RU2336969C1 - Device for fabricating hollow ingots - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: device contains pan, bottom, hollow former, filled with bulk material, and cover installed on upper end of former. Burned-off material such as plastic foam is placed in central part of former. Flexible frame consisting of layers of metal wire mesh is installed outside burned-off material. Sleeves are arranged in bottom and cover. There is through hole in burned-off material; said hole together with sleeves forms gas withdrawal channel. Bulk material is chosen out of row: metal powder, pellets, shavings and high-silica sand.

EFFECT: upgraded quality of interior surface of ingots due to avoiding of hot cracks.

2 dwg

Description

The invention relates to metallurgical production, in particular to the manufacture of hollow ingots.

A known rod for producing hollow ingots containing a mold, a pallet, a sealing element, a hollow mandrel, the cavity of which is filled with metal shavings, and a damper with holes through which cooling gas is supplied (AS No. 1205988 USSR, MKI B22D 7/04 15 / 4, 1986).

The disadvantages of this device (rod) is the compaction of the filler (shavings) under the action of shrinkage arising from the solidification and cooling of the metal of the ingot, which causes the termination of the passage (supply) of cooling gas through the bulk material, sintering and, after that, difficulty knocking it out of the formed hole. This, in turn, leads to the formation of cracks on the surface of the inner cavity (hole) of the ingot.

The closest to the proposed technical essence and the achieved effect is a device for producing a hollow ingot containing a mold, a pallet, a hollow mandrel, the cavity of which is filled with a filler containing bulk material from the series: metal powder, shot, shavings, quartz sand and easily burned material, mainly polystyrene foam or polystyrene placed in the central part of the mandrel along its vertical axis (AS No. 1694323 USSR, B22D 7/04, 1991).

The main disadvantages of this device are the compaction of bulk material under the action of shrinkage forces that occur during solidification and cooling of the ingot, the difficulty of knocking it out of the formed hole, as well as the absence of constructive measures aimed at removing and trapping emissions of styrene and carbon monoxide harmful to humans and the environment. formed during heating and combustion of polystyrene foam (polystyrene).

This device for producing a hollow ingot has a low technical level, which is due to the lack of the ability to prevent compaction of bulk materials, increase ductility, improve conditions for their knockout, as well as capture and purification of environmentally harmful vapors of styrene and carbon monoxide (carbon monoxide).

In this regard, an important task is to create a new type of device for producing hollow ingots with structural elements that ensure the elimination (prevention) of compaction of bulk materials, reliable compliance, selection and capture of environmentally harmful substances, which allows you to create an environmentally friendly technological process for producing hollow ingots with high quality surface of the formed hole (clean, smooth, without cracks).

This result is achieved in that the device for producing hollow ingots contains a mold, a pallet, a hollow mandrel, the cavity of which is filled with a filler containing loose material from the series: metal powder, shot, shavings, quartz sand and easily burned out material, mainly polystyrene foam or foam, placed in the central part of the mandrel along its vertical axis, inside of which there is a through coaxial hole of circular cross section, which together with nozzles made respectively in the pallet and Ryshkov mounted on the upper end of the mandrel forms the exhaust duct for the removal of combustion products, wherein the material outside legkovyzhigaemy has a flexible frame consisting of layers of metal wire mesh.

Figure 1 shows a General view of a device for producing hollow ingots in section, figure 2 is a section along aa in figure 1.

The device contains a mold 1, a pallet 2, a hollow mandrel (with a lid) 3 filled with loose filler material (metal powder, shot, shavings, quartz sand, etc.) 4. In the central part of the mandrel 3 along its vertical axis is easily burned material 5 (mainly polystyrene foam or polystyrene) with a through coaxial hole 6 of circular cross section made inside it. Outside the easily burned material (foam) has a frame 7, consisting of layers of a metal wire mesh. The lower end of the mandrel 3 is located in the socket (recess) of the pallet 2, and the upper end is in the central opening of the intermediate casting tank 8. At the upper end of the mandrel 3 there is a lid 9 with a nozzle 10. A nozzle 11 made in the pallet 2, hole 6 in the easily burned material ( foam) 5 and the nozzle 10 in the cover 9 are interconnected and form a single gas outlet to remove gaseous products of combustion (styrene vapor and carbon monoxide) in the unit 12 capture and purification.

Expanded polystyrene, widely used for the manufacture of gasified models in foundry, is a cellular plastic with non-communicating cells filled with gas. It can be of two types: in the form of granules and blocks (polystyrene). When foaming polystyrene granules at a temperature of 100 ° C in an open space, granular polystyrene foam is obtained. If foaming is carried out in the molds, then a foam is formed. Expanded polystyrene (polystyrene) is easily removed from the mold by melting, gasifying and burning out at 350-400 ° C and above when it comes in contact with a warmer medium (for example, filled metal). In this case, vapors of styrene, carbon monoxide (carbon monoxide) and carbon dioxide (carbon dioxide) are formed. Styrene vapors have general toxic (narcotic) and irritating effects, causing irritation of the mucous membranes of the upper respiratory tract and organs of vision, weakness, fatigue, irritability, impaired coordination of movements, nausea, cough. Carbon monoxide is a colorless, odorless gas that causes poisoning. Therefore, at the first moment of pouring and solidification of the ingot without applying protective measures, the content of styrene and carbon monoxide vapor near the mold (in this case, near the device) will exceed the permissible concentration.

When trapping and cooling the styrene vapor, the latter is condensed and disposed of.

The operation of this device is as follows.

After pouring liquid metal through the intermediate casting tank 8 into the cavity formed by the mold 1, the pan 2, the mandrel 3, and solidifying and cooling it as the bulk material 4 is heated at a temperature of 350-400 ° C and above, melting, gasification and combustion will occur (burning) of easily combustible material (polystyrene foam, polystyrene) 5. The resulting gaseous products - styrene vapors, carbon monoxide and carbon dioxide through a gas outlet channel, consisting of a pipe 11, made in the pallet 2, through coaxial round holes 6 in the easily burned material (foam) 5 and the nozzle 10 in the lid 9 mounted on the upper end of the mandrel 3 are removed by natural traction or forcibly to the capture and cleaning unit 12.

After the combustible material 5 is completely burned, the frame 7 made (consisting of) layers of a metal wire mesh prevents the shedding and collapses of bulk material (metal powder, shot, shavings, silica sand, etc.). The flexibility (non-rigidity) of the mesh metal frame 7 provides the flexibility of the mandrel-bulk material system due to the release of the volume which, prior to combustion (burning), took up the foam 5, which, in turn, provides free shrinkage of the ingot. In this case, the mandrel 3 is welded to the ingot and is one with it, forming a cavity (hole). Cold air passing through the exhaust duct under the influence of natural draft helps to cool the bulk material.

When knocking out, the frame 7 is freely (freely) removed, and the bulk filler material (metal powder, shot, shavings, silica sand, crushed chromium ore) is completely poured out of the formed hole at the corresponding position (inclination) of the hollow ingot.

Due to free shrinkage, hot (shrink) cracks do not form, and the formed hole has a smooth surface.

The proposed device allows to obtain hollow ingots of various masses from various alloys with a defect-free structure and a high-quality internal surface in compliance with the required sanitary and hygienic working conditions, without exceeding the maximum permissible concentrations (MAC) of styrene and carbon monoxide vapor in the air (air) of the production room.

Claims (1)

A device for producing hollow ingots containing a mold, a pallet, a hollow mandrel filled with a bulk material selected from a number of metal powder, shot, shavings, quartz sand, and a foam material burned in the central part of the mandrel along its vertical axis, characterized in that it is provided with a lid mounted on the upper end of the mandrel, nozzles made in the pallet and lid, a flexible frame consisting of layers of a metal wire mesh and placed outside of the material to be burned while in the burned-out material a through hole of circular cross-section is made, which together with the nozzles forms a gas exhaust channel to remove combustion products.

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