RU2330744C2 - Gate-feeding device for casting on melted models - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: device consists of ceramic casing with metal inlet channel, thermostating ceramic unit with system of slot gate channels and feeder cavity. Thermostating unit is installed on the casing bottom. Between external surface of the unit and internal surface of ceramic casing annular header is formed. Thermostating unit consists of top and bottom ceramic discs, and thin-walled cylindrical ceramic shells, which are coaxially installed in respect to each other with radial gap. Shells are alternately connected to top and bottom discs. Vertical slot channels are arranged in the shells, and end gaps are created between shells ends and internal surfaces of discs. Feeder cavity is installed in the centre of thermostating unit. Feeder output is connected to feeder journal, which is arranged as integral with the bottom of ceramic casing.

EFFECT: achievement of reduction of metal consumption for gate-feeder system and increase of foundry quality and reliability.

9 cl, 3 dwg, 1 ex

Description

The invention relates to foundry, in particular to gate-feeding devices, in which profits are heated by the heat of a flowing metal and in which there are means for cleaning metal from non-metallic inclusions.

Lost wax casting is widely used to produce castings of complex configurations. Using it, problems arise associated with the appearance of shrinkage defects in castings and the presence of pores and shells in the castings as a result of particles of slag, oxide films, gas bubbles, and other inclusions entering them. . To solve these problems, ceramic casting molds use gate-feeding devices in the form of thermal units, inside of which there is a thermostatic unit with a system of slotted channels. The melt is maintained in a fluid state throughout the casting solidification period. As a result, the formation of shrinkage defects in the casting is excluded.

A gate-feeding device is known that contains an inner part in the form of honeycomb cells and an outer casing for an auxiliary cavity for heating metal located along the perimeter of the inner part and a profitable cavity, while the auxiliary cavity is in communication with the profitable cavity with slot feeders (ed. Certificate of the USSR No. 740403, MKI B22D 27/04, 1978). This technical decision is taken as an analogue of the claimed invention.

The disadvantage of this device is the increased consumption of metal on the sprue channels - sprue, auxiliary cavity and slag trap. These channels serve as a source of heat loss, for the compensation of which additional metal consumption is required.

Also known is a gate-feeding device comprising a ceramic body with a metal supply channel, a thermostatic ceramic block with a slotted gate system, a profitable cavity and a metal outlet channel, the metal supply channel being connected to the central part of the thermostatic ceramic block, and its slotted gate system located above the profitable cavity (ed. certificate of the USSR No. 1063537, MKI B22D 27/04, 1983). This technical decision is taken as a prototype of the invention.

The disadvantage of this device is that the gate system of the slotted channels of the thermostatic unit is not effective enough to remove non-metallic inclusions from the melt. In addition, the location of the thermostatic unit under the profitable cavity increases its dimensions and, accordingly, requires increased metal consumption for the manufacture of castings.

The objective of the invention is to reduce the consumption of metal, and increase the degree of purification of metal from non-metallic inclusions, and increase the yield of products.

The technical result from the use of the invention is to reduce the volume of the profitable cavity and improve the quality of metal cleaning due to the zigzag flow in the vertical and horizontal planes of slotted gate channels of the thermostatic unit.

This problem is solved due to the fact that in the gating-feed device for investment casting, containing a ceramic body with metal channels, a thermostatic ceramic block with a slotted channel system, a profitable cavity and a metal channel, the thermostatic block is installed on the bottom of the specified body and coaxially with it, while between the outer surface of the indicated block and the inner surface of the ceramic casing an annular collector is formed, and the thermostatic block is made in the form of a thin bone cylindrical ceramic shells coaxially located relative to each other, with a radial clearance between them, of the upper and lower ceramic discs, said shells being alternately connected to the upper and lower ceramic discs, in addition, vertical shell channels are made in said shells, and between the ends of said shells end gaps are formed and the inner surfaces of these disks, while the profitable cavity is located in the center of the thermostatic unit, and its output is connected to linen neck, made in one piece with the bottom of the ceramic body.

Other features of this device are:

- the ceramic case is made with a lid, which is connected to it by a heat insulating material;

- the width of the slotted channels in the cylindrical shells is selected in the range from 0.08 to 0.15 of their height;

- the size of the end gaps between the inner surfaces of the ceramic discs and the ends of the cylindrical shells is 0.8-1.5 mm;

- the outer surface of the ceramic disk of the thermostatic block from the side of the entrance to the block is made with a conical divider flow of liquid metal;

- the surface of the thin-walled cylindrical ceramic shells of the thermostatic unit is made rough;

- the inner thin-walled cylindrical ceramic shell of the profitable cavity is made with a height greater than the height of the remaining cylindrical shells by the size of the end gap;

- the thermostatic unit has a means for fixing thin-walled cylindrical ceramic shells, which is made in the form of a pin connection, with a pin made on one of the shells and a blind hole on the other;

- vertical slotted channels of adjacent thin-walled cylindrical ceramic shells are offset relative to each other in the circumferential direction.

Brief Description of the Drawings

The essence of the invention is illustrated by figure 1, which shows the gate-feeding device, figure 2 - section aa figure 1, figure 3 - section bb figure 2.

An example embodiment of the invention

The device comprises a ceramic body 1, which is closed by a lid 2 from the top and a bottom 3, in which a metal-outlet channel 4 is made in the form of a profitable neck 5. The cover 2 is connected to the body 1 by means of a heat-insulating material 6. There is a metal-in channel 7 in the lid 2 , which, in this case, is a pouring funnel 8. Inside the ceramic body 1, a ceramic thermostatic block 9 is fixed on its bottom 3. Between the outer surface of the thermostatic ceramic block 9 and the inner surface of rpusa 1 is formed an annular manifold 10 which is fluidly connected to channel 7 metallovvodnym.

Thermostatic unit 9 is a set of several thin-walled cylindrical ceramic shells 11, coaxially located relative to each other. Between these shells there is a radial clearance δ. The surfaces of the cylindrical shells are made rough.

Above and below, ceramic shells 11 are closed by ceramic discs 12 and 13. Moreover, these shells 11 are alternately connected to the upper 12 and lower 13 ceramic discs. Each cylindrical shell 11 has several vertical slotted channels 14, and these channels are made over the entire height h of the shell. The channels 14 of adjacent cylindrical shells are offset relative to each other in the circumferential direction by an angle α.

The width of the slotted channels δ _{1 is} selected in the range from 0.08 to 0.15 of their height h. Between the ends 15 of the cylindrical shells 11 and the inner surfaces 16 and 17 of the ceramic disks 12 and 13, end gaps δ _{2 are formed} . The size of the end clearances δ ₂ is in the range from 0.8-1.5 mm.

The presence in the cylindrical shells of vertical slotted channels δ ₁ displaced circumferentially by an angle α and end gaps δ ₂ provides a zigzag metal flow in vertical and horizontal planes inside the thermostatic unit. This significantly improves the cleaning of metal from non-metallic impurities. The rough surfaces of the cylindrical shells and large contact areas of the flowing metal with them contribute to better adhesion of impurities to these shells.

The quality of metal purification from non-metallic impurities in this block design was also achieved by lowering the initial speed of the metal flowing through slotted gate channels. For this, the width of the slotted vertical channels δ ₁ , the size of the annular gaps δ between the cylindrical shells and the end gaps δ ₂ increases from the periphery of the block to the center.

The inner cylindrical shell 18 of the thermostatic unit forms the volume of the profitable cavity 19. The height of the shell 18 is greater than the height of the remaining cylindrical shells 11 by the value of the end gap δ ₂ .

Placing a profitable cavity 19 inside the thermostatic unit, in its center, significantly reduces its volume and completely thermally insulates it, thereby preventing solidification of the melt.

The outer surface of the ceramic disk 12 from the entrance to the thermostatic unit is made with a conical flow divider of the liquid melt 20. This prevents the turbulence of the flow of the current melt when it enters the thermostatic unit.

The relative position of the disks 12 and 13 with the corresponding cylindrical shells of the thermostatic unit is fixed by three latches 21 (figure 3), evenly spaced around the circumference of the block. The latches 21 are made in the form of a pin connection, while on the outer cylindrical shell 11 belonging to the disk 12, a pin 22 is made, on the lower disk 13 there is a blind hole 23.

Device operation

The gate-feeding device is poured with molten metal through a metal-water channel 7 (pouring funnel 8), from where it passes through a divider 20 into an annular collector 10, then passes through slotted gate channels 14 of the thermostatic block 9, and from it into a profitable cavity 19, a profitable neck 5 and into the working cavities of the mold (not shown).

The melt enters the thermostatic unit 9 through vertical slotted channels 14 made in the outer cylindrical shell 11, and through the end gap δ ₂ between the end face 15 of this shell and the inner surface 17 of the lower disk 13 (Fig. 1 and Fig. 2). Of these, the melt enters the annular gap δ between adjacent cylindrical shells. Further, part of the stream that fell into the gap δ flows in the circumferential direction, and part to the upper disk 12, to the end gap δ ₂ between the end face 15 and the inner surface 16 of the upper disk 12. As a result, the melt flows in a zigzag fashion (in the vertical and horizontal planes) from one annular gap δ to another. In the profitable cavity 19, the melt enters through vertical slotted channels made in the last cylindrical shell 18.

The zigzag flow of the molten metal in the thermostatic unit contributes to its rapid heating to the temperature of the liquid metal, while ensuring good thermal insulation of the central profitable cavity, preventing its solidification. In addition, this flow regime allows better purification of the melt from non-metallic impurities.

Industrial applicability

The present invention will find application in the performance of responsible casting of stainless and heat-resistant grades of steel and alloys. This will reduce the metal consumption for gate-feeding systems and improve the quality and reliability of cast products.

Claims (9)

1. A casting feeder for investment casting, comprising a ceramic body with a metal channel, a thermostatic ceramic block with a slotted channel system, a profitable cavity and a metal channel, characterized in that the thermostatic block is installed coaxially with the bottom of the ceramic body, an annular collector is formed between the outer surface of the block and the inner surface of the ceramic body, the thermostatic block is made in the form of thin-walled ceramic cylinders shells, coaxially located relative to each other with a radial clearance, of the upper and lower ceramic disks, the shells being alternately connected to the upper and lower ceramic disks, vertical slotted channels are made in the shells, and end gaps are formed between the ends of the shells and the inner surfaces of the disks, the profitable cavity is located in the center of the thermostatic unit and is connected to the metal-outlet channel made in the form of a profitable neck in one piece with the bottom of the ceramic body sa. 2. The gate-feeding device according to claim 1, characterized in that the ceramic body is made with a lid that is connected to it by means of a heat insulating material. 3. The gate-feeding device according to claim 1, characterized in that the width of the slotted channels in the cylindrical shells is from 0.08 to 0.15 of their height. 4. The gate-feeding device according to claim 1, characterized in that the size of the end gaps between the inner surfaces of the ceramic discs and the ends of the cylindrical shells is 0.8-1.5 mm. 5. The gate-feeding device according to claim 1, characterized in that on the outer surface of the ceramic disk of the thermostatic block from the side of the entrance to the block, a conical splitter of the liquid metal flow is made. 6. The gate-feeding device according to claim 1, characterized in that the surfaces of the thin-walled ceramic cylindrical shells of the thermostatic unit are made rough. 7. The gate-feeding device according to claim 1, characterized in that the internal thin-walled ceramic cylindrical shell forming a profitable cavity is made with a height greater than the height of the remaining cylindrical shells by the size of the end gap. 8. The gate-feeding device according to claim 1, characterized in that the thermostatic unit is equipped with a means for fixing ceramic cylindrical shells, which is made in the form of a pin on one of the shells and a blind hole on the other. 9. The gate-feeding device according to claim 1, characterized in that the vertical slotted channels of adjacent thin-walled cylindrical ceramic shells are offset relative to each other in the circumferential direction.

Images