JPH08199277A - Door panel made of aluminum die casting and its production - Google Patents

Abstract

PURPOSE: To obtain a door panel assembled to window of an automobile, electric railcar,. etc. CONSTITUTION: The aluminum alloy consisting of, by weight, 3-12% Si, 0.3-2.0% Fe, 0.1-1.0% Mg, 0.3-1.0% Mn, as necessary, 1.0-5.0% Cu is die cast to a product shape reinforced with a rib to obtain a door panel made of aluminum die casting. The die used consists of the fixed die 11 forming a runner 34, the intermediate die 12 forming runners 35, 36 and gates 37, 38 and the moving die 13 inserted with a pushing pun 39, and one or more gates 37, 38 are arranged in the circle having a diameter of 50-100 times of product thickness. By this method, a door panel of complicated shape is produced as integrated by die casting and the product excellent in strength is obtained at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a door for automobiles, trains, etc., which is required to be lightweight and strong, and a method for manufacturing the door.

[0002]

2. Description of the Related Art When a panel such as a door having a large area is made of an aluminum material or the like, it is difficult to integrally form the panel,
Each part was divided and press molded to assemble each molded part. When a door is attached to the body of an automobile or train, excessive force is applied to the pivot and its vicinity.
Therefore, a thick aluminum plate is press-molded at a portion where a large load is applied, and is welded to a press-molded product made of another thin plate.

[0003]

In the conventional method, it is necessary to press-mold each part and assemble each of the divided parts, which requires a lot of man-hours and causes an increase in manufacturing cost. Moreover, since the shape of the mold differs for each product, it is required to prepare a large number of molds. Moreover, since the portions having different plate thicknesses are welded for reinforcement, not only the welding process is required, but also the shape of the obtained door panel is restricted. As a result, it is not possible to meet the demand for products having various shapes. The present invention has been devised to solve such a problem, and by adopting a die casting method capable of freely changing the wall thickness, the number of man-hours and press die costs can be reduced or reduced, and the design The purpose is to obtain a highly flexible aluminum door of any shape at low cost.

[0004]

The aluminum die-cast door panel according to the present invention has the following object.
i: 3 to 12% by weight, Fe: 0.3 to 2.0% by weight, M
An aluminum alloy containing g: 0.1 to 1.0% by weight and Mn: 0.3 to 1.0% by weight is die cast into a rib-reinforced product shape. The aluminum alloy used may further contain Cu: 1.0 to 5.0% by weight. The rib formed for reinforcement is provided in a substantially trapezoidal cross section having a height of 30 mm or less and an upper side length of 15 mm or less in consideration of the occurrence of defects during die casting. During die casting, it is composed of a fixed type with a runner formed, an intermediate type with a runner and a gate formed, and a movable type with an extrusion pin inserted.
It is preferable to use a mold in which at least one gate is provided in a circle having a diameter of 100 times.

After the die casting, when any one of the heat treatments (1) to (3) is applied, the mechanical properties in the as-cast state are improved. After keeping at a temperature of 300 ° C. or higher for 1 hour or longer, it is allowed to cool. Hold at 450 to 550 ° C for 10 minutes or more and then quench. After keeping at 130 to 250 ° C. for 1 to 5 hours, it is allowed to cool. After holding at 450 to 550 ° C. for 10 minutes or more, it is rapidly cooled, and further held at 100 to 250 ° C. for 1 to 5 hours and allowed to cool. The door panel according to the present invention is die cast using, for example, the mold shown in FIG. Mold 10 is fixed mold 1
1, the intermediate mold 12 and the movable mold 13 are combined, and a casting space 14 corresponding to the product shape is formed between the intermediate mold 12 and the movable mold 13. Fixed type 11, intermediate type 12
The movable mold 13 includes a fixed platen 21 and a movable platen 2.
It is sandwiched between two. Movable die 13 and movable platen 22
The die base 23 is inserted between and.

The cast aluminum alloy 30 is housed in a sleeve 32 whose one end is closed by a plunger 31. The other end of the sleeve 32 is open to the spool 33 formed on the fixed mold 11. The spool 33 communicates with the casting space 14 via a runner 34 formed on the fixed mold 11 and runners 35 and 36 and gates 37 and 38 formed on the intermediate mold 12. Aluminum alloy 30
It is pressurized by the plunger 31 and is pressed into the casting space 14 through the plurality of gates 37, 38, ... The aluminum alloy 30 is cooled by the mold 10 in the casting space 14 and solidifies. When the cast aluminum alloy 30 is cooled to a predetermined temperature, the extrusion pins 39, 39 ... Are extruded from the die base 23 side toward the casting space 14 to separate the cast aluminum alloy product from the mold 10.

In the casting using the die 10 composed of the fixed die 11, the intermediate die 12 and the movable die 13 as described above, molten alloy is cast through the runners 34 to 36 penetrating the fixed die 11 and the intermediate die 12. The aluminum alloy die casting is separated from the mold 10 by the extrusion pins 39, 39, ... Which are supplied to the space 14 and are extruded from the other side. Therefore, even if the target shape has a larger area than the thickness, the molten metal can be supplied to the central portion of the casting space 14, and a sufficient amount of molten metal is filled in each portion. As a result, compared to the die-casting die design of the two-die die that supplies the molten alloy from the side surface of the product, there are less restrictions on the shape of the product to be cast, and a cast product having a large area can be easily manufactured. In addition, the runner 35 is used in the thickened portion for reinforcement.
By providing a dedicated runner on the intermediate die 12 as shown by the gate 37, a thick portion having a required thickness can be easily formed.

The aluminum alloy 30 cast using this mold has Si: 3 to 12% by weight and Fe:
Aluminum alloy containing 0.3 to 2.0% by weight, Mg: 0.1 to 1.0% by weight and Mn: 0.3 to 1.0% by weight, or further Cu: 1.0 to 5.0% by weight. % Aluminum alloy is used. The components of aluminum alloy are
It affects the properties of the castings obtained as follows. Si: 3 to 12% by weight It is an alloying element that affects the castability, and if 3% by weight or more of Si is contained, good melt flowability can be obtained. However, a large amount of Si content exceeding 12% by weight promotes crystallization of primary crystal Si and tends to reduce the toughness of the obtained cast product.

Fe: 0.3 to 2.0% by weight It is an effective element for improving the separability of the cooled and solidified casting from the inner surface of the mold 10. Fe content 0.3% by weight
If less than, seizure easily occurs on the inner surface of the mold 10,
The separability is lowered and surface defects are easily generated in the obtained cast product. However, a large amount of F exceeding 2.0% by weight
When e is contained, a huge Fe-based intermetallic compound is likely to be generated, which lowers the toughness of the cast product. Mg: 0.1-1.0 wt% Mg ₂ Si is deposited on the aluminum matrix and improves the strength of the cast product. This effect is
It becomes remarkable when the g content is 0.1% by weight or more. But,
When the Mg content exceeds 1.0% by weight, the fluidity of the molten metal is lowered, and defects such as lack of meat are likely to occur.

Mn: 0.3 to 1.0 wt% A granular Al-Fe-Mn-based intermetallic compound is formed together with Fe to improve the toughness of a cast product. However, Al-Fe
If the Mn content is less than 0.3% by weight, the —Mn-based intermetallic compound does not exhibit a sufficient granulation effect. Further, if a large amount of Mn exceeding 1.0 wt% is contained, a huge massive Al
A -Fe-Mn-based intermetallic compound is generated, which causes a hard spot. Cu: 1.0 to 5.0% by weight It is an alloying element added as necessary, and has an effect of improving mechanical strength such as proof stress. Such an effect is
It becomes remarkable when the Cu content is 1.0% by weight or more. But,
When a large amount of Cu exceeding 5.0% by weight is contained, elongation and corrosion resistance tend to deteriorate.

In the mold 10 having the structure shown in FIG. 1, the reinforcing thick portion can be easily formed. However, when considering shrinkage when the cast product solidifies and cools, various casting defects are likely to occur in the thick portion where cooling is likely to be delayed. Therefore, the thick portion needs to be formed by ribs having a size shown in FIG. The rib 40 has a trapezoidal cross section in which the height H from the product portion 41 is 30 mm or less and the width W of the upper side is 15 mm or less. The trapezoidal cross section improves the mold separability when the cast product is taken out from the mold. The height H and the width W are as follows:
It is defined to prevent (Fig. 2b) from occurring. H = 30 mm and W = 15 mm are the limits of occurrence of the shrinkage cavities 42, and a cast product in which the shrinkage cavities 42 are generated shows a significant decrease in strength.

The casting space 14 is designed according to the product shape. For example, when the product shape has a plurality of window portions 51, 51, ... As shown in FIG.
At positions corresponding to 51 ..., The intermediate mold 12 and the movable mold 13 are brought into close contact with each other so that the molten alloy does not enter. Window 5
Since the edge of 1,51 ... is not strong enough,
The rib 40 is formed so as to surround the window portions 51, 51. The rib 40 continuous in this way is, for example, an intermediate mold 1.
It can be formed by a groove formed on the surface of the movable die 13 which is in contact with 2. Further, when the contact surface between the intermediate die 12 and the movable die 13 is curved, a product having a curved surface of a predetermined shape as shown in FIG. 3B is obtained. Die casting of products having a large area requires that a sufficient amount of molten alloy be spread over each part. In particular, as shown in FIG. 3, when a cast product having many relatively thin portions is produced, the amount of molten metal supplied to the thin portion is insufficient, and defects such as wall thickness fluctuations and shape defects are likely to occur in the product.

In the present invention, the gate 37 for supplying the molten metal to the thin portion and the gate 38 for supplying the molten metal to the thick portion are distributed as shown in FIG. In order to secure a sufficient molten metal supply amount in each part, according to experiments by the present inventors, the gate gap is set to 50 mm or less.
It turns out that it needs to be multiplied by 100. That is,
At least 1 in a circle whose diameter is 50 to 100 times the plate thickness
When the individual gates are provided, a sufficient amount of molten metal is supplied to each part. For example, when the plate thickness is 2 mm, the gate gap is 100 to 200 mm, that is, the radius is 50 to 10 mm.
When providing at least one gate in a circle of 0 mm,
A cast product free from defects such as lack of meat and defective shape can be obtained.

The obtained cast product may be used as it is without being cast, but in consideration of the performance required depending on the application, the heat treatments 1 to 3 are performed as necessary. This is an annealing treatment in which the temperature is kept at 300 ° C. or higher for 1 hour or more and then allowed to cool, and although the tensile strength and the yield strength are reduced, the elongation is improved. To obtain sufficient elongation, a heating temperature of 300 ° C. or higher and a holding time of 1 hour or longer are required. This is a treatment in which the alloy components are solid-solved in an aluminum matrix, which is held at 450 to 550 ° C. for 10 minutes or more and then rapidly cooled. This treatment softens the cast product, lowers the tensile strength and increases the elongation. A heating temperature of 450 ° C. or higher is required to form a solid solution of the alloy components, but a heating temperature of higher than 550 ° C. may cause local melting. Further, if heated for less than 10 minutes, solid solution formation does not proceed sufficiently.

This is a heat treatment for enhancing the strength by forcibly precipitating the solid-dissolved alloy elements by die casting. By holding at 130 to 250 ° C. for 1 to 5 hours and then allowing to cool, the tensile strength and yield strength of the material are improved.
If the heating temperature is lower than 130 ° C. and the heating time is shorter than 1 hour, a sufficient precipitation reaction cannot be obtained. However, 250 ° C
On the contrary, if the heating temperature exceeds 5 hours or the heating time exceeds 5 hours, the softening phenomenon due to overaging tends to occur. 450 to 550 ° C. × 10 minutes or more → Temperature-quenched solution treatment is followed by artificial aging at 100 to 250 ° C. × 1 to 5 hours, which is a heat treatment for precipitating solid solution alloy elements by solution treatment. By this heat treatment, the elongation is slightly lowered, but the tensile strength and the yield strength are increased.

[0016]

【Example】

Example 1: The cross-sectional area of each gate 37, 38 ...
Using the mold 10 of FIG. 1 designed to m ² , Si: 9.0
% By weight, Fe: 0.47% by weight, Mn: 0.34% by weight
And an inner door frame was cast from an aluminum alloy containing Mg: 0.27% by weight. Mold 10 at 170 ℃
And heat the molten aluminum alloy to a casting temperature of 670 ° C.
Then, the back surface was cast into an inner door frame having the shape shown in FIG. 3 (a) and the side surface into the shape shown in FIG. 3 (b). Sleeve 32
The aluminum alloy 30 stored in the
It was pressurized by the plunger 31 penetrating into the sleeve 32 at a moving speed of 1.7 m / sec so as to be 0 kg / cm ² . At this time, the molten alloy passed through the gates 37, 38, ... At a flow velocity of 70 m / sec.

The gate positions have the distribution shown in FIG.
It was attached directly to 0 and to the thin part. In this embodiment,
Forty-three gates 37 and 38 were provided in a distribution in which one gate exists within the maximum radius of 162 mm and the minimum radius of 23 mm. The casting obtained has a length of 1284 mm and a width of 593.
mm (FIG. 3a) and height 170 mm (FIG. 3b),
It had a plurality of windows 51, 51 ... A rib 40 having a height H of 25 mm and an upper side width W of 9 mm was formed on the periphery of each window 51. In the place where there is no rib 40, the plate thickness is 2
It was designed to be 10 mm. The rib 40 is formed of a single portion and a double portion in consideration of required strength.

The mechanical properties of the obtained cast product were investigated after the as-cast condition and after the heat treatment of. The heating conditions for each heat treatment were set as follows. Heat treatment: 300 ° C × 4 hours → Air cooling Heat treatment: 510 ° C × 2 hours → Water cooling Heat treatment: 170 ° C × 4.5 hours → Cooling Heat treatment: 510 ° C × 2 hours → Water cooling → 170 ° C
× 4.5 hours → Cooling As is clear from Table 1 showing the experimental results, mechanical properties such as tensile strength, proof stress and elongation are different depending on the as-cast condition or heat treatment. Therefore, by selecting the as-cast condition or the heat treatment, a product having the properties required depending on the application can be obtained.

[0019]

[Table 1]

Example 2: Si: 9.0% by weight, Fe:
0.47% by weight, Cu: 1.5% by weight, Mn: 0.34
An aluminum alloy containing wt% and Mg: 0.27 wt% was cast as in Example 1. The cast product obtained is
Tensile strength 290 N / mm ² , 0.2% in as-cast condition
The yield strength was 160 N / mm ² and the elongation was 3%.

[0021]

As described above, in the present invention, the door panel is formed by die-casting an aluminum alloy having different mechanical properties depending on the as-cast or heat-treated state. Since die casting uses a die that is a combination of a fixed die, an intermediate die, and a movable die, even if it is a cast product that has a large area compared to the thickness, products that do not have defects due to lack of meat, etc. It can be obtained with a high degree of design freedom. In addition, since the reinforcing ribs that do not include defects such as sinkholes are integrally molded, the number of steps is significantly reduced compared to the conventional door panel in which the thick member is assembled by welding,
The strength as a structure is also improved.

[Brief description of drawings]

1 is a mold apparatus for manufacturing a door panel according to the present invention.

FIG. 2 is a rib (a) provided on a door panel and a rib (b) having a shrinkage cavity.

FIG. 3 is a back surface (a) and a side surface (b) of the die-cast inner door frame.

[Fig. 4] Position of the gate of the inner door frame

[Explanation of symbols]

10: Mold 11: Fixed type 12: Intermediate type 1
3: Movable type 14: Casting space 21: Fixed platen 22: Movable platen 30: Aluminum alloy (molten metal) 31: Plunger 32: Sleeve 33: Sprue 34-36: Runner 37-3
8: Gate 39: Extruding pin 40: Rib 41: Product part 42: Sink cavity 51: Window part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Mori 161 Kambara, Kambara-machi, Anbara-gun, Shizuoka Prefecture Nippon Light Metal Co., Ltd. Kambara factory

Claims (8)

[Claims] 1. Si: 3 to 12% by weight, Fe: 0.3 to
2.0 wt%, Mg: 0.1-1.0 wt% and Mn:
An aluminum die cast door panel obtained by die casting an aluminum alloy containing 0.3 to 1.0% by weight into a rib-reinforced product shape. 2. An aluminum die-cast door panel, wherein the aluminum alloy according to claim 1 further contains Cu: 1.0 to 5.0% by weight. 3. An aluminum die-cast door panel having a substantially trapezoidal cross section having a height of 30 mm or less and an upper side length of 15 mm or less. 4. A fixed die having runners formed when die-casting the aluminum alloy according to claim 1 or 2,
It is composed of an intermediate die having runners and gates and a movable die having push-out pins fitted therein, and has a product thickness of 50 to 10
A method for manufacturing an aluminum die-cast door panel, characterized in that a mold having at least one gate provided in a circle having a diameter of 0 times is used. 5. A method for manufacturing an aluminum die-cast door panel, which comprises subjecting a die-cast aluminum alloy having a product shape according to claim 4 to a heat treatment of holding at a temperature of 300 ° C. or higher for 1 hour or more and then allowing to cool. 6. A method of manufacturing an aluminum die-cast door panel, which comprises subjecting an aluminum alloy die-cast to a product shape according to claim 4 to a heat treatment of quenching after holding at 450 to 550 ° C. for 10 minutes or more. 7. A method for producing an aluminum die-cast door panel, which comprises subjecting a die-cast aluminum alloy having a product shape according to claim 4 to a heat treatment in which it is left to cool at 130 to 250 ° C. for 1 to 5 hours. 8. An aluminum alloy die-cast into a product shape according to claim 4, which is heat-treated by holding at 450 to 550 ° C. for 10 minutes or more, then rapidly cooling, further holding at 100 to 250 ° C. for 1 to 5 hours, and allowing to cool. A method for manufacturing an aluminum die-cast door panel, which is characterized in that: