to be forged at 400 ° C. and the mold temperature T ₂ set to 0.5T ₁ ≦ T ₂ ≦ 0.9T ₁ in relation to the forging temperature T _1. A method is provided.

An Al alloy having a fine metal structure as described above is disclosed by one of the present applicants in Japanese Patent Application Laid-Open No.
It has excellent heat resistance as described in Japanese Patent No. 0378.

When a material made of this Al alloy is subjected to forging in the range of the forging temperature T ₁ , the material shows good plastic deformability due to grain boundary sliding. On the other hand, since no work hardening occurs, partial deformation occurs, which tends to concentrate, causing cracks. Therefore, the mold temperature T _2, the forging temperatures T ₁ used to set the lower the range than by thereby higher than that of the internal resistance to deformation of the mold contact portion side of the material, parts such as the It is possible to avoid the concentration of temporary deformation. Thus, a sound heat-resistant Al alloy structural member can be efficiently obtained. However, forging temperature T ₁ is T ₁ <At 200 ° C., the material is not constant quality of the structural member is liable cause temperature drop, whereas, T _1> 400 the prior art Similarly in ° C.,
This leads to a decrease in productivity of structural members. The mold temperature T ₂ is T ₂ <mold contact portion of the material in the 0.5 T ₁ is prone to cracking due to its temperature drop, whereas, T _2> 0.9 T
_{In the case of 1} , the material is easily seized to the mold and cracked.

[0007] In order to improve the wear resistance of structural members, materials
Contains ceramic particles so as to be dispersed therein.
In this case, the average particle diameter d of the ceramic particles_ThreeIs 1.5 μm
≦ d _Three≦ 10 μm and the content c is 0.5 vol
% ≦ c ≦ 20 vol%. Ceramic
Alumina particles, silicon nitride particles, carbonized particles
Silicon particles, aluminum nitride particles and the like are used. Was
However, the average particle diameter d of the ceramic particles_ThreeIs d_Three<1.5μ
With m, the effect of improving the wear resistance of the member cannot be obtained, while d_Three
If it is> 10 μm, the forgeability of the raw material is deteriorated. Also contained
When the amount c is c <0.5 vol%, ceramic particles are added.
There is no significance, on the other hand, forging of the material at c> 20vol%
Workability deteriorates.

A first example of the composition of the Al alloy is represented by a chemical formula A
1 _bal TM _4-7 X _0.5-3 . The unit of these numerical values is atomic%, which is the same in the following chemical formula. The alloy element TM is at least one selected from Fe and Ni, and the alloy element X is Ti, Zr, M
g and at least one selected from rare earth elements.

The alloy element TM has an effect of improving the heat resistance of the Al alloy. However, when TM <4 atomic%, T
There is no significance in adding M. On the other hand, when TM> 7 at%, the intermetallic compound increases and the toughness of the structural member decreases. Further, the alloy element X has an effect of promoting the miniaturization of the intermetallic compound. However, when X <0.5 atomic%, there is no significance in adding X, while when X> 3 atomic%, the toughness of the structural member is reduced because an AlX-based intermetallic compound is generated.

A second example of the composition of the Al alloy is represented by a chemical formula A
1 _bal TM _4-7 X _0.5-3 Si _1-3 . The reasons for adding the alloy elements TM and X are the same as described above.
The alloy element Si has an effect of refining the metal structure. However, when Si <1 at%, there is no significance in adding Si, while when Si> 3 at%, the toughness of the structural member is reduced since primary Si is crystallized.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [I] Production of material (1) Example 1 Al ₉₁ Fe ₆ Ti ₁ S under the application of the air atomizing method
An Al alloy powder having a composition of i ₂ was produced, and then the Al alloy powder was subjected to a classification treatment to obtain an Al alloy powder having a particle size of 90 μm or less.

A billet having a diameter of 55 mm and a length of 55 mm was formed by using an Al alloy powder (particle size of 90 μm or less) and performing CIP under a pressure of 400 MPa.

The billet is placed in a muffle furnace at 530 ° C., degassed by being kept in an Ar gas atmosphere for 15 minutes, and the billet is extruded at a temperature of 530 ° C.
The temperature was raised to ° C.

The billet is subjected to indirect extrusion,
Example 1 of a material having a diameter of 16 mm was obtained. Processing conditions are: container temperature 400 ° C, die temperature 450 ° C, container inner diameter 5
6mm, Die hole inner diameter 16mm, Extrusion speed 0.5-1.0
cm / sec was set.

In Example 1, the density was about 100%, and when the metal structure was observed with a TEM (transmission electron microscope), the average particle diameter d ₁ of Al crystals constituting the matrix was d ₁ = The average particle size d ₂ of the intermetallic compound dispersed in the matrix is d ₂ = 20.
It was found to be 0 nm.

(2) Example 2 Al alloy powder used in the production of Example 1 (particle size: 90 μm or less)
The average particle diameter d ₃ is d ₃ = 3 μm in the same Al alloy powder as
Of alumina particles having a content c = 5
vol%, and then they were charged to a mixer and mixed well.

After that, using the mixed powder, the same procedure as in Example 1 was repeated to sequentially carry out the above-mentioned steps to obtain Example 2 of the raw material. Density in Example 2 and A constituting the matrix
1 crystal average particle diameter d ₁ and intermetallic compound average particle diameter d
₂ were the same as those of Example 1.

(3) Example 3 Under the application of the air atomizing method,_78.5Si₁₇Fe
_2.5Ni₁Cu_0.5Mg _0.5Alloy powder having the composition of
Powder and then classify the Al alloy powder
Thus, an Al alloy powder having a particle size of 90 μm or less was obtained.

Thereafter, as in the case of Example 1, using the Al alloy powder (having a particle size of 90 μm or less), each of the above-mentioned steps was successively performed to obtain a material example 3.

The density in Example 3 is approximately 100%, and the average grain size d of the Al crystals constituting the matrix is
₁ was d ₁ = 5 μm, and the average particle diameter d ₂ of the intermetallic compound was d ₂ = 1 μm.

(4) Example 4 Al alloy powder used in the production of Example 3 (particle size: 90 μm or less)
The average particle diameter d ₃ is d ₃ = 3 μm in the same Al alloy powder as
Of alumina particles having a content c = 5
vol%, and then they were charged to a mixer and mixed well.

After that, using the mixed powder, in the same manner as in Example 1, the above-mentioned steps (1) to (4) were successively performed to obtain Material Example 4. Density in Example 4, A constituting matrix
1 crystal average particle diameter d ₁ and intermetallic compound average particle diameter d
₂ were the same as those in Example 3.

[II] Measurement of marginal swaging ratio In this measurement, as shown in FIG.
The predetermined forging temperature T ₁Specimen with circular cross section heated to
Tp is set, and then swaging is performed as shown in FIG.
The test piece Tp is deformed by pressing the test piece Tp with the ram 2.
When cracks occurred in p, the pressurization was stopped. And the test piece
In Tp, the length before swaging is L₁And then crack
L is the length when_TwoAs the limit swaging rate ε
(%), Ε = ｛(L₁-L_Two) / L₁｝ × 100 formula
I asked more. The test piece Tp was prepared from the material examples 1-4.
With a diameter of 8 mm and a length of 10 mm.
Was decided.

FIG. 2 shows the measurement results. From Figure 2, Examples 1 and 2 used in the examples, the high limit upsetting ratio ε is at each forging temperatures T ₁ compared to Examples 3 and 4, it is found to have good plastic deformability. In particular, forging temperature T ₁ is 2
In the range of 00 ° C. ≦ T ₁ ≦ 400 ° C., the critical swaging ratio ε of Examples 1 and 2 is as high as 50% or more, and their plastic deformability is substantially constant. Therefore, for Examples 1 and 2, mass production of structural members by forging in this temperature T ₁ range is expected.

[III] Relationship between Forging Temperature T ₁ and Mold Temperature T _{2 In} FIG. 3, the closed forging mold 3 is composed of an upper mold 4 and a lower mold 5.
And The lower die 5 has an upper large-diameter concave portion 6 and a lower small-diameter concave portion 7 coaxially with the upper concave portion 6, and a knockout pin 9 is slidably fitted in a pin hole 8 opened in the bottom surface of the small-diameter concave portion 7. Are combined. The upper mold 4 is slidably fitted in the large-diameter recess 6 of the lower mold 5.

[0026] Moreover, the lower mold 4, 5 is provided with a plurality of cartridge heaters (not shown) respectively, above by their cartridge heater, the temperature of the lower mold 4, 5, i.e. the mold temperature T ₂ is accurately adjusted Is done. In the lower mold 5, the inner diameter D ₁ = 23 mm for the large-diameter portion 6, the depth H ₁ = 15 m
m; inner diameter D ₂ of small-diameter recess 7 = 15.6 mm, depth H ₂ = 5 m
m.

Using the mold 3, closed forging was performed in the following procedure to examine the relationship between the forging temperature T ₁ and the mold temperature T ₂ .

(A) A plurality of test pieces Tp having a diameter of 15 mm and a length of 11 mm were prepared from the material example 1.

(B) Each test piece Tp was subjected to a lubrication treatment for applying molybdenum disulfide.

(C) Each test piece Tp was placed in an electric furnace and heated to a predetermined temperature, and the mold 3 was also heated to a predetermined temperature.

(D) As shown in FIG. 3, the test piece Tp was set up on the lower mold 5 in the small-diameter recess 7. In this case, approximately half of the test piece Tp protrudes into the large-diameter recess 6.

(E) The lowering position of the upper mold 4 is determined in advance.
That is, the upsetting ratio was set to a predetermined value, and the upper die 4 was lowered to perform closed forging. Therefore, the outer diameter of the large-diameter disk portion 11 of each forged product 10 formed in the large-diameter recess 6 changes stepwise as indicated by a chain line.

(F) As shown in FIG. 4, the outer peripheral surface of the large-diameter disk portion 11 of the forged product 10 is checked for the presence or absence of cracks 12, and if a crack 12 has occurred, the large-diameter disk portion at that time is examined. Eleven outer diameters D were determined. Therefore, the larger the outer diameter D, the better the plastic deformability.

FIGS. 5 to 7 show that the mold temperature T _{2 is set} to the normal temperature (25 ° C.).
C.), 130 ° C., and 170 ° C., respectively, showing the relationship between the forging temperature (including normal temperature) T ₁ and the outer diameter D at the time of occurrence of cracks. In the figure, the mark “○” indicates the outer diameter D =
No cracks were generated at 23 mm, "△" indicates that cracks occurred at the outer diameter D = 22 mm, and "x" indicates that cracks occurred at the outer diameter D≤21 mm. Are respectively shown.

In FIG. 5, the mold temperature T ₂ is set to normal temperature (25
In the case of ° C.) can be varied forging temperatures T ₁ in the range of 25 to 500 ° C., 12 cracked all the large diameter disc portion 11 has occurred.

In FIG. 6, when the mold temperature T ₂ is set to 130 ° C., when the forging temperature T ₁ is changed in the range of 25 to 500 ° C., no crack 12 occurs at the forging temperature T ₁ = 200 ° C. large diameter disc portion 11 is molded, other forging temperature T 12 cracks the large diameter disc portion 11, the _first has occurred.

In FIG. 7, when the mold temperature T ₂ is set to 170 ° C., when the forging temperature T ₁ is changed in the range of 25 to 500 ° C., the crack 12 at the forging temperature T ₁ = 200,300 ° C. is the large diameter disc portion 11 is formed with no, 12 occurs cracking forging temperatures T ₁ in the large diameter disc portion 11 otherwise.

In the same manner as described above, the forging temperature T ₁ and the mold temperature T ₂ are respectively changed to perform closed forging, and the outer peripheral surface of the large-diameter disk portion 11 is checked for cracks 12 in the same manner as described above. When the diameter D was determined, the result of FIG. 8 was obtained. In the figure, the meanings of the marks “○”, “△”, and “×” are the same as described above.

As is apparent from FIG. 8, the test piece Tp is
Therefore, in Example 1 of the material, the forging temperature T ₁At 200 ° C ≦ T₁
≤ 400 ° C and mold temperature T_TwoThe forging temperature T₁When
0.5T₁≤T_Two≤0.9T₁Into it
When forging is performed with each setting, a forged product without cracks 12
(Structural member) 10 can be obtained.

The same considerations as described above were conducted for Example 2 of the material, and it was confirmed that the same relationship as described above was established between the forging temperature T ₁ and the mold temperature T ₂ . Material example 3,
_No. 4 cracked at a forging temperature T ₁ ≦ 400 ° C. regardless of the mold temperature.

In each of the material examples 1 and 2, 0.5
When the same considerations were made for the two types of materials to which atomic% was added, it was confirmed that the same relationship as described above was established between the forging temperature T ₁ and the mold temperature T ₂ .

[IV] Valve spring retainer for engine
The same material as in Example 2 above and having a diameter of 25 mm
The extruded material is manufactured and the material is used as shown in FIG.
Outer diameter D of the valve spring contact portion 13_ThreeIs D _Three= 22
Forged valve spring retainer (structural member) 14 mm
Manufactured by processing. Forging conditions are forging temperature T₁: 30
0 ° C, mold temperature T_Two: 220 ° C (about 0.73T)₁)
Was decided.

When this forged product 14 was compared with a cut product obtained by total cutting from the above-mentioned material, the forged product 14
Has the same strength, wear resistance and impact resistance as
Or better. Also, the forged product 14 exhibited sufficient durability in bench durability tests and actual running durability tests, and was found to have extremely high practicality.

Furthermore, since the weight of the forged product 14 is substantially half that of a steel product, replacing the forged product 14 with a steel product can reduce the engine rotation limit to about 500.
It was confirmed that the rpm was improved and the effect on power and fuel consumption was great.

In the forging process, since the forging temperature T ₁ is relatively low, the forged product, that is, the valve spring retainer 14, has a cycle time close to the cold forging process of steel.
Can be manufactured, and the substantial yield is about 92%.
It was also confirmed that a significant improvement such as% to 99% or more could be achieved. These are the valve spring retainer 1
This is extremely effective in mass-producing the No. 4.

When a valve lifter and a piston for an engine were prototyped by forging using the same material as in Example 2, good results similar to those of the valve spring retainer 14 were obtained. It has been confirmed that it is effective in manufacturing a structural member made of a wear-resistant Al alloy.

[0047]

According to the present invention, by selecting the heat-resistant Al alloy material having a specific metal structure as described above, the mold on the forging temperatures T ₁ it is possible to realize a reduction in the forging temperatures T ₁ By correlating the temperature T ₂ , plastic working can be achieved, thereby providing the manufacturing method capable of efficiently obtaining a sound structural member having excellent heat resistance.

According to the present invention, a sound structural member having not only excellent heat resistance but also good wear resistance can be efficiently obtained by including a specific amount of ceramic particles in the material. The above-mentioned manufacturing method can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method of measuring a limit swaging ratio.

FIG. 2 is a graph showing a relationship between a forging temperature T ₁ and a limit upsetting ratio ε.

FIG. 3 is a longitudinal sectional view of an essential part showing a relationship between a closed forging die, a test piece and a forged product.

FIG. 4 is a front view of a forged product.

FIG. 5: Mold temperature T ₂ : Forging temperature T at normal temperature
₆ is a graph showing a relationship between ₁ and an outer diameter D when a crack occurs.

FIG. 6 shows a forging temperature T at a mold temperature T _{2 of} 130 ° C.
₆ is a graph showing a relationship between ₁ and an outer diameter D when a crack occurs.

FIG. 7: Forging temperature T at mold temperature T ₂ : 170 ° C.
₆ is a graph showing a relationship between ₁ and an outer diameter D when a crack occurs.

FIG. 8 is a graph showing a relationship between a forging temperature T ₁ and a mold temperature T ₂ .

FIG. 9 is a front view of an engine valve spring retainer.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B22F 3/17 C22C 1/05 C C22C 1/05 21/00 E 21/00 C22F 1/00 601 // C22F 1/00 601 603 603 604 604 627 627 651B 651 683 683 694B 694 B22F 3/02 101C (72) Inventor Hiroyuki Horimura 1-4-1, Chuo, Wako-shi, Saitama Pref. Honda Research Institute, Inc. (72) Inventor Masahiro Sawai Toyama, Toyama 455 Shinjo-cho, Tanaka-shi (72) Inventor Kazuhisa Nagamori 455 Shinjo-cho, Toyama-shi, Toyama Pref.

Claims (5)

[Claims] 1. A material comprising a matrix A
Average grain size d of 1 crystal ₁Is d₁≦ 1000 nm
Mean particle size of the intermetallic compound dispersed in the matrix
d_TwoIs d_TwoConsists of heat-resistant Al alloy with ≦ 500 nm
The forging temperature T₁To 200
℃ ≦ T₁≤ 400 ° C and mold temperature T_TwoThe forging temperature
Degree T₁0.5T₁≤T_Two≤0.9T
₁It is characterized by setting for each and performing forging processing
A method for manufacturing a heat-resistant Al alloy structural member. 2. The raw material contains ceramic particles dispersed therein, the average particle diameter d ₃ of the ceramic particles is 1.5 μm ≦ d ₃ ≦ 10 μm, and the content c is 0.5 vol% ≦ c The method for producing a heat-resistant Al alloy structural member according to claim 1, wherein ≤ 20 vol%. 3. The composition of the Al alloy is Al _bal TM
_4-7 X _0.5-3 (The unit of the numerical value is atomic%, TM is at least one selected from Fe and Ni, X is Ti, Zr,
At least one selected from Mg and rare earth elements)
The method for producing a heat-resistant Al alloy structural member according to claim 1 or 2, wherein: 4. The composition of the Al alloy is Al _bal TM
_4-7 X _0.5-3 Si _1-3 (The unit of numerical value is atomic%, TM is F
at least one selected from e and Ni, X is T
3. The method for manufacturing a heat-resistant Al alloy structural member according to claim 1, wherein the structural member is at least one selected from i, Zr, Mg, and a rare earth element). 5. The method for manufacturing a heat-resistant Al alloy structural member according to claim 1, wherein the structural member is at least one of a valve spring retainer, a valve lifter, and a piston of an engine.