JPS62270252A - Continuous casting method for strip - Google Patents

Abstract

PURPOSE:To uniformize the development of solidified shell by giving ultrasonic vibration to water cooling drums at the time of continuously casting a strip by two water cooling drums rotating to different direction for each other drum. CONSTITUTION:A space is shaped by the two water cooling drums 1, 1' arranged in parallel horizontally and having different rotating direction for each other, and two weirs 2, 2', abutting to the end face of the drums 1, 1'. Molten metal 4 is poured into the space from a tundish 3 and the solidified shell 8, 8' is developed to produce the strip 9. Then, the ultrasonic vibrating device 10 is set at reverse side of the neutral point P of the drums 1, 1' and a vibrator 11 of the ultrasonic vibrating device 10 is abutted on the drums 1, 1', and at the time of casting, the ultrasonic vibration is directly given to the drums 1, 1', to give high frequency vibration. In this way, the developed solidified shell 8, 8' is grown at uniform thickness as touching with and leaving from the drums 1, 1' is come to in a body at the neutral point P, to produce the strip.

Description

[Detailed description of the invention] 3 Detailed explanation of the invention [Industrial application field] The present invention relates to a continuous thin plate casting method.

[Conventional technology]

A conventional thin plate continuous casting means will be explained based on FIGS. 5 and 4. FIG. 3 is a longitudinal sectional view of a conventional thin plate continuous casting apparatus, and FIG. 4 is a sectional view taken along the line -- in FIG. In this conventional device, molten metal (molten metal) is placed in a space formed by two horizontally parallel internal water-cooled drums 1. When the gold ff1) 4 is poured, a solidified shell 8,8' is formed at the portion in contact with the drums 1, 1'. The produced solidified shells 8, 8' are integrally formed into a thin plate 9 at the neutral point P of the drums as the drums 1, 1' rotate in the direction of the arrow. In addition, in FIG. 3, 3 is a tundish, 5 is a nozzle, 6 is a vinyl roll, and 7 is a guide roll.

[Problem that the invention seeks to solve]

By the way, in the conventional thin plate continuous casting means described above, the solidified shells 8, 8' produced tend to separate from the drums 1, 1' as shown in FIG.
A phenomenon occurs in which 8' itself becomes uneven, resulting in the following drawbacks.

That is, the generated solidified shells 8, 8' are transferred to the drums 1, 1.
The solidified shells 8, 8' tend to peel off from the surface in some places, and the solidified shells 8, 8' come into contact with the drum 1.1' at some places and at other places where they do not, and the solidified shells 8,8' become uneven. In addition, the shell thickness is large at the 9 points that are in close contact with the surfaces of the drums 1 and 1', while the 7L thickness is small at the points where the peeling occurs.For this reason, the solidified shells 8 and 8' at the peeled points are stronger than the solidified shells that are in close contact. Cracks occur during contraction of the weakly solidified shells 8, 8'. Cracks that occur during shrinkage are called shrinkage cracks, and these cracks remain even in the thin plate 9 after casting, significantly reducing the quality of the thin plate 9 manufactured.

〔the purpose〕

Therefore, the present invention aims to solve the drawbacks of the above-mentioned conventional means, and provides a continuous thin plate casting method in which vibration is applied to the drum body to uniformize the growth of the solidified shell. With the goal.

[Means for solving problems]

Further, the present invention uses ultrasonic vibration as a means for imparting vibration to the drum body.

That is, the present invention involves pouring molten metal into a space formed by two drums arranged horizontally in parallel and having different rotational directions, and two fixed weirs pressed against the end faces of the drums, This is a continuous casting method for thin plates, characterized in that casting is carried out while applying ultrasonic vibrations to the drum.

Specifically, the present invention transmits ultrasonic vibrations to the drum itself by installing an ultrasonic vibrator on the opposite side of the neutral point of the drum. For this reason, vibrations are transmitted to the solidified shell itself, and due to this influence, the V solidified shell repeats υ of attaching to and separating from the drum surface, and grows more or less uniformly. When the solidified shell grows uniformly in this way, there are no weak points in the solidified shell itself (points where hardening is slow, places where the solidified shell is thin), and the effect is that there is no cracking during shrinkage.

〔Example〕

The present invention will be explained in detail below based on FIGS. 1 and 2. FIG. 1 is a longitudinal sectional view of a continuous thin plate casting apparatus suitable for carrying out the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. This device consists of a water-cooled drum 1゜1' for casting thin plates (slabs) 9, side weirs 2, 2' for preventing leakage of molten metal 4 between water-cooled drums 1.1', and molten metal 4 such as molten steel. The main components are a tundish 3, a nozzle 5, and an ultrasonic vibration device 10, which is the key point of the present invention.

To explain this device in detail, it is installed horizontally on a water-cooled drum 1° 1' and is driven to rotate in the direction of the arrow by a drive device (not shown). The water-cooled drums 1, 1' are made of copper, copper alloy, or steel, for example, and have a built-in water-cooling mechanism, and have a considerably large diameter in order to obtain a contact area with the molten metal 4. Further, side weirs 2, 2' made of fireproof material are pressed against both ends of the water-cooled drums 1, 1' to prevent leakage of molten metal 4 from the sides. It has a structure that allows the inside to be heated with a heater, etc. The molten metal 4 stored in a tundish 3 is poured into the space formed by the water-cooled drums 1 and 1' and the two side weirs 2 and 2' through a nozzle 5.

? ? −? Todoroki ＾ Zeno・/L Jihon 1 Kokan auxiliary flood device 10
To explain, the device 10 is installed on the opposite side of the neutral point P of the drums 1, 1', and the ultrasonic vibration device 10
The vibrator 11 rests against the drum 1.1'. For this reason, during casting, ultrasonic vibrations are applied directly to the drums 1 and 1'.
Gives high cycle vibration.

The poured molten metal 4 is cooled by contacting the surfaces of the water-cooled drums 1, 1', and a solidified shell 8° 8' is formed on the drum 1.
The solidified shell 8°8/ itself due to the vibration of drum 1.
It grows to a uniform thickness because it attaches to and separates from fc at 1'. The grown solidified shells 8.8' are integrated at the neutral point P of the drum to form a thin plate (slab) 9. The thin plate (slab) 9 is pulled out by a vinyl roll 6, and then passed through a guide roll. is transferred to the next process. FIG. 2 is a cross section taken along the line AA in FIG. 1, and shows how the solidified 7-wells 8, 8' have grown uniformly.

〔Concrete example〕

In the case of casting stainless steel, the constituent materials and various conditions are as follows.

(The 1-inch water-cooled drum is made of alloy and has an internal water-cooled structure, the drum diameter is 1200φ, the drum width is 1000", the slab thickness is 3 nt, and the casting speed is about 28 m/m x n.

(2) Side Weir A mixture of boron nitride and silicon nitride was used as the refractory at the side weir in contact with the end face of the drum, and was preheated from the back side to about 15,000 ℃ with a platinum heater.

(3) Molten metal 180r-8Ni-based 5US13 (JrS) was cast. At this time, the temperature of the molten metal in the tandish was approximately 15
It is 45C.

(4) Ultrasonic vibrator The vibrator of the ultrasonic vibrator is in contact with the drum, and the vibration condition is 20 KIlz. Note that since the vibrator of the vibrator is for the purpose of vibrating the water-cooled drum, it may be in contact with the drum shaft.

By casting under the above conditions, we were able to stably cast a good thin plate without shrinkage cracking.

〔effect〕

As described in detail above, the present invention uniformizes the growth of the solidified shell produced by applying ultrasonic vibration to the drum. Therefore, weak points (thin shell thickness) in the solidified shell, which are the cause of shrinkage cracks, are eliminated, resulting in the effect that a good crack-free cast plate can be cast.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a continuous thin plate casting apparatus suitable for carrying out the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. FIG. 5 is a longitudinal cross-sectional view of a conventional thin plate continuous casting apparatus, and FIG. 4 is a cross-sectional view taken along the line shown in FIG. 5. 1.1'...Water cooling drum, 2,2'...Side weir,
3... Tanditshu, 4... Molten metal (molten metal),
5... Nozzle, 6... Vinci roll, 7... Guide roll, 8, 8'... Solidified shell, 9... Thin plate,
10... Ultrasonic imaging device, 11... Ultrasonic transducer,
P...Drum neutral point Figure 1

Claims (1)

[Claims] Two drums arranged horizontally and rotating in different directions,
A method of manufacturing thin plates by pouring molten metal into a space formed by two fixed weirs pressed against the end face of the drum and rotating the drum, in which casting is performed while applying ultrasonic vibration to the drum. A continuous casting method for thin plates characterized by: