JPS5877767A - Method and mold for casting ball used for grinding - Google Patents

Abstract

PURPOSE:To prevent shrinkage and to improve productivity by stacking sand molds formed with many semispherical cavities successively, and charging molten steel along the metal molds coinciding with the semispherical cavities on the outer side, thereby allowing the molten metal to solidify directionally from the outer side in the metal molds. CONSTITUTION:Molten metal is charged into respective runners through the sprue 4b of a mold 1 wherein shape members 2c divided by parting lines 2b running the central parts of respective cavities 2a are stacked successively on both sides of shape members 2c provided with the runners 4 formed therein. Then, the molten metal flows through the runners 4a into the respective cavities 2a, and solidification of the molten metal is initiated from the molten metal arriving at the cavities 3a of metal mold 3 as said metal is cooled by the mold 3. The molten metal on the runner 4a side is solidified with delay. Thus, the directional solidification is effected and the generation of shrinkage in the molten metal in the cavities 2a, 3a is obviated. Sand mold 2 is divided by the parting lines 2b in parallel with the runners 4 and it is also acceptable to divide the same by the parting lines 2b intersecting orthogonally with the runners 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to a method for casting grinding balls used for grinding raw materials in cement factories and the like, and a casting mold.

Conventionally, this type of grinding ball was manufactured by the disamatic method using a mold as shown in Figure 1. However, this method required a large amount of feeder, resulting in a low yield of 40 to 50%. There are drawbacks. In order to improve this problem, a method was proposed in which half of the mold was used as a metal mold to continuously cast balls while preventing sink marks, as proposed in a patent application filed in 1983.
It was proposed in No. 8480. However, in this method, the balls are cast at the boundary between a shell mold or a sand mold, so casting a large number of balls at one time inevitably requires a large mold.

This invention was made with the aim of improving these drawbacks, and it is a sand mold (t) in which a large number of hemispherical cavities are continuously formed.
A mold is formed by stacking small pieces of sand molds parallel to or perpendicular to the runner, and placing a mold with a hemispherical cavity along the outermost sand mold.1. To provide a method for casting a grinding ball and a casting mold, which are characterized in that the molten metal is injected into the mold from the runner and the molten metal in each cavity is directionally solidified in a first-generation mold, and a casting mold for achieving a yield of 1. This made it possible to mass-produce grinding balls while making improvements.

An embodiment of the present invention will be described below in detail with reference to the drawings shown in FIG. . The sand mold 2 has a structure in which a runner 4 is in the center, and a number of hemispherical cavities 2α are branched on both sides so that each cavity 2α is continuous, and the number of cavities at each branch is, for example, 6, and the branch For example, six cedar branches are formed on both sides of the wk#'i runner 4. In addition, three runners 4 are formed per mold body, so two runners 4 are formed at a time by the mold body 1.
16 balls can be cast.

On the other hand, parallel to the two sand mold runners 4, and each cavity 2
The structure is divided by a division f112k passing through the center of the mold member 2C, and the mold members 2C divided by the dividing line 2b are the mold members 2 in which the rear lagoon path 4 is formed for each mold member 2C.
The required number of pieces are sequentially stacked on both sides of C.
Therefore, by selecting the number of laminated layers, the number of balls that can be cast at one time can be arbitrarily set. In addition, the mold 3 located on both sides of the sand mold 2 has a hemispherical cavity 3 in each branch.
The cavity 2 of the outermost mold member 2C has a
One ball is cast between the cavities 2α and 3 using this mold 3 as follows.
Directional solidification of the molten metal injected into the chamber a is performed.

When casting balls, a plurality of mold bodies 1 are arranged side by side on a production line as shown in FIG. inject. The molten metal injected into the runner 4 flows into each cavity 2a via the riser 4α, and the molten metal that reaches the cavity 3α of the mold 3 is cooled by the mold 3 and begins to solidify. I'll be late. This causes directional solidification to occur in each cavity.

The molten metal within 3α is solidified without causing sink marks. When the molten metal in each cavity 2α, 3a solidifies, the mold body 1
After dividing the molded product from the split surface 1b passing through the center of the runner 4 and taking out the cast product from each cavity 2α, 3α, one grinding ball is obtained by separating the balls using an appropriate means. You will be able to get it.

In addition, in the above embodiment, the sand mold 2 is separated from the parting line 2 parallel to the runner 4.
Although it is divided at 1.b, it may be divided at a dividing line 2h orthogonal to the runner 4, as shown in FIG. 5 and below.

By employing the method detailed above, this invention has a yield of 7% compared to the conventional disamatic method, which has a yield of 40 to 50%.
It is significantly improved by 0 to 80%, and since directional solidification is performed by a mold provided outside the sand mold, defects such as sink marks hardly occur. In addition, since a large number of balls can be cast per lot, productivity is improved, and by making the sand mold into a divided structure and stacking them, any number of balls can be cast. It also becomes easier to respond to plans.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a mold made by the conventional disamatic method.
Fig. 2 is a vertical cross-sectional view of a mold used in one embodiment of the present invention; Fig. 3 is a top view of the same; Fig. 4 is an explanatory diagram showing the same casting method; Figs. 5 to 7 are other embodiments. It is an explanatory diagram showing an example. 2 is a sand mold (or shell M), 2a is a cavity, 3 is a mold, 3α is a cavity, 4! /'i Yudo. Applicant Komatsu Ltd. Representative Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto Figure 3 Figure 4

Claims (1)

[Claims] ■ Sand molds (or shell molds) 2 in which a large number of hemispherical cavities 2a are continuously formed are stacked one after another in a direction parallel to or perpendicular to the runner 4, and the sand molds on the outside are stacked one after another in a direction parallel to or perpendicular to the runner 4. ! The sand mold 2 on I2
The hemispherical cavity 2α matches the hemispherical cavity 3α
After injecting the molten metal into each cavity 2a e3a through the runner 4 along the mold 3 having the above-mentioned mold 3, the molten metal in each cavity 2gtl is directionally solidified by the mold 3. Method for casting balls for grinding O ■ A sand mold 2 having a large number of hemispherical cavities 2G continuously and stacked in a direction parallel or orthogonal to the runner 4, and a sand mold 2 located outside the sand 112; Casting order 1 for a grinding ball consisting of a mold 3 having a hemispherical cavity 3α matching the hemispherical cavity 2α of 2.