JPH01218748A - Molten metal trough for twin belt caster - Google Patents

Abstract

PURPOSE:To prevent turbulent flow of molten metal supplying into caster and to manufacture a continuously cast strip having high quality by making the specific construction composing of front chamber and rear chamber of a molten metal trough supplying the molten metal in a tundish into the caster at the time of continuously casting the cast strip from the molten metal with twin belt caster. CONSTITUTION:The molten metal 2 in the tundish 1 is supplied on lower belt 8 in the twin belt caster through the molten metal trough 5 via a sliding nozzle 3 and carried, cooled and solidified to continuously cast the cast strip. In this case, by passing through the front chamber 17, in which the width of the molten metal trough 5 is gradually made to larger toward downstream, and the rear chamber 18 having the fixed large width, the molten metal is supplied on the lower belt 8 as the uniformly straightening molten metal flow. Then, by flowing the molten metal 2 into the rear chamber 18 through a diving passage 13A and raising-up passage 13B formed with a weir 13 between the front chamber 17 and the rear chamber 18, as the molten metal is supplied at uniform flow speed to the width direction and the straight flow state in the rear chamber 18, the metal strip having good quality is stably obtd. without developing the blow hole, etc., caused by the turbulent of the molten metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a twin-belt caster monthly hot water supply gutter in a track type continuous casting facility.

[Conventional technology and its issues]

In general, in order to cast particularly thin slabs using this type of continuous track casting equipment, it is necessary to control the amount of molten metal supplied to the twin belt casters.

Therefore, the following proposal is introduced in Japanese Unexamined Patent Publication No. 61-42461. In other words, the molten metal is injected from a large tundish into a small tundish through a sliding nozzle, is fed to a twin belt caster, and is cooled and solidified by the twin belt caster to cast a thin slab. Before molten metal is supplied to the twin belt casters, the flow rate of molten metal injected from the large tundish to the small tundish is actually measured, and the hot water supply capacity of the small tundish is set based on the temporal change in the flow rate. In order to match this hot water supply capacity with the target hot water supply amount by the twin belt caster, the opening degree of the sliding nozzle is controlled. Next, the start of hot water supply to the twin belt casters is detected, and a run-up operation is performed until the total amount of hot water supplied from the small tundish to the twin belt casters matches the total amount of slab pulled out from the twin belt casters. ,
An operating method for continuous track casting equipment is introduced in which if these conditions match, steady operation begins.

Here, hot water is supplied from the small tundish to the twin belt casters using a so-called elephant type system, in which a sliding nozzle is provided horizontally at a predetermined height position on the side wall of the small tundish, and a water heater is connected to this sliding nozzle. It is done by a nozzle.

Therefore, in such a continuous track type continuous casting equipment, it is possible to match the target values of the scene level of the small turntable and the pull-out speed of the twin belt casters, so that a stable casting state force j can be obtained, and as a result, the slab surface It prevents the formation of hot water wrinkles and double skin, improves the yield of slabs, and prevents dangers such as breakouts and overflow of molten metal from twin helt casters. has been done.

However, as a result of testing and research on the elephant-type nozzle used in such track-type continuous casting equipment, we found that the quality of the slabs still deteriorated.When we analyzed the causes of this, we found the following problems. found. That is, conventional elephant-type nozzles are shown in FIGS. 3, 4, and 5. 1 is a tundish; 2 is a molten metal injected into the tundish 1 from an appropriate ladle; 3 is a sliding nozzle installed horizontally at a predetermined height on the side wall of the tundish l; Its opening degree is controlled. 5 is a water heater, sliding nozzle 3
This is called an elephant-type nozzle. 6 is a twin heel caster, and side wall dam blocks 7.7 are arranged on both sides thereof. 8.9 shows the lower and upper belt of the twin belt caster 6.

- Here, the water heater 5 has a side wall dam block 7
．． 7, only the middle W of the gutter gradually expands, and it now faces above the lower belt 8 of the twin belt caster 6.

Thus, the molten metal 2 in the tundish 1 is transferred to the lower belt 8 of the twin helt caster 6 via the sliding nozzle 3 whose opening degree is controlled and the water heater 5.
Hot water is supplied above. During this hot water supply, the molten metal 2 is ejected from the nozzle hole of the sliding nozzle 3, and then expands and flows into the gutter W in the water heater 5, resulting in a turbulent flow within the water heater 5, as shown in FIG. A vortex 2a is generated.

Further, as shown in the figure, the flow velocity V of the molten metal 2 is also uneven in the direction of the gutter. ...■7.

Therefore, when the molten metal 2 is supplied into the twin belt caster 6 in such a state, bubbles 2b are generated in the meniscus portion 10, as shown in FIG.
Small air bubbles called blowholes 11 form cavities inside the slab, resulting in harmful defects in the rolled product.

In addition, in such a state, the upper belt 9 and the lower belt 8
and the contact points of the molten metal 2 with the meniscus portion 10, that is, the upper and lower belt shore lines 1'5. 1 and 6 become extremely unstable, and defects such as hot water wrinkles and double skin are likely to occur on the surface of the slab.

[Means to solve the problem]

Therefore, the present invention was created to solve the problems of the prior art, and its gist is that the water heater, which supplies hot water from the tendish unit to the twin belt casters via the nozzle, is directed downstream. It is composed of a front chamber that gradually expands in the direction and forms a water pool, and a rear chamber that has a constant expanded width and a shallow water-like depth and faces the twin belt casters. This twin belt caster monthly hot water supply gutter is characterized in that a weir forming a series of sinking passages and rising passages between the bottom wall of the front chamber and the downstream side wall of the front chamber is installed in the hot water pool part.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of the present invention will be explained in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 is a plan sectional view of an embodiment of the present invention, showing a sectional view taken along line AA in FIG. 2, and FIG. 2 shows a sectional view taken along line BB in FIG. Note that the same parts in the conventional example explained in FIGS. 3, 4, and 5 are indicated by the same reference numerals, and the explanation thereof will be omitted.

In these figures, the water heater having an elephant-type nozzle is constructed as follows. That is, in the width direction, just the middle W of the gutter is gradually expanded toward the side wall dam block 7.7 so as to face the lower belt 8. .

To be more specific, the water heater 5 is composed of a front chamber 17 and a rear chamber 18 in the flow direction. It is expanding to Further, the side wall of the rear chamber 18 is a parallel wall 2.
1.21 to form W in the gutter.

Next, in the vertical direction of the water heater 5, in the front chamber 17, the ceiling 22 and the floor 23 are respectively enlarged downstream at an angle of about 30 degrees. Therefore, the front chamber 17 forms a relatively large water reservoir 14 with the trumpet wall 19, 19, the ceiling 22 and the floor 23. In addition, the rear chamber 18
In this case, the ceiling 24 and the floor 23 are parallel to each other. In other words, the depth is constant.

At the boundary between the front chamber 17 and the rear chamber 18, a weir 13 is inserted between the ceiling 22 of the front chamber 17 and the bottom wall 23 of the front chamber 17, and a passage 13A and a downstream wall 17B of the front chamber 17. Suspended so as to form a series of gushing passages 13B between them,
This weir 13 slows down the flow of the molten metal 2 so that it passes through the lower part of the weir 13 and rises to the parallel portion of the rear chamber 18.

The sliding nozzle 3 of this embodiment includes a pair of fixed nozzles 3b, 3b, and a sliding nozzle 3a that slides between these fixed nozzles 3b to open and close the nozzle hole.

Since the configuration of this embodiment is as described above, the following operations are performed. That is, the molten metal 2 ejected from the sliding nozzle 3 gradually expands its flow path in the front chamber 17, reducing the flow velocity, hits the □ weir 13, further reduces the flow velocity, and is discharged in the sump 14. Once it spreads smoothly in the middle direction. Thereafter, the water passes through the submerged passage 13A at the lower part of the weir 13 and rises up from the rising passage 13B to the parallel portion of the rear chamber 18. At this time, already within the gutter direction of the rear chamber 18,
The distribution of the flow velocity is approximately uniform, forming a smooth layer bar. In this state, the molten metal 2 is fed into the twin belt caster 6.

Note that the water heater 5 of this embodiment is horizontal or slightly inclined.

[Effects of the Invention] According to the present invention, since molten metal is supplied from the tundish to the twin belt caster through the nozzle, the scene level inside the twin belt caster can be stabilized without changing the drawing speed of the twin belt caster. let me,
Not only does it enable continuous operation directly connected to the rolling mill, but it also suppresses turbulence when hot water is supplied by ejecting from the nozzle and expanding into the gutter.
Therefore, generation of bubbles and air bubbles can be prevented, and a slab of good quality can be obtained without the need for back surface treatment in a post-process. As a result, the number of tundishes can be reduced, so-called two-stage hot water supply becomes possible, and equipment and operating costs can be reduced, resulting in many excellent effects.

Furthermore, since only a sump and a weir are added to a conventional water heater, the structure is simplified and the water heater, which performs severe work, can be made more durable.

[Brief explanation of the drawing]

1 is a plan sectional view of an embodiment of the present invention, AA sectional view in FIG. 2, BB sectional view in FIG. Figure 4 is a plan view of the main part of Figure 3.
FIG. 5 shows a detailed longitudinal section of FIG. 4, corresponding to the figure. 1... tanditshu, 2... molten metal, 3...
Sliding nozzle, 5... Water heater, 6... Twin belt caster, 13... Weir, 13A... Submerged passage, 13B... Swelling passage, 14... Hot water pool, 17...・Anterior chamber, 17B... Downstream side wall, 18...
・Back chamber. Agent: Patent attorney Masanobu Kato (and 1 other person)

Claims (1)

[Claims] (1) The amount of hot water supplied from the tundish to the twin belt caster via the nozzle is gradually expanded in the width direction toward the downstream, and a front chamber with a pool formed, and the expanded width and shallow water shape. a rear chamber having a constant depth and facing the twin belt caster, and a submerged passageway and a rising passageway are provided in the water reservoir section between the bottom wall of the front chamber and the downstream wall of the front chamber. A hot water gutter for twin belt casters, characterized by having a weir that forms a series of erected.