DE1015988B - Casting mold and process for the production of hollow blocks - Google Patents

Description

GERMAN

It has already been proposed to cast steel blocks in a casting mold, whose inner boundary consists of a cylinder made of sheet steel or a thin-walled tube, between the and the outer reinforcement a helical coil is arranged, which is filled with a coolant, in particular compressed air, water and mixtures thereof, can be charged and also optionally with electrical energy to be in the poured, liquid steel by inducing a To achieve current low bath movement and thus favorable crystallization. Between this coil and the inner boundary, the sheet metal or the pipe, is free-flowing sand or another fine-grained one Material filled.

The invention relates to a casting mold for hollow blocks and a method for their operation in which the above findings are appropriately applied.

According to the invention, the casting mold has for production of hollow blocks and the like made of steel, refractory metals or their alloys inside a core, which has a boundary consisting of thin-walled sheet metal or pipe on the outside, behind the pourable sand or another fine-grained substance is filled in. Also located behind the boundary a helical coil which is charged with the said coolants. There is the Possibility to use an electric current, preferably an alternating current of a relatively low frequency, to send through the coil when the coil turns are isolated from each other. The fine, pourable one Fabric fills at least the space between the sheet metal border and the coil. The fat this layer depends on the type of cast material and the desired cooling conditions. she can e.g. B. 2 mm to several centimeters. The thicker the layer, the lower it is for a given Coolant flow of heat extraction. However, in order to achieve perfect operational safety, this Layer should not be chosen too thin. However, experience has shown that when the Sheet metal at weak points of the silver sand, which otherwise flows at these temperatures, when in contact with Steel forms iron silicates, which immediately sinter to a tough shell. As a result of ability of the fine-grained substance, e.g. B. of silver sand, free-flowing and weakly deformable, can The core yields when the hollow casting shrinks. This avoids any cracking.

To achieve a controlled solidification from bottom to top, the coil can be divided, wherein the cooling effect of the coil sections arranged one above the other is regulated individually according to the casting mold and methods of making hollow blocks

Applicant:

Bochumer Verein für Gußstahlfabrikation Aktiengesellschaft, Bochum

Dr.-Ing. Werner Coupette, Wattenscheid-Eppendorf, and Dipl.-Ing. Adolf Sickbert, Bochum, have been named as the inventor

can. It is advisable, as already suggested, to first cool with compressed gas and only gradually to switch to water cooling. After the casting has solidified, the silver sand can move drained from the bottom or sucked upwards, whereupon the helical coil can be pulled out without difficulty. That welded Sheet metal will scale when heated to deformation temperatures and protect the block in the process.

As the outer boundary of the hollow block, for. B. used an ordinary cast iron mold will. But it is also easily possible to use the one already proposed on the outside instead of a conventional mold Casting mold, consisting of sheet metal border, silver sand and helical coil, to be used.

The invention offers several advantages. The mold is cheap to run, easy to manufacture, dry, Firing and stenciling are superfluous, a quick detachment of the form even from the warm Casting is easily possible.

The primary crystallization is largely improved; in particular, there is no unfavorable segregation in the direction of the inner boundary of the casting instead.

The effects that can be achieved with a mold made according to the invention Has core, cannot be achieved with the help of a known core for casting heavy Steel hollow blocks, which has a sheet metal jacket on the outside and a hollow housing on the inside, the The space between the two is filled with dry sand or the like and in the case of the inside of the housing the pouring funnel is arranged in the sub-floor for pouring. Such a core is lacking

709 697/3 »

1

a cooling coil at a short distance from the outer boundary of the core cannot be cooled.

Another known core for producing cast hollow blocks has the following structure:

The outer jacket of the core is made from sheet metal. At a distance from this sheet is further ' arranged inside a thick-walled metallic insert body, and between sheet metal and insert body Liquid lead is used as a filler. Inside the thick-walled insert body, cooling or heating devices can be arranged. Even if cooled inside the thick-walled insert body it is impossible to carry out a guided solidification from below upwards, since the The heat conduction through the liquid lead is so good that temperature differences within the lead are evened out would. The thick-walled insert body would also contribute to the temperature equalization. As a result of the long distance of any coolant from the ingot and as a result of its use of lead as a transfer medium for heat is the possibility of different heat dissipation very low. You can have the effect of the invention at a short distance from the outer boundary Do not bring about the cooling coil arranged in the core.

Claims (4)

Patent claims: 1. Casting mold for the production of hollow blocks made of steel, refractory metals or their alloys by means of a core whose äossi
Boundary made of a cylindrical sheet metal behind which a free-flowing, fine-grained substance, e.g. B. sand is filled in, characterized in that-in the free-flowing, fine-grained SίοίΡ a helical, optionally charged and coolable coil with electric current is annecudnet, namely at such a distance from the outer sheet border of the core d & B the layer of free-flowing, fine-grained substance Between the outer sheet metal jacket of the core and the helical coil has a thickness of about 2 to 25 mm. 2. Casting mold according to claim 1, characterized dadurrh, that the outer boundary is preferably also from a sheet metal border, underlying fine-grained substance and one if necessary subdivided, helical coil consists. 3. A method for operating a casting mold T && claim 1 and 2, characterized in that the hollow, helical Sp ₁ UIe ^{1 is} charged with a coolant, in particular compressed air, water and mixtures thereof, to bring about a regulated solidification after pouring. 4. The method according to claim 3, characterized in that that the helical coil ^ | §teea (i cooling with an alternating current fails will. Considered publications
German patent specifications No. 642 560, 692 432 709697/360 i.57