SU1222398A1 - Stepped ingate system for metal-pouring - Google Patents

Description

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The invention relates to foundry, in particular, to gating systems for metal casting.

The aim of the invention is to improve the reliability of the gating system.

The drawing shows a mold, a vertical section.

In the upper 1 and lower 2 half-molds, a rod 3 is installed, the image of a singing working cavity 4, which is connected by feeders 5 to a stand 6. Over all the feeders 5, except the upper one, there are cavities 7 in which there are fire-resistant balls 8, and the entrance to The feeders, except for the lower one, and the cavity 7 are closed with a gas-generating insert 9 at the lower feeder, inserts 10 and 11 at the middle feeder and insert 12 at the upper feeder.

Step gating system works as follows.

In the manufacture of the upper half-mold 1, cavities 7 are made above the feeders, into which refractory balls 8 are installed, and the outlet from the cavities 7 and the entrance to the feeders are closed with inserts made of gasified material, for example, expanded polystyrene sheet. The length (height) of the inserts h is selected so that the height h of the insert 9 at the lower feeder is greater than the height hj of the insert 10 at the middle feeder, but less than the sum of the heights of the inserts 10 and 1 at the same feeder.

At the same time, the height h of the gas-producing insert 12 at the upper feeder is greater than the separately taken heights h, and hj of the inserts 9 and 10, but less than h and contact the sum of the heights () of the inserts 10 and 11 of the average feeder, i.e., ( + h,), hg.

At the beginning of the pouring, the metal by the stack 6 flows into the cavity 4, cutting the lower feeder 5 ru with gasifying inserts 9 and 10, begins to burn them. In this case, in accordance with the length (the height of the vstvok of the first burns out the insert 10 at the midpoint of the feeder, thus opening the way for the liquid metal from the drain to the working cavity. The short period of time fills the cavity 4 through the lower and middle feeders. Then the insert burns 9 y

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bottom feeder, ball 8 from the cavity. 7, the pad down, closes this feeder and the cavity fills only through the middle feeder.

5 By the time the metal in the cavity approaches the upper feeder, insert 12 at the top feeder burns and for a short time the cavity 4 is filled simultaneously through the middle and

10 top feeders. Then insert 11 in the cavity burns. 7 at the middle feeder and the ball 8, falling down, covers this feeder. Starting from this moment, cavity 4 is already filled with metal only through the upper feeder.

After the casting is completed and the castings are cooled, the refractory balls B are removed from the mold and prepared for the next casting.

20 Due to the fact that the refractory balls are installed in special cavities above the feeders, the liquid metal, the passage through the feeders, does not prevent them from falling down, which ensures reliable overlapping of the feeders after the combustion of the gasified material of the inserts 9-12.

The proposed gating system has been tested in the manufacture of production batches of shaped castings in sand molds from aluminum alloy AL9 and steel castings from steel 35l,

The mass of castings from alloy AL9 035 70 kg with a height of 500-850 mm and a wall thickness of 12-20 mm. The weight of steel castings is 80-230 kg with a height of 480-720 mm and a wall thickness of 15-35 mm.

Balls with a diameter of 30-50 mm made 40 wali from cast iron and covered with refractory paint. Inserts for overlapping feeders were made of expanded polystyrene sheet. Storages, feeders and cavities above them for balls 45 are in the form of refractory inserts and partially in rods.

Investigation of the quality of castings by X-ray and metallographic analysis of individual sections showed their higher density, fewer slag inclusions and shrinkage porosity, i.e. those defects that were observed in the manufacture of these

55 of the same castings on the base technology with a well-known gating system.

The proposed stepped gating system ensures reliable

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regulation of the process overrides their quality. Its use is a supportive one. Sequential input is effectively effective when metal is poured into operation, it creates optimal scraper castings weighing from 30 kg and conditions for bottom-up spinning from colored and black alloys to solidify castings, which increases by 5 BOB.

Claims (1)

STEEP GATHER SYSTEM FOR FILLING METAL, including a riser, feeders adjacent to it at different levels, each of which, except the lower one, is filled with gas-fired material, and fireproof balls for covering the feeders, characterized in that, in order to increase the reliability of work on the feeders in addition to the upper one, cavities connected to them are made, while refractory balls are placed in the cavities, and the exit from the cavities is filled with gas-fired material. <