JPH03285739A - Vertical split copper alloy mold for casting iron - Google Patents

Abstract

PURPOSE:To reduce the shock of molten metal to projecting parts or pocket parts in a cavity and to prolong the service life of a metallic mold by specifying cross sectional thickness and width size of a vertical split copper alloy mold and boring a sprue over the part from the upper end part to the lower position of the mold. CONSTITUTION:In the center part of the vertical split copper alloy mold D, the sprue 1 which is made to <=6mm thickness size in the cross section and of which the width size is made to 5-10 times the thickness size is bored over the part from the upper end part to the lower position of mold. As the molten metal poured into a sprue cup 2 has large contacting area with the metallic mold at the sprue 1 part, the flowing down velocity is controlled and the molten metal is allowed to flow into the cavity 4 through runners 3. As the molten metal flow is controlled, the colliding shock of molten metal to the pocket part in the cavity 4 is reduced, and by reducing erosion at this part and the development of cracking at the sprue bottom 6, the service life of metallic mold is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vertical split copper alloy mold for so-called cast iron mold casting, in which cast iron is cast using a mold.

(Prior art and problems) Conventionally, vertically split copper alloy molds (10
) When mold casting of cast iron is performed using a mold (10), the sprue (11) of the mold (10) is generally a round bar-shaped hole with a diameter of about 20 m.

In casting using such a sprue (11), the sprue cup (
The molten metal injected into the runner (12) is flowed down at high speed into the runner (1
3) and the cavity (14) through the weir not shown.
The molten metal flows into the cavity at high speed, but the molten metal flows from the weir into the cavity (
14) If the flow directly collides with a protrusion or island in the cavity (14) (for example, the island shown in Figure 3), the protrusion or island may be melted (15).
There was a fatal problem that the life of the mold was shortened (less than 5,000 shots) due to severe cracking and cracks occurring at the bottom of the sprue (16). It was created with the purpose of solving the problem of

(Progress of the Invention) In order to achieve the above object, the inventors conducted various tests on the sprue shape of a vertically split copper alloy mold.

An example of this is shown in Figure 8.9.
The shape and number of sprues (4) are the same as those in Fig. 1.2, and the diameter of the sprue is about iomm, and two sprues are installed so that the cross section is the same as that of the conventional sprue (11). ，
A) As a result of performing the pouring test l- as (1, 1, A,), the mold life was extended to about 1.0,000 shots, but it was still not satisfactory, so various tests were continued. As a result, by adopting the configuration described in the next section "Means for Solving Problems", it has become possible to extend the life of the mold to 35,000 shots or more.

(Means for solving the problem) In order to achieve the above object, the vertically split copper alloy mold for cast iron casting according to the present invention has a cross-sectional thickness of 6 mm or less and a width of 6 mm or less. It is characterized by having a sprue 5 to 10 times larger in size and having a sprue extending from the two ends to the lower part.

(Function) By adopting the above-described configuration, the present invention allows the molten metal poured into the sprue cup to flow down with the flow rate controlled by the sprue, thereby reducing the collision impact of the molten metal. As a result, the life of the mold can be greatly extended by suppressing the occurrence of protrusions in the cavity, melting damage of the partitions, cracks at the bottom of the sprue, etc.

(Example) Hereinafter, an example of the present invention will be explained with reference to FIGS. 4 to 6. In the center part of the vertically split silver alloy mold (D), the thickness dimension (1) of the cross section is 6 nm or less. and width dimension (w)
A sprue (1
) is perforated from the upper end to the lower position.

Note that the sprue (1), not shown in FIG. 4, has a tapered shape that becomes continuously narrower from the upper end toward the lower position. Other components such as the hot water cup (2), runner channel (3), KiA bitty (4), and sprue bottom (6) are the same as those in Figure 1.

When mold casting of cast iron is performed using the vertically split silver alloy mold (D) configured in this way, the molten metal poured into the sprue cup (2) will meet the mold at the sprue (1). Because the contact area becomes larger, the flow rate is controlled and flows down the runner (
3) The flow of the molten metal flows into the cavity (4) via a weir (not shown), but since the flow of the molten metal is controlled, the collision impact of the molten metal against the partition of the cavity (4) is minimized to prevent the melting of this part. It was possible to significantly reduce the loss and reduce the occurrence of cracks in the sprue bottom (6), thereby significantly extending the life of the mold (from 35,000 shots 1 to 2).

The sprue (1) may have a shape that gradually becomes narrower from the upper end toward the lower position, as shown in FIG. In this case, the impact from the head of the molten metal injected into the sprue cup (2) against the lower cavity (4) is weakened once at the point where it becomes narrower in stages.
), the impact of the molten metal can be made even smaller.

Furthermore, since the flow velocity of the molten metal is controlled even if the width of the molten metal (1) is the same throughout from the top end to the bottom position, the collision impact of the molten metal can be reduced in almost the same way as the above. I also understood.

(Effects) As is clear from the above description, the present invention is a vertically split copper alloy mold with a specially constructed sprue in the form of a thin plate, so the molten metal poured into the sprue cup flows down at a controlled flow rate. This has the excellent effect of reducing the impact of the molten metal on the protrusions or partitions in the cavity and greatly extending the life of the mold.

[Brief explanation of drawings]

Fig. 1 is a front view showing a conventional vertical split copper alloy mold, Fig. 2 is a plan view of the same, Fig. 3 is a view taken along arrow AA in Fig. 1, and Fig. 4
7 and 7 are front views showing the vertically split copper alloy mold of the present invention, FIG. 5 is a plan view of the same, FIG. 6 is a view taken along the line B-B in FIG. 4, and FIG. FIG. 9 is a front view showing the vertically split copper alloy mold devised in the process. (1): Sprue (2): Sprue cup (3): Runway (4): Cavity (6): Sprue bottom 4 Figure

Claims (1)

[Claims] 1) The thickness of the cross section is 6 mm or less, the width is 5 to 10 times the thickness, and a sprue is bored from the upper end to the lower part. 2) The vertically split copper alloy mold for casting cast iron according to claim 1, wherein a sprue is bored whose width becomes continuously narrower from the upper end toward the lower position. Mold 3) The vertically split copper alloy mold for cast iron casting according to claim 1, wherein a sprue is formed in which the width dimension gradually narrows from the upper end toward the lower position.