JPH03110060A - Method for casting molten metal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a molten metal product that reduces product defects caused by foreign substances such as slag and refractory materials entering a cast product (influenza) and product defects caused by gas. Regarding the casting method.

When manufacturing products using conventional casting techniques, molten metal at a high temperature of about 1,400 to 1,500°C is poured into a mold, but slag in the molten metal and refractory material that has peeled off from the ladle that holds the molten metal occur. Influences have become a problem when foreign objects enter the casting product and cause product defects. To solve this problem, ceramic strainers are commonly used in conventional molten metal casting methods. To explain this based on FIG. 3, the strainer 6 is connected to the sprue 4 formed in the upper mold 1.
It is supported by a strainer pedestal formed at the bottom of the sprue of the lower mold 2. The molten metal poured into the sprue cup 3 from a ladle (not shown) is guided to the sprue 4 and flows into the strainer 6, where foreign matter such as slag and refractory material is removed and the molten metal flows into the runner 5. Then, it is further guided to the runner 5 and reaches the casting product section.

Problems to be Solved by the Invention In casting, it is very important to maintain the proper flow rate and amount of molten metal, and ideally the cleaned molten metal should be poured as quietly and quickly as possible.

However, in manual pouring work, there are differences in the skill of the workers, so it is unavoidable that the molten metal enters faster or slower, causing variations in the speed of the vortex flow. For this reason, there are disadvantages in that the metal is easily oxidized, resulting in slag being mixed into the molten metal, or gas defects caused by gas generated in the molten metal. As a countermeasure to these problems, the way the molten metal enters is usually controlled by the molding method used to form the mold, but it has been difficult to implement sufficient countermeasures.

Means for Solving the Problems The present invention solves the above-mentioned problems by installing a strainer at the lower end of the sprue and guiding the molten metal poured into the sprue cup from the sprue to the strainer to remove foreign matter. In this method, a thin iron plate is placed on the upper surface of the strainer, the molten metal is temporarily stored in the sprue and the sprue cup, and the molten metal that has melted the iron plate flows into the strainer. This is a molten casting method characterized by pouring molten metal continuously from the time it starts flowing.

According to the method described above, the molten metal poured from the ladle into the sprue cup is dammed up by the iron plate and temporarily accumulates in the sprue and sprue cup.During this time, slag with a light specific gravity floats to the top, causing problems inside the product. It becomes difficult to enter. When the iron plate melts into the hot molten metal, the molten metal that had accumulated in the sprue and sprue cup begins to flow into the runner through the strainer, and by continuously pouring into the sprue cup, the molten metal is always kept in the sprue cup. It is kept in an accumulated state. Therefore, the molten metal flowing into the runner flows under a substantially constant static pressure, and flows quietly and quickly without becoming turbulent, and flows into the cast product part in the mold.

Embodiment An embodiment of the molten metal casting method according to the present invention will be described with reference to FIGS. 1 and 2. The molten metal injection part of the mold is shown in which an upper mold 1 and a lower mold 2 are overlapped. The lower ends of the sprue cup 3 and sprue 4 provided on the upper mold 1 communicate with a runner 5 that leads the molten metal to the product section. At the lower end of the sprue where the sprue 4 and the runner 5 are connected, a strainer 6 is provided so as to be supported by a strainer pedestal formed at the bottom of the sprue of the lower mold 2.
Further, an iron plate 7 having a thickness of about 0.5 μ is placed on the sprue cup 3 side of the strainer 6, that is, on the upper surface of the strainer 6. In addition, the strainer 6 is 1400~1
A material made of ceramic such as SiC that can withstand high temperatures of 500° C. is generally used, and the iron plate 7 may be made by cutting scrap material, which is the main raw material for the molten metal, to match the shape of the strainer 6.

When a cast product is cast using a mold with a molten metal injection part having the structure described above, the molten metal poured from a ladle (not shown) into the sprue cup 3 passes through the sprue 4 and is placed at the lower end of the sprue. It tries to flow from the strainer 6 to the runner 5. but,
Since the iron plate 7 placed on the top surface of the strainer 6 acts as a temporary plug and dams up the molten metal, the iron plate 7
The poured molten metal is temporarily stored in the sprue cup 3 and the sprue 4 until it melts into the molten metal, which is at a high temperature of 00°C.

At this time, since the slag in the molten metal has a low specific gravity even when the molten metal rises, it floats from the sprue 4 to the sprue cup 3, making it difficult to enter the runner 5 or the product. When the iron plate 7 is melted by the hot molten metal and no longer functions as a stopper, the molten metal stored in the sprue cup 3 and the sprue 4 flows into the runner 5 through the strainer 6, and the molten metal in the sprue cup 3 flows into the runner 5. The liquid level begins to drop.

Furthermore, by continuously pouring the molten metal from the ladle into the sprue cup 3 after confirming that the liquid level has dropped, it is possible to replenish the molten metal while keeping the liquid level in the sprue cup 3 and sprue 4 almost constant. . Therefore, the molten metal poured into the sprue cup 3 flows into the strainer 6 under almost constant static pressure, and the strainer 6 removes foreign substances such as slag and refractory material peeled off from the ladle. 5 and flow to the product department (not shown). At this time, the molten metal flows to the product section in a pressurized state, not in a turbulent flow, so by adjusting the shape and dimensions of the sprue 4, runner 5, etc., the desired inflow suitable for the molten metal can be achieved. It is relatively easy to achieve high speeds regardless of the skill of the pouring worker, and it is also easier to take measures to prevent product defects due to gas generation. It goes without saying that the size, shape, and thickness of the iron plate 7 will vary depending on the weight of the cast product, the shape of the strainer 6, etc., and since the iron plate 7 is the same as the raw material for the molten metal, it will vary depending on the weight of the cast product and the shape of the strainer 6. It does not affect quality.

Effects of the Invention According to the present invention described above, a step is added in which an iron plate is placed on the top surface of the strainer to temporarily store the molten metal in the sprue and sprue cup, and during this time, the slag in the molten metal floats toward -F. This makes it difficult to get into the product. Moreover, since the molten metal with less slag due to flotation passes through a strainer before flowing into the runner, the slight remaining slag will be removed by the strainer along with other foreign matter, and there is a possibility that these will flow into the product. becomes very small. Furthermore, since the molten metal can be poured quickly and quietly without depending on the skill of the pouring operator, product defects caused by gas generation can be significantly reduced. In this way, although it has the effect of greatly reducing the incidence of infiltration caused by foreign matter entering the casting product, it does not require large-scale equipment or expensive materials, and the rate of defective products is almost completely reduced. It also has a great economic effect as it directly reduces the product cost.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the molten metal inlet of a mold showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the line It is a sectional view of the hem part. ■...Upper mold, 2..Lower mold, 3.. Sprue cup, 4.. Sprue, 5.. Runway, 6.. Strainer, 7.. Iron plate.

Claims (1)

[Claims] A molten metal casting method in which a strainer is installed at the lower end of the sprue, and the molten metal poured into the sprue cup is guided from the sprue to the strainer to remove foreign matter before flowing into the runner. A molten metal casting method characterized by placing an iron plate to temporarily store molten metal in the sprue and the sprue cup, and pouring the molten metal continuously after the molten metal from the iron plate begins to flow into the strainer. .