JP3153458B2 - Lower plate for slide gate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower plate for a slide gate for adjusting a flow rate of a molten metal.

[0002]

2. Description of the Related Art When a molten metal is poured from a ladle, a tundish, or the like into an upper casting mold or a lower casting mold, it is necessary to adjust the flow rate of the molten metal. Conventionally, flow rate adjustment is performed by a nozzle stopper method or a slide gate method.

The nozzle stopper system is a system in which a stopper is moved up and down above a through hole of a nozzle to control a flow rate. In this method, the flow rate can be adjusted relatively easily, but on the other hand, since the stopper and its supporting member are immersed in the molten metal for a long time, problems are likely to occur in the pressure resistance and durability of these members.

[0004] On the other hand, the slide gate system is a system in which the flow rate is adjusted by sliding two gates to change the opening of the through-flow opening. This method has excellent characteristics that can withstand long-time casting, and has recently been used frequently in place of the nozzle stopper method.

[0005]

There are a wide variety of castings manufactured by pouring a molten metal into a mold, ranging from one kilogram to several tons. As shown in FIG. 6, there are many molds for products of about one kilogram that are manufactured in several tens at the same time.

When a molten metal is injected into such a mold by a slide gate method, products having defects due to air bubbles on the surface or inside of the product sometimes occur frequently. This is thought to be because the molten metal flowing out of the lower nozzle became a vortex and a flow velocity and entrained a large amount of air.

In particular, in the early stage of the injection, the flow rate of the molten metal flowing out of the lower nozzle is high, and the entrainment of air due to the eddy current / flow rate and scattering of the droplets becomes severe, and product defects are likely to occur.
Further, if the injection is completed before the air in the mold is completely removed, more product defects will occur.

In view of the problems of the prior art described above, the present invention provides a lower plate for a slide gate for producing a cast product in which air entrainment due to eddy currents and flow velocities is suppressed and product defects due to air bubbles are reduced. It is intended to be.

[0009]

A solution of the present invention is a lower plate for a slide gate according to the above-mentioned claims 1-4.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The lower plate for a slide gate according to the present invention has a configuration in which a vortex / velocity suppressing recess is provided adjacent to a sliding surface side of a through-hole serving as a flow path of a molten metal. The eddy current / velocity suppressing recess has a bottom portion, and the rectification is performed by reducing the flow speed of the molten metal by the bottom portion, thereby suppressing the eddy current / flow speed.

[0011] In this specification, rectifying molten metal means preventing or suppressing eddy currents and flow velocities.

The bottom of the vortex / velocity suppressing recess has a flat portion, and the flat portion has a flow passage cross-sectional area of 0.2 to 0.2 mm.
It is preferable to have about seven times the area.

If the area of the flat portion is less than the minimum value, it is not possible to obtain a sufficient vortex / flow velocity suppressing effect.
On the other hand, if the area of the flat portion exceeds the maximum area, erosion due to the rectifying action becomes severe, and the life of the lower plate may be shortened.

A part or most of the molten metal that has flowed downward through the through-hole of the upper plate of the slide gate,
It hits a flat part at the bottom of the recess, which leads to a rectification of the molten metal.

The distance (B) between the bottom end of the vortex / velocity suppressing recess and the through-hole can be 0.2 to 0.5 times the diameter of the through-hole. Further, the distance (A) between the upper end of the vortex / flow velocity suppressing recess and the through-hole can be 1 to 1.5 times the distance (B).

The distances (B, A) may be a representative length at the bottom of the recess and a representative length at the top.

As described above, by forming the eddy current / velocity suppression recess into a shape that is open at the top, the side surface of the recess becomes oblique (or funnel-shaped), so that the bottom can be more appropriately hit against the flat portion. It is possible to make it. As a result, the effect of suppressing eddy currents and flow velocities can be further improved.

The vortex / velocity suppressing recess is formed in a frustum-like shape, the through-hole diameter is D, the distance between the upper end of the vortex / velocity suppressing recess and the through-hole is A, and the bottom end is the through-current. When the distance from the hole is B, the radius of curvature of the upper part of the eddy current / velocity suppressing recess is 10 mm or more and {(3/4) × D + A} / 2 or less, and the bottom of the eddy current / velocity suppressing recess is Radius of curvature of 10
mm and {(3/4) × D + B} / 2 or less. By forming the eddy current / velocity suppressing recess with such a dimension and shape, the rectification efficiency can be improved while maintaining the service life.

The depth of the vortex / velocity suppressing recess is 10
mm or more and １ ／ or less of the plate thickness. By forming the eddy current / velocity suppressing recess at this depth, it is possible to improve the rectification efficiency while maintaining the service life.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing one embodiment of a slide gate lower plate according to the present invention, and FIG. 2 is a sectional view thereof.

The lower plate 11 has a through hole (through hole) 12 which serves as a passage for the molten metal. The periphery of the through-hole 12 protrudes to the opposite side of the sliding surface and is thick. Other parts have a uniform thickness T. The through-hole diameter is D.

On the sliding surface side 15 of the lower plate 11, a vortex / velocity suppressing recess 13 is formed adjacent to the through hole 12.

The vortex and flow suppression recess 13 has a substantially flat bottom 14. The bottom 14 has a curvature R at the right end.
2 and it extends straight from there to the through hole. The distance B from the right end of the bottom portion 14 to the through hole 12 is 0.2 to 0.5 times the diameter D of the through hole 12.

The curvature R2 is 10 mm or more and Δ (3 /
4) It is determined to be equal to or less than × D + B｝ / 2.

The bottom 14 is substantially perpendicular to the axial direction of the through-hole, ie substantially horizontal. However, as long as the flow of the molten metal can be rectified, it may be inclined by about 20 degrees from horizontal.

The area of the bottom 14 is about 0.2 to 0.7 times the cross-sectional area of the through hole.

The vortex / velocity suppressing recess 13 is open upward, and the right side surface is inclined. Therefore,
The cross-sectional area of the flow passage of the recess 13 becomes smaller as it approaches the bottom 14, and the flow is restricted. Therefore, the rectifying action can be further improved.

The distance A from the upper right end of the recess 13 to the through hole 12 is 1 to 1.5 times the distance B. Also,
The depth C of the recess 13 is 10 mm or more and the lower plate 11
Is less than half the thickness T.

The upper right side of the recess 13 has a semicircular shape with a curvature R1. From there, the through hole 12 is straight. The curvature R1 is 10 mm or more and ｛(3 /
4) It is set to less than × D + A｝ / 2.

The boundary between the bottom 14 and the side surface of the recess 13 may be curved so as to make a smooth transition.

FIG. 5 is an explanatory view conceptually showing a rectifying operation (a vortex / flow velocity suppressing operation) using the recess 13. The vortex and the flow velocity X flowing through the through-hole in the upper plate are
The flow Y is decelerated and straightened by hitting the bottom portion 14 of the flow velocity suppressing recess, and becomes a flow Y having a small vortex component, and exits from the lower nozzle 30.

Next, another embodiment of the slide gate lower plate of the present invention will be briefly described with reference to FIGS.

In this embodiment, the eddy current / velocity suppressing recess 23
Is the curvature R1 at the bottom boundary of the recess 23.
It is significantly larger than 2.

Also in this embodiment, the cross-sectional area of the flow passage of the recess 23 becomes smaller as it approaches the bottom 24.

The values of A, B, C, R1 and R2 were set as shown in Table 1 to produce Examples 1 to 3 of the present invention, and a pouring test was conducted together with Comparative Examples 1 to 6. Note that Comparative Example 1 is an example in which a vortex / velocity suppression recess is not provided. The diameter of the through hole is 3
0 mm and the plate thickness was 40 mm.

The state of the pouring test in Example 1 is shown in FIG. FIG. 8 shows a pouring test of Comparative Example 1.
FIG. 6 is a cross-sectional view of the mold 40 used in the pouring test. Arrow M indicates the flow of the molten metal, and arrow A indicates the state of degassing.

The results of the pouring test are shown in Table 1. here,
A defective product means a product having a defect due to air bubbles on the surface or inside of the product due to air entrapment or insufficient deaeration of air in the mold.

Hereinafter, the test results will be compared.

The occurrence rate of non-repairable defective products in Examples 1 to 3 was reduced to about 1/3 to 1/2 of Comparative Example 1. Therefore, it was confirmed that the defective product occurrence rate can be reduced by forming the eddy current / flow velocity suppressing recess.

Examples 1 and 2 and Comparative Examples 2 and 5 are compared.
In Comparative Example 2 in which the dimensions of A and B are small, the rejection rate is improved, but it is only 2/3 that of Comparative Example 1.
It was not a significant decrease. . On the other hand, in Examples 1 and 2, the defective product occurrence rate was greatly reduced, and the effect of providing the recess was confirmed. In Comparative Example 5, in which the dimensions of A and B were large, the rate of defective products could be reduced, but the edge of the plate through-hole had a large melting loss and the life of the plate was shortened.

Examples 1 and 3 are compared with Comparative Examples 3 and 6.
In Comparative Example 3 in which the dimension of C was small, the defective product occurrence rate was about 1 /
3, the effect of providing the recess was observed. However, if the recess is shallow, the path through which the molten metal flows downward becomes narrow, so that the upper plate operating surface that is in contact with the through-hole of the lower plate is greatly melted and the life of the upper plate is shortened. In Examples 1 and 3, the defective product occurrence rate was reduced, and the effect of providing the recess was confirmed. On the other hand, in Comparative Example 6 in which the dimension of C was large, the defective product occurrence rate was slightly lowered, but the erosion at the edge of the plate through hole was large.

Example 1 and Comparative Example 4 will be compared. R1 and R
In Comparative Example 4 in which the size of No. 2 was large, the reject rate was equal to that of Example 1, but the erosion of the edge portion of the recess was large,
It was found that the life of the plate was shortened.

[0044]

[Table 1]

[0045]

According to the slide gate lower plate of the present invention, it is possible to reduce the outflow speed of the molten metal and to straighten the molten metal flowing out from the lower nozzle, and to reduce the product yield due to entrapment of air bubbles. Can be improved.

[Brief description of the drawings]

FIG. 1 is a top view showing an embodiment of a lower plate for a slide gate according to the present invention.

FIG. 2 is a sectional view of a lower plate for the slide gate of FIG. 1;

FIG. 3 is a top view showing another embodiment of the slide gate lower plate of the present invention.

FIG. 4 is a sectional view of the lower plate for the slide gate of FIG. 2;

FIG. 5 is an explanatory view showing the operation of the slide gate lower plate of the present invention.

FIG. 6 is a sectional view showing an example of a mold.

FIG. 7 is an explanatory view showing a state of a pouring test in Example 1 of the present invention.

FIG. 8 is an explanatory view showing a state of a pouring test of Comparative Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Lower plate for slide gates 12 Through hole 13 Concavity for suppressing eddy current and flow velocity 14 Bottom 9, 10 Slide gate 20 Upper plate 30 Lower nozzle

Continued on the front page (72) Inventor Hideaki Kato 1 Minamito, Ogakie-cho, Kariya-shi, Aichi Prefecture Toshiba Ceramics Co., Ltd. In-house (72) Inventor Osamu Morita 1 Minamito, Ogakie-cho, Kariya-shi, Aichi Prefecture Toshiba Ceramics Co., Ltd. Kariya Works (56) References JP-A-46-3408 (JP, A) JP-A-3-66470 (JP, A ) Japanese Utility Model Showa 52-41318 (JP, U) Japanese Utility Model Showa 51-7413 (JP, U) Japanese Utility Model Showa 51-25531 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 41/28 B22D 11/10 340

Claims (4)

(57) [Claims] 1. A slide for adjusting a flow rate of a molten metal.
Sliding of through-hole (12) in lower plate for gate
A vortex / velocity suppression recess (13,
23), the bottom of the vortex / velocity suppression recess (13, 23)
The portions (14, 24) have flat portions (14, 24),
The area of the flat portions (14, 24) of the
The cross section is 0.2 to 0.7 times the cross-sectional area of the road.
Lower plate for ride gate. 2. A slide for adjusting the flow rate of molten metal.
Sliding of through-hole (12) in lower plate for gate
A vortex / velocity suppression recess (13,
23), the bottom of the vortex / velocity suppression recess (13, 23)
The distance (B) between the end and the through-hole is 0. 0 of the through-hole diameter (D).
2 to 0.5 times the eddy current / velocity suppression recess (13, 2
The distance (A) between the upper end of 3) and the through-hole (12) is the distance (A).
Characterized in that it is 1 to 1.5 times the separation (B).
Lower plate for gates. 3. A slide for adjusting the flow rate of molten metal.
Sliding of through-hole (12) in lower plate for gate
A vortex / velocity suppression recess (13,
23), and the vortex / velocity suppression recesses (13, 23)
It is formed in a trapezoid shape, the through-hole diameter is D, and the vortex / velocity suppression recess (1
A, the distance between the top end and the through-hole in (3, 23) is A, and the bottom end is
When the distance from the flow hole (12) is B, eddy current and flow velocity
The radius of curvature (R1) of the upper part of the control recess (13, 23) is 10
mm and {(3/4) × D + A} / 2 or less,
Also, the curvature half of the bottom of the vortex / velocity suppression recess (13, 23)
The diameter (R2) is 10 mm or more and {(3/4) × D + B}.
/ 2 or lower plate for slide gate
rate. 4. A slide for adjusting the flow rate of molten metal.
Sliding of through-hole (12) in lower plate for gate
A vortex / velocity suppression recess (13,
23), and the depth (C) of the vortex / velocity suppressing recess is 10
mm or more and 1/2 or less of the plate thickness (T)
A lower plate for a slide gate.