JP2002079363A - Low velocity high pressure casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low velocity high pressure casting method with which such fear as to spout out molten metal from the mating surfaces of metallic molds and a mating surface with a core, etc., is not developed only by fastening the metallic molds with the ordinary fastening force even in the case of not manufacturing the metallic mold so high precision. SOLUTION: In the low velocity high pressure casting method, with which after filling up the molten metal into a cavity 2, the molten metal M in the cavity, is pressurized at the low velocity and the high pressure with a pressurizing element 5 and cast, the casting pressure with the pressurizing element is divided into few times and discontinuously loaded, and firstly, the pressurization is applied with such degree of the casting pressure as not to spout out the molten metal from the mating surfaces of the metallic molds, and after solidifying the outer peripheral portion of the molten metal in the cavity in such degree as not to spout out from the mating surfaces of the metallic molds, the pressurization is applied with further higher casting pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a molten metal inlet provided in a middle part of a runner leading to a cavity, and a pressurizer is provided in the runner so as to be able to advance and retreat toward the cavity. The present invention relates to a casting method called low-speed high-pressure casting in which a molten metal in a cavity is cast at a low speed and a high pressure by a pressurizer after being filled with a low pressure, and more particularly to a control of a casting pressure.

[0002]

2. Description of the Related Art Products cast by a low-speed high-pressure casting method have almost no casting cavities (pinholes), have a clean casting surface and have excellent dimensional accuracy, and at the same time, have a finer structure and improved mechanical properties. There are excellent features such as. However, if the casting pressure is set high to exert the above features, the mold is made with high precision so that there is no distortion or gap in the mating surface of the fixed mold and the movable mold, and the mold is formed with a considerably strong mold. If it is not tightened by the tightening force, there is a risk that the molten metal will blow out from the mating surface of the mold, the core mating surface and the like.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. Even when the mold is not made with high precision, the mold is subjected to a normal clamping force. It is an object of the present invention to provide a low-speed and high-pressure casting method in which the molten metal does not blow out from the mating surface of the mold or the core mating surface by simply tightening the mold.

[0004]

According to the present invention, there is provided a low-speed and high-pressure casting method according to the present invention, in which a molten metal inlet is provided in a middle part of a runner leading to a cavity, and a pressurizer is moved toward and away from the cavity in the runner. In a low-speed and high-pressure casting method, the pressurizing element is arbitrarily provided, and the molten metal in the cavity is filled at a low pressure from the molten metal inflow port at a low pressure, and then the molten metal in the cavity is pressurized at a low speed and a high pressure by the pressurizing element. The casting pressure is divided into several batches and applied discontinuously.At first, the casting pressure is such that the molten metal does not blow out from the mating surface of the mold, and then the outer peripheral portion of the molten metal in the cavity is blown from the mating surface of the mold. It is characterized in that when it is solidified to the extent that it does not come out, it is pressurized with a higher casting pressure.

[0005]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The drawings show an example of a mold apparatus for performing the low-speed and high-pressure casting method according to the present invention, and do not limit the present invention.

Reference numeral 1 in the figure denotes a mold (fixed mold side).
A cavity 2 for molding a product and a runner 3 communicating with the cavity 2 are formed, a melt inlet 4 is formed in the middle of the runner 3, and a pressurizer 5 is provided in the runner 3. It is provided to be able to advance and retreat toward the gate section 6.

The runner 3 guides the molten metal supplied from the molten metal supply pipe 7 connected to the molten metal holding furnace to the cavity 2. The molten metal supply pipe 8 communicates with the molten metal supply pipe 7 through the molten metal supply port 8 to the cavity 2. Formed over the sprue 6. A melt inlet 4 is formed in the middle of the runner 3, and a pressurizer 5 is provided to open and close the melt inlet 4 so as to advance and retreat toward the gate 6 of the cavity 2.

The pressurizing element 5 is for applying a casting pressure to the molten metal M filled in the cavity 2, and has a pressurizing cylinder 10 attached via a bracket 9 to a lower part of a mold (fixed mold side) 1. And a sleeve 11 formed on a mold (fixed mold side) 1 is provided so as to be able to advance and retreat toward the gate 6 of the cavity 2. On this occasion,
The top dead center of the pressurizer 5 is set in the spout 6 of the cavity 2, the bottom dead center is set in a position directly below the molten metal inlet 4, and the position of the spout 6 in the cavity 2 and the position directly below the molten metal inlet 4 are set. It is preferable to perform the reciprocating operation between them.

Thus, when casting a product, the mold 1
After the mold is clamped, the molten metal is supplied from the molten metal supply pipe 7 into the cavity 2 through the molten metal supply port 8 → the runner 3 → the molten metal inlet 4 → the gate 6 at a low pressure (about 0.01 MPa to 0.1 MPa). To charge. Thereafter, the pressurizing cylinder 10 is operated to move the pressurizer 5 toward the gate 6 of the cavity 2 at a low speed (0.05 m / sec to 0.2 m / sec) and a high pressure (about 80 MPa to 140 MPa). By operating, the molten metal M filled in the cavity 2 is pressurized and cast.

At this time, the casting pressure by the pressurizing element 5 is discontinuously applied several times (about two to three times).
That is, at the beginning (first stage), the casting pressure is such that the molten metal in the cavity 2 does not blow out from the mating surface of the mold or the like, specifically, about 30 MPa to 60 MPa, and the pressure is increased for t time (about 1 hour). After 5 seconds), when the outer peripheral portion of the molten metal M in the cavity 2 is solidified to the extent that it does not blow out from the mating surface of the mold, then (as the second stage) a higher casting pressure, specifically 100
A pressure of about MPa to 200 MPa is applied (see FIG. 2).

[0011]

The low-speed and high-pressure casting method according to the present invention has
In a low-speed and high-pressure casting method in which the molten metal in the cavity is cast at a low speed and a high pressure with a pressurizer after the cavity is filled with the molten metal, the casting pressure by the pressurizer is applied discontinuously in several times. Initially, pressurize at a casting pressure that does not allow the molten metal to blow out from the mating surface of the mold, and then pressurize at a higher casting pressure when the outer peripheral portion of the molten metal in the cavity solidifies so as not to blow out from the mating surface of the mold. Because it was
Even when the mold is not made with such high precision, there is no fear that the molten metal will blow out from the mating surface of the mold, the core mating surface and the like only by tightening the mold with a normal mold clamping force. Therefore,
In low-speed, high-pressure casting, the casting pressure that can be set is not affected by the quality of the mold, making it possible to apply high casting pressure to the molten metal in the cavity regardless of the mold quality. In addition, the manufacturing cost of the mold can be reduced. In addition, a product with less casting burrs can be cast.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of a mold apparatus for performing low-speed and high-pressure casting according to the present invention.

FIG. 2 is a graph showing a pressure curve of casting pressure according to the present invention.

FIG. 3 is a graph showing a pressure curve of a conventional casting pressure.

[Explanation of symbols]

 1: mold 2: cavity 3: runner 4: melt inlet 5: pressurizer 6: gate 7: melt supply pipe 8: melt supply port 9: bracket 10: pressurized cylinder 11: sleeve M: melt

Claims (1)

[Claims] 1. A molten metal inflow port is provided in a middle part of a runner leading to a cavity, and a pressurizer is provided in the runner so as to be able to advance and retreat toward the cavity, and the molten metal is filled into the cavity from the melt inflow port at a low pressure. In a low-speed high-pressure casting method in which the molten metal in the cavity is cast at a low speed and a high pressure by the above-mentioned pressurizer later, the casting pressure by the pressurizer is discontinuously divided into several times, and the molds are first aligned. Pressing at a casting pressure that does not allow the molten metal to blow out from the surface, and then pressurizing at a higher casting pressure when the outer peripheral portion of the molten metal in the cavity solidifies so as not to blow out from the mating surface of the mold. Low speed high pressure casting.