JPH0377765A - Castable forming body - Google Patents

Abstract

PURPOSE:To prevent deformation caused by thermal or mechanical stress and to improve durability by using skeleton of the specific expanded metal to castable forming body for casting molten metal. CONSTITUTION:By using the expanded metal of plain steel having >=1mm plate thickness, the cylindrical skeleton 2 having closed heat at tip side is manufactured. Further, plural positions in the expanded metal are cut and bent to form the studs 3 of strand parts so as to be bit into the castable. Successively, the skeleton 2 is changed into the prescribed mold and the castable refractory 4 is poured to execute molding. Then, the forming body released from the mold, is dried to obtain a lance pipe 1. Therefore, the strength of forming body comes to high and breakage or crack at the time of conveying and crack, bending, etc., at the time of using, are eliminated, and the castable forming body having excellent durability can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to the improvement of a castable molded body for molten metal casting, in which a frame is formed with a required expanded metal,
The present invention relates to a castable molded body that is finished into a predetermined shape with castable refractory material and is fused with a product between the metal and the refractory material to improve durability.

Conventional technology The various refractories used in molten metal casting are exposed to high heat during casting and are subject to large thermal and mechanical stresses, making them prone to cracking and breakage, short lifespans, and poor durability. was there.

For example, in molten metal containers such as ladles and tundishes, lance pipes are immersed in the molten metal and discharge inert gas to stir the molten metal, and large cylinders are used to prevent slag from being entrained. also had the problem mentioned above.

In addition, in the air seal pipe for molten metal casting used for the purpose of preventing oxidation of molten metal when pouring molten metal into a tundish, a mesh structure is inserted into a refractory molded body made of alumina-graphite. An air seal pipe (Japanese Utility Model Publication No. 5942189) has been proposed.

However, the mesh structure used in this air seal pipe is made of metal or carbon fiber, and its thickness is also 0.
．． The structure itself is thin, with a diameter of 3 to 2.0 mm, and has poor shape retention, deforms even under small stress, and has problems in preventing cracks and breakage.

Purpose of the Invention The present invention provides various castable molded bodies for molten metal casting that have a structure that has high strength, prevents deformation due to thermal and mechanical stress, and has excellent durability with few cracks and breakage. The purpose is to provide a castable molded body consisting of.

Summary of the Invention The present invention provides a castable molded body for molten metal casting with a plate thickness of 1
The core is a framework made of expanded metal of mm or more in size, which is then finished into a specified shape with castable refractories, and the expanded metal and castable refractories are fused together using the product generated between the expanded metal and the castable refractories during use. It is a castable molded body with special characteristics.

Further, the present invention is a castable molded body having the above-mentioned configuration, preferably characterized in that the strands of the expanded metal are used as cut-out studs at required locations.

Structure of the Invention In this invention, the castable refractory is a mixture of refractory aggregate and hydraulic cement, and any publicly known castable refractories used in various castable molded bodies for molten metal casting can be used. However, as will be described later, in order to generate products at high temperatures between expanded metal and castable refractories, applications and requirements vary depending on castable materials such as alumina-graphite, alumina, spinel, and alumina-magnesia. It can be selected as appropriate depending on the durability.

In this invention, the expanded metal constituting the framework of the castable molded body preferably has a correct mesh shape, uniform increments, and a plate thickness of 1 mm or more, depending on the size of the castable molded body and the refractory material. , JIS X5-31 to JIS XS-73.

If the expanded metal plate thickness is less than 1 mm, the strength of the castable molded body for molten metal casting cannot be increased, and the desired long life cannot be achieved.

Further, the material of the expanded metal is preferably - rolled steel for membrane structure, - ordinary steel such as cold rolled steel.

In this invention, the position of the expanded metal within the molded body is important from the viewpoint of the strength of the castable molded body and the generation of products described below, and it is preferable to place it on the side where the temperature is high during use, and the thickness of the molded body When set to 100,
It is preferable to provide the lance at a position within 30% from the high temperature side or working side, for example, when used in a lance, at the position where the lance is immersed in molten metal (1 to 1.5 m in length).

The products that are produced by heat during use and which fuse both expanded metal and castable refractories, which is a feature of this invention, are Fed, Fe2O3, Fe3O4, 5i02
etc., and it survives at about 150°C, and partially fuses both the expanded metal and castable refractory using the following mechanism.

In other words, expanded metal Fe to castable
Fusion is achieved by a mechanism in which 01Fe203 infiltrates.

In addition, the size of each part of expanded metal varies depending on the size of the castable molded body, usage conditions, and location, so the heat during use reacts with the castable to create a product, and this product separates the expanded metal and castable. It is necessary to select a value that allows for fusion bonding and increases the strength of the castable molded product.

The manufacturing process of the castable molded body according to the present invention will be explained as follows: (1) A frame of a predetermined shape is made from expanded metal.

Furthermore, when the molded body is large, a skeleton made of wire or the like is used in combination.

■Cut and bend the expanded metal in places to make the strands into studs and bite into the castable.

■The expanded metal framework is placed inside the castable molded body on the side where the temperature is higher during use.

■The expanded metal should be installed within 30% of the total thickness from the high temperature side or working side.

■Insert a framework into the mold material, inject castable refractories into the mold, and dry to obtain a castable molded body.

Example The manufacturing process of the lance pipe according to the present invention will be explained.

FIG. 1a is a front explanatory view of the lance pipe according to the present invention, and the same figure is a BB sectional view. FIG. 2 is a perspective explanatory view of the expanded metal used in the framework of the present invention.

A cylindrical frame (2) with a closed end is made using expanded metal of JIff X8-41 standard ordinary steel.Furthermore, as shown in Figure 2, the expanded metal is cut and bent in places to form strands. The part is made into a stud (3), and it bites into the castable.

When creating the frame (2), the dimensions were determined so that the expanded metal would be located within 30% of the total thickness from the outer peripheral surface of the lance pipe (1) when completed.

Put the above-mentioned frame (2) into a required mold material (not shown), and
A castable refractory (4) containing 2O3 as a main component was injected and molded.

The molded product removed from the mold material was dried at 350° C. for 3 days to obtain a lance pipe (1) with a dehydration rate of 95% or more.

When the lance pipe according to the present invention was used to produce molten metal, it had a lifespan of up to 110 uses.

By the way, with the conventional lance pipe that does not use the expanded metal framework of this invention, the maximum number of times it can be used is 63.
It can be seen that the life of the lance pipe according to the present invention has been significantly extended.

Effects of the Invention This invention uses a specific expanded metal framework in various castable molded bodies for molten metal casting, thereby increasing the strength of the molded body and preventing deformation due to thermal and mechanical stress. It is possible to provide a castable molded body with excellent durability, which eliminates chips and cracks during transportation, cracks and bends during use, and has excellent durability.

[Brief explanation of drawings]

FIG. 1A is a front explanatory view of a lance pipe according to the present invention, and the same figure is a sectional view taken along line B-B in FIG. FIG. 2 is a perspective explanatory view of the expanded metal frame used in this invention. 1... Lance pipe, 2... Frame, 3... Stud, 4... Castable refractory.

Claims (1)

[Claims] 1. In a castable molded body for molten metal casting, the plate thickness is 1 m.
The core is a framework made of expanded metal with a diameter of 1.5 m or more, which is finished into a specified shape with castable refractories, and the expanded metal and castable refractories are fused together using a product generated between the expanded metal and the castable refractories during use. Characteristic castable molded body.