US2976585A - Continuous casting apparatus - Google Patents

Description

March 28, 1961 SCHEUFELE ET L 2,976,585

CONTINUOUS CASTING APPARATUS Filed Jan. 6, 1959 States 2,976,585 CONTINUOUS CASTING APPARATUS Filed Jan. 6, 1959, Ser. No. 785,270 Claims priority, application Germany Jan. 6, 1958 4 Claims. (Cl. 22-572) This invention relates to continuous casting of hollow castings in apparatus of the kind wherein a conical, double conical or cylindrical mandrel is located in the centre of a vertical through-flow mould and wherein the casting is initiated with a starting head located between the mandrel and the mould wall, which head is gradually withdrawn after casting commences.

In the continuous casting of hollow bodies, more particularly the continuous casting of iron and steel, difliculties often occur due to the fact that the material, as a result of the shrinkage which occurs during the solidification operation, bears so tightly against the mandrel arranged inside the mould that the hollow casting fractures under the tractive force of the conveying rollers. It has been attempted to avoid this difliculty, which often occurs at the beginning of casting but also occurs during the further course of the casting operation, by making the mandrel conical in various ways. Despite this, however, in many cases it has not been possible to prevent the hollow casting from breaking.

The present invention aims to overcome this problem.

According to the invention in apparatus of the kind referred to above one or more separating plates are mounted on the face of the starting head against which the casting is initiated. The plates project upwardly away from the face into the interior of the mould.

With this apparatus the bottom end portion of the hollow body which is being cast is divided along the direction of casting movement into several separate sections during the initial stage of the casting operation. The part sections subsequently merge into a completely closed annular section.

As a result of the fact that the bottom end portion of the solidified hollow casting is divided up into a plurality of sections, the casting can no longer grip the mandrel tightly as a result of the shrinkage which occurs, and the danger of fracture is substantially avoided.

In general, the plates arranged on the upper surface of the starting head will be of refractory material, asbestos, sheet metal lined with asbestos or the like. These plates do not melt when the liquid metal is poured on to the starting head, and they prevent the formation of a closed ring of solidifying material before the hea lowering operation begins.

The height of the separating plates depends on the diameter or wall thickness of the hollow body to be cast.

Care must be taken that the casting is allowed to have a sufiicient grip for the connecting loops and hooks or the like which are arranged in known manner on the starting head and which become welded to the solidifying casting material.

When a plurality of separating plates are provided, and a plurality of annular nozzles are used for the molten material, it has been found advantageous to construct the separating plates in such a manner that the part sections of the solidifying material are connected together at one or more points, in order to fill the sep- 2,976,585 Patented Mar. 28, 1961 ice arate compartments uniformly. Accordingly, the separating plates have one or more apertures in them communicating with neighbouring chambers, or alternately the upper edge of the plates are cut so as to form communicating channels over which the molten metal can spill.

The short bottom end portion of the hollow casting which is divided up in this matter is, of course, removed after the casting operation has been concluded.

An example of apparatus for carrying out the process according to the invention will now be described with reference to the accompanying drawings in which:

Figs 1 and 2 are a cross-sectional view and a longitudinal sectional view respectively showing the arrangement and construction of the separating plates.

The mould is designated as K, the mandrel as D and the hollow casting as S. Where in the claims we speak of the mandrel as having a suitable circular shape in cross section it will be understood that we refer to either a conical, double conical or cylindrical cross section.

Fig. 1 shows a cross-section through the mould K with the mandrel D and the separating plates a and a which are formed of sheet metal plates c about which asbestos cord b is wound. The connecting loops which project into the mould K and are arranged on the starting head for the casting S, are designated as d.

Fig. 2 shows the mould K, the mandrel D and the starting head e with the separating plates a and a mounted thereon, in a longitudinal sectional view. The separating plate ain the left hand half of the figurecomprises a hole 1, whereas the separating plate a -in the right hand halfis bevelled towards the outer side thereof. Both constructions have the object of guaranteeing that, when a plurality of inlet nozzles are used, uniform filling of the separate compartments will be achieved without permitting the formation of a closed ring of material over the entire cross-section.

We claim:

1. A starting device for the continuous casting of hollow bodies by means of a mandrel located within a vertical through-flow mould open at both ends, the space between said mandrel and the mould wall being closed before casting is started by means of a starting head against which the casting is initially formed and which casting head is gradually withdrawn as casting progresses, said starting head having at least two plates upwardly directed from the face thereof against which casting is initially formed to provide at least two initially separate portions in the initially-formed portion of the casting, said plates extending radially from the mandrel to the mould wall.

2. Apparatus for the continuous casting of hollow bodies according to claim 1 wherein the plates are made of a refractory material.

3. Apparatus for the continuous casting of hollow bodies according to claim 1 wherein the plates are made of asbestos.

4. Apparatus for the continuous casting of hollow bodies according to claim 1 wherein the plates are made of metal and are covered with asbestos.

References Cited in the file of this patent UNITED STATES PATENTS 1,926,320 Trembour Sept. 12, 1933 FOREIGN PATENTS 704,512 Germany Apr. 1, 1941 751,355 Germany Oct. 3, 1950 891,444 Germany Sept. 28, 1953 948,275 France Ian. 24, 1949

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