RU2344017C1 - Device for production of casts with crystallisation under pressure - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to foundry. Device incorporates casting mold assembled above a furnace with metal melt, and a complex metal line with a separate cylinder part. The cylinder part of the metal line is made out of sand-kernel mixture.

EFFECT: simplification of the structure of the device and also reduction of labour intensiveness of metal line fabrication as well as reduction of prime cost of produced casts.

3 dwg

Description

The invention relates to the field of mechanical engineering and can be used in foundry in the production of castings from liquid-solid metal melts with filling molds through a metal wire directly from a melting furnace with crystallization under pressure (LPVKD method).

A device for producing castings with crystallization under pressure, containing a sealed container in which is placed a mold located above the furnace with molten metal, a metal wire that connects the melt in the crucible of the furnace with the lower part of the mold. Moreover, the crucible of the furnace is also located in a sealed container equipped with a gas pipeline for supplying gas pressure (Japanese application No. 59-54458., Application. September 20, 82 No. 57-164438, published on March 29, 84, MKI B22D 18/02) .

This device has a significant drawback, because it is designed to fill in the form of a melt heated above the liquidus temperature and solidify it in the form under low pressure, mainly 0.06 MPa. The device does not allow filling the mold with a liquid-solid melt and solidifying it in the mold under the most effective pressure of 0.4-0.6 MPa to obtain castings with improved mechanical properties at the level of forgings and rolled products.

The closest analogue adopted for the prototype is a device for producing castings with crystallization under pressure, containing a mold located above the furnace with molten metal and a metal wire (RU 58966 U1, B22D 18/00, 12/10/2006).

The disadvantage of this device is that when receiving castings from liquid-solid melt, this design of the metal wire is very complex and low-tech for single use, because It is associated with the great complexity of manufacturing and cost (the execution of the cylindrical part from refractory material is associated with high energy consumption, and the production of the cylindrical part from basalt and fluorophlogopide is a complex process). The use of such a metal wire makes the resulting castings more expensive.

The aim of this invention is to remedy these shortcomings, namely: simplifying the design of the metal wire in the manufacture of castings from liquid-solid melts, respectively, simplifying the technology for its manufacture.

This goal is achieved by the fact that in the device for producing castings with crystallization under pressure, containing a mold located above the furnace with molten metal, a composite metal wire with a separate cylindrical part made of refractory material, a separate cylindrical part of the metal wire is made of sand-rod mixture. The manufacture of a separate cylindrical part of a metal wire from a sand-rod mixture is equivalent to the manufacture of a conventional sand rod, which simplifies the design of the metal wire and the technology of its manufacture in the preparation of castings from liquid-solid melts.

The cylindrical part of the metal wire made of a sand-rod mixture is connected to the flange, which also has a small cylindrical part, by gluing.

The metal wire is immersed in the molten metal so that the cylindrical portion of the flange is also in the molten metal. Moreover, if a separate cylindrical part is made of sand mixture, a crust of solid metal is formed on its surface immediately after immersion in a liquid-solid melt and this cylindrical part becomes gas-tight from the outside. At the same time, the design of the metal wire is greatly simplified, and accordingly the technology of its manufacture is simplified and the cost of castings is reduced.

Figure 1 shows a mold container for casting a turnout cross (before pouring), figure 2 - a container with a mold for receiving this casting with a melting furnace (after pouring), figure 3 - composite metal wire.

The device consists of a polystyrene foam model 1, molded with dry quartz sand in a detachable container 2, with a sealing seal 3 of a metal wire 4 mounted in an arm 6 through a seal 5. In the upper lid of the container 2 there are gas pipelines 7, 8, 9, respectively, for evacuation, gas pressure supply and communication with the atmosphere. In the lower part of the container 2 there is a sand insert 10, an annular groove 11 for sealing the container 2 in the process of pouring the melt. For horizontal movement of the metal wire 4 there is a power drive 12 with a rod 13 (figure 2, figure 1).

The metal wire 4 consists of a steel flange 13 and a thin-walled cylindrical part 14 with a height of 150-250 mm. The cylindrical part of the metal wire 15, having a Central plane 16, is made of liquid glass rod composition.

The device operates as follows. Expanded polystyrene gasified models of railway crosses (Fig. 1) are filled with quartz sand in a container 2 having a sealing seal 3. Steel is melted according to the known regime. The prepared steel is cooled in a furnace to a solidus temperature (1300 ° C), while the gases dissolved in the steel are removed, and then the steel quickly heats up to a temperature of 1340 ° C (to a liquid-solid state). The metal wire 4, its cylindrical part 15, made of a liquid-glass mixture, is immersed in the melt to the level of the dashed line shown in Fig.3.

The container 2 is connected to the vacuum system through a gas pipeline 7 (a gas-tight crust of a solid metal immediately forms on the surface of the cylindrical part 15). The molten steel through a metal wire 4 enters the container 2 at a speed of 5 m / s, burning a polystyrene foam model. The first portions of metal are poured into the groove 11 and the container 2 is sealed from below. The gasification products of the models are sucked out of the container 2 by a vacuum system through the gas pipeline 7. After filling the working cavity of the molds, the hydraulic cylinder 12 is turned on and the rod 13 moves the metal wire to the right, cutting off the metal melt in the metal wire from the metal melt in the mold, after which compressed air is supplied to the container 2 through gas pipeline 8 under a pressure of 0.5 MPa and exposure is carried out until the casting hardens. After the casting has hardened, the container 2 is connected to the atmosphere through a gas pipeline 9, the casting is removed from the sand and the process is repeated.

The composite one-time metal wire, including a separate cylindrical part made of a sand-rod composition, has a simple design, simple manufacturing technology and, accordingly, allows to reduce the cost of the resulting casting.

The use of the invention allows to simplify the design of the metal wire in the manufacture of castings from liquid solid melts and reduce the cost of manufacturing castings.

Claims (1)

A device for producing castings with crystallization under pressure, containing a casting mold located above the furnace with molten metal, a composite metal wire with a separate cylindrical part made of refractory material, characterized in that the separate cylindrical part of the metal wire is made of a sand-rod mixture.

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