JPS629751A - Continuous casting method for thin metallic sheet - Google Patents

Abstract

PURPOSE:To continuously form an ingot having good surface characteristics without having cold shut, laps, cracks, etc. in a continuous casting of a thin metallic sheet with a twin drum type by heating the molten metal surface near the wall surfaces of stationary gates. CONSTITUTION:Two water-cooled casting drums 1, 1' are horizontally juxtaposed apart from each other at a prescribed space. The stationary gates 2, 2' are provided to both ends of the drums 1, 1' to prevent the leakage of the molten metal 4 between the drums 1 and 1'. A molten metal 4 is supplied from a tundish 5 and the ingot 3 is continuously formed. Heaters 10 are disposed above the drums 1, 1' to heat the molten metal 4 surface near the wall surfaces of the gates 2, 2'. The molten metal 4 surface near the gates 2, 2' is heated by such heaters 10 upon starting of casting to prevent the formation of the solidified mater by the temp. drop of the molten metal 4 near the same. The ingot 3 having the good surface characteristics is thus formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for continuous casting of thin metal sheets for manufacturing thin metal sheets using a twin-drum type continuous thin sheet casting apparatus.

[Conventional technology]

The mechanism of the conventional twin-drum continuous casting machine is summarized in Part 3.
This will be explained based on the diagram. This apparatus includes a water-cooled casting drum 1-' for casting a thin plate slab 3, and a water-cooled casting drum 1.1.
The main structural members include a side fixed weir 2.2' for preventing leakage of molten metal between 1 and 2', and a tandai 5-5 for storing molten metal 4 such as molten steel.

To explain this device in detail, the water-cooled casting drum 1.1'
is installed horizontally and is driven to rotate (in the direction of the arrow) by a drive device (not shown). This water-cooled casting drum 1,1
' is made of copper, copper alloy, or steel, for example, and has a built-in water cooling mechanism, and has a fairly large diameter drum in order to obtain a large contact area with the molten metal 4. Furthermore, fixed weirs 2.2' made of refractory material are installed at both ends of the water-cooled casting drums 1 and 1' to seal the sides.
The two water-cooled casting drums 1 and 1'
The molten metal 4 is poured into the space formed by the two fixed weirs 2 and 2'. The molten metal 4 comes into contact with the surfaces of the water-cooled casting drums 1 and 1' and is cooled, resulting in a solidified shell that is integrated into a slab 3. This slab 3 is pulled out by a vinyl roll 6.

Note that 7 is a guide roll.

[Problem that the invention seeks to solve]

In the above conventional technology, the molten metal 4 poured into the space formed by the water-cooled casting drum 1°1' and the fixed weir 2.2' solidifies (forms a skin) at the surface near the fixed weir 2.2'. Since the solidified material and the solidified shell formed on the surface of the drum 1.1' are pulled downward, the solidified material formed on the surface of the molten metal causes wrinkles, caps, or cracks on the surface of the slab 3. Cracks, etc. occurred, and the properties of the slab surface were significantly damaged.

[Object of the present invention]

The present invention solves the above-mentioned problems, and eliminates hot water wrinkles, fogging, and
Another object of the present invention is to provide a method for continuously casting thin metal sheets, which continuously produces slabs with good surface properties without cracks or the like.

[Means for solving problems]

The present invention is characterized in that, as a means for achieving the above object, the surface of molten metal poured into a space consisting of a drum and a fixed weir near the fixed weir is heated. That is, the present invention uses a continuous casting apparatus having two water-cooled casting drums arranged horizontally with a gap corresponding to the thickness of the thin metal sheet to be manufactured and rotating in different directions to form a thin metal sheet. This continuous casting method for thin metal sheets is characterized in that the surface of the molten metal near the fixed weir wall surface is heated.

The present invention will be described in detail below with reference to the drawings. A suitable continuous metal sheet casting apparatus for carrying out the method of the present invention is basically the same as the conventional apparatus described above. As shown in FIG. 3, this device includes a water-cooled casting drum 1.1' for casting thin plate slabs 3, a fixed weir 2.2' for preventing leakage of molten metal 4 between the water-cooled casting drums 1.1', The molten metal 4 is supplied in a fixed amount, and the dish 5 is used as a component.

However, a suitable apparatus for carrying out the method of the present invention is similar to that shown in FIG. A heating device 10 is arranged as shown in FIG. 2 (a longitudinal cross-sectional view of a preferred device in FIG. 1) and FIG. The heating device 10 is located above the water-cooled casting drums 1, 1', and has a fixed weir 2 that is pressed against the end surface of the drum with a constant surface pressure by the water-cooled casting drums 1, 1' and a hydraulic cylinder (or air cylinder) 11. , 2' face downward in order to heat the area where they come into contact. Simultaneously with the start of casting, the surface of the molten metal 4 near the fixed weir 2.2' is heated.

By heating the surface of the molten metal in the vicinity of the fixed weir in this manner, it is possible to prevent the formation of coagulated material due to a decrease in the temperature of the molten metal in this area.

〔Example〕

The dimensions and various conditions of the structural members when cast steel are as follows.

(1) Water-cooled casting drum Made of steel, internal water cooling system, drum diameter is 2000-φ, drum width 120G, slab size is 50fit x 1200-width, drum rotation speed (casting speed) at this time is about 29
It is 91v/mln.

(2) Fixed weir Boron nitride (BN) as a fireproof material for fixed weirs
was used. It was also preheated to a high temperature and heated during casting.

(3) Molten metal temperature in the tundish: 1520-1 in the case of normal -
The temperature is 560°C.

(4) Heating device A plasma flame was used as a heating device for the hot water surface near the fixed weir. The number of units installed was one on each side.

By casting under the above-mentioned conditions, it was possible to produce a good slab free of defects such as creases, caps, and cracks.

[Effects of the present invention]

In addition to the above, the present invention prevents the formation of coagulum caused by a drop in the temperature of the molten metal in this area by heating the molten metal surface near the fixed weir, thereby preventing water wrinkles, caps, and cracks. It is possible to produce high-quality slabs without such defects.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the main parts of a continuous metal sheet casting apparatus suitable for carrying out the present invention, and FIG. 2 is a plan view of the main parts of the apparatus. FIG. 3 is a longitudinal sectional view of a conventional continuous thin metal plate casting apparatus. 1.1'... Water-cooled casting drum 2.2'... Fixed weir 3... Slab 4... Molten metal 5... Tundish 6...・Vinch roll 7...Guide roll 10...Heating device 11...Hydraulic cylinder sub-agent 1) Meifuku agent Ryo Hagiwara - Sub-agent Atsuo Anzai

Claims (1)

[Claims] In a method of manufacturing a thin metal sheet using a continuous casting device having two water-cooled casting drums arranged horizontally with a gap corresponding to the thickness of the thin metal sheet to be manufactured and rotating in different directions, A continuous casting method for thin metal sheets characterized by heating the surface of the molten metal near the weir wall surface.