JP2008221277A - Ladle insulating cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ladle insulating cover for a molten steel ladle or the like which is lightweight in structure, is excellent in insulating performance and durability and is suitable for Ca treatment in a steel making stage. <P>SOLUTION: The inside face of the cover is pasted with an insulating material, preferably, with a ceramic fiber, the surface to be the molten steel side in the insulating material is covered with an SUS310S steel sheet, and, in the case its insulating properties are improved, the surface to be the insulating material in the SUS310S steel sheet is subjected to ceramic coating or spraying. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a warming lid for a ladle used in a steelmaking process, and more particularly to a ladle warming lid that has less adhesion of molten steel splash generated during Ca addition treatment and is excellent in durability.

  In continuous casting, molten steel is cast from a ladle through a tundish into a mold to form a slab. A ladle is attached to the ladle because the temperature of the molten steel drops during transportation of the molten steel and during the casting time.

  The casting time is usually 30 minutes to 1 hour, but if it is a long time, the temperature of the molten steel in the ladle will drop to a temperature that is not suitable for casting, and casting may not be completed. Various attempts have been made to maintain the molten steel temperature in the ladle such as by spraying a heat-insulating castable on the inner surface side of the steel plate.

  Patent Document 1 relates to a heating lid for a ladle, and describes that a heating element is installed on the inner surface of the heating lid for a ladle. As a heating element, a plate-like refractory that is heated by the combustion heat of combustible gas or an energizing heat generation is disclosed. It is disclosed that an exothermic temperature is preferably about 1000 ° C. or higher.

  Patent document 2 relates to a heat insulation lid of a molten metal container, and describes that a heat insulating material having a two-layer structure in which a molten metal side is refractory castable and a lid side is ceramic fiber is attached to the inner surface of the heat insulation lid.

  Patent Document 3 relates to a heat retaining method for a ladle, in order to keep the temperature in the ladle above a certain temperature without removing the pan lid until after casting and receiving new molten steel, One of the two sand introduction holes provided in the above is used as a burner outlet, and the other is used as an exhaust outlet.

  In addition, ladle, ladle lids, and related technologies have been proposed for the purpose of reducing equipment costs and operating costs and improving workability in heating and refining molten steel in the ladle, such as adding Ca-based wires to molten steel.

  Patent Document 4 relates to a Ca-based wire addition method to molten steel, and a guide pipe for guiding the wire is communicated with a Ca-based wire insertion hole provided in a ladle lid, and a guide is provided at a wire receiving end of the guide pipe. It is described that a means is provided to add Ca-based wire into molten steel without reducing the dust collection effect.

  Patent Document 5 relates to a method for heating and refining molten steel in a ladle. Flux is blown by a flux injection lance that penetrates a sealed space provided in the upper portion of the ladle, the molten steel is stirred, and the molten steel is heated by heating the formed slag. It is described that the temperature is raised by heating.

Patent Document 6 relates to a wire-type additive feeding device, and a hood that covers the molten steel is provided above the ladle, and the wire including the filler is fixed to the hood and is fed into the molten steel by a guide pipe that passes therethrough. Be paid. Since the guide pipe is fixed in a state close to the molten steel, the swinging of the wire is prevented, and “spinning” is prevented.
Japanese Patent Laid-Open No. 5-57425 Japanese Utility Model Publication No. 7-26056 JP-A-9-277023 JP 63-7319 A Japanese Patent Laid-Open No. 62-136515 JP-A-7-126735

  By the way, in continuous casting, in order to improve productivity, it is required to increase the amount of molten steel used for one casting, but the crane ability to transport a ladle filled with molten steel from the converter to the continuous casting machine is Therefore, there is a demand for a ladle that is excellent in heat retention and lightweight.

  In addition, it is not preferable in terms of operation that the structure of the ladle is complicated and expensive, or that maintenance and inspection are time-consuming.

  It is difficult to achieve such a problem sufficiently with the ladle warming pot described in Patent Documents 1 to 3 and the heat retaining method. For example, as in the pot lids described in Patent Documents 1 and 2, a bulk material is pasted. Although it is possible to reduce the weight, the material cost is very expensive, and depending on the construction technique, peeling may occur after pasting and it is difficult to stably secure the desired performance.

  When spraying heat insulation castable on the inner surface side of the pan lid, the thickness is required to be about 100 to 150 mm and the weight is about 5 tons to obtain the heat insulation effect. It is necessary to reduce the amount of molten steel inside.

  Furthermore, it is required for the ladle lid that the molten steel splash generated when adding the CaSi wire is difficult to adhere to the inner surface when the Ca-added steel type is melted at the steelmaking factory. Is not described.

  Accordingly, the present invention provides a ladle warming lid that can obtain stable heat retention performance with a light-weight structure, and that the molten steel splash generated when Ca addition treatment is performed is less likely to adhere to the inner surface and that can be easily maintained and inspected. The purpose is to do.

The object of the present invention can be achieved by the following means.
1. A ladle warming lid, wherein a heat insulating material is attached to the inner surface of the lid, and the surface of the heat insulating material on the molten steel side is covered with SUS310S.
2. The ladle warming lid according to 1, wherein the ladle warming lid is a ladle warming lid for Ca treatment.
3. The ladle heat insulating lid according to 1 or 2, wherein the heat insulating material is ceramic fiber.

  According to the present invention, compared to the case where a heat insulating castable is sprayed on the inner surface side of the lid, the weight is reduced by about 35% and about 3.5 tons, the amount of molten steel corresponding to the weight is increased, and the productivity is increased. Can be significantly improved.

  Moreover, even if the splash generated when the CaSi wire is poured into the molten steel reaches the inner surface of the lid, it hardly adheres and the durability increases, which is extremely useful industrially.

  The present invention is characterized in that a heat insulating material is applied over the entire inner surface of the ladle heat insulating lid, and the surface of the heat insulating material on the molten steel side is covered with a SUS310S steel plate. Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view illustrating the structure of a ladle warming lid for Ca treatment according to an embodiment of the present invention, and FIG. 2 is a top view.

1 shows a state in which the ladle 10 is installed in the CaSi on position in steel mills, lifting collector composed of the inner cylinder 2 and the outer cylinder 21 in the Ca treatment ladle insulation cover 1 indoor dust duct 11 The state connected via a dust duct is shown.

  In these figures, 1 is a Ca treatment ladle warming lid, 2 is an inner cylinder of a lifting dust collection duct, 3 is a hook attachment member of a lifting wire rope of the lifting dust collection duct, 4 is a lid body, and 5 is a Ca wire input Receiving port, 6 is a wire guide, 7 is a Ca wire, 8 is a hook attachment member, 9 is a dust collecting hole, 10 is a ladle, 11 is an indoor dust collecting duct, 12 is an overhead crane chain, 13 is an overhead crane chain 12 , 14 is an overhead crane, and 21 is an outer cylinder of the dust collecting duct.

  The illustrated Ca treatment ladle warming lid 1 has a dust collection hole 9 opened at the center of the circular lid body 4 and a Ca wire insertion receptacle 5 opened independently in the vicinity thereof. The Ca wire 7 is inserted into the molten steel from the Ca wire insertion receptacle 5 through the wire guide 6, and performs Ca treatment.

The dust collecting hole 9 is connected in order of the outer cylinder 21 of the lifting / lowering dust collecting duct and the inner cylinder 2 of the lifting / lowering dust collecting duct, and the dust from the dust collecting hole 9 is discharged to the indoor dust collecting duct 11. The hook mounting component 3 is attached to the outer peripheral portion of the outer cylinder 21 of the lifting / lowering dust collecting duct, and the chains 12a and 12b suspended from the small overhead crane 14 are connected.

  The Ca treatment ladle warming lid 1 and the hook attachment component 3 are hooked on the hook attachment member 8 attached on the Ca treatment ladle insulation lid 1 and hooked below the hook attachment component 3. Connecting.

  On the other hand, guides 15a and 15b through which the wires 12a and 12b are inserted are attached to the outer peripheral portion of the inner cylinder 2 of the elevating and dust collecting duct, and the inner cylinder 2 and outer cylinder 21 of the elevating and lower dust collecting duct and the dust collecting hole 9 are attached. And the connection state of the indoor dust collection duct 11 is stably maintained.

  The lower ends of the guides 15a and 15b are supported by the work floor 16 and maintain the connection state between the inner cylinder 2 of the elevating and lowering dust collecting duct and the indoor dust collecting duct 11.

  The Ca treatment ladle insulation lid 1 and the indoor dust collection duct 11 are connected via the inner cylinder 2 and the outer cylinder 21 of the lifting dust collection duct having the above-described configuration. The connection state can be released at any time, such as when the ladle 10 is detached or when the ladle 10 is moved.

  The outer diameter of the elevating and lowering dust collecting duct (outer cylinder) 21 is slightly larger than the hole diameter of the dust collecting hole 9 and is prevented from falling into the ladle 10 when it falls off from the overhead crane 14.

  FIG. 3 is a diagram schematically showing a cross-sectional structure of the lid main body 4 of the Ca treatment ladle warming lid 1, in which a heat insulating material 42 is attached to the entire inner surface of the iron skin 41 having an external shape, The entire surface on the molten steel side is covered with a SUS310S steel plate 43.

  A heat test was conducted to select a steel plate covering the surface of the heat insulating material 3 on the molten steel side. The test steels were SUS304 and SUS310S, and after 30 minutes heating in an electric furnace maintained at 1250 ° C., the cooling cycle was repeated 10 times to evaluate the deterioration state.

  As a result, in the case of SUS304, deterioration due to surface oxidation was recognized, but in SUS310S, no change was observed, and SUS310S was selected as a steel plate covering the surface of the heat insulating material 3 on the molten steel side. Table 1 shows an example of the component composition of SUS310S.

  The heat insulating material 42 is preferably a ceramic fiber (for example, trade name: ISOWOOL, manufactured by Isolite Kogyo Co., Ltd.) having a thickness of 100 mm that is lightweight and excellent in heat insulating properties.

  When ceramic fiber is used as the heat insulating material 42, the durability on the inner surface of the iron skin 6 depends on the skill and attachment method of the operator, and may fall off early and have poor durability. Also, molten steel splash adheres and is damaged.

  Therefore, in the present invention, the entire surface on the molten steel side of the heat insulating material 42 is covered with the SUS310S steel plate 43 to hold the ceramic fiber and shield it from the molten steel. The SUS310S steel plate 43 is preferably about 0.5 mm thick for weight reduction, and when damaged, it is preferably attached to the iron shell 6 with bolts or the like so that the steel pipe is easy.

  According to the present invention, the heat insulating material 42 is shielded from the splash of molten steel by the SUS310S steel plate 43 and is not damaged. Moreover, even if the splash of molten steel scatters on the SUS310S steel plate 43, the cooling rate is fast and the surface is smooth, so the amount of adhesion is small and the durability is excellent.

  In order to improve the heat insulation effect, ceramic coating or spraying is performed on the surface of the SUS310S steel plate 43 on the heat insulating material 42 side.

  As the steel plate covering the entire surface of the heat insulating material 42 on the molten steel side, a SUS310S steel plate 43 may be used instead of a SUH standard material having equivalent high-temperature performance.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic sectional drawing explaining the structure of the ladle thermal insulation lid for Ca processing which concerns on one Example of this invention. The top view of the ladle thermal insulation cover for Ca processing shown in FIG. The schematic diagram explaining the heat insulation structure of the ladle thermal insulation lid for Ca processing shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ca treatment ladle thermal insulation lid 2 Inner cylinder of raising / lowering dust collection duct 3 Hook attachment member 4 Lid body 5 Ca wire insertion receptacle 6 Wire guide 7 Ca wire 8 Hook attachment member 9 Dust collection hole 10 Ladle 11 Indoor dust collection Duct 12a, 12b Overhead crane chain 13 Mounting part 14 Overhead crane 15a, 15b Guide 16 Work floor 21 Outer cylinder of lifting dust collecting duct 41 Iron skin 42 Heat insulating material 43 SUS310S steel plate

Claims (3)

A ladle warming lid, wherein a heat insulating material is attached to the inner surface of the lid, and the surface of the heat insulating material on the molten steel side is covered with SUS310S.   The ladle warming lid according to claim 1, wherein the ladle warming lid is a ladle warming lid for Ca treatment.   The ladle heat insulating lid according to claim 1 or 2, wherein the heat insulating material is ceramic fiber.

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