JPS61242745A - Endless track type continuous casting machine - Google Patents

Abstract

PURPOSE:To produce a steel ingot having a good shape and good quality without welding by providing short gates with guide rollers which contact with upper and lower belts on both sides between the upper and lower belts of an endless track type continuous casting machine and moving back and forth the gates at high cycles in the casting direction. CONSTITUTION:The short gates 15 with the guide rollers 17 which contact with the upper and lower belts 13, 11 are provided on both sides between the upper and lower belts 13 and 11 of the endless track type continuous casting machine. The gates 15 are moved back and forth at high cycles by an oscillation generator 23. A molten metal 24 admitted from a pouring spout 19 is filled between the upper and lower belts 13 and 11, by which the molten metal is cooled; at the same time, the molten metal solidifies and shifts toward the down stream without welding to the short side gates 15 on both sides. The generation of defects such as cracks and inclusion on the surface of the ingot 18 is thus obviated and the shape and quality of the ingot 18 are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Related Industrial Field) The present invention relates to an improvement of a hot water supply section in a continuous track type casting machine.

(Prior Art) Fig. 4 shows a conventional endless track type continuous casting machine (hereinafter referred to as a caster), particularly a twin-belt caster for production use. The twin belt caster mold is
As shown in FIG. 4, a dam block 3 is sandwiched between the sides of the lower belt 1 and the upper belt 2, and is configured to be inclined downward. In this mold, as shown in FIG. 5, molten metal 5 is supplied by flowing down onto the lower belt 1 from a water heater 4.

Therefore, the molten metal 5 flows into the mold at a distance from the downstream point of the lower belt 1, but even before it flows, it is cooled and starts to solidify at the contact surface with the lower belt 1.

However, it is subsequently remelted by molten metal supplied later.

Further, due to fluctuations in the amount of hot water supplied and fluctuations in the flow of hot water flowing into the mold, the mold surface 6 constantly fluctuates along the lower belt 1, and this also causes the molten metal 5 to repeatedly solidify and remelt.

In this way, the lower surface of the slab 7 undergoes a complicated solidification process, and wavy wrinkles called molten metal wrinkles are formed on the surface, and in severe cases, the molten metal further covers the solidified film, causing the solidified film to form. A surface flaw called double skin is formed. Moreover, when the hot water flows to the hot water surface (meniscus) 6, the falling energy due to the height difference from the hot water supply @4 to the hot water surface 6 causes bubbles due to vortices and vigorous stirring. These bubbles permeate into the caster along with the flow of molten metal, and are captured when the slab solidifies, creating cavities called blowholes.

Such defects on the slab 7 cause blemish defects and the like in subsequent rolling steps, so surface treatment is required to remove them, and untreated rolled products cannot be made into products.

In addition, the molten metal 8 flowing down from the water heater 4 also flows up to the opposite side of the mold from its flow point, and the smaller the inclination angle θ of the mold, the more the molten metal 8 exceeds the upper limit U point of the molten metal level 6 in the mold and overflows. Furthermore, the smaller the inclination angle θ of the mold, the more the fluctuation along the lower belt 1 is magnified with respect to the vertical fluctuation of the melt level 6 in the mold. The problem was that it overflowed beyond the U point, which was extremely dangerous.

On the other hand, as shown in Fig. 6, a method of inserting a hot water supply nozzle 9 between the upper and lower belts 1 and 2 to maintain the molten metal level 5 outside the mold is also considered, but the level of the molten metal is high when viewed from the mold entrance. Therefore, the static pressure of the molten metal 5 at the nozzle tip is large, causing the molten metal to leak from the gap between the upper and lower belts 1.2 and the nozzle tip, and due to thermal deformation of the nozzle tip, the upper and lower belts It may come into contact with 1 and 2 and damage them. Furthermore, if the thickness of the slab is thin, the nozzle hole will inevitably become smaller, and the nozzle will easily become clogged, making it extremely difficult to put it into practical use.

Furthermore, in the conventional twin belt caster shown in Fig. 4, if a fixed short side weir and upper base were simply provided instead of the dam block 3, the solidified shell would remain attached to the weir, making continuous casting impossible. Ta.

(Problems to be solved by the invention) To solve the problems faced by conventional technology.

In other words, ■ Eliminating the occurrence of hot water wrinkles, double skin, etc. on the surface quality of the slab, ■ Eliminating blowholes that occur inside the slab, and ■ Reducing thermal shock to the belt, significantly increasing its life. ■ Stabilize operation by eliminating the insertion of molten metal into the gap in the dam block, which accounted for most of the operational troubles of conventional twin belt casters; The task is to prevent the risk of overflow.

(Solution Means of the Invention) A U-shaped weir is formed by short side weirs provided with guide rollers on both left and right sides between the lower belt and the upper belt, and an upper base connecting these left and right short side weirs at the entry side. Provided in the hot water supply section, and
The feature is that the shape of the weir can be reciprocated at high cycles in the casting direction using a vibration generator.

(Embodiments of the invention) This will be explained with reference to FIGS. 1 and 2. A lower belt 11 is inclined downward from the horizontal, and is rotatably wound by a drive device (not shown) between a lower nip pulley 12 and a lower tension pulley (not shown). Reference numeral 13 denotes an upper belt that is parallel to the lower belt 11 and shifted in the casting direction, and is wound rotatably at the same speed as the lower belt 11 by a drive device (not shown) between an upper nip pulley 14 and an upper tension pulley (not shown). .

These upper and lower belts 13.11 constitute the long side walls of the mold. Reference numeral 15 denotes left and right short side weirs forming the short sides of the mold. Also, on the entry side of the mold, the left and right short side weirs 15
．． 15 and an upper base 16 close to the lower belt 11 on the lower nip pulley 12 forms a U-shaped dam.

Guide rollers 17 are attached to the left and right short side weirs 15 and 15.
They are installed at several locations on the opposite side to the surface in contact with the belt 8, and are designed so that the short side weir 15 and the upper base 16 can reciprocate with appropriate sliding contact or with a slight gap between the upper and lower belts 13 and 11. ing.

19 is a water heater, and at the bottom of this there is an upper base 16 and a short side weir 15.
A power transmission unit consisting of a crank lever 201, a fixed fulcrum 21, and a crank arm 22 to reciprocate in the casting direction with minute strokes, and a vibration generator that generates high-cycle reciprocating vibrations through eccentric rotational movement! ! 23
and is provided.

(Function of the invention) The water heater is installed in the mold while rotating the upper and lower belts 13 and 11 and applying high-cycle reciprocating motion with minute strokes to the U-shaped short side weir 15 and the upper weir 16 by the vibration generating device 23. When the molten metal 24 is supplied from the mold 19, the molten metal 24 is continuously cast as a strip-shaped slab 18 under cooling action from outside the mold.

(Effect of the invention) During this casting work, the upper weir 16 is used to raise the molten metal level to ensure the molten metal depth H from the molten metal surface 25 at the hot water supply position a (Fig. 2) to the lower belt. Therefore, the falling flow of the molten metal 24 does not wash the slab shell solidified at the contact portion with the lower belt 11 and prevent it from being remelted.

In addition, since the head Ho from the water heater 19 to the hot water surface becomes smaller, an extremely quiet vortex flow occurs at the hot water supply position a, and no air bubbles are generated. This prevents molten metal from adhering and solidifying compared to a fixed weir. On the other hand, since the dam block 5 is not used as in the conventional method, there is no need to insert molten metal into the gaps between the dam blocks, which was a problem in the conventional method, and the operation is very stable.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a hot water supply section according to the present invention. FIG. 2 is also a side sectional view. Figure 3 is a view in the direction of the ■ arrow in Figure 2. FIG. 4 is a side view of a known endless track type continuous casting machine. FIG. 5 is a side sectional view of the hot water supply section. FIG. 6 similarly shows another example of the hot water supply section. In the figure: 1, 11 Lower belt 2.13 Upper belt 3 Dam block 9 Hot water nozzle 12 Lower nip pulley 14 Upper nip pulley 15 Short side weir 16 Upper weir 17 Guide roller 18 Slab 19 Water heater 2
0 Crank lever 21 Fixed fulcrum 22
Crank arm 23 Vibration generator 24 Molten metal 25 Molten metal surface (meniscus) Above

Claims (1)

[Claims] A U-shaped weir is provided in the hot water supply section, consisting of short side weirs provided with guide rollers on both left and right sides between the lower belt and the upper belt, and an upper weir connecting these left and right short side weirs at the inlet side. U
An endless track type continuous casting machine characterized by a character-shaped weir that can be reciprocated at high cycles in the casting direction using a vibration generator.