JPS61293634A - Production of clad ingot - Google Patents

Abstract

PURPOSE:To continuously obtain a clad ingot having the core of a different molten steel with high reliability by supplying alloy powder into the unsolidified steel on the inside of an in completely solidified ingot in parallel with drawing of the ingot. CONSTITUTION:The incompletely solidified ingot C1 formed with a solidified shell (a) in a mold 2 is drawn from a lower aperture 2b to an ingot drawing passage 4. The alloy powder P is supplied by using an immersion lance 5 into the unsolidified steel A existing on the inside of the solidified shell (a) of the in completely solidified ingot C1 through an upper aperture 2c of the mold 2. The molten steel is forcibly stirred by an electromagnetic stirrer 6 as necessary. The ingot is then cooled with water 7 while the in completely solidified ingot C2 filled with the different molten steel B in the solidified shell (a). The clad ingot D coating the solidified core steel (b) of the different molten steel B with the solidified shell (a) is obtd. by the above-mentioned method. The various clad ingots are produced if the components and supply rate of the alloy powder are changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for continuously manufacturing clad slabs.

[Prior Art and Problems] Composite clad metal materials are known in which the surface of a base material made of an arbitrary material is covered with a covering material made of another material, and the interface thereof is metallurgically bonded. .

Conventionally, methods for producing clad metal cladding materials include a method in which a covering material is applied onto a base material under a vacuum condition and then hot-rolled to adhere the two, and a method in which the covering material is placed on top of the covering material via a buffer. A method using explosive bonding, in which the first material is impact-bonded to the base material using the explosive force of an explosive, a method using overlay welding, in which the covering material is welded to the base material by various overlay welding methods, and a method using overlay welding, in which the base material is placed in a hollow mold. There are methods such as casting, in which a molten covering material is injected between the base material and the base material. However, in all of the above conventional methods, a clad metal material is obtained by joining a coating material to a single base material, and it is not possible to manufacture a continuous material. Therefore, there were disadvantages in that the productivity was extremely poor and the yield was also low. Furthermore, each of the above manufacturing methods had the following inherent drawbacks. That is, the method using hot rolling has the disadvantage that the types of covering materials that can be manufactured are relatively limited. The method using explosive bonding produces a loud explosion sound;
The disadvantage is that it can only be used when manufacturing relatively small items in a specific location. The overlay welding method has the drawback of requiring appropriate consideration in the selection of welding materials, welding method, heat treatment after welding, and the like. Furthermore, in the most commonly used method of casting, it is possible to avoid the situation where the coating material, which is injected in a molten state only in its raw form, is rapidly cooled by contact with the low-temperature base material, which has a large heat capacity. Therefore, it is necessary to maintain good bonding properties at the interface between the base material and the material to be FW. For this reason, the casting method requires a special heating device such as an electric TaX conduction heating device to prevent rapid cooling of the coating material, resulting in an increase in the size of the equipment and a rise in equipment costs.

[Object of the Invention] In order to solve the above-mentioned drawbacks, the present invention aims to provide a manufacturing method capable of obtaining a clad slab by a continuous casting method.

[Structure of the Invention] The gist of the present invention is to inject mother molten steel from a tundish into a mold with a submerged nozzle, and to form an incomplete solidified shell formed by solidifying the mother molten steel in the mold by contacting the inner wall of the mold. In a continuous casting method in which a solidified slab is pulled out from a lower opening of a mold and then cooled to form a completely solidified slab, the unsolidified molten steel inside the solidified shell of the incompletely solidified slab is drawn from the upper opening of the mold. The method is to supply the alloy powder with an immersion lance.

[Description of Examples] Hereinafter, the present invention will be described based on an example shown in FIG. First, the base layer IIA is injected into the mold 2 from the base layer temperature 1a of the tundish 1 with the immersion nozzle 3, and then the base layer IIA is poured into the mold 2.
The inner mother layer! The incompletely solidified slab C1, which has formed a solidified shell a formed by solidifying IIA by contact with the inner wall 2a of the mold 2, is pulled out from the lower opening 2b of the mold 2 to the slab drawing passage 4. In parallel with the drawing of the slab by the drawing rolls 9, 9..., unsolidified melt inside the solidified shell a of the incompletely solidified slab C1 is drawn from the upper opening 2C of the mold 2!
*Alloy powder P (e.g. 50
~100 meshes) and forcibly stirred with a 1611 stirring device 6 as necessary to obtain a homogeneous heterogeneous groove &lB. The spout 5a of the immersion lance 5 is located at a lower position than the spout 3a of the immersion nozzle 3, and is used to form an incompletely solidified slab C1 of arbitrary length. The position and ejecting direction are such that the alloy powder P is not mixed into the IA. Next, solidify shell a
The incompletely solidified slab C2 filled with dissimilar molten steel B is cooled with cooling water 7 while being pulled out, and the core rjA in which dissimilar molten steel B has solidified is drawn out.
Clad slab D (second
(see figure).

In addition, as a method of supplying the alloy powder P to the immersion lance 5, the alloy powder stored in the pressurized tank 8 is gas-transported using an inert gas such as argon gas or nitrogen gas to supply the desired amount to the immersion lance 5. There are methods such as supplying at high speed.

[Function 1] Next, the function of the present invention will be explained based on the embodiment shown in FIG. The mother molten steel A injected into the mold from the tundish 1 cools on the inner wall 2 while passing through the mold 2.
A part of the cast slab C1 is solidified by contact with a to form an annular solidified shell a, and the solidified shell a is filled with unsolidified molten steel Δ. The incompletely solidified slab C1 is drawn from the lower opening 2b of the mold 2 to the slab drawing passage 4, where alloy powder P is added to the unsolidified melt mA, and the dissimilar groove mB
The incompletely solidified slab C2 is filled with the following conditions. The incompletely solidified slab C2 is entirely cooled while passing through the slab drawing passage 4 formed from the drawing rolls 9, 9, . . . and becomes a completely solidified clad slab D (see FIG. 2).

[Effects of the Invention] As detailed above, the method for manufacturing a clad slab according to the present invention has the following excellent effects.

■ Clad slabs can be continuously cast, which significantly improves productivity and yield, and significantly reduces manufacturing costs.

■ By simply supplying alloy powder into the unsolidified molten steel of an incompletely solidified slab, it is possible to obtain molten steel of different quality, making it possible to eliminate the need to prepare two types of material, the base material and the rfI material, in advance. , it is possible to reduce manufacturing costs.

■ Since the alloy border is supplied from the incompletely solidified slab into the unsolidified molten steel in a non-oxidizing atmosphere, no oxide film is generated on the cladding boundary, and the incompletely solidified slab is Since it is possible to cool at a cooling rate, a completely welded clad boundary can be obtained, and a highly reliable clad slab can be obtained.

(2) A clad slab with a desired cladding ratio can be obtained by simply adjusting the handling speed of the incompletely solidified slab and/or the supply position of the alloy powder.

(2) Various types of clad slabs can be easily obtained by simply changing the composition of the alloy powder and/or the supply port.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a main part showing an embodiment of the method for manufacturing a clad slab according to the present invention, and Fig. 2 shows an example of an 11-layer clad slab by the method for manufacturing a clad slab according to the present invention. FIG.

Claims (1)

[Claims] 1. Inject the mother molten steel from the tundish into the mold with an immersion nozzle, and pour the incompletely solidified cast slab, which has formed a solidified shell formed by solidifying the mother molten steel in the mold by contacting the inner wall of the mold, into the lower opening of the mold. In a continuous casting method in which a completely solidified slab is produced by cooling the slab after being drawn from the slab, alloy powder is supplied by an immersion lance from the upper opening of the mold into the unsolidified molten steel inside the solidified shell of the incompletely solidified slab. A method for producing a clad slab, characterized by: