Converter vessel for steel preparation

Abstract

 A converter vessel for steel preparation has an outwardly convex bottom III and a side wall I and refractory permanent and working linings which are applied on the side wall in horizontal layers 2, 3 and on the bottom in layers 4-7 which generally follow the shape of the bottom. At a transition region II between the bottom and the side wall an inwardly projecting peripheral steel flange 9, which supports the permanent lining 2 of the side wall, is secured to the vessel wall. To strengthen the flange 9 and absorb the expansion forces of the bottom lining the flange 9 forms part of a rigid hollow tubular steel structure which also includes a peripheral support wall 8 extending inwardly obliquely relative to the adjacent part of the vessel wall and transversely to the adjacent parts of the layers 4-6 of the permanent lining of the bottom.

Description

[0001] The invention relates to a converter vessel for steel preparation, having a vessel wall and refractory permanent and working linings.

[0002] Where reference is made in this description and claims to a converter vessel, no distinction is made between the different types of vessels which are used for various methods of steel preparation, such as the method in which oxygen is blown into the vessel by a lance from above, or the method in which oxygen and/or inert gases are blown through the vessel bottom, or a combination of these two methods. Such methods may be further combined with the supply of lime, carbon or other solids to the molten metal.

[0003] By the term "permanent lining" is meant the layer(s) of the brickwork which is (are) applied very securely to the vessel wall and which is (are) in principle maintained unchanged in a repair to the lining. The working lining, on the other hand, is subjected to wear and attack during the steel making, and must therefore be replaced'from time to time.

[0004] Typically, in such a converter, the vessel wall has an outwardly convex bottom and a side wall, as seen in the vertical position of the converter. On the side wall, the brickwork of the linings is applied in horizontal layers, and on the bottom the linings are installed in layers which generally follow the shape of the bottom. At a transition region of the wall between the bottom and the side wall there is a flange or horizontal ring secured to the vessel wall, which supports the permanent lining of the side wall.

[0005] It is known that the transition region between the, for example, almost cylindrical, vessel side wall and the bottom gives rise to problems in practice. At this point the bricks on the vessel bottom are usually connected to the permanent lining of the vessel wall by high quality special shaped bricks. These shaped bricks must provide a consistently good connection between the two parts of the lining in the different positions of the converter vessel. As mentioned above, in most cases a horizontal steel ring or flange is secured to the vessel side wall, between these connecting specially shaped bricks and the permanent lining of the vessel side wall.

[0006] In practice however, due to variations in the temperature of the vessel bottom and/or the penetration of dust and slag particles into the bottom brickwork, the permanent lining of the vessel bottom exerts high pressures on the specially shaped connecting bricks, so that the latter are crushed and lose their supporting function. Furthermore, this high expansion pressure may also continue as far as the welded-on steel ring, which is pushed upwards as a result. This in turn pushes up the permanent lining of the side wall, so that cohesion in the permanent lining is lost.

[0007] The object of the invention is to provide a vessel in which these difficulties are avoided or mitigated.

[0008] The invention consists in that the said horizontal flange secured to the vessel wall forms part of a rigid hollow tubular steel structure which also includes a support wall extending obliquely relative to the adjacent vessel wall and transversely to the adjacent parts of the layers of the permanent lining on the vessel bottom.

[0009] This tubular steel structure can provide very great rigidity so that it cannot be pushed upwards by expansions in the bottom lining. The expansion pressure is thus completely absorbed by the vessel wall and is therefore no longer exerted on the permanent lining of the vessel wall. At the same time, this construction can avoid the use' of the expensive specially shaped bricks at the transition region, which represents a considerable saving in the costs of the vessel lining.

[0010] In order to increase the rigidity of the tube, and also in order to limit the flow of heat through the tube, it is preferred that the hollow steel tubular structure is filled with refractory concrete. Suitable openings can be provided in the structure for this purpose.

[0011] The layers of brickwork of the permanent lining in the vessel bottom cannot all extend right up to the said support wall of the tubular structure, due to the curvature of the transition region from the bottom towards the side wall. In practice the lowest layer is terminated before it reaches this support wall, and the space thereby formed, between the subsequent layers and the support wall of the tubular structure may be filled with concrete. However, if the lowest layer now expands, for whatever reason, then its expansion pressure will be transmitted to this concrete region which may be crushed as a result. It is preferred therefore, in the practice of the invention, that an additional peripheral steel flange is provided extending transversely.to the vessel bottom adjacent to the peripheral edge lowest layer of the permanent lining of the bottom,.this flange having about the same height as this layer, and that the space between this flange and the hollow tubular structure is filled with refractory concrete, which is preferably anchored. Compressive forces in the lowest layer, resulting from its expansion, are not absorbed by the concrete, but are absorbed by the steel flange which in itself is a continuous ring.

[0012] The compressive forces transmitted by the different layers of brickwork in the vessel bottom to the said additional steel flange, and to the hollow tubular structure can be further reduced by ending these layers at a distance from the hollow tubular structure and/or the flange on the vessel bottom and by filling the spaces thus left free with a refractory ramming mass. Since the layers of brickwork consist of individual bricks, a free space will generally be left at the edges of these layers in any case. Refractory ramming masses are generally fairly compressible, so that by their use the compressive forces acting on the steel tubular structure and on the flange can be limited.

[0013] The preferred embodiment of the invention is illustrated below by way of non-limitative example and with reference to the accompanying drawings, in which

Fig. 1 shows in section half of the bottom end of a steel converter embodying the invention; and

Fig. 2 shows a detail of Fig. 1 at the transition region on a larger scale.

[0014] In the part of a converter vessel shown in Fig. 1 there is a steel outer shell 1 comprising the vessel side wall, the transition region and the outwardly convex vessel bottom which are denoted as regions I,II and III respectively. A permanent lining 2 and a working lining 3 are located against the side wall, inside the steel outer shell 1 of the vessel, both being constructed from bricks which are arranged in horizontal layers (courses).

[0015] The lining of the vessel bottom comprises three layers of permanent brickwork 4,5 and 6 forming the permanent lining, together with a working lining 7. The bricks of the bottom brickwork are laid in layers which follow the shape of the vessel bottom.

[0016] At the lower end of the side wall I, a horizontal steel ring 9 is welded to the outer shell 1, to form a peripherally extending flange extending inwardly to the width of the permanent lining of the side wall at the location of the transition between vessel wall I and transition region II. The permanent lining 2 of the side wall I is constructed on this ring 9.

[0017] Fig. 2 shows the portion of the structure at the transition region II, on a larger scale. A support wall 8 extends inwards obliquely from the outer shell 1 to the inner edge of the ring 9. The wall 8 is welded securely to the ring 9 and the shell 1. The portion of the shell 1 between the outer edges of the ring 9 and the wall 8, the wall 8 and the ring 9 thus form a rigid annular steel tubular structure. The ring 9 is drilled at various points (not shown) to provide holes through which the space inside this tubular structure has been injected with refractory concrete 14. This tubular structure extends peripherally around the vessel and provides a very strong structure capable of absorbing and resisting the forces exerted on expansion of the permanent lining layers 5,6 of the bottom.

[0018] A peripheral steel flange 10 is welded to the bottom so as to extend transversely thereto as seen in Fig. 2, at the location of the transition from the vessel bottom III to the transition piece II. This flange has a height which corresponds to the thickness of the lowest layer 4 of the bottom lining, and thus serves to absorb the forces arising on expansion of the layer 4. The space thus left between the layer 5, the steel shell 1 of the vessel, the flange 10 and the support wall 8 is filled with concrete 11.

[0019] The spaces left between the flange .10 and the layer 4, and the spaces between the support wall 8 and the layers 5 and 6, are filled with refractory ramming mass 12,13. Furthermore, all free spaces around the bottom bricks of the working lining 3 are filled with refractory ramming mass 15.

Claims

1. Converter vessel for steel preparation, having (as seen in the vertical position of the vessel) a vessel wall comprising an outwardly convex bottom and a side wall and refractory permanent and working linings which are applied on the side-wall in horizontal layers and on the bottom in layers which generally follow the shape of the bottom, there being a transition region of the vessel wall between the bottom and the side wall where an inwardly projecting peripheral steel flange, which supports the permanent lining of the side wall, is secured to the vessel wall
characterised in that
said flange forms part of a rigid hollow tubular steel structure which also includes a peripheral support wall extending inwardly obliquely relative to the adjacent part of the vessel wall and transversely to the adjacent parts of the layers of the permanent lining of the bottom.

2. - Converter vessel according to claim 1 wherein said rigid hollow tubular structure is comprised of said flange, said.support wall and a portion of said vessel wall which extends between the respective outer ends of said flange and said support wall.

3. Converter vessel according to claim 1 or claim 2 wherein said hollow tubular structure is filled with refractory concrete.

4. Converter vessel according to any one of claims 1 to 3 having a further peripheral steel flange extending inwardly from the bottom transversely thereto adjacent the peripheral edge of the lowest layer of the permanent lining of the bottom, the height of said further steel flange corresponding to the thickness of said lowest layer and the space between said further steel flange and the said hollow tubular structure is filled with refractory concrete forming an extension of said lowest layer.

5. Converter vessel according to any one of claims 1 to 4 wherein spaces between on the one hand the layers of the permanent lining of the bottom and on the other hand the said hollow tubular structure and said further steel flange are filled with refractory ramming mass.

Drawing