SU365102A1 - Mandrel for making cavity in ingot for water-cooled mould of electroslag remelting unit - Google Patents

Description

The invention relates to equipment for electric sink remelting, namely v. mandrels for forming a cavity in a casting for an electroslag remelting mold crystallizer

WA (ESR),

Rods for molds are known, which are used in the smelting of hollow billets by the ESH method. Such rods are made in the form of thin-walled water-cooled bare shells. The metal is deposited in the gap between the mold and the core with a fixed casting. However, during shrinkage, the casting engages the core, and it must be removed, for example, by a bore, and the core is used only once.

The purpose of the invention is to create a mandrel for crystallizers of an ESR installation that can be reused. This is achieved in that the mandrel is made in the form of a monolithic metallic rod.

In the mandrel can be made chiahH for cooling, in addition, the mandrel can be supplied with a cooled jacket

FIG. 1 shows possible structures of the mandrel; FIG. 2 - rods

with cooling jacket, in FIG. 3 is a diagram of the installation of the mandrel on the pallet; FIG. 4 and 5 - molds with mandrels, in FIG. 6 shows a mold with holes, front view} in FIG. 7 the same, side view.

In the drawings, the following designations are accepted: 1 - mandrel, 2 - coolant channel, 3 - manifold for supplying and discharging cooling medium, 4 - jacket, 5 - pallet 6 - crystallizer, 7 - casting body, 8 - bottom, 9 - cheek, 10 - electrode.

A metal rod located in the mold is designed to form both internal and external cavities in the casting. The shape of the rod corresponds to the shape of the cavity being formed, its cross section can be in the form of a circle, square, rectangle, etc., it can be variable in height and have any arbitrary shape. For simplicity, consider the round-section mandrel. Dorn 1 (Fig. 1) is made in a polyester monolithic rod continuous. or discontinuous section. The cross section of the rod give such a shape. The geometrical dimensions of which not iiptv would tolerate a residual change in

rem casting. The design of the rod must be of such rigidity that, in each particular case of obtaining a casting of appropriate dimensions, the compressive stresses in it will not exceed the yield strength of the material from which it is made.

A mandrel may not have a cooling system if it is used to produce castings from low-melting materials, such as aluminum, lead. For the smelting of steel castings, it is supplied with a cooling system, for example, in the form of channels 2 located on the periphery of the rod and collectors 3 for receiving and draining the cooling medium.

To cool the mandrel, its body may have a jacket 4 made of a material with high thermal conductivity, for example copper. In jacket 4, either channels 2 or the circulation of the cooling medium can be performed at the same time in the body of the core 1 or both.

The described rod can be reused when using the ESR method for shaped castings. For this, the casting and the core are subjected to temperature effects simultaneously if the core is made of a material (carbon steel) which has a coefficient of thermal expansion less than the material (austenitic steel) of the casting. Then, the rod is separated by heating the casting and the rod, when a sufficient gap is formed between their contacting surfaces. It is also possible to separate the core from the casting, when the core material has a coefficient of thermal expansion equal to or greater than the casting material, for this the casting is heated and the core is simultaneously cooled.

When the material (austenitic steel) of the rod has a coefficient of thermal expansion more material (carbon steel) casting, the casting and the core is heated and cooled simultaneously. When heated, the rod stretches the casting on itself, and after cooling, a gap forms between their surfaces. The separation of the rod can be accelerated if it is cooled at a faster rate than the casting. In this case, the rod can be separated from the casting, if immediately after the end of the melting the cooling of the rod is turned off, allowed to warm up, and then resume cooling.

Repeated use of the rod greatly simplifies the technology for producing castings, and in particular, castings having a bottom (Fig. 3). Dorn 1 is installed on a pallet 5 inside the crystallizer 6 and the casting is melted by the ESR method. The hull is first melted.

7, and then form its bottom 6. After the bottom 8 smelting is completed, the casting, together with the mandrel, is removed from the crystallizer 6 and separated from the rod by one of the methods described.

To obtain a hollow casting with or without it, you can use a mold with a rod with thin walls, i.e. disposable (Fig. 4, 5). If, for example, two or more mandrels with a height less than the height of the casting are installed in the pallet in the direction of ingot injection, a hollow casting with a bottom and, for example, two or more channels (cavities) in the axial direction can be obtained. Bottomless casting can be used, for example, as a billet for pressing multi-channel pipes.

By installing a mandrel or several such mandrels in the side wall of the mold b, castings with cavities located, for example, in the radial direction are obtained (Fig. 5). In some cases, in order to obtain castings with cavities arranged in mutually perpendicular directions, the mandrels can be simultaneously installed on the pallet 5 and on the side wall of the mold 6. In order to obtain castings with a hole, such as cheeks. crankshaft cranks for powerful marine diesel engines (figs. b and 7), the dorva mounted on the side wall of the mold 6 or passing through this wall has a height greater than the thickness of the casting. Obtaining a casting of the crank cheek 9 with a hole is substantially simplified if the movable electrode 10 is exposed to electroslag remelting with a hole prepared in it before and inside which Dorn is placed.

The proposed mandrel has successfully passed an industrial inspection and is recommended for use in the smelting of hollow shaped castings with and without bottom.

Claims (3)

1. Dorn for cavity formation in the casting for the mold, the installation of electroslag remelting, characterized in that, for the purpose of its repeated use, it is made in the form of a monolithic metal rod. 2. Dorn according to claim 1, characterized in that we have channels for cooling. 3. Dorn on p. 1, characterized in that it is equipped with a cooled rubgy. five xj Figg but G / 7L 7 / 2 FIG. 5 eee (Rig-6 7