JP3233095B2 - Manufacturing method of aluminum cast-in products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycle, corrosion-resistant material having no erosion, melting, etc.
The present invention relates to a method for producing a cast-in product having excellent oxidation resistance and the like.

[0002]

2. Description of the Related Art Casting an aluminum member to be cast (hereinafter referred to as a cast-to-be-stuffed material) with an aluminum-cast-to-fill material is required.
This is a very advantageous method in consideration of the later scrap processing. Particularly, an aluminum material manufactured by consuming a large amount of power is advantageous from the viewpoint of effective use of resources and energy. However, since the melting end temperature of the to-be-cast material is lower than the temperature at which the to-be-cast aluminum material is poured into the mold, a phenomenon in which the to-be-stuffed material is partially melted frequently occurs. When a hollow member such as a pipe is used as a to-be-filled material, when the molten aluminum is poured into a mold, a coolant such as air or water is supplied to the inside of the hollow member to cool the hollow member, thereby causing erosion and erosion. Etc. are prevented, and a good cast-in product is obtained.

[0003] For example, when pouring a molten metal of an Al-Si based cast-in material into a mold, the molten cast-in material is maintained at a pouring temperature of about 720 ° C in order to ensure a molten metal flow in the mold. However, the temperature is lowered to about 660 to 670 ° C. in the vicinity of the surface of the to-be-cast material incorporated in the mold. On the other hand, when the 6063 alloy having a melting end temperature of about 654 ° C. is used as a to-be-stuffed material, the to-be-stuffed material is partially melted. As a result, when the hollow member was cast, the proportion of defective products was high. In order to prevent the melting of the hollow member, a method of cooling the hollow member by supplying a refrigerant has been adopted.

[0004]

However, when casting is performed while supplying a coolant to the hollow member, the equipment attached to the mold tends to be complicated. Thus, Japanese Patent Application Laid-Open No. 3-142058 introduces coating of a material to be cast with a high melting point metal such as Ni or Cr. The coating layer of the high melting point metal prevents the heat of the molten cast material from being directly transmitted to the cast material, and suppresses erosion and melting of the cast material. The present inventors have also developed a casting coated with a heat insulating material such as nitride, oxide, boride, carbonate, phosphate, graphite, calcium carbonate, feldspar, iron oxide, boric acid, mica, chalk, titanium oxide, and the like. It has been proposed in Japanese Patent Application No. 9-270972 to use a loose material.

However, in the case of coating with a high melting point metal,
Since it becomes a cast-in product mixed with Ni, Cr and the like, recyclability and corrosion resistance are deteriorated. For example, in the case where waste is collected and used as a metal source, a special treatment is required for removing impurities. Moreover, since a foreign metal exists at the contact interface between the to-be-cast material and the to-be-cast material, it is likely to be a starting point of corrosion or the like. In this regard, the heat-insulating substance floats and separates on the surface of the molten metal by re-dissolving during recycling, and therefore is not carried into a recycled product. However, a coating process is required to cover the to-be-cast material with a heat-insulating substance, thereby increasing the manufacturing cost.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been devised to solve such a problem. The present invention is directed to the selection of the material to be cast and the material to be cast and the casting according to the shape of the product. It is an object of the present invention to eliminate the need for a coating process on a material to be cast by selecting conditions, and to produce a good aluminum product with a low casting temperature at low cost. The present invention
In order to achieve the object, set the stuffed aluminum alloy material in the mold, and when casting with the stuffed aluminum alloy for casting, the shortest distance from the surface of the stuffed material to the inner surface of the mold When the maximum value is d (mm) and the pouring temperature of the cast-in-place material poured into the mold is T ₄ , the maximum value d and the pouring temperature T ₄
Is maintained in the shaded area B of FIG. However, points A to D in FIG. 2 are indicated by the following coordinates, respectively. A point: (7,705) B point: (40,673) C point: (7,645) D point: (40,622) In casting, the molten metal of the insert material near the surface of the insert material The temperature is T ₁ (° C.), the solidification end temperature of the as-cast material is T ₂ (° C.), and the melting end temperature of the as-cast material is T.
When the temperature is set to ₃ (° C.), it is preferable to control the temperature T ₁ of the melt of the as-cast material so that (T ₂ + 5 ° C.) <T ₁ <T ₃ . By controlling both the melt temperature T ₁ and the pouring temperature T ₄ ,
Melting of the cast-in-place material is more reliably prevented. When the hollow member is used as a to-be-filled material, the hollow member can be filled with the to-be-filled material while supplying a refrigerant.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Cast-in method is a casting method which is usually employed when the machining of a cast product is too complicated and the processing is costly or impossible. For this reason, it is common to mold the to-be-cast material into a required shape in advance,
A hollow member such as a hollow pipe having a predetermined curved shape is used as a material to be cast. Examples of the hollow member include an extruded material, a drawn material, an electric resistance welded tube manufactured from a plate material, and the like. Due to the method of manufacturing such a hollow member, the aluminum material used as the cast material is generally an aluminum alloy for drawing, and has a thickness of 1 to 3 in consideration of formability.
mm hollow material is common. On the other hand, cast-in insert materials are generally alloys for Al-Si castings having good melt flowability, alloys for Al-Cu castings having good strength, and A having good corrosion resistance.
It is selected from 1-Mg based casting alloys and the like.

[0008] A typical aluminum material used for a cast-in-place material and a cast-in material has a temperature characteristic as shown in Table 1. Therefore, in the present invention, based on the performance and the like required for a cast-in product, the cast-filled material and the casting material are set so that the solidification end temperature of the cast-in material becomes lower than the melting end temperature of the cast-filled material. Select the aluminum material used as the wrapping material.

[0009]

[0010] The selected cast-in-place material is set in a mold, and the molten cast-in-place material is poured into the mold. In particular,
As shown in FIG. 1, a to-be-stuffed material 5 is set in a mold 4 in which a cavity 3 communicates with a basin 2 via a runner 1. The molten metal of the cast-in material 6 is supplied to the basin 2 by the ladle 7, and sent into the cavity 3 through the runner 1. Alternatively, it may be supplied directly from the ladle 7 to the mold 4. The to-be-cast material 5 is backed up by a core 8 as necessary, and is secured at a predetermined position in the cavity 3. At this time, the temperature of the molten metal of the stuffed material 6 near the surface of the stuffed material 5 is T ₁ (° C.), the solidification end temperature of the stuffed material 6 is T ₂ (° C.), and the melting end temperature of the stuffed material 5 To T ₃
As (° C.), the pouring temperature of the as-cast material 6 is controlled in the range of (T ₂ + 5 ° C.) <T ₁ <T ₃ . If the temperature T ₁ of the melt of the stuffed material 6 does not reach (T ₂ + 5 ° C.), the flow of the molten metal is poor, voids and poor fusion occur, and a good stuffed product cannot be obtained. However, when the temperature T _{1 of} the molten metal exceeds the melting end temperature T ₃ of the material 5 to be cast, the material 5 to be cast partially melts. The temperature T ₁ of the molten metal is measured by a thermometer 9 provided in the cavity 3 so as to approach the material 5 to be cast.

In relation to the material 5 to be cast (T ₂ + 5 ° C.)
<T ₁ <T _{3 When the} as-cast material 6 whose temperature is controlled to T ₃ is brought into contact with the as-cast material 5, the as-cast material 5 and the as-cast material 6 are melted without causing melting of the as-cast material 5. It is integrated and a good cast-in product is obtained. Prior application (Japanese Patent Application No. 9-
27097), since the material 5 to be cast is not covered with a heat insulating material, the adhesion between the material 5 to be cast and the material 6 can be improved. When pouring the cast-in material 6 from the ladle 7 to the mold 4 directly, the ladle 7
The temperature of the cast-in material 6 inside is accurately controlled in operation.
After pouring the cast-in material 6 into the mold 4, the cast-in material 6 near the surface of the cast-to-be-molded material 5 set in the mold 4.
In order to adjust the molten metal temperature T ₁ within the range of (T ₂ + 5 ° C.) to T ₃ , it is effective to control the temperature of the cast-in material 6 in the pool 2. Based on the results of a number of investigations and studies, the present inventors have found that when the temperature of the cast-in material 6 of the pool 2 is controlled in the hatched area B of FIG. 2, the relationship of (T ₂ + 5 ° C.) <T ₁ <T ₃ Was found to be maintained.

The molten metal temperature T ₁ of the stuffed material 6 poured into the mold 4 depends on the overall shape and size of the stuffed product, the size of the mold 4, and the amount of the stuffed material 5 to be cast. It is determined by the heat capacity and the positional relationship between the cast material 5 and the mold 4. Qualitatively, when the stuffed portion of the stuffed product is thin and the heat release amount of the mold 4 is large, the stuffed material 5 hardly melts even at a high pouring temperature. Conversely, if the thickness of the cast-in product becomes thicker, the cast-to-be-filled material 5 is liable to be melted and damaged. This means
Variation due to thermal conditions of the surrounding molten metal temperature T ₁ of the insert casting material 6 is in the vicinity of the surface of the insert casting material 5 means affecting the how erosion of the insert casting material 5. In general,
As the distance from the surface of the to-be-molded material 5 to the inner surface of the mold 4 becomes shorter, the pouring temperature T of the as-molded material 6 poured into the mold 4 becomes smaller.
_{Even if 4} is high, no erosion occurs in the cast-in material 5. On the other hand,
When the distance from the surface of the insert casting material 5 to the inner surface of the mold 4 is long, it is necessary to lower the pouring temperature T ₄ in consideration of the thermal influence on the casting-material 5. The present inventors have this distance and pouring temperature T ₄ and where the relationship was investigated and examined in detail, melting of the insert casting material 5 effectively by establishing the specific relationship between the two Found to be suppressed.

According to an experiment conducted by the present inventors, the temperature T ₁ of the molten metal near the surface of the material 5 to be cast is set to the shaded area B in FIG.
Is in a preferable state in which no erosion occurs in the material 5 to be cast. However, the hatched area B is point A: (7, 70
5) B point: (40,673) C point: (7,645) D point: This is a rectangular area surrounded by (40,622).

In FIG. 2, the vertical axis represents the temperature of the molten metal in the pool 2 as the pouring temperature T ₄ (° C.) of the cast-in material 6 supplied to the mold 4. The horizontal axis represents the maximum value d (mm) of the shortest distance at each position of the cast product up to the mold 4. The maximum value d of the shortest distance is determined, for example, as follows. Corresponding to a target shape of the insert casting products varies with d ₁ to d _3, as shown in the distance of the insert casting material 5 in FIG. 3 in the product the position (A) ~ (C) with the inner surface of the mold 4 In the case, d ₃ > d ₂ > d ₁
, The distance d ₃ is taken as the maximum value d of the shortest distance. In the mold design of FIG. 1, the maximum value d of the shortest distance is taken at a position where the inclined portion of the material 5 to be cast faces the inner surface of the mold 4.

[0015] In region A of Figure 2, was measured the melt temperature T ₁ of the insert casting material 6 is in the vicinity of the surface of the insert casting material 5 in thermometer 9, the melt completion temperature T ₃ of the insert casting material 5 molten metal temperature T ₁ had become higher. On the other hand, in the area C,
Molten metal temperature T ₁ of the insert casting material 6 is too low, it can not be obtained satisfactory insert casting products. On the other hand, in the hatched area B, the molten metal temperature T ₁ was properly maintained, and it was found that the cast material 5 was cast with good adhesion. In addition, since the maximum value d of the shortest distance is hardly less than 7 mm or more than 40 mm in practical use, the maximum value d is selected in the range of 7 to 40 mm. Therefore, the shape of the stuffed product is determined, and the maximum value d of the shortest distance from the surface at each position of the material 5 to be cast to the inner surface of the mold 4 (corresponding to the surface of the stuffed product), in other words, the stuffed product If the maximum value of the thickness of the as-cast material 6 in the portion is known, a preferable pouring temperature T ₄ to the mold 4 can be selected in consideration of the material of the as-cast material 6 and the to-be-cast material 5. When the to-be-cast material 5 is thus stuffed, it becomes unnecessary to heat-insulate the to-be-stuffed material 5, so that the process is simplified and the manufacturing cost is reduced.

Under the above-described conditions, the hollow member used as the to-be-stuffed material 5 may be supplied with a refrigerant such as air or water, or the supply of the refrigerant may be omitted. In the case of supplying the refrigerant, the cost is increased, but the casting condition is eased because the to-be-cast material 5 is cooled. When casting under the conditions specified in the present invention, a material coated with a heat insulating material or an aluminum material having an oxide film artificially formed thereon can be used as the material to be cast. Adhesion is determined by applying a flux of several microns (specifically, 1 to
It can be further improved by coating with a thickness of 5 μm.
As the flux, potassium cryolite, for example, (KF +
AlF ₃ ), a fluorine-based flux of 50 to 60 mol% of AlF ₃ is used. The flux improves the adhesion by dissolving a thin aluminum oxide film formed on the surface of the to-be-cast material 5 and bringing the as-cast material 6 into contact with the active surface of the to-be-cast material 5.

When pouring the melt of the cast-in material 6 into the mold 4, it is preferable to preheat the mold 4 to 200 to 300 ° C. If the mold temperature is lower than 200 ° C., the solidification speed of the poured molten metal is too fast, and the flow of the molten metal becomes poor. Further, heat transfer between the mold 4 and the stuffed material 6 becomes unstable, and it is difficult to obtain a stuffed product having a fixed shape and quality. Conversely, if the mold temperature exceeds 300 ° C., it takes a long time to solidify the cast-in material 6 and the productivity decreases. To ensure good shape and quality of the cast-in product, it is preferable to adjust the solidification rate of the poured cast-in material 6 in the range of 0.5 to 10 ° C / sec.

[0018]

Embodiment 1 As insert material 6, Si: 7.2% by weight, Mg: 0.48% by weight, Fe: 0.15% by weight, C:
A containing u: 0.10% by weight and Sr: 0.007% by weight
1 alloy was melted in a melting furnace. After degassing, slagging, and refinement of eutectic Si with Sr, etc., 1.5 kg of the casting material 6 necessary for one casting operation was supplied to the pool 2 with a ladle 7. As the mold 4, a mold that can be separated into an upper mold 4 u and a lower mold 4 d and preheated to 200 to 300 ° C. was used.
After setting the lower mold 4d, the non-preheated to-be-cast material 5 was arranged at a predetermined position and was brought into contact with the core 8. The cast material 5 is made of 6063,3003 alloy and has an outer diameter of 6 mm.
A pipe having an inner diameter of 3 mm, an inner diameter of 3 mm, and a weight of 32 g was used. After placing the to-be-cast material 5, the upper mold 4u was clamped.
The formed mold cavity 3 has a height of 140 mm and a width of 2 mm.
50 mm and depth 150 mm. No coolant was supplied to the to-be-stuffed material 5.

The mold 4 and the basin 2 are inclined, and the basin 2
Then, the cast-in material 6 was fed into the cavity 3 via the runner 1. The pouring took about 25 seconds. It took about 1 minute for the cast-in insert 6 poured into the mold 4 to solidify, and the cooling rate at this time was about 1.7 ° C / sec. The temperature T ₁ of the molten metal of the stuffed material 6 was measured by the thermometer 9 at a position where the stuffed material 6 poured into the mold 4 was located near the surface of the stuffed material 5 to be cast. In addition, the thermometer 9 is a
Was placed at a position 1 mm away from the surface of the to-be-cast material 5 near the center.

The molten metal temperature T detected by the thermometer 9₁ And most
Influence of the maximum value d of the short distance on the erosion of the stuffed material 6
investigated. The survey results are shown in Table 2 and graphed in Figure 2.
Was. From Table 2, the melt temperature T₁ Is (T_Two + 5 ° C) <T₁ <T
_Three When the temperature is within the range, no erosion occurs in the material 5 to be cast.
I knew it. Samples 5, 12 to 14 have a molten metal temperature T ₁ 
Was too low, the run-off was poor and the product was poorly filled. Ma
In addition, as is apparent from FIG.₁ And the shortest distance
When the maximum value d of the separation is in the shaded area B in FIG.
It was found that no erosion occurred in the filler material 5. In contrast,
In the sample in which the stuffed material 5 has melted, the melt temperature T₁ But
(T_Two + 5 ° C) to T_Three Out of range or shortest distance
Is out of the shaded area B.

[0021]

[0022]

Example 2 The same conditions as in Sample Nos. 2 to 4 and 9 to 11 of Example 1 except that air was supplied to the pipe used as the to-be-stuffed material 5 at a flow rate of 0.1 m ³ / min by a suction method. Manufactured below under cast products. Observation of the resulting cast-in product showed that the cast-in material 6 was in close contact with the cast-in material 5 without any inferior flow of the molten metal.

[0023]

As described above, in the as-cast method of the present invention, the maximum value of the shortest distance from the surface of the as-cast material to the inner surface of the mold is adjusted in relation to the pouring temperature of the as-cast material. By adjusting the molten metal temperature of the as-cast material further in relation to the solidification end temperature of the as-cast material and the melting end temperature of the as-cast material, it is preferable to suppress the erosion of the as-cast material. Manufactures rich cast-in products. According to this method, there is no need to coat the high melting point metal or the heat insulating material on the to-be-cast material, so that the manufacturing process is simplified and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a cast-in method for pouring molten metal of a cast-in material into a mold in which a material to be cast is set.

FIG. 2 is a graph showing the effect of the maximum value of the shortest distance from the surface of the cast-to-fill material to the inner surface of the mold and the pouring temperature of the cast-to-fill material on the erosion of the cast-to-fill material.

FIG. 3 is a view for explaining the maximum value of the shortest distance from the surface of the material to be cast to the inner surface of the mold.

[Explanation of symbols]

1: runner, 2: pool, 3: cavity, 4: mold, 4u: upper mold, 4d: lower mold, 5: cast-molded material 6: cast-molded material, 7: ladle, 8: core,
9: Thermometer T _1: temperature of molten metal in the casting-material, T _2: the solidification completion temperature of the casting-material, T _3: the melting completion temperature of the casting-material, T _4: the insert casting material pouring temperature d: the the maximum value d ₁ to d of the shortest distance from the surface of the insert casting material to the mold inner surface _3: the shortest distance from the surface of the insert casting material in the position to mold the inner surface

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kaoru Sugita 2-20 Higashishinagawa, Shinagawa-ku, Tokyo Japan Light Metal Co., Ltd. (56) References JP-A-8-215829 (JP, A) JP JP-A-3-142057 (JP, A) JP-A-3-142058 (JP, A) JP-A-3-18961 (JP, A) JP-A-60-184460 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) B22D 19/00

Claims (2)

(57) [Claims] (1) setting a stuffed aluminum alloy material in a mold;
When casting with aluminum alloy forgings,
Maximum value of the shortest distance from the surface of the cast-in material to the inner surface of the mold
Is d (mm), the pouring temperature of the cast-in material poured into the mold
When to the T _4, the maximum value d and poured temperature T ₄ in FIG. 2 swash
A method for producing a cast aluminum product maintained in the line area B. Was
However, points I to D in FIG. 2 are indicated by the following coordinates, respectively.
You. Point A: (7,705) Point B: (40,673) Point C: (7,645) Point D: (40,622) 2. A method for setting an as-cast aluminum alloy material in a mold.
When casting with aluminum alloy forgings,
The temperature of the molten metal of the insert near the surface of the insert is T
₁ (° C), the solidification end temperature of the as-cast material is T ₂ (° C),
When the melting end temperature of the loose material is T ₃ (° C.), (T ₂
+ 5 ℃) <T ₁ <molten metal temperature of as insert casting material becomes T ₃
Adjust T _1, and the mold inner surface or from the surface of the insert casting material
The maximum value of the shortest distance at d (mm) is poured into the mold
When the pouring temperature of the cast-in material is T ₄ , the maximum value d and
Pouring temperature T ₄ of the aluminum castings and tool for maintaining the hatched region B in FIG. 2
Manufacturing method of lump products . However, the points I to D in FIG.
Show. Point A: (7,705) Point B: (40,673) Point C: (7,645) Point D: (40,622)