JPH0249822B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cleaning molten metal in a molten metal forging method.

(Conventional technology) Conventionally, the molten metal forging method using a plunger was
As shown in the figure, molten metal is injected into a cavity 9 whose bottom surface is the sleeve 5 on the lower mold 2 side and the upper surface of the plunger 6 that can move up and down inside the sleeve 5, and then the upper mold 1 and the lower mold 2 are clamped. plunger 6
Generally, the molten metal in the sleeve 5 is sent through a runner into the mold cavity 9 between the upper and lower molds, solidified under pressure by a plunger 6, and formed into a forged product. In order to improve this and purify the molten metal, we developed a device that filters the molten metal inside the sleeve through a wire mesh body using a pressurizing process using a plunger (Utility Model Application No. 59-34856).
Alternatively, a weir is used to collect floating impurities on the upper surface of the molten metal in the space above the sleeve (Japanese Patent Laid-Open No. 56-163070
No.) etc. have been proposed.

(Problem to be Solved by the Invention) However, in the conventional method described above, before the molten metal is poured into the sleeve during pouring, oxides generated in the melting furnace or in the ladle during transportation mix into the molten metal. Furthermore, after pouring, oxides are generated inside the sleeve along the inner wall of the sleeve, and in the next pressurization process, they are fed into the mold cavity and mixed into the product, resulting in a decrease in the strength of the product and blistering during heat treatment. Even the above-mentioned proposal to improve this problem only collects impurities generated or mixed in the molten metal in the cylinder, making it difficult to sufficiently clean the molten metal. . Therefore, the present invention aims to improve the above-mentioned drawbacks of the conventional method, and aims to improve the quality of the molten metal forging method through a simple process.

(Means for solving the problem) For this purpose, in particular, molten metal that has been degassed and sludged by a conventional method is injected into the sleeve of the lower mold through a glass cloth filter net stretched above the opening. After removing the object, the opening of the sleeve of the lower mold is coated with a filter net having a size sufficiently larger than the diameter of the sleeve, and the upper mold and the upper mold are formed to form a recess that is at least higher than the mold cavity directly above the lower mold and the sleeve. The periphery of the filter net is clamped by closing the sleeve, and the filter net removes oxides generated inside the sleeve due to the rise of the plunger, and the fine particles passing through the filter net are collected in the recess provided in the upper mold. This is to clean the molten metal.

(Function) Since this invention consists of the above steps, the oxide is removed by the filter net in the two steps of injecting the molten metal into the sleeve and feeding it into the cavity. Since the molten metal is cleaned in a total of three steps by collecting fine oxides that may be present in the recesses above the sleeve, the molten metal can be sufficiently cleaned. When feeding the molten metal, this can be easily done by sandwiching a filter net larger than the sleeve diameter between the upper and lower dies.

(Example) This invention will be further explained with reference to an example shown in the drawings. As shown in Fig. 1, with the upper mold 1 open, hold the glass cloth filter net 8, which is slightly larger than the sleeve diameter, at a height h of 10 to 15 mm higher than the runner, and hold the ladle 7. From there, the metal is poured into the sleeve 5 through the filter net 8.

As a result, oxides generated in the ladle 7 in the melting furnace or during transportation are removed. Next, as shown in FIG. 2, before closing the upper mold 2 with the runner 3 connected to the peripheral mold cavities 9 on the left and right and the runner 3 located on the sleeve 5, Place a filter net 10 that is 20 to 30 mm larger than the diameter,
The periphery is clamped and fixed between the lower surface of the closed upper mold 1 and the upper surface of the lower mold 2 (FIG. 3).

Thereafter, the plunger 6 is raised to pressurize the molten metal toward the upper mold 1. A portion 12 of the oxides generated within the sleeve 5 is transferred to the filter net 10.
The fine particles 11 that are captured by and pass through are pushed up into the sump 4 directly above the sleeve 5 and are collected. Clean molten metal passes through runner 3 and enters mold cavity 9.
A forged product is obtained by feeding the forged product into a forged product and press-forming it.

(Effects of the Invention) As shown in the above examples, this invention reduces the defective rate by about 8 to 10% by the second stage of filtration, and by about 5% by collecting the hot water, compared to the 20% defect rate of the conventional method. % and about 3 to 5% due to being captured by the filter net.In the molten metal forging method of this invention, the oxides newly generated in each of the above steps are removed, and the defective rate is less than 2%. The formed forged product has the following characteristics: (1) Reduction of defect rate due to the inclusion of oxides in the three steps; (2) The collection part of the sump becomes the final solidification part, making directional solidification easier.

(3) Glass cloth is used for the filter net, and because it is not made of metal, it does not melt when the runners are remelted, making processing easy and reducing costs.

As a result, this invention has excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the first and second steps in an embodiment of the present invention, FIGS. 2 and 3 are a plan view and front view showing the third step, and FIG. 4 is a diagram showing the same after pressurization. FIG. 5 is a diagram showing a conventional method. 1... Upper mold, 2... Lower mold, 3... Runway, 4... Hot water reservoir, 5
... Sleeve, 6... Plunger, 8, 10... Filter net, 11, 12... Oxide.

Claims (1)

[Claims] 1. A molten metal forging method in which molten metal or alloy is injected into a cavity consisting of two upper and lower molds that can be opened and closed and then press-formed, characterized by comprising the following steps (1) to (5). Molten metal forging method. (1) Opening the upper and lower molds (2) A conventional method is applied to the inside of the sleeve of the lower mold, which has a sleeve with a vertically movable plunger as its base, through a glass cloth filter net stretched over the opening of the sleeve. (3) In order to remove the oxides generated inside the sleeve, the opening is covered with a filter net that is sufficiently larger than the diameter of the sleeve, and the opening is placed directly above the sleeve. Step (4) of closing the upper mold in which a concavity at least higher than the mold cavity is formed, and clamping and fixing the periphery of the filter net between the upper and lower molds. Step (5) of removing the oxides generated during the process (5) The fine particles of oxides that have passed through the filter net are collected in the filter net and the sump of the upper mold, and the cleaned molten metal is passed through the runner. The process of being fed into a mold cavity, pressurized and solidified.