GB1589614A - Method of bottom teeming molten metal from a vessel provided with a valved outlet - Google Patents
Method of bottom teeming molten metal from a vessel provided with a valved outlet Download PDFInfo
- Publication number
- GB1589614A GB1589614A GB4595976A GB4595976A GB1589614A GB 1589614 A GB1589614 A GB 1589614A GB 4595976 A GB4595976 A GB 4595976A GB 4595976 A GB4595976 A GB 4595976A GB 1589614 A GB1589614 A GB 1589614A
- Authority
- GB
- United Kingdom
- Prior art keywords
- melt
- crust
- granular
- granular material
- upper layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims description 23
- 239000002184 metal Substances 0.000 title claims description 6
- 229910052751 metal Inorganic materials 0.000 title claims description 6
- 239000000155 melt Substances 0.000 claims description 46
- 239000008187 granular material Substances 0.000 claims description 38
- 239000000463 material Substances 0.000 claims description 37
- 239000010410 layer Substances 0.000 claims description 31
- 239000011449 brick Substances 0.000 claims description 20
- 229910000831 Steel Inorganic materials 0.000 claims description 15
- 239000010959 steel Substances 0.000 claims description 15
- 230000035515 penetration Effects 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 11
- 239000011819 refractory material Substances 0.000 claims description 10
- 238000005245 sintering Methods 0.000 claims description 10
- 239000002344 surface layer Substances 0.000 claims description 10
- 230000008018 melting Effects 0.000 claims description 8
- 238000002844 melting Methods 0.000 claims description 8
- 230000015572 biosynthetic process Effects 0.000 claims description 5
- 230000002401 inhibitory effect Effects 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 230000004888 barrier function Effects 0.000 claims description 3
- 230000003993 interaction Effects 0.000 claims description 3
- 230000004807 localization Effects 0.000 claims description 3
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims description 3
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 3
- 235000014380 magnesium carbonate Nutrition 0.000 claims description 3
- 239000001095 magnesium carbonate Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 239000013535 sea water Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 2
- 230000008014 freezing Effects 0.000 claims description 2
- 238000007710 freezing Methods 0.000 claims description 2
- 230000000750 progressive effect Effects 0.000 claims description 2
- 239000007788 liquid Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/14—Closures
- B22D41/44—Consumable closure means, i.e. closure means being used only once
- B22D41/46—Refractory plugging masses
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Description
(54) METHOD OF BOTTOM TEEMING MOLTEN METAL FROM
A VESSEL PROVIDED WITH A VALVED OUTLET (71) We, STOPINC
AKTIENGESELLSCHAFT, a Company organised under the laws of Switzerland of
Zugerstrasse 76a, CH 6340 Baar, Switzerland 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:
The invention relates to improvements in, and the operation of, slide gate nozzles including rotary and longitudinal sliding gate nozzles for metallurgical vessels in particular for the bottom teeming of steel or other metals from ladles and the like.
The closure plane of the slide gate nozzle is inevitably below the shell of the ladle, i.e.
at the lower end of the discharge duct in the nozzle brick. As this duct is of comparatively small diameter, e.g. 5 to 7 cm., the steel is liable to freeze in it and make the device inoperative during the waiting period between the filling of the ladle and the beginning of teeming.
One way of overcoming this problem is described in British Patent 1112368 (Paderwerk Gebr Benteler). According to this specification the said nozzle brick has a funnel shape which, before each charge of the ladle, is filled with highly refractory granular material, the free surface of the granular material in the funnel being at least 150 square centimetres with a following neck portion at least 30 mm long. A crust is formed at the interface of the refractory granular material with the molten steel, which prevents further penetration of steel into the dry granular material. On opening the slide gate valve the granular material below the crust flows out freely under its own weight, leaving the crust, which spans the funnels, unsupported. Under the weight of the liquid steel above it, the crust collapses thus allowing the steel to be teemed without difficulty.
It will be noted that the refractory material not only fills the narrow neck portion, but also the funnel. This is essential because according to the known method the crust only collapses if it has a sufficiently wide span. This in turn means that a substantial quantity of granular material has to be used which is undesirable as it increases the risk of contaminatig the molten steel. A further drawback is the fact that the technique does not work without a certain percentage of failures, in which the crust does not collapse and has to be destroyed by an oxygen lance.
The reasons for this were not understood.
It is the object of the present invention to at least reduce the severity of these drawbacks.
We now believe that the success of the above technique depends not so much on the diameter of the crust (its "span") but at least as much on the ratio of diameter to the thickness of the crust. The diameter of the crust, and hence the cross section of the part of the funnel in which it forms, may be smaller than the minimum of 150 square centimetres stipulated in the known technique, provided that the thickness of the crust is kept sufficiently small and does not materially increase with increasing waiting time prior to teeming.
The present invention is a method of bottom teeming molten metal from a vessel provided with a valved outlet having an outlet opening communicating with a nozzle brick located in the lining of the vessel, which comprises locating granular refractory material in the outlet passage of the nozzle brick so that the top surface of the said material is within the nozzle brick and selecting the composition or arrangement of the granular material in relation to the melt which is to be teemed to ensure that the interaction of the melt with the granular material is localised at the surface thereof.
The localisation of the formation of the crust is preferably achieved by using a two component granular material for the filling, the upper layer at the interface with the melt being a layer of refractory material which will sinter to a dense crust on contact with the melt thus inhibiting further penetration by the melt, the mass of granular material below the upper layer being of a different composition such as not to sinter in contact with the melt or at the temperatures to which it may be raised in use due to conduction from the melt. The material of the upper layer preferably has a sintering temperature close to the melting point of the melt, that is to say not far below the latter, e.g. not more than 200"C below the melting point of the melt.
The effect of this arrangement is threefold:
(1) The surface layer of the granular material becomes rapidly impervious to the penetration of steel due to the sintering together of the grains forming the surface layer.
(2) The crust is only formed by the surface layer so that its depth remains small.
(3) The crust does not increase in depth even for a long waiting time, because the progressive increase in temperature of the principal mass of material below the crust can never reach the sintering temperature of the latter.
A suitable material for the principal mass of granular material is granular magnesite produced from sea water. There are many materials suitable for the surface layer. One such material is granular Transvaal chrome ore which tends to sinter between 1400 and 14500"C.
In applying the method according to this invention to a funnel shaped nozzle brick it is not advisable to fill only the neck portion of the nozzle brick if the latter is relatively short compared to the funnel portion. The danger in this case is not that the crust forms in a different manner, but that, due to the depth of the funnel, the lowermost layer of molten steel above the granular material freezes. If this occurred it would make the valve inoperative, or at least would necessitate burning a hole into the frozen steel layer with an oxygen lance.
It is preferred to use a nozzle brick of which the conical portion is shorter than the cylindrical portion and in which the outlet passage is almost filled with the granular material so that the crust is near the inside surface of the lining of the ladle. In this case the funnel shaped portion will have relatively small free opening which may be less than 150 square centimetres. In this case, the nozzle brick can be filled or almost filled without using a great amount of granular material. But as the crust would be near the bottom of the ladle, there would be little or no danger of the steel freezing above the granular material.
The upper or surface layer of granular material could be a mixture of such sinterable material and other refractory material which would not sinter with the melt involved, the mixture however being such as still to inhibit further penetration by the melt.
Preferably the mass of granular material below the upper layer material has a higher sintering temperature and melting point than the sinterable material of the upper layer.
The particle size of the sinterable material of the upper layer is preferably smaller than that of the non-sinterable material so as to form an effective barrier to penetration by the melt.
In order to facilitate the formation of a layer of sinterable material at the interface with the melt of correct thickness, the sinterable material may be supplied in disc shaped bags which may be of flat cylindrical shape or flat truncated cone shape. The bags are preferably of impermeable material which is imflammable and will be destroyed when the melt is placed in the vessel.
WHAT WE CLAIM IS:
1. A method of bottom teeming molten metal from a vessel provided with a valved outlet having an outlet opening communicating with a nozzle brick located in the lining of the vessel, which comprises locating granular refractory material in the outlet passage of the nozzle brick so that the top surface of the said material is within the nozzle brick and selecting the composition or arrangement of the granular material in relation to the melt which is to be teemed to ensure that the interaction of the melt with the granular material is localised at the surface thereof.
2. A method as claimed in Claim 1 in which the localization of the formation of the crust is achieved by using a two component granular material for the filling, the upper layer at the interface with the melt being a layer of refractory material which will sinter to a dense crust on contact with the melt thus inhibiting further penetration by the melt, the mass of granular material below the upper layer being of a different composition such as not to sinter in contact with the melt or at the temperatures to which it may be raised in use due to conduction from the melt.
3. A method as claimed in Claim 2 in which the material of the upper layer in contact with the melt has a sintering temperature the value of which is not more than 200"C below the melting point of the melt.
4. A method as claimed in claim 2 or claim 3 in which the particle size of the sinterable material of the upper layer is
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (9)
1. A method of bottom teeming molten metal from a vessel provided with a valved outlet having an outlet opening communicating with a nozzle brick located in the lining of the vessel, which comprises locating granular refractory material in the outlet passage of the nozzle brick so that the top surface of the said material is within the nozzle brick and selecting the composition or arrangement of the granular material in relation to the melt which is to be teemed to ensure that the interaction of the melt with the granular material is localised at the surface thereof.
2. A method as claimed in Claim 1 in which the localization of the formation of the crust is achieved by using a two component granular material for the filling, the upper layer at the interface with the melt being a layer of refractory material which will sinter to a dense crust on contact with the melt thus inhibiting further penetration by the melt, the mass of granular material below the upper layer being of a different composition such as not to sinter in contact with the melt or at the temperatures to which it may be raised in use due to conduction from the melt.
3. A method as claimed in Claim 2 in which the material of the upper layer in contact with the melt has a sintering temperature the value of which is not more than 200"C below the melting point of the melt.
4. A method as claimed in claim 2 or claim 3 in which the particle size of the sinterable material of the upper layer is
smaller than that of the non-sinterable material so as to form an effective barrier to penetration by the melt.
5. A method as claimed in Claim 2, 3 or 4 in which the material of the upper layer is granular Transvaal chrome ore which sinters between 1400 and 1450"C.
6. A method as claimed in any one of
Claims 1 to 5 in which the principal mass of granular material is granular magnesite produced from sea water.
7. A method as claimed in any one of
Claims 1 to 6 in which the outlet passage of the nozzle brick is funnel shaped, the conical portion of the funnel being shorter than the cylindrical portion of the funnel and in which the outlet passage is almost filled with the granular material so that the crust is near the inside surface of the lining of the ladle.
8. A method as claimed in any one of
Claims 1 to 7 in which the sinterable material is supplied in disc shaped bags which are of flat cylindrical shape or flat truncated cone shape.
9. A method as claimed in Claim 8 in which the bags are of impermeable material which is inflammable and will be destroyed when the melt is placed in the vessel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4595976A GB1589614A (en) | 1977-11-04 | 1977-11-04 | Method of bottom teeming molten metal from a vessel provided with a valved outlet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB4595976A GB1589614A (en) | 1977-11-04 | 1977-11-04 | Method of bottom teeming molten metal from a vessel provided with a valved outlet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1589614A true GB1589614A (en) | 1981-05-13 |
Family
ID=10439253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4595976A Expired GB1589614A (en) | 1977-11-04 | 1977-11-04 | Method of bottom teeming molten metal from a vessel provided with a valved outlet |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1589614A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2120588A (en) * | 1982-05-27 | 1983-12-07 | British Steel Corp | Introduction of refractory filler material into nozzle assemblies of molten metal-holding vessel |
| US4525463A (en) * | 1982-04-17 | 1985-06-25 | Heinz Dislich | Spout-filling mass |
| GB2226262B (en) * | 1988-12-21 | 1993-02-10 | K S R International Limited | Improvements in or relating to pouring of metals |
-
1977
- 1977-11-04 GB GB4595976A patent/GB1589614A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4525463A (en) * | 1982-04-17 | 1985-06-25 | Heinz Dislich | Spout-filling mass |
| GB2120588A (en) * | 1982-05-27 | 1983-12-07 | British Steel Corp | Introduction of refractory filler material into nozzle assemblies of molten metal-holding vessel |
| GB2226262B (en) * | 1988-12-21 | 1993-02-10 | K S R International Limited | Improvements in or relating to pouring of metals |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |