GB2141956A

GB2141956A - A casting mould and a method of preparing the mould for casting

Info

Publication number: GB2141956A
Application number: GB08411150A
Authority: GB
Inventors: Manfred Guenther; Bernd Grothe; Werner Gehre; Dieter Erben; Rolf Arnold; Helmut Eberhardt; Anna-Maria Bartl; Rolf Halbich
Original assignee: Heidenau Netz & Seil Veb
Current assignee: Heidenau Netz & Seil Veb
Priority date: 1983-06-21
Filing date: 1984-05-01
Publication date: 1985-01-09
Also published as: YU102784A; GB8411150D0; JPS609558A; RO90423A; HUT35195A; GB2141956B; DE3414132A1; HU189410B; IT8448431A0; IT1177816B; SE8403354D0; SE8403354L

Abstract

The method of the invention is for use predominantly in continuous casting plants. A soft textile material predominantly consisting of cellulose fibres is packed into the joint between a mould wall (2) and a starter bar head (4) with an increasing packing density. <IMAGE>

Description

SPECIFICATION A casting mould and a method of preparing the mould for casting This invention relates to a casting mould and to a method of preparing the mould for casting, and has particular application to use in the metallurgical industry, for example in steelworks, for example for the packing of cold casting heads in continuous casting plants.

A number of methods for the packing of the head joints of cold casting heads are known.

It is known to pack the joints with asbestos cord. This material can be easily compressed.

to achieve a permanent compression, but this has the disadvantage that material often reemerges from the joints and then needs to be repacked, which takes a long time. In addition asbestos packing materials have the drawback that they cause contamination of the plant components and have effects which are prejudicial to health (asbestosis).

In order to avoid the disadvantageous effects of sealing cords containing asbestos, a method for the packing of the joints by means of a paper seal has been developed. For this purpose a cord is rigidly twisted together from very non-absorbent kraft paper, and the cord is then clamped in the joints. The non-absorbent property of the kraft paper is required in order to prevent the saturation of the paper cord if it comes into contact with water, as no moisture must be allowed to penetrate into the liquid or molten steel. However, the paper cord is for this reason relatively easily combustible. In order to prevent the combustion of the seal until the liquid steel has crystallised, it is necessary to use, in addition, larger amounts of cooling material (aluminium or iron scrap).A further drawback of the kraft paper cord lies in its arched surface which prevents the optimum contact of the surface with the seal. As a result of its stiffness, the paper seal requires greater work and is relatively costly as a result of its raw materials.

The present invention provides a sealing method for cold casting heads, in which combustible materials leaving non-adhesive residues are used in such a way that even in the case of slight irregularities, a seal which is flush with the surface is ensured, in which there may be no inclusions of atmospheric oxygen in its upper layer and which provides for its own cooling, wherein additional cooling materials are not required, and wherein effects which are prejudicial to health and the contamination of plant components are avoided.

More particularly, from one aspect the invention provides a method of preparing a casting mould comprising first and second mould members defining cavity to receive material to be cast, the method including packing the joint between the mould members with textile material consisting at least predominantly of cellulose fibres.

The invention also provides a casting mould comprising first and second mould members defining a cavity to receive material to be cast, the mould members having a joint therebetween the joint being packed with textile material consisting at least predominantly of cellulose fibres.

The textile material may be readily compressed but remains resilient. Preferably the textile material comprises a loosely formed viscose fibre fleece. As a result of the fibrous and heavily textured surface of the loosely shaped compound the seal is provided with a high degree of contact, as irregularities in the cold casting head and the ingot mould are also filled. This ensures a seal which adheres tightly to the surface. The mould can be used with advantage to cast steel utilising a cold casting head. A very high packing density of the textile material may be achieved in the area of the surface of reaction between the packing material and the liquid steel, and consequentally inclusions of atmospheric oxygen and therefore an immediate combustion of the packing is prevented.This effect is increased, as a portion of the textile material which does not come into contact with the liquid steel, absorbs moisture and therefore provides for the cooling of the packing. For these reasons it is not necessary to cover the packing with aluminium or iron scrap which is used as cooling material in order to prevent damage to the cold casting head.

A further advantage provided by the invention consists in that textile material may be combustible so that it is possible to use secondary textile raw materials. These are simply formed by means of a coarse woven mesh structure into a loose compound and held together such that the advantages of their heavily textured fibrous surface come into effect. The combustibility of the packing material is important for the subsequent removal.

After removal of the cold casting head the textile packing material comes into contact with atmospheric oxygen and burns, wherein the combustion residues may be removed very easily as they do not adhere. The previously used asbestos cords may be replaced according to the invention and their effects which are prejudicial to health may be avoided. The contamination of the plant components by non-combustible, adhesive residues of the packing may be prevented according to the invention.

The invention is described in further detail with reference to an embodiment thereof, in relation to the accompanying drawings wherein: Figure 1 is an schematic diagram (in crosssection) of the packing of a cold casting head and Figure 2 shows the detail Y from Fig. 1.

Using the Maliwatt method, edge strips in the form of viscose fibre fleeces are formed loosely together into a linear compound 5 which may be compressed from approximately 20 mm to 5 mm in accordance with a known sheathing method.

The cover thread has little effect on the texture so that the fibrous surface of the edge strips of the fleece project greatly. The linear compound 5 is packed in layers into the joints 6 disposed between the copper plate of an cylindrical ingot mould 2 member, which is cooled via cooling ducts 3, and a mould member comprising a cold casting head 4 received in the mould member 2. The mould members 2, 4 define a cavity to receive liquid steel to be cast. The linear compound 5 is packed in with a varying density. The packing density of the packed joint decreases from the top, i.e. ffrom the cavity which receives the liquid steel, to the bottom.As a result of the lower packing density of the cord 5' in the lower area a relatively high absorption of moisture is enabled by means of the water mist 7 resulting from the direct cooling, this absorption of moisture causing cooling and thus preventing combustion. As a result of the more tightly packed layers, 5" and 51"' the water is prevented from rising and the penetration of atmospheric oxygen is prevented, as a result of which an inert zone is provided.

After packing, the cold casting head 4 may be covered with casting splinters or scrap 9. In the area of the highest packing density of the cord 5"" there is a sintering effect at the surface of reaction 8 between the liquid steel 1 and the linear compound 5.

After removal of the cold casting head 4 in the removal direction 10 atmospheric air is enabled to come into contact with the linear compound 5, as a result of which oxidation leaving a small residue takes place enabling a simple removal.

Claims

1. A casting mould comprising first and second mould members defining a cavity to receive material to be cast, the mould members having a joint therebetween the joint being packed with textile material consisting at least predominantly of cellulose fibres.

2. A casting mould according to claim 1 wherein the textile material comprises a viscose fibre fleece loosely formed prior to packing into the joints.

3. A casting mould according to claim 1 or 2 wherein said textile material is in strip form.

4. A casting mould according to claim 1 wherein said textile material is in flock or chip form.

5. A casting mould according to any preceding claim wherein the packing density of the textile material in the joint increases in a direction towards the cavity.

6. A casting mould according to any preceding claim wherein the textile material is packed in layers into the joint, the layers having different packing densities.

7. A casting mould according to any preceding claim wherein said mould member comprises a generally cylindrical ingot mould and the second mould member comprises a casting head received within the ingot mould.

8. A casting mould according to claim 7 wherein the ingot mould includes cooling ducts.

9. A casting mould substantially as hereinbefore described with reference to the accompanying drawings.

10. A method of preparing a casting mould comprising first and second mould members defining cavity to receive material to be cast, the method including packing the joint between the mould members with textile material consisting at least predominantly of cellulose fibres.

11. A method according to claim 10 including exposing the textile material in the joint to a water mist from a side of the joint opposite said cavity.

12. A method according to claim 10 or 11 including packing the material into the joint in such a manner that the packing density of the material increases in a direction towards the cavity.

1 3. A method according to claim 1 2 including packing said material in layers having different packing densities.

14. A method according to any of claims 10 to 13 further including casting molten material in the prepared mould.

15. A method according to claim 14 including moving one of said mould members after said casting in such a manner as to cause oxidation of said packing material.

16. A method according to claim 14 or 15 including casting molten steel in the mould, without first covering the textile packing material with aluminium or iron scraps.

1 7. A method of preparing a mould for casting substantially as hereinbefore described with reference to the accompanying drawings.

18. A method of casting substantially as hereinbefore described with reference to the accompanying drawings.

1 9. A method of packing cold casting heads by packing of the joints with rope products, wherein a loosely shaped linear compound of soft textile material predominantly consisting of cellulose fibres is packed into the joints with a packing density which increases in the direction of the surface of reaction.