GB1601944A

GB1601944A - Well blocks for ladles

Info

Publication number: GB1601944A
Application number: GB2932777A
Authority: GB
Original assignee: GLOCAST PRODUCTS Ltd
Current assignee: GLOCAST PRODUCTS Ltd
Priority date: 1978-03-14
Filing date: 1978-03-14
Publication date: 1981-11-04

Description

(54) IMPROVEMENTS IN OR RELATING TO WELL BLOCKS FOR LADLES (71) We, GLOCAST PRODUCTS LIM- ITED, of Savile House, Savile Road, Elland in the County of York, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- Industrial ladles used for the pouring of metals, particularly iron and steel, have a lining built of refractory bricks. In the case of a bottom-pour ladle a well block is fitted in the bottom of the ladle, the well block having a hole in which a nozzle can be fitted and a recess which forms a well in the floor of the lining around the top of the hole. The nozzle is itself usually made of refractory material and it is customary to change the nozzle after each heat. The hole through the nozzle is closed by a vertically shiftable stopper, the lower end of which is guided into the nozzle by the recess in the well block, and when the stopper is raised, molten metal is able to flow out of the ladle through the nozzle.

The bottom lining of a ladle of this type tends to wear quite rapidly, and this is especially true of the well block, which is subjected to erosion by the flowing molten metal, and mechanical wear due to the impact of the stopper. Hence, it is necessary to replace the bottom lining of the ladle at frequency intervals (after each pour in some instances) and this involves breaking the lining and fitting a new lining.

1 > is the object of the invention to provide a well block which will have an increased life, compared with the conventional well block, at an economic price.

According to this invention a well block for use in an industrial molten metal ladle comprises a liner and a body, the liner forming at least the well recess and having a greater resistance to wear than the body.

Wear of the well block can take place due to erosion by the molten metal, erosion by slag, impact by the stopper or spalling. The expression "wear resistance" is therefore used to describe resistance to one or more of these forms of wear.

Preferably the liner forms substantially the entire top surface of the block. It is further preferred that the liner is shaped to provide a flared well, and in the preferred construction the liner has a well which is frusto-conical in shape.

The well block may be formed so that the liner is held in the body by a physical gripping force exerted on the liner due to the manner in which the well block is formed in which case it will be virtually impossible to separate the liner from the body, and the two can be considered to be integral for all practical purposes--or the liner and the body may be formed separately and the liner then secured in the body.

According to a preferred feature of the invention, the liner is made of a material which has a greater wear resistance than the fireback refractory materials conventionally used. It will be appreciated however, that whilst in a general sense the wear resistance increases with hardness, there is a threshold above which wear resistance may fall off due to the material becoming too brittle and therefore more susceptible to spalling. It is preferred therefore to make the liner in a material which has the optimum hardness having regard to the primary objective of good wear-resistance.

The liner may be made of a hard refractory material such as sintered Mullite, Zircon, Fused Alumina, Chrome Alumina, Zirconia, or Tabular Alumina bonded with a suitable bonding agent, such as ethyl silicate.

Other bonding agents suitable for this purpose include that sold by I.C.I. Limited under the Trade Mark WINNOFOSS and the gelable alumina bonding agents described in the Specification of United Kingdom Patent No: 1,356,247. The body on the other hand may be made of refractory concrete or ordinary firebrick, since it is not required to provide the principal wear resistant part of the block.

According to another preferred feature of the invention, a method of manufacturing a well block for use in an industrial molten metal ladle, comprises forming a hard, wear resistant liner in a shape which provides at least the well, in a material such as sintered Mullite, Zircon, Fused Alumina, Chrome Alumina, Zirconia and Tabular Alumina; forming a body in a shape such that it complements the liner shape so as to provide the complete well block, in a heat resistant material softer than the liner, and fixing the liner in the body.

In one method of manufacture the liner is fired at a high temperature, and the body is cast around the liner and then fired at a lower temperature than the fusing temperature of the liner, whereby the body physically grips the liner due to its own contraction on to the liner.

Various forms of the invention will now be described by way of examples only, with reference to the accompanying drawings in which: Figure 1 is a vertical cross-section through a well block, Figure 2 is a plan view of the well block shown in Figure 1, and Figure 3 is a vertical cross-section through an alternative form of well block.

The well block 10 illustrated in Figures 1 and 2 is generally in the form of a square prism, and the external dimensions of the block are the same as those of a conventional well bock, so that it is adapted to be fitted into a built-up floor of a steel ladle. Also, the block has the usual bore 12, to receive a nozzle (not shown) and part conical well or throat 14 leading from the top surface of the block, to the upper end of the bore 12.

Whereas the conventional well block is manufactured as a unitary fired block, the well block 10 is made in two parts, namely a liner 16, and a body portion 18. The liner is of substantial thickness (say about 1 inches) and provides the entire top surface portion 20, the complete throat portion 14, and a cylindrical portion defining the bore 12. The body portion 18 is generally in the form of a square block, formed with a bore 22, and a tapered bore 24, to receive the liner 16.

The liner 16 is made in sintered Mullite, chemically bonded, using ethyl silicate as the bonding material. The method of manufacture of the liner is as described in the Article No: 34 in Transactions and Journals of the British Ceramic Society by H. G. Emblem, entitled "The Use of Ethyl Silicate as a Binder in Refractory Technology". The liner is formed in a mould, and fired at approximately 1650"C. This produces a very hard liner, which has excellent wear resisting properties, in relation to the molten metal which flows over the liner, and in relation to the impact of the stopper which engages with the throat 14.

After formation of the liner 16, the body portion 18 is moulded around the liner, this portion being - manufactured in refractory concrete containing for example 42% aluminum oxide, and the body portion is fired at approximately 1250 C. The firing will have no effect on the already completed liner 16, but it does have the effect of shrinking the body portion 18 tightly on to the liner 16, whereby the two parts of the well block become united.

The well block 10 illustrated in Figures 1 and 2 is used in exactly the same manner as the conventional well block, but by virtue of the hardness and wear resisting property of the liner 16, it has a longer working life than the conventional well block. At the same time, since the bulk of the material in the well block is the refractory concrete forming the body portion 18, the cost of the block is not excessive. Also, the body portion 18 has good impact resisting qualities, and provides a necessary degree of rigidity to the liner 16.

Figure 3 illustrates a well block 50 which has the same external shape and dimensions as the well block 10, and which also has a liner 56, and a body portion 58. Once again, the liner 56 is made in sintered Mullite using an ethyl silicate bonding material, and the body portion is made in refractory concrete or firebrick. However, in this construction it will be noted that the cylindrical portion of the liner 56 only extends part way down the bore 52 of the well block, the bottom portion of the bore 52 being defined by the body portion 58. Hence, the body portion 58 has to be formed with an annular rebate 60 to receive the cylindrical portion of the liner 56.

The well block 50 is somewhat cheaper to produce than the well block 10 shown in Figure 1, because the liner 56 is smaller, but since the majority of the wear occurs at the throat of the well block, it is therefore likely that the block 50 will be almost as effective as the block 10.

WHAT WE CLAIM IS: 1. A well block for use in an industrial molten metal ladle comprising a liner and a body, the liner forming at least the well recess and having a greater resistance to wear than the body.

2. A well block as claimed in Claim 1, in which the liner forms substantially the entire top surface of the block.

3. A well block as claimed in Claim 1 or Claim 2, in which the liner is shaped to provide a flared well.

4. A well block as claimed in Claim 3, in which the liner has a well which is hollow frusto-conical in shape.

5. A well block as claimed in any one of Claims 1 to 4, which is so formed that the liner is held in the body by a physical gripping force exerted on the liner.

6. A well block as claimed in any one of Claims 1 to 5, in which the liner is made of a hard refractory material such as sintered Mullite, Zircon, Fused Alumina, Chrome Alumina, Zirconia, or Tabular Alumina

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Mullite, Zircon, Fused Alumina, Chrome Alumina, Zirconia and Tabular Alumina; forming a body in a shape such that it complements the liner shape so as to provide the complete well block, in a heat resistant material softer than the liner, and fixing the liner in the body. In one method of manufacture the liner is fired at a high temperature, and the body is cast around the liner and then fired at a lower temperature than the fusing temperature of the liner, whereby the body physically grips the liner due to its own contraction on to the liner. Various forms of the invention will now be described by way of examples only, with reference to the accompanying drawings in which: Figure 1 is a vertical cross-section through a well block, Figure 2 is a plan view of the well block shown in Figure 1, and Figure 3 is a vertical cross-section through an alternative form of well block. The well block 10 illustrated in Figures 1 and 2 is generally in the form of a square prism, and the external dimensions of the block are the same as those of a conventional well bock, so that it is adapted to be fitted into a built-up floor of a steel ladle. Also, the block has the usual bore 12, to receive a nozzle (not shown) and part conical well or throat 14 leading from the top surface of the block, to the upper end of the bore 12. Whereas the conventional well block is manufactured as a unitary fired block, the well block 10 is made in two parts, namely a liner 16, and a body portion 18. The liner is of substantial thickness (say about 1 inches) and provides the entire top surface portion 20, the complete throat portion 14, and a cylindrical portion defining the bore 12. The body portion 18 is generally in the form of a square block, formed with a bore 22, and a tapered bore 24, to receive the liner 16. The liner 16 is made in sintered Mullite, chemically bonded, using ethyl silicate as the bonding material. The method of manufacture of the liner is as described in the Article No: 34 in Transactions and Journals of the British Ceramic Society by H. G. Emblem, entitled "The Use of Ethyl Silicate as a Binder in Refractory Technology". The liner is formed in a mould, and fired at approximately 1650"C. This produces a very hard liner, which has excellent wear resisting properties, in relation to the molten metal which flows over the liner, and in relation to the impact of the stopper which engages with the throat 14. After formation of the liner 16, the body portion 18 is moulded around the liner, this portion being - manufactured in refractory concrete containing for example 42% aluminum oxide, and the body portion is fired at approximately 1250 C. The firing will have no effect on the already completed liner 16, but it does have the effect of shrinking the body portion 18 tightly on to the liner 16, whereby the two parts of the well block become united. The well block 10 illustrated in Figures 1 and 2 is used in exactly the same manner as the conventional well block, but by virtue of the hardness and wear resisting property of the liner 16, it has a longer working life than the conventional well block. At the same time, since the bulk of the material in the well block is the refractory concrete forming the body portion 18, the cost of the block is not excessive. Also, the body portion 18 has good impact resisting qualities, and provides a necessary degree of rigidity to the liner 16. Figure 3 illustrates a well block 50 which has the same external shape and dimensions as the well block 10, and which also has a liner 56, and a body portion 58. Once again, the liner 56 is made in sintered Mullite using an ethyl silicate bonding material, and the body portion is made in refractory concrete or firebrick. However, in this construction it will be noted that the cylindrical portion of the liner 56 only extends part way down the bore 52 of the well block, the bottom portion of the bore 52 being defined by the body portion 58. Hence, the body portion 58 has to be formed with an annular rebate 60 to receive the cylindrical portion of the liner 56. The well block 50 is somewhat cheaper to produce than the well block 10 shown in Figure 1, because the liner 56 is smaller, but since the majority of the wear occurs at the throat of the well block, it is therefore likely that the block 50 will be almost as effective as the block 10. WHAT WE CLAIM IS:

1. A well block for use in an industrial molten metal ladle comprising a liner and a body, the liner forming at least the well recess and having a greater resistance to wear than the body.

bonded with a suitable bonding agent.

7. A well block as claimed in Claim 6, in which the bonding agent is ethyl silicate, or the gelable alumina bonded agents described in the Specification of United Kingdom Patent No: 1,356,247.

8. A method of manufacturing a well block for use in an industrial molten metal ladle comprising forming a hard, wear resistant liner in a shape which provides at least the well recess in a material such as sintered Mullite, Zircon, Fused Alumina, Chrome Alumina, Zirconia and Tabular Alumina; forming a body in a shape such that it complements the liner shape so as to provide the complete well block, in a heat resistant material softer than the liner, and fixing the liner in the body.

9. A method of manufacturing a well block as claimed in Claim 8, in which the liner is fired at a high temperature, and the body is cast around the liner and then fired at a lower temperature than the fusing temperature of the liner, whereby the body physically grips the liner due to its own contraction on to the liner.

10. A well block for use in an industrial molten metal ladle constructed and arranged substantially as herein described with reference to Figures 1 and 2, or Figure 3 of the accompanying drawings.

11. A method of manufacturing a well block for use in an industrial molten metal ladle substantially as herein described with reference to Figures 1 and 2, or Figure 3 of the accompanying drawings.