JPS6352985B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application for Industrial Materials) The present invention relates to a method for manufacturing a continuous casting nozzle that improves the heat insulation properties used in continuous casting of molten metal, particularly steel.

(Prior art) Conventionally, nozzles for continuous casting of steel, such as set nozzles in tundish or immersion nozzles, are made of materials containing carbon, so cooling from the outside is large during casting of steel, and these nozzles Blockages often occurred as the molten steel cooled and solidified inside.

Until now, the solution to this problem was to cover the outside of the continuous casting nozzle (hereinafter referred to as the nozzle) with an insulating material such as asbestos, but the shape of the nozzle, especially the set nozzle in the tundish, However, this method cannot be used because the heat insulation is insufficient, and it is also environmentally unfavorable for submerged nozzles. Therefore, in recent years, a method has been adopted in which a heat insulating material is provided inside the nozzle body.

As shown in Figures 3 and 4, this method uses a cylindrical drill bit to create a concentric cylindrical space in the side wall of the upper part of the nozzle body 1a, which has been formed in advance. Pack material 5, mortar 6
The method was to seal it by filling it with water.

(Problems to be Solved by the Invention) However, in the conventional machining method using a lever, chips and destruction of the inside of the space are likely to occur due to machining, so naturally the heat insulating part filled with the heat insulating material 5 is There were limitations on the length of the cylinder, and it was only possible to manufacture cylinders with a diameter of 150 mm or less in the cylindrical direction.

Further, there was a problem in that the repaired portion using the mortar 6 after filling the heat insulating material 3 lacked smoothness in the upper socket portion of the nozzle.

(Means for Solving the Problems) The present invention is manufactured by embedding a heat insulating material molded body of a predetermined shape in a predetermined position when molding the nozzle in advance, instead of using the conventional cutting method. The method is characterized by the use of a heat insulating material molded body impregnated with paraffin.

(Function) First, to make a paraffin-impregnated insulation material molding,
A pre-made asbestos-like molded body is heated to 30 to 40°C and immersed in a bath of solid paraffin melted at about 110°C for several seconds to completely spread the paraffin into the gaps between the asbestos. Remove it from the bath and wash off any excess paraffin from the surface. This is left at room temperature to allow the impregnated paraffin to completely solidify.

Since the heat insulating material molded body is impregnated with paraffin, it is hardly compressed during nozzle pressure molding and maintains its original shape, and the impregnated paraffin flows out and is removed by volatilization during the next firing process. The condition of the insulation material is returned to the state before it was impregnated with paraffin.

If the insulation layer is required to be longer, a hole may be made in a part of the insulation molded body to maintain strength by creating a joint between the outside and inside of the insulation layer provided inside the nozzle. can do.

Next, an embodiment of the present invention will be described based on FIGS. 1 and 2.

First, in the side wall of the nozzle body 1, a bulk specific gravity of 0.25~
0.30g/cm ³ , thermal conductivity 0.12Kcal/mh℃ (800
°C), 0.16Kcal/mh °C (1000 °C), composition
A heat insulating molded body 2 made by impregnating paraffin into a heat insulating molded body made of a ceramic fiber aggregate consisting of 51% Al ₂ O ₃ and 49% SiO ₂ was embedded and molded using a rubber press. Then, this was fired in a non-oxidizing atmosphere in a coke breeze to obtain a nozzle having a heat insulating layer 3. Note that reference numeral 4 designates a through hole that serves as a connection between the inside and outside of the heat insulating layer 3.

(Effects of the Invention) According to the present invention, a heat insulating layer can be placed at a desired position, and a nozzle having a longer heat insulating layer can be manufactured with relative freedom. In addition, it is possible to omit the conventional processes such as machining with a drill and packing insulation material, improving work efficiency, and since the insulation layer is completely hidden from the outside, the smoothness of the socket part is maintained. The problem of nozzle sealing was also resolved.

In continuous bloom casting at K Steel Works, a immersion nozzle with a heat insulating layer of 5 mm thick and 300 mm in length according to the present invention was actually used. There was no blockage due to steel solidification, and it could be used for stable casting for a long time of about 1000 minutes.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a nozzle according to an embodiment of the present invention, FIG. 2 is a perspective view of the same heat insulating material molded body, and FIG.
The figure is a longitudinal sectional view showing a conventional processing state, and FIG. 4 is a longitudinal sectional view of the same nozzle. 1, 1a...Nozzle body, 2...Insulating material molded body, 3...Insulating layer, 4...Through hole, 5...Insulating material,
6...Mortar.

Claims (1)

[Claims] 1. A method for producing a continuous casting nozzle, which comprises embedding a paraffin-impregnated heat insulating molded body inside the nozzle body of the continuous casting nozzle, molding and firing.