Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0637—Accessories therefor
  • B22D11/0648—Casting surfaces
  • B22D11/066—Side dams

Definitions

• the invention relates to a side face for a continuous sheet metal casting machine consisting of a frame on which are mounted two movable walls, such as two cylinders rotating in opposite directions, and two lateral faces placed at each of the ends of the cylinders. to define a continuous casting mold in which a given quantity of liquid metal is retained.
• a thin sheet continuous casting machine generally comprises two movable nostrils which face each other and which delimit a mold with movable walls.
• the liquid steel coming from the distributor is introduced into this mold via a nozzle of suitable geometry.
• the lateral faces consist of a base plate of refractory material, of an element of ceramic material which comes into contact with the friction surface of the end of the cylinders and which is embedded in the base plate.
• the assembly is mounted in a metal envelope which covers the rear face of the base plate leaving only the ceramic element free. It is the bottom of this envelope which ensures the transmission of the pressure exerted by the mechanical system located behind the side face and which allows the tight application of the side face against the cylinders in order to avoid any leakage. liquid steel between them and the side walls.
• the heat flow from the molten metal through the plate of refractory material causes a significant increase in the temperature of the bottom of the shell.
• this increase in temperature causes a deformation of the bottom, for example a bending.
• This deformation is responsible, among other things, for poor transmission of the pressure exerted by the mechanical system on the rear of the refractory plate.
• the pressure does not apply uniformly on the plate of refractory material but is concentrated at certain points thereof. For example, if the plate is curved, the bottom of the metal envelope will only be applied to the plate of refractory material by the top of this curved area.
• the resulting stress concentration can go as far as breaking the plate of refractory material.
• the deformation of the envelope can also cause a change in the parallelism of the front face of the lateral face (refractory material) with its rear face (metallic bottom).
• the friction surface is no longer applied uniformly, that is to say with constant pressure, to the end of the cylinders. This phenomenon can lead to an infiltration of liquid steel between the cylinder and the friction surface of the lateral face.
• the base plate of refractory material is cemented in the metal envelope in order to hold it in place.
• the cement is steamed according to a thermal cycle which can reach and exceed 200 ° C.
• This parboiling cycle causes a deformation of the metal casing which destroys the parallelism which existed before the parboiling of the cement. It is not easy to restore the parallelism between the front face and the rear face by a new rectification because it is necessary to lubricate during the rectification, which humidifies the cement so that it must be reboiled .
• the present invention specifically relates to a side face for a m., Continuous casting of thin sheet metal which overcomes the drawbacks of the art anter .. ar which have just been exposed.
• This lateral face must make it possible to transmit and distribute the application pressure exerted on its rear face in an equal manner so as to avoid any risk of leakage of liquid steel. It must also make it possible to ensure good parallelism between its front face and its rear face.
• This solution allows both good geometrical support of the plate of refractory material, easy fixing of the side face on the frame of the continuous casting machine and good parallelism between the two faces of the side wall whatever the temperature.
• This solution also makes it possible to produce a side face entirely of refractory material at the level of all of the zones in contact with the liquid steel or with the cylinders, as well as with the device for applying the pressure.
• the assembly of the metal belt and the refractory plate can be carried out by cementing or by hot shrinking.
• the metal belt and / or the plate of refractory material has grooves or anchors which can be filled with cement so as to ensure better retention of the material plate refractory in the belt.
• the plate of refractory material is cemented by zone in the metal belt.
• the fixing cement may also not be placed around the entire periphery of the piece of refractory material, depending on the shape of the metal belt.
• the differences in expansion between the belt and the plate of refractory material require not to cement all the periphery of the plate to avoid cracking of the latter.
• the presence of cement on either side of the level of the axis of the cylinders causes, at high temperature, a tightening of the plate of refractory material at this level.
• the belt is made of metal (steel, cast iron or other) whose coefficient of thermal expansion is higher than that of the refractory material which constitutes the plate. As a result, at high temperature, the metal expands more. The belt then causes the plate of refractory material to be put in traction, which can go as far as breaking it.
• metal steel, cast iron or other
• the cement used can for example be a silico-aluminous cement with a silicate binder. Its function is to permanently or temporarily hold the plate of refractory material in the belt.
• the flatness of the rear face of refractory material is at least 0.5 mm.
• the surface of the rear face must be entirely contained between two parallel planes distant at most 0.5 mm.
• the refractory material plate can be made in one piece. It can also be produced in several parts, in particular a friction zone and a central zone only in contact with the liquid steel contained in the continuous casting mold.
• the central zone is preferably made of a ceramic material with carbon binder.
• At least part of the friction zone is located below the plane defined by the axes of rotation of each of the two cylinders.
• the invention also relates to lateral faces for a continuous sheet metal casting machine consisting of a frame on which are mounted two cylinders rotating in opposite directions and of two removable lateral faces placed at each end of the two cylinders and of means to apply with contact pressure the side faces on the ends of the cylinders.
• the means for applying a contact pressure of the lateral faces on the ends of the cylinders comprise a plate which is applied to the rear face of the refractory plate without contact with the metal belt of this plate of refractory material, the thickness of the plate being greater than the thickness of the belt.
• the pressure exerted on the lateral face and intended to ensure a seal between the cylinders and the friction surface of this last side face is exerted by means of a part which can be metallic and independent of the lateral face itself.
• This plate is of course subjected to the flow of heat which passes through the plate of refractory material.
• the temperature rise of the metal plate is limited by the fact that an independent insulator (for example a silica foam plate) can be introduced between the push plate and the lateral face proper and that it does not there is no thermal bridge between the metal belt which holds the plate of refractory material and the push plate which applies pressure to the rear face of the plate of refractory material.
• the thickness of the metal belt is less than that of the plate of refractory material so that the surface of the belt is set back relative to the surface of the material plate. refractory.
• the invention relates to a continuous casting device between cylinders of thin metallic products, comprising two cooled counter-rotating cylinders, two lateral closure walls and means for supporting and applying pressure of said closure walls against the edges. cylinders, characterized in that each closure wall is constituted by a plate of hard refractory material surrounded by a metal belt to which it is linked.
• FIG. 1 a very schematic perspective view of a machine for casting thin sheet between cylinders
• - Figure 2 is a perspective view of a first embodiment of the invention
• Figure 3 is a sectional view of a detail of the plate of Figure 2.
• Figures 4 and 5 show two other alternative embodiments
• Figure 6 is a sectional view.
• Figure 7 is a sectional view of another alternative embodiment.
• Figure 1 a schematic perspective view of a thin sheet metal casting machine. It comprises two cylinders, 2 which rotate in opposite directions, as shown diagrammatically by the arrows 4, around horizontal axes 6. Plates 10, applied against the ends of the cylinders, constitute a mold into which the liquid steel is poured.
• FIG. 2 a first embodiment of a side wall for a continuous sheet metal casting machine according to the invention.
• This side wall designated by the general reference 10, consists of two parts, namely a plate of refractory material 12 and a metal belt 14.
• the plate of refractory material has a shape which is adapted to that of cylinders of the continuous casting machine. It has two large sides substantially in the form of a circular arc, the center of curvature of which is on the central axis of the rolls of the casting machine.
• the plate 12 has a small side at its lower part and a large side at its upper part.
• the plate 12 is held by a metal belt 14 which, in the embodiment shown, surrounds the plate 12 over its entire periphery, the belt can be mounted in particular by hooping.
• the metal belt 14 includes fixing means such as screws, bolts, studs or the like which allow it to be fixed to the frame of the continuous casting machine. Since these fixing means are conventional, they have not been shown in the figure.
• the plate of refractory material 12 has a thickness which is greater than that of the metal belt 14. In this way the refractory material protrudes on both sides of the belt.
• a lateral face was produced in accordance with the invention in which the metal belt was set back 3 mm relative to each of the front and rear faces of refractory material 12. In other words, the thickness of the material plate refractory was 6 mm higher than that of the metal belt 14.
• FIG. 3 which shows a cross-sectional view of the metal belt 14 and part of the plate of refractory material 12
• the metal belt 14 has a groove 14a
• the material plate refractory has a groove 12a.
• the grooves 12a and 14a are filled with a cement 16 which maintains the plate 12 in the belt 14.
• a push plate 15 makes it possible to transmit an application force transmitted by application means 17. It is noted that the the thickness of the pia 12 is greater than that of the metal belt 14. In this way there is no thermal bridge between the thrust plate 15 and the belt, nor between the belt and the edge of the cylinder 2.
• FIG. 4 shows a plate 12 made up of 2 parts, namely respectively a zone 18 comprising the part of the plate working in friction 11 and a central zone 20.
• the friction zone 18 is made of a refractory material which has good friction characteristics with a metal, in particular a high hardness and a good coefficient of friction, for example a material comprising at least 15% of boron nitride.
• the central zone is formed by a part of the zone of the refractory plate which is in contact with the liquid metal. For this reason, it must have very good resistance to corrosion by steel. It can be constituted, for example, by a ceramic material with carbon binder.
• the friction zone 18 consists of a single element.
• This element has a substantially Y shape. It comprises the friction zone 18 which consists of a crown arc concentric with one roller, and a crown arc concentric with the other roller. These two branches of the Y join at their lower part to form a central zone.
• part of the friction zone is located below the level of the axis 22 of the two cylinders of the continuous casting machine, shown diagrammatically by a dashed line (see Fig. 1 ).
• the end of the friction zone, located below the axis of the cylinders, in the solidification zone of the sheet ends with a recess 24 of at least 2 mm which can be a chamfer or a rounding so that the sheet does not come, after its solidification, rub on a heel of refractory material 26 located below the recess 24.
• edges of the friction zone 18 located on the side of each of the two cylinders comprises a chamfer 28 or a rounding of at least 2 mm by 2 mm in order to limit the level of mechanical stresses at these edges.
• a chamfer there is indeed a systematic flaking of the edges which may ultimately generate infiltration of liquid metal.
• the friction zone consists of four elements 30 in the form of crown arcs concentric with the cylinders and of a block 32 joined to the crown sections 30.
• the block 32 comprises, like the friction zone 18 of the figure 3, a part located below level 22 of the axis of the cylinders.
• crown arcs 30 and the central zone 20 are held in the metal belt 14 by three cemented zones 34.
• the differences in expansion between the metal belt 14 and the refractory materials which constitute the central zone 20 and the elements 30 and 32 respectively impose not to cement the entire periphery of the plate 12 in order to avoid cracking of the latter.
• the rest of the periphery of the plate is filled for example with fibers 36.
• the plate 12 of refractory material comprises an independent rear plate 38 made of a non-metallic refractory material.
• This plate 38 serves as a support for the other elements which have been described previously, namely the crown arcs 30, the central block 32 and the central zone 20. All these elements can be simply placed on the rear plate 38 or else they can be fixed to this plate for example by means of a silico-aluminous cement or the like.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Coating With Molten Metal (AREA)
• Metal Rolling (AREA)

Applications Claiming Priority (5)

Publications (2)

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Family Applications (1)

Country Status (15)

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• 1995
  • 1995-06-23 AU AU28901/95A patent/AU695332B2/en not_active Ceased
  • 1995-06-23 CZ CZ19963838A patent/CZ292908B6/cs not_active IP Right Cessation
  • 1995-06-23 SK SK1680-96A patent/SK283307B6/sk not_active IP Right Cessation
  • 1995-06-23 HU HU9703603A patent/HU218547B/hu not_active IP Right Cessation
  • 1995-06-23 PL PL95318137A patent/PL178918B1/pl not_active IP Right Cessation
  • 1995-06-23 WO PCT/FR1995/000842 patent/WO1996000626A1/fr active IP Right Grant
  • 1995-06-23 CN CN95194684A patent/CN1071605C/zh not_active Expired - Fee Related
  • 1995-06-23 CA CA002193243A patent/CA2193243C/fr not_active Expired - Fee Related
  • 1995-06-23 JP JP8502866A patent/JPH10506327A/ja active Pending
  • 1995-06-23 EP EP95924361A patent/EP0767714B1/de not_active Expired - Lifetime
  • 1995-06-23 DE DE69502607T patent/DE69502607T2/de not_active Expired - Lifetime
  • 1995-06-23 BR BR9508141A patent/BR9508141A/pt not_active IP Right Cessation
  • 1995-06-23 ES ES95924361T patent/ES2118606T3/es not_active Expired - Lifetime
  • 1995-06-23 AT AT95924361T patent/ATE166266T1/de active
• 1996
  • 1996-12-30 NO NO19965622A patent/NO313581B1/no not_active IP Right Cessation

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