EP0043670A1 - Giessen von Metallen und bekleidete Gefässe dafür - Google Patents

Giessen von Metallen und bekleidete Gefässe dafür Download PDF

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Publication number
EP0043670A1
EP0043670A1 EP81302810A EP81302810A EP0043670A1 EP 0043670 A1 EP0043670 A1 EP 0043670A1 EP 81302810 A EP81302810 A EP 81302810A EP 81302810 A EP81302810 A EP 81302810A EP 0043670 A1 EP0043670 A1 EP 0043670A1
Authority
EP
European Patent Office
Prior art keywords
ladle
lining
boards
metal
refractory
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.)
Granted
Application number
EP81302810A
Other languages
English (en)
French (fr)
Other versions
EP0043670B1 (de
Inventor
Bryan Howard Hearne
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Foseco Trading AG
Original Assignee
Foseco Trading AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Foseco Trading AG filed Critical Foseco Trading AG
Priority to AT81302810T priority Critical patent/ATE5800T1/de
Publication of EP0043670A1 publication Critical patent/EP0043670A1/de
Application granted granted Critical
Publication of EP0043670B1 publication Critical patent/EP0043670B1/de
Expired legal-status Critical Current

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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
    • B22D41/02—Linings

Definitions

  • the invention relates to the lining of metallurgical ladles of the type used in foundries to supply molten metal to, for example, a casting mould and especially to means for reducing the content of inclusions in molten metal emerging from such ladles and for reducing the need for preheating of the ladles.
  • ladles are of generally bucket form, and have either an outlet i.e. nozzle in the floor or are shaped to be emptied over the lip of the ladle.
  • the ladle usually consists of an outer metal shell on which is superimposed a relatively permanent lining of refractory brickwork or a rammed or cast refractory concrete to form a monolithic refractory lining.
  • molten metal is poured from a furnace, such as a high frequency induction furnace, into the ladle and from there to a casting mould.
  • the molten metal is held in the ladle while it is moved from one location to another, for example from a tapping position to various pouring positions.
  • the molten metal may be held in the ladle for about 30 minutesi usually the ladle is filled and then emptied within 20 minutes. While the molten metal is present in the ladle it tends to attack the refractory lining and this generally means that each time the ladle is emptied the rela- .tively permanent lining needs to be repaired and eventually it must be replaced. It is known that one can protect the relatively permanent lining by a refractory dressings this is cheap but not sufficiently erosion-resistant.
  • the foundryman is concerned with the quality of the metal in the castings he produces and to ensure this he takes certain precautions.
  • One problem is the loss of temperature of the molten metal in the ladle; heat is lost while the metal is tapped from the furnace and the metal also loses heat when held in the ladle which may be moved from mould to mould.
  • To ensure that the metal temperature is sufficiently high for a casting of correct quality to be formed it is standard practice to tap the metal at a temperature higher than that needed for casting and also to preheat the ladle to compensate for the thermal losses that will occur.
  • Another problem concerns the risk of inclusions in the- metal.
  • a method of supplying substantially inclusion- free-molten metal from an unpreheated ladle to a mould comprising,
  • the molten metal may be any metal or alloy composition commonly used in foundries, examples being steel, iron, copper, aluminium and alloys of these.
  • An important advantage of this invention is that because the lining is heat insulating to a desired extent, there is little or no need to superheat the metal in the furnace above a normal casting temperature.
  • Ladles take several forms.
  • the ladle has a sealed bottom and the molten metal is poured into a casting mould from the top via a lip.
  • a version of a lip pour ladle in which the metal is drawn from the bottom of the ladle is a so-called "teapot"ladle.
  • the ladle floor has an outlet containing a replacable nozzle so that the metal is poured out from the bottom. The invention is applicable to all these. forms of ladle.
  • the used lining will be discarded after one use since the risk that the inclusions will have reached an unacceptable level cannot be tolerated.
  • the lining may however, be used for more than one furnace tap and this can happen where economy is more important than the metallurgy of the cast metal.
  • the decision when to discard the used lining is in the control of the foundryman who will balance his need for economy with the desire to achieve castings of a defined quality; in any event the use of the invention will reduce the cost and need for preheating and will simplify the relining when it is required.
  • the lining may be used more than once when the time from one tap to another is very short and to meet this case the lining can be adapted for multiple use as there is insufficient time for.relining. Linings which are to be used more than once will tend to be thicker than those used once only.
  • a foundry ladle comprising,
  • Such a ladle may be of any of the forms mentioned above. Where the ladle has a nozzle in the floor, the lining an the floor may have a bore into which the nozzle may key and this will lock the nozzle into position. This means that the usual self setting or ramming composition to hold the nozzle is not needed - not only does this remove a dirty and time consuming job but we have found that the risk of inclusions is reduced.
  • the protective discardable lining is preformed of one or more boards.
  • the lining may be formed as a one piece item.
  • the lining is formed of a set of boards of the composition.
  • the set of boards comprises one or more floorboards shaped and arranged to cover the-ladle floor. Where the floor has an outlet nozzle, the floorboard will have a bore to key the nozzle so avoiding any ramming or setting material.
  • the set also includes side boards which are dimensioned to extend from the floorboard to the top of the ladle and most preferably the floorboard is shaped for example by edge recesses to receive or register with the side boards in sealed manner.
  • the side boards be shaped so that they are wider at th.e end remote from the floorboard than at the floorboard end so that they taper outwardly to the top of the ladle. This feature assists in the removal of the used inner lining after the ladle has been emptied of molten metal.
  • Most preferably adjoining side walls of the boards are shaped to form a seal to prevent the passage of molten metal thereacross and it is much preferred that the boards be trapezoidal in section. For enhanced sealing it is possible to apply a refractory cement across the joints.
  • the lining must be formed of a composition which is refractory,' has a relatively high heat insulation and a relatively low heat conductivity.
  • these criteria can be satisfied by controlling physical parameters of the boards.
  • the boards forming the inner protective 'lining should be at least 10mm thick and preferably 15mm to 20 or 25mm thick. If they are more than 50mm thick they tend to occupy a relatively high proportion of the volume of a small ladle which restricts the amount of molten metal it can hold.
  • the boards have a density in the range of from about 0.3 to about 1.5 preferably about 0.5 to 1.1 gm/cc.
  • the thermal conductivity should be in the range of about 0.1 to 1.0, preferably 0.3 to 0.5 W/mK
  • the boards should have a transverse strength of about 5 to 25 Kg/sq.cm, preferably 15 to 20 Kg/sq.cm.
  • the permeability of the boards may be important; in the case of boards formed from an organically. bonded composition the permeability should be of the order of 10 AFS units (American Foundryman Society).
  • the boards may be formed from a variety of compositions used to make boards for forming the expendable lining of a tundish.
  • a tundish is a constant head vessel used in the continuous casting of steel and interposed between the ladle and the continuous casting mould.
  • Such tundish linings are well known under the registered trade mark.GARNEX and there is thus no need for a detailed explanation here of the chemical compositions of which they may be formed.
  • the inner protective discardable lining of this 'invention may be formed of fibrous materials, refractory fillers and binders.
  • inorganic fibres such as paper, and as inorganic fibres asbestos, calcium silicate, aluminium silicate fibres; as refractory fillers silica, alumina, magnesia, refractory silicates; and as binders both inorganic and organic, colloidal silica sol, sodium silicate, starch, phenolformaldehyde resin or urea-formaldehyde resin.
  • tundish lining boards for the purposes of this invention has not been proposed.
  • the boards in a tundish the constant inflow of superheated molten metal keeps the temperature of the molten metal fairly uniform, and because the slabs and billets formed are subjected to secondary processing inclusions are removed and their presence in the molten metal is simply discounted.
  • the boards must have the criteria of shape, thickness, density, thermal conductivity etc., mentioned above if the advantages of avoiding preheating and inclusions are to be optimised.
  • a set of boards to be fitted into the ladle to form an inner protective discardable lining comprising one or more floorboards and one or more sideboards, each board being formed of a composition which is refractory, and has high heat insulation, a density in the range of about 0,3 to 1.5 gm/cc, a thermal conductivity in the range of 0.1 to 1.0, W/mK and a thickness of from 10 to 25mm.
  • the ladle of Figure 1 comprises a bucket-like vessel 1 having a base 2 and upwardly outward flared sidewall 3.
  • a nozzle 4 is set in the floor 2, to receive a stopper rod 5.
  • the vessel base and sidewall are made up of an outer metal shell 6 on which is set a relatively permanent lining 7 of refractory bricks as shown or a shaped monolithic lining.
  • the vessel has an internal volume to accommodate about 0.3 to 10 tons of molten steel.
  • the inner diameter of the floor is about 80 cm and the diameter at the top is about 100 cm and the internal height of the sidewalls is about 120 cm.
  • the lining comprises a set of boards, each formed of refractory heat insulating material.
  • the boards comprise a pair of floorboards 11 covering the whole of the floor area and ten upstanding side boards 12.
  • Each side board is wider at its upper end than at its base which rests on a ledge formed in the floorboard 11.
  • the side boards are each trapezoidal in section so that a tight joint A is formed between adjacent side boards when they are abutted together.
  • the floorboards 11 are joined together in overlapping manner as at A.
  • Sufficient side boards are present to cover the inner surface of the relatively permanent lining.
  • Each board measures 108 cm high, and about 3 cm thick and the front surface measures 27 cm across and the rear surface 29 cm across.
  • Each side board and the floorboard has a density of 1.1 gm/cc, and a thermal conductivity of 0.6 W/mK.
  • the boards include an organic binder they are made from an aqueous slurry of the following (part.s by weight): to form a damp shape which is then dried.
  • Loose sand 13 is located between the floor 2 of the vessel and the floorboards 11 and also in the gap between the inner surface of the relatively permanent lining and the set of the side boards 12.
  • the sand at the top of the ladle, at least in-the region of a cut out 14 in the upper corners of two adjacent side boards and defining a lip-pouring spout 15, is mixed with sodium silicate to harden it so that it will not fall out when the ladle is tilted.
  • a preformed sealant such as a clay or alumino-silicate fibre rope may also be used to hold the loose sand in the desired position.
  • molten steel at about 1650 0 C is tapped from a furnace into the ladle.
  • the stream of steel impinges on the side and floorboards but despite this the boards are not severely eroded.
  • the resin binder therein is carbonised but only a part of the binder suffers this fate since the front face of the boards sinters to form an impervious skin, or layer L which seals the inner lining from attack by molten metal.
  • the ladle When the ladle is filled to the desired level with the molten steel - which by then has cooled to about 1600°C -it may be stored for up to 20 minutes or more.
  • the metal When desired the metal is released via the nozzle 4 until the ladle is completely empty.
  • the molten metal temperature falls much more.slowly while it is in the ladle because of the thermal insulation of the inner protective discardable lining.
  • the inner protective lining retains its integrity and at the end of the pour when the ladle is fully inverted, the inner lining is discarded by falling out as a one piece, bucket-like element together with the loose sand, leaving a clean relatively permanent lining 7.
  • the ladle can be reused more speedily than would be the case in the absence of a lining, and turn-around is generally improved. Between each pour the nozzle 4 is conveniently removed from the outside of the ladle without any need to have access to.the interior.
  • the ladle of the invention was used in comparison with a ladle having no inner protective lining to supply molten steel to a sand mould in a foundry.
  • the ladle without the inner protective lining it was found that there were slag and refractory inclusions in the castings made from the molten steel whilst in the case of the ladle of the invention no such inclusions were present.
  • Two bottom pour ladles each having a capacity of 3000 kg were taken.
  • the floorboard had a bore to register with the nozzle outlet and the nozzle was keyed in that bore so avoiding the need for ramming materials.
  • the boards were trapezoidal in plan and were wedged together with their wider ends uppermost.
  • the ladle having the 65 mm refractory cement lining was preheated to 600 - 700°C for 2 hours using gas burners. The other ladle was not preheated.
  • Carbon steel was tapped into two ladles, prepared in the manner of Example 1 and the metal was run into test moulds formed of zircon sand and refractory holloware. The metal was allowed to cool and the castings were removed. The castings surface were machined level and then coated by the Dynatron technique to show exogenous inclusions arising from the erosion of ladle refractories and slag only. The surfaces were photographed and the results are shown in Figure 4 (no magnification) in which the lower photograph shows the results from a casting from the ladle having no inner protective lining and the upper . photograph shows the results from a ladle of the invention. These results clearly show the advantages of using the lining to reduce the risk of inclusions.
  • Example 2 The method of Example 2 was repeated using a high alloy steel and the same results were obtained.

Landscapes

  • Mechanical Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Glass Compositions (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Table Devices Or Equipment (AREA)
  • Table Equipment (AREA)
  • Food-Manufacturing Devices (AREA)
  • Confectionery (AREA)
  • Mold Materials And Core Materials (AREA)
EP81302810A 1980-07-02 1981-06-23 Giessen von Metallen und bekleidete Gefässe dafür Expired EP0043670B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81302810T ATE5800T1 (de) 1980-07-02 1981-06-23 Giessen von metallen und bekleidete gefaesse dafuer.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8021684 1980-07-02
GB8021684 1980-07-02

Publications (2)

Publication Number Publication Date
EP0043670A1 true EP0043670A1 (de) 1982-01-13
EP0043670B1 EP0043670B1 (de) 1984-01-11

Family

ID=10514482

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81302810A Expired EP0043670B1 (de) 1980-07-02 1981-06-23 Giessen von Metallen und bekleidete Gefässe dafür

Country Status (10)

Country Link
EP (1) EP0043670B1 (de)
JP (1) JPS5779067A (de)
AT (1) ATE5800T1 (de)
AU (1) AU542404B2 (de)
BR (1) BR8104202A (de)
CA (1) CA1195472A (de)
DE (1) DE3161885D1 (de)
ES (1) ES268137Y (de)
MX (1) MX157795A (de)
ZA (1) ZA814207B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0160384B1 (de) * 1984-04-07 1991-06-05 Foseco Trading A.G. Induktionsöfen

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113070468B (zh) * 2021-03-30 2022-05-03 武汉钢铁集团耐火材料有限责任公司 适用于智能整体浇注钢包工作衬套浇工艺的胎模及其使用方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2169807A1 (de) * 1971-12-07 1973-09-14 Foseco Int
FR2318696A1 (fr) * 1975-07-23 1977-02-18 Chemincon Inc Element isolant faconne pour doublures interieures de moules metallurgiques
GB1487040A (en) * 1976-03-01 1977-09-28 Labate M Tundish liners
GB1521177A (en) * 1977-05-10 1978-08-16 Foseco Trading Ag Retractory heat insulating compositions for use in the metallurgical industry
US4216944A (en) * 1977-03-02 1980-08-12 Nippon Kokan Kabushiki Kaisha Casting vessel having basic lining

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5123432A (de) * 1974-08-21 1976-02-25 Aikoh Co
GB1540090A (en) * 1976-04-07 1979-02-07 Foseco Trading Ag Tundishes
JPS5927272B2 (ja) * 1977-05-06 1984-07-04 日鐵建材工業株式会社 溶融金属収容容器

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2169807A1 (de) * 1971-12-07 1973-09-14 Foseco Int
FR2318696A1 (fr) * 1975-07-23 1977-02-18 Chemincon Inc Element isolant faconne pour doublures interieures de moules metallurgiques
GB1487040A (en) * 1976-03-01 1977-09-28 Labate M Tundish liners
US4216944A (en) * 1977-03-02 1980-08-12 Nippon Kokan Kabushiki Kaisha Casting vessel having basic lining
GB1521177A (en) * 1977-05-10 1978-08-16 Foseco Trading Ag Retractory heat insulating compositions for use in the metallurgical industry

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0160384B1 (de) * 1984-04-07 1991-06-05 Foseco Trading A.G. Induktionsöfen

Also Published As

Publication number Publication date
ES268137U (es) 1983-05-01
MX157795A (es) 1988-12-15
CA1195472A (en) 1985-10-22
ATE5800T1 (de) 1984-01-15
AU542404B2 (en) 1985-02-21
JPS5779067A (en) 1982-05-18
DE3161885D1 (en) 1984-02-16
EP0043670B1 (de) 1984-01-11
BR8104202A (pt) 1982-03-23
AU7243881A (en) 1982-01-07
ES268137Y (es) 1983-11-16
ZA814207B (en) 1982-07-28

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