Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/16—Making or repairing linings ; Increasing the durability of linings; Breaking away linings
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B14/00—Crucible or pot furnaces
  • F27B14/08—Details specially adapted for crucible or pot furnaces
  • F27B14/10—Crucibles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/0003—Linings or walls
  • F27D1/0006—Linings or walls formed from bricks or layers with a particular composition or specific characteristics
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B14/00—Crucible or pot furnaces
  • F27B14/08—Details specially adapted for crucible or pot furnaces
  • F27B14/10—Crucibles
  • F27B2014/104—Crucible linings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B14/00—Crucible or pot furnaces
  • F27B14/08—Details specially adapted for crucible or pot furnaces
  • F27B14/10—Crucibles
  • F27B2014/106—Ladles

Definitions

• the invention concerns the lining of containers for molten metal.
• Containers for molten metal commonly comprise a metal casing lined with refractory brickwork or a monolithic refractory lining and this lining is often termed the permanent lining.
• the permanent lining is subject to damage and is expensive and time-consuming to repair or replace.
• a residue (skull) of solidified molten metal and slag may adhere to the lining, and require removal before re-use of the container, and may be difficult to remove and its removal may damage the lining.
• U.K. patent specification 1477632 discloses application of two layers over the permanent lining.
• the first layer is a parting layer comprising particulate carbonaceous material e.g. coke dust and is free or substantially free of permanent binding agent.
• the first layer may be applied as a liquid or paste composition by, for example, spraying or trowelling.
• the second,i.e. inner, layer is of bonded particulate refractory material and may be applied by, for example, trowelling on a coating composition.
• the combination of the two layers protects the permanent lining and in particular enables clean stripping of skull e.g. from a tundish without damage to the permanent lining.
• the layers are re-applied before each re-use of the container.
• a container for molten metal has a permanent refractory lining, an inner, refractory lining and, in at least one place separating the permanent and inner linings, a layer substantially consisting of heat-carbonisable sheet material.
• the inner lining may be pre-heated before molten metal in introduced into the container and pre-heating may suffice to carbonise the sheet material to yield a carbonaceous residue.
• the carbonaceous residue provides a valuable parting layer facilitating removal of skull and the inner lining and without damage to the permanent lining.
• the heat-carbonisable sheet material may be, for example, newsprint, kraft paper, cardboard (e.g. laminated corrugated cardboard), wallpaper, hessian, straw matting or woven polyethylene or polypropylene.
• the heat-carbonisable sheet material is flexible and this is of value in positioning it as desired, especially if the permanent lining has irregularities at its surface e.g. cavities or areas of adhering extraneous matter.
• suitable sheet materials are available as large pieces and can easily be cut to size. Accordingly the layer of heat-carbonisable sheet material can be provided quickly and easily.
• clips or an adhesive can be used if desired, for example at places where the permanent lining is generally upright and if the sheet material is very flexible e.g. newsprint rather than less flexible e.g. cardboard. In the case of newsprint even water will provide sufficient adhesion and in general a variety of widely available inexpensive adhesives e.g. starch-based ones are suitable.
• the sheet material used is thin e.g. newsprint it may be desirable to use a number of pieces of it superimposed to form the layer whereas with thicker sheet materials' e.g. cardboard a single thickness may suffice.
• the thickness of the layer is from 0.1 mm to 2 mm.
• the tendency for the inner lining (with adhering skull) to become fused to the permanent lining may only be significant at certain parts of the container.
• the above tendency for fusion to occur is most marked at the floor of the tundish and at the slag line i.e. the usual level of slag on the top surface of the molten metal in the tundish.
• the heat-carbonisable sheet material may be provided only at those places where there is a significant risk of the inner lining becoming fused to the permanent lining.
• the inner lining keeps the carbonaceous residue in place to serve its eventual function as a parting layer.
• the inner lining and the carbonaceous residue also protect the permanent lining from attack by molten metal and slag in the container.
• the inner lining may be provided by a set of slabs of refractory heat-insulating material as described in relation to tundishes in U.K. patent specification 1364665. In accordance with the invention it is however sometimes preferred that the inner lining should be of a unitary construction, preferably formed in situ.
• the inner lining may be formed by applying a refractory, coating composition and this may be done, for example, by trowelling but it is preferred to apply the composition by spraying.
• Coating compositions for forming the inner lining are preferably based on one or more particulate refractory materials and an inorganic binding agent.
• suitable particulate refractory materials include silica, chamotte, olivine, sillimanite, zircon, magnesia, alumina and zirconia.
• suitable inorganic binding agents include silicates, phosphates and aluminates of alkali or alkaline earth metals, colloidal oxide hydrosols and clays.
• a proportion preferably 0.5 to 5% by weight, of fibre may be included in the composition.
• the fibres may also serve to enhance the heat-insulation provided by the composition. It is usually preferred that the inner lining should be heat-insulating.
• the fibre content may be organic and/or inorganic and an example of organic fibre is chopped straw whilst an example of an inorganic fibre is glass fibre.
• Organic binder may also be present in the composition.
• the thickness of the inner lining is preferably from 10 to 50 mm.
• the inner lining is provided by use of a coating composition containing a significant proportion of moisture or a binder that requires heating to harden, the composition after application can be heated to drive off moisture or harden the binder.
• the inner lining is provided by pre-formed articles e.g. slabs
• certain consitituents of the lining e.g. soda may tend to migrate to the back of the lining under the influence of the heat and, in the absence of the parting layer cause the inner lining to adhere to the permanent lining.
• any water-soluble binder e.g. sodium silicate in the composition may tend to migrate to the back of the lining during use or any pre-heating. In such cases the parting layer present in accordance with the invention is particularly valuable.
• the invention is of particular value where the container is a tundish but it is also of use in the case of other containers for molten metal e.g. ladles.
• the invention is particularly useful in the case of containers for molten ferrous metals e.g. steel.
• the method of lining the container forms a part of the invention.
• An example of a container according to the invention is a tundish (for use in the continuous casting of steel) having an outer, metal shell, a monolithic permanent lining of cast refractory material adjacent the shell, a parting layer overlying the permanent lining and provided by laminated corrugated cardboard (thickness about 1.5 mm) on the floor of the tundish and a number of layers (total thickness about 0.2 mm) of newsprint on the walls of the tundish, and, overlying the parting layer, a layer applied by spraying a composition of particulate refractory material and inorganic binder.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Laminated Bodies (AREA)
• Vertical, Hearth, Or Arc Furnaces (AREA)
• Carbon Steel Or Casting Steel Manufacturing (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=10569124

Family Applications (1)

Country Status (9)

Families Citing this family (3)

Family Cites Families (4)

• 1984
  • 1984-11-01 GB GB848427711A patent/GB8427711D0/en active Pending
• 1985
  • 1985-10-18 DE DE8585307558T patent/DE3574942D1/de not_active Expired - Fee Related
  • 1985-10-18 EP EP85307558A patent/EP0180388B1/de not_active Expired
  • 1985-10-18 AT AT85307558T patent/ATE48962T1/de not_active IP Right Cessation
  • 1985-10-22 CA CA000493541A patent/CA1261147A/en not_active Expired
  • 1985-10-23 AU AU49001/85A patent/AU576910B2/en not_active Ceased
  • 1985-10-24 ZA ZA858177A patent/ZA858177B/xx unknown
  • 1985-10-30 JP JP60243787A patent/JPS61119371A/ja active Pending
  • 1985-10-31 ES ES548437A patent/ES8701559A1/es not_active Expired

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