JPH08108266A - Refractory lining layer in molten metal pouring device - Google Patents

Abstract

PURPOSE: To restrain the solidified stickiness of remaining molten metal and slag to a refractory lining layer in a molten metal pouring device, such as ladle, hopper, used to a casting operation of a high Cr iron alloy, etc., to the min. limit. CONSTITUTION: The lining refractory layer is formed with a zircon base refractory. For example, kneaded material adjusted by adding aluminum phosphorous (binder) to zircon sand frequently used to a mold material as an aggregate, is used and heated with a burner, etc., and consolidated. By this method, even in the casting operation of molten Cr-Fe alloy containing high Cr of high m.p., the development of fume of hexavalent chromium and the solidified-stickiness, etc., of the remained molten metal, etc,, after casting is restrained to the min. limit and prevented and the effect of the smooth performance of the casting operation and the improvement of cast quality, etc., is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a refractory liner layer such as a ladle used as a pouring device for molten alloy containing Cr having a high melting point.

[0002]

2. Description of the Related Art Various refractory materials are known for the lining layer of a pouring device such as a ladle used for pouring molten alloy melt produced in a melting furnace. Silica-based refractory materials are one of the most common lining layer refractory materials. However, as a molten alloy, for example, a high melting point Cr-Fe melted in a high frequency melting furnace is used.
If a ladle provided with a silica sand lining layer is used for pouring the molten alloy, slag with extremely high fluidity is generated on the molten metal surface. For this reason, in a tilting ladle, when pouring the molten metal in the ladle into the casting hopper, a large amount of slag flows out together with the molten metal, making casting operation difficult and mixing slag into the molten metal Significant quality defects occur in castings.

This problem can be solved by using a magnesia stamp material such as seawater magnesia instead of silica sand as the lining refractory material. However, since the magnesia lining layer has a high thermal conductivity, it has a high Cr content. In the case of a melt of a high melting point alloy such as a Cr-Fe alloy containing Cr (about 70% or higher) (melting point of about 1670 ° C. or higher), the melt or slag is likely to adhere to the surface of the lining layer. Therefore, it is necessary to scrape off the solidified or semi-solidified material (skull) such as the molten metal or slag remaining in the ladle after the casting is completed. The repeated execution of the scraping operation causes the damage of the lining layer to be accelerated. Moreover, in the ladle of the magnesia-based lining layer, in addition to the above problems, there is a problem that hexavalent chromium fumes are generated. The generation of hexavalent chromium is caused by the reaction between Cr in the molten metal and oxygen in the atmosphere (Cr +
3O ₂ → Cr ⁺⁶ + 3O ^-2 ) is promoted by using the magnesia-based lining layer (which is alkaline) as a catalyst.

As a method for preventing the above hexavalent chromium formation reaction from being suppressed, it is conceivable to apply an acidic refractory as the lining layer refractory in the upper part of the ladle (the region above the molten metal surface). However, in that case, there is a disadvantage that a melting damage reaction occurs at the joint between the lining layer of the acid refractory material in the upper part of the ladle and the magnesia-based lining layer in the lower region, and the molten metal is likely to be diced. . The present invention provides an improved refractory lining layer of a pouring device for solving the above problems associated with pouring of a high-melting point Cr-rich alloy melt or the like.

[0005]

The refractory lining layer for a high Cr alloy pouring apparatus according to the present invention is characterized by being made of a zircon refractory material.

[0006]

The zircon refractory layer forming the lining layer of the pouring apparatus of the present invention does not generate high-fluidity slag as in the case of the silica sand lining layer, and is a magnesia lining layer. The thermal conductivity and heat capacity are smaller than those of the thermal conductivity (cal / se
c ℃ cm ^-1 ): Magnesia about 0.025, Zircon about 0.00
Five . Specific heat (cal / g ℃) Magnesia About 0.025, Zircon
About 0.13, at 700 ℃). Therefore, the outflow of slag that accompanies the pouring of the molten metal during casting is prevented, and the temperature decrease and thickening of the molten metal and the accompanying generation of skulls are also prevented.
Furthermore, its lining layer has high heat resistance and high strength, and
Since it has resistance to collapse and has no reactivity with the molten metal, it is possible to avoid difficulty in removing the residual molten metal and slag after the completion of casting. Moreover, since it is an acid refractory, the reaction of hexavalent chromium generation is suppressed and prevented.

The formation of the refractory lining layer of the pouring device of the present invention is
Except for using zircon refractory, it is constructed according to the usual method. The zircon refractory is, for example, zircon sand (ZrO ₂ · SiO ₂ ) known as a zircon template material.
Is used as an aggregate, and primary aluminum phosphate is added as a binder, and stamping is performed to form a predetermined layer thickness in a ladle, and heat treatment is performed to consolidate. The compounding ratio (weight ratio) of zircon sand / binder is
A range of about 100/3 to 100/10 is suitable, and the heat treatment is achieved by heating to about 700 to 1000 ° C with a burner or the like.

The refractory lining structure of the present invention is applied not only to the ladle, but also as a lining layer of a casting hopper for guiding the molten metal supplied from the ladle into the mold.

[0009]

【Example】

[1] Formation of the lining layer of the tilting type ladle (1) an inner layer material composition Aggregate: zircon sand _{(Australia) ZrO2 2 66.7, SiO 2 32.5} , TiO 2 0.1, Fe 2 O 3 0.08. Binder: Aluminum monophosphate compounding ratio (zircon sand / binder) 100/5 (weight ratio) Heating temperature: 700-1000 ° C [2] Pouring operation Fe-Cr alloy (Cr content 80) melted in a high frequency melting furnace
%, Melting point 1725 ° C.) was received in the ladle and cast.

[3] Operation Results In the operation of casting the molten metal into the mold, there was no obstacle to the inflow of slag from the ladle and the casting operation. Also, there was no generation of hexavalent chromium fumes. Furthermore, there is almost no residual hot water or slab adhesion in the ladle after the end of casting,
Removal of the skull was easy and easy and there was virtually no damage to the lining layer due to the removal work.

[0011]

EFFECTS OF THE INVENTION By forming the refractory lining layer of the present invention in a ladle, even when pouring a high-Cr alloy containing a high melting point,
It is possible to prevent the slag from flowing out of the ladle during the casting operation and prevent the generation of harmful hexavalent chromium, and also to suppress the residual hot water in the ladle and the adhesion of slag to a minimum. The same effect can be obtained by applying it as a lining layer of a casting hopper or the like in addition to a ladle, and it is possible to obtain effects such as smooth execution of casting operation and improvement of casting quality.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C04B 35/49 F27D 1/00 N C04B 35/49 Z (72) Inventor Shin Shinozaki Osaka Hirakata City Nakamiya Oike 1-1-1, Ltd. Kubota Hirakata Manufacturing Company

Claims (2)

[Claims] 1. A refractory lining layer of a pouring device for molten alloy containing high melting point Cr, which is composed of a zircon refractory material. 2. A refractory lining layer for a high melting point Cr-containing molten alloy pouring device according to claim 1, which is composed of a kneaded material in which zircon sand is used as an aggregate and a primary aluminum phosphate is added as a binder thereto.