JP2010131612A - Pipe casting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe casting method by which, even when a pipe is cast by a die casting method, the matter filled into the pipe is satisfactory discharged. <P>SOLUTION: In the pipe casting method by which a pipe 1 filled with artificial sand is arranged inside the cavity 12 of a die casting mold 10 and then a molten metal is filled into the cavity 12, the inner circumferential face of the pipe 1 is coated with a water glass-like coating material before the pipe 1 is filled with the artificial sand. The artificial sand is spherical one with a grain size distribution of 30 to 1,180 μm, and the surface of the artificial sand is coated with a lubricant before being filled into the pipe 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for casting a pipe, and more particularly, to a method for casting a pipe in which a pipe filled with a filler such as sand is placed in a cavity of a mold and then a molten metal is filled into the cavity.

As a method of forming a cast product having a hollow portion such as a passage for circulating a cooling medium, a sand-filled pipe is placed in the cavity of the mold as described in Patent Document 1 below. A method of filling a molten metal is known.
Japanese Utility Model Publication No. 7-3857

  However, when the casting method of this pipe is performed by the die casting method, the pipe disposed in the die casting mold is deformed even if it is minute by the molten metal pressure, so that the sand filled in the pipe bites into the inner wall of the pipe, There is a problem that even when trying to discharge sand from the pipe, it cannot be discharged sufficiently. Since the inside of the product pipe is used as a passage through which a cooling medium flows, etc., if sand remains in the pipe, the product may be defective.

  Therefore, the present invention has been made in view of the above-mentioned conventional problems, and provides a method for casting a pipe with good dischargeability of a filler such as sand filled in the pipe even when the pipe is cast by a die casting method. Is an issue.

  The present invention has been made to solve the above-mentioned problems, and a pipe casting method according to the present invention is a method in which a pipe filled with a filler is placed in a cavity of a die-casting mold, and then a molten metal is placed in the cavity. In the method of casting a pipe that fills the pipe, a water glassy coating material is applied to the inner peripheral surface of the pipe before filling the pipe with the filler.

  The filler is a spherical substance having a particle size distribution of 30 to 1180 μm, and it is preferable that a lubricant is applied to the surface of the filler before filling the pipe.

  The filler is preferably artificial sand mainly composed of synthetic mullite.

  According to the pipe casting method of the first aspect of the present invention, since the water glassy coating material is applied to the inner peripheral surface of the pipe before filling the pipe with the filler, the pipe is cast by the die casting method. Even in such a case, it is possible to prevent the product from being defective due to the good dischargeability of the filling from the pipe and the filling remaining in the pipe. Moreover, since the surface roughness of the inner peripheral surface of the pipe can be reduced, the circulation of the cooling medium in the pipe can be improved when the inside of the product pipe is used as a passage through which the cooling medium flows. .

  According to the pipe casting method of the second and third aspects of the present invention, the filler is a spherical object having a particle size distribution of 30 to 1180 μm, and the surface of the filler is lubricated before being filled into the pipe. Since the agent is applied, the dischargeability of the filler from the pipe can be further improved.

  A method for casting a pipe according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the pipe 1 in a state where the filling filling process is completed, and FIG. 2 is a front view of the fixed die 11 in a die open state of the die casting die 10.

  The pipe casting method includes a lubricant application step of applying a lubricant while stirring the artificial sand 2 as a filler, a pipe processing step of applying heatless glass to the inner peripheral surface 1a of the pipe 1, and an artificial sand 2 Filling process for filling the pipe 1, pipe placement process for placing the pipe 1 in the cavity 12 of the die casting mold 10, and melt filling process for casting the pipe 1 by filling the cavity 12 with the molten metal And a filling material discharging step of discharging the artificial sand 2 from the pipe 1 of the product taken out from the die casting mold 10.

  First, a lubricant application process is performed. In the lubricant application step, the lubricant is applied while stirring the artificial sand 2 with a mixer. Artificial sand 2 is a spherical material mainly composed of synthetic mullite. Specifically, it is a spherical material mainly composed of synthetic mullite of 40 to 90% by weight of alumina and 60 to 10% by weight of silica, and has a particle size of 30 to 1180 μm. It has a distribution, and has a surface area (cm 2 / cm 3) per unit volume in the range of 60,000 / d to 1,800,000 / d (d is the average particle diameter (μm) of the spheres). Since this artificial sand 2 has a round particle size and a shape close to a true sphere, the fluidity is very excellent. As the lubricant applied to the artificial sand 2, it is preferable to use a lubricant containing a solid lubricant powder such as molybdenum disulfide or graphite. By applying the lubricant while stirring the artificial sand 2 with a mixer, the lubricant can be uniformly applied to the surface of the artificial sand 2 which is a spherical object. In this way, by applying a lubricant to the surface of the artificial sand 2, the slip of the artificial sand 2 can be improved, and the discharge performance of the artificial sand 2 in the filling discharge process described later is improved. Can do. The artificial sand 2 corresponds to a filler.

 Next, a pipe processing step is performed. The pipe 1 to be used is, for example, an aluminum alloy pipe having a wall thickness of 2.0 mm and an outer diameter of 40 mm. In the pipe processing step, a water glassy coating material (a room temperature glass coating material for forming a hard glassy film) is applied to the inner peripheral surface 1 a of the pipe 1. In this way, by applying a water glassy coating material to the inner peripheral surface 1a of the pipe 1 before the filling filling process described later, the molten metal is filled into the cavity 12 in the molten metal filling process described later. The hard sandy film formed on the inner peripheral surface 1a of the pipe 1 can prevent the artificial sand 2 from coming into contact with the inner peripheral surface 1a of the pipe 1 due to the pressure of the molten metal.

  Next, a filling material filling step is performed. In the filling process, a pipe-shaped aluminum alloy lid 3 is fitted into one opening 1b of the pipe 1 by screwing or press-fitting, and then the artificial sand 2 is poured from the other opening 1b. Fill inside. When the artificial sand 2 has been filled into the pipe 1, the lid 3 is fitted into the other opening 1 b of the pipe 1. A cross-sectional view of the pipe 1 after the filling filling process is completed is as shown in FIG. 1, and the water glassy coating is formed between the inner peripheral surface 1a of the pipe 1 and the artificial sand 2 in the pipe processing process described above. A hard glassy film (not shown) is formed by applying the material.

  Next, a pipe placement process is performed. As shown in FIG. 2, the die casting mold 10 has a fixed mold 11, and a movable mold (not shown) is clamped to the fixed mold 11. In the pipe arranging step, first, both ends of the pipe 1 are held by the recesses 13 formed in the fixed mold 11 in a mold open state in which a movable mold (not shown) is separated from the fixed mold 11. Next, the movable mold (not shown) is brought close to the fixed mold 11 and clamped, and both ends of the pipe 1 are held also by concave parts (not shown) formed in the movable mold. By this pipe arrangement process, the pipe 1 is arranged in the cavity 12 of the die casting mold 10.

  Next, a molten metal filling process is performed. As shown in FIG. 2, the fixed mold 11 is provided with a sleeve 14, and a runner is moved by moving a plunger tip (not shown) made of a molten metal (not shown) made of an aluminum alloy fed into the sleeve 14. 15 is injected and filled into the cavity 12. Regarding the casting conditions, the injection speed of the plunger tip was 1.8 m / s, and the casting pressure was 60 MPa.

  After the molten metal in the cavity 12 is solidified, the movable mold (not shown) is separated from the fixed mold 11 and opened, and the molded die cast product is taken out from the die casting mold 10. Finally, a filling discharge process is performed. In the filling discharge process, the artificial sand 2 is removed from the end opening of the pipe 1 by cutting the portion where the lid 3 is fitted at both ends of the pipe 1 or by screwing the lid 3 from both ends of the pipe 1. Is discharged. In the present embodiment, artificial sand 2 bites into the inner peripheral surface 1a of the pipe 1 by a hard glassy film by applying a water-glassy coating material to the inner peripheral surface 1a of the pipe 1 in the pipe processing step. In the lubricant application step, the slipperiness of the artificial sand 2 is improved by further applying a lubricant to the spherical artificial sand 2 having excellent fluidity. The discharge of the artificial sand 2 is very good. Therefore, it is not necessary to apply vibration to the product to discharge the artificial sand from the pipe 1 or to prick out the artificial sand 2 from the pipe 1, and the artificial sand 2 from the pipe 1 only by its own weight. Can be dropped naturally and discharged.

  The surface roughness of the inner peripheral surface 1a of the pipe 1 after performing the filling discharge process was 19.1 μm in Rz, but this is only the fact that no water glassy coating material is applied to the inner peripheral surface of the pipe. In the pipe casting method different from the embodiment, the surface roughness of the inner peripheral surface of the pipe after the filling discharge process was 25.4 μm in Rz. By applying a water glassy coating material to the inner peripheral surface 1a of the pipe 1 as in this embodiment, the artificial sand 2 is prevented from biting into the inner peripheral surface 1a of the pipe 1 by a hard glassy film. Therefore, the surface roughness of the inner peripheral surface 1a of the pipe 1 after performing the filling discharge process can be reduced. Therefore, when the inside of the product pipe 1 is used as a passage through which a cooling medium such as cooling water flows, the circulation of the cooling medium in the pipe 1 can be improved.

  The present invention is not limited to the above-described embodiments, and various improvements and modifications can be made within the scope described in the claims. For example, in the above-described embodiment, the pipe treatment process is performed after the lubricant application process, but the pipe treatment process may be performed before the lubricant application process.

  In the above-described embodiment, the filler is the artificial sand 2 mainly composed of synthetic mullite, but is not limited thereto. A spherical substance having heat resistance and having a particle size distribution of 30 to 1180 μm may be used as the filler.

It is sectional drawing which shows the state which the filling filling process of the pipe which concerns on this embodiment was completed. It is a front view of the fixed mold | type in the mold opening state of the die-casting mold which concerns on this embodiment.

Explanation of symbols

1 Pipe 1a Inner peripheral surface 2 Artificial sand (filler)
3 Lid 10 Die-casting die 11 Fixed die 12 Cavity 13 Recess 14 Sleeve 15 Runner

Claims (3)

  In a method of casting a pipe in which a pipe filled with a filler is placed in a cavity of a die-casting mold and then the molten metal is filled into the cavity, an inner peripheral surface of the pipe before filling the pipe with the filler A method for casting a pipe, characterized in that a water glassy coating material is applied to the pipe.   2. The filler according to claim 1, wherein the filler is a sphere having a particle size distribution of 30 to 1180 [mu] m, and a lubricant is applied to the surface of the filler before filling the pipe. Pipe casting method.   3. The pipe casting method according to claim 2, wherein the filler is artificial sand mainly composed of synthetic mullite.

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