JPH0330458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inclined or vertical belt type continuous casting machine.

(Prior art) In recent years, as part of the rationalization of rolling, for example, the material to be rolled (slab) supplied to a hot strip mill has been thinned closer to the thickness of the hot strip product, including the rough rolling process. It is expected to significantly omit the rolling process and save energy. For this reason, various types of continuous metal sheet casting machines have been proposed, but the following description will mainly be made in relation to a twin belt type continuous casting machine (belt caster).

Figures 3 and 4 are conceptual diagrams of a molding device in a conventional twin-belt continuous casting machine.
The figure is a side cross-sectional view, and Figure 4 is B-B in Figure 3.
It is an arrow view. The molding device 1 is composed of main members: tension pulleys 2, 2', drive pulleys 3, 3', steering pulleys 4, 4', steel belts 5, 5', and a belt cooling device 6.
Each belt 5, 5' is endlessly wound around the above-mentioned pulley, and a power drive device (not shown) rotates the drive pulley 3, 3' to periodically rotate the two belts in the direction of the arrow. do. Belts 5, 5' are
A gap corresponding to the thickness T of the slab 7 is left in place to allow the belt to run, and a pair of short-side molds are disposed at both ends of the gap in the belt width direction to form a mold. Molten metal (hereinafter referred to as molten metal) 10 is supplied to this mold from a tundish 9, and by cooling the back surface of the belt, a solidified shell is formed in the mold,
The cast piece 7 of a thin metal plate is continuously cast and is configured to be led to the next step via a large number of guide rolls 11 and pinch rolls (not shown) below the molding device 1.

Conventionally, jet coolers and closed coolers have been used in the above-mentioned molding apparatus.

As shown in FIGS. 3 and 4, the conventional jet cooler has a large number of annular grooves 12 arranged in parallel in the axial direction on the outer periphery of the tension pulleys 2 and 2', and each groove 12 has a jet tube. 13, the cooling water from the header 14 is jetted at high speed onto the back surface of the belts 5, 5' (the surface opposite to the surface in contact with the molten metal) to cool the molten metal 10, and the cooling water after cooling is is scooped up by the lower scoop 15 and appropriately collected into the return line 16.

Further, on the vertical plane of the belts 5, 5' between the tension pulleys 2, 2' and the drive pulleys 3, 3', a plurality of fin rolls 17, 17' having a large number of disc fins 17a in the axial direction are installed in the vertical direction. and are rotatably supported by the base 18, and are arranged so as to abut against the back surface of the belt, and resist the static pressure of the molten metal acting on the surfaces of the belts 5 and 5' during operation. to support the belt. Also, between the upper and lower fin rolls 17, 17', there is a cooling water header 2 having a large number of jet pipes 19 arranged in parallel in the belt width direction.
0 and jet guide plates 21a and 21b are installed, and cooling water is sprayed at high speed toward the back of the belts 5 and 5' along the lower surface of the guide plates for cooling, and the upper surface of the guide plates forms a scoop 15. ing. Most of the cooling water from the jet pipes 13 and 19 is collected by the scoop 15, but the rest is collected by the belt 5,
5'. Lower drive pulley 3,
3' also has an annular groove 22 similar to the tension pulleys 2, 2', and cooperates with the back surface of the belt to introduce and collect the flowing water into the return pipe 23.

However, in this jet cooler, since the cooling water is a jet type, the pressing force acting on the back surface of the belt is relatively low.As a result, in the vicinity of the meniscus 24 where the static pressure of the molten metal 10 is low, The cooling water pressure (velocity) can be adjusted to the molten metal so as not to exceed the pressing force on the belt surface due to the belt surface. It is difficult to secure a pressure with cooling water that can counteract the pressing force, and the pressure is often lower than the pressing force. As a result, the belts 5, 5' in this area bulge outward (back side), causing bulging of the slab 7, and depending on the situation, cracks may occur on the surface, deteriorating the surface quality, and especially breakout. However, there were drawbacks such as the occurrence of very serious accidents such as suspension of operation.

On the other hand, a conventional hermetic cooler will be explained with reference to FIGS. 5 to 7. Fig. 5 is a side sectional view, Fig. 6 is a partially enlarged view of Fig. 5, and Fig. 7 is a C of Fig. 5.
-C arrow view. This cooler has a pair of closed box-shaped cooling pads 26, 26' covering at least the entire width of the slab on the back of the vertical part of the belts 5, 5' between the tension pulleys 2, 2' and the drive pulleys 3, 3'. They are fixed to a base (not shown) facing each other. The cooling pads 26, 26' are divided into a plurality of chambers in the vertical direction (in the case of FIG. 5 29a, 29b, 30a, 30
cooling water discharge pipes 34 and supply pipes 33 are connected alternately from above to the anti-belt wall 32 of each chamber, and the belt-side wall 2
7 has a slit 36 extending in the belt width direction along the inclined surface of the upper edge or lower edge of the horizontal partition wall 28a;
37, the lower slits of each chamber serve as cooling water supply ports, and the upper slits 36 serve as discharge ports.
Further, on the belt-side surface of the wall 27, a large number of vertical partition walls 38 are arranged in parallel in the belt width direction, projecting at a predetermined height (for example, about several mm), and
By bringing the tips of the horizontal partition walls 28a and the tips of the horizontal partition walls 28a into contact with the back surfaces of the belts 5, 5', grooves 39a, 39 having a rectangular cross section are formed between the belt surface and the wall 27.
b, 39c to form a cooling water passage between the two slits.

In addition, the drive pulleys 3, 3' are provided with a large number of annular grooves 22 on their outer peripheries, similar to the jet cooler described above, and the cooling water flowing down the back of the belt is passed through the return pipe 23.
is configured to be collected.

Therefore, if this closed type cooler is used, the cooling water flows through the cooling pads 26, 26' and the narrow space on the back of the belt, so the belt height is higher than that of a conventional jet type cooler with the same amount of cooling water required. A pressing force is generated. For this reason, the belt 5 in the casting area 25 where the static pressure of the molten metal is high below the meniscus 24,
It becomes possible to easily suppress the 5' bulge,
The disadvantages of this area in conventional jet coolers can be overcome.

However, near the meniscus 24 where the molten metal static pressure is low,
Conversely, the belt pressing force caused by the cooling water tends to be greater than the static pressure of the molten metal, and the belt in this area swells inward. This also has drawbacks such as deterioration in the quality of the slab and occasional breakout.

(Problems to be Solved by the Invention) Therefore, the present invention eliminates the above-mentioned drawbacks, supports the back surface of the belt from the meniscus part where the static pressure of molten metal is low to the lower part where the static pressure is high, and can support the bulging The present invention aims to provide a twin-belt continuous casting machine that can produce slabs with excellent surface quality without worrying about cracking or breakout.

(Means for Solving the Problems) The present invention includes a pair of endless belts for casting that run downward with an interval corresponding to the thickness of the thin metal sheet to be manufactured, and a means for cooling the belts. , in a twin-belt continuous casting machine in which molten metal poured between the belts is cooled on the belt surface to form a solidified shell, and a thin metal plate is continuously taken out from below,
A jet cooler consisting of a pair of freely rotatable fin rolls and a number of pairs of cooling water jet tubes arranged in parallel in the width direction of the belt is installed on the back of the belt near the meniscus where the static pressure of molten metal is low. A closed type with a pair of closed box-shaped cooling pads arranged vertically adjacent to each other in multiple stages on the back of the belt in the casting area where static pressure is high. This is a twin-belt continuous casting machine that is equipped with a cooler.

Note that the cooling pad has a compartment formed by a first wall facing the belt, a second wall located at the rear of the side, and two adjacent horizontal partitions, and the tips of the horizontal partitions are A horizontal intermediate partition wall is provided between adjacent horizontal partition walls in contact with the belt to divide the partition upwardly, forming a lower cooling water supply chamber and an upper cooling water discharge chamber. A cooling water supply pipe and a cooling water discharge pipe are respectively connected to the second wall, and a large number of vertical partition walls are provided on the belt-side surface of the first wall to form vertical grooves on the partition surface, and the surface of the vertical partition wall is connected to the belt. The lower end of the first wall and the horizontal partition form a cooling water supply slit, the upper end of the first wall and the horizontal partition form a cooling water discharge slit, and the two slits It is preferable that the upper and lower ends of the horizontal partition wall and the first wall are formed so as to be inclined upward toward the belt.

(Function) The present invention prevents the belt pressing force caused by cooling water from becoming greater than the molten metal static pressure by providing a rotatable jet cooler with fin rolls on the back of the belt near the meniscus where the molten metal static pressure is low. At the same time, the fin roll supports the differential pressure on the belt,
In addition, by installing an enclosed cooler with a large belt pressing force of cooling water in the casting area below the meniscus where the static pressure of the molten metal is high, the pressure applied to the belt can be easily followed by cooling water from the back side. As a result, the belt can be kept flat, slabs with excellent surface quality can be cast with high productivity, and the life of the belt can be significantly extended. Ta.

(Example) Fig. 1 is a side sectional view of a belt-type continuous casting apparatus which is an embodiment of the present invention, and Fig. 2 is a
-A arrow view. Since the members having the same reference numerals as those in the conventional belt-type continuous casting apparatus shown in FIGS. 3 to 7 are the same and have the same functions and effects, their explanation will be omitted here.

In this belt-type continuous casting device, belts 5, 5' run between tension pulleys 2, 2', drive pulleys 3, 3', and steerer pulleys 4, 4'. , 5' is maintained at the thickness of the thin metal sheet to be manufactured, and the molten metal 10 is supplied from the tundish 9 to the space between the vertical parts of the belts 5, 5', and is cooled from the back side of the belts 5, 5' to form a solidified shell. The thin metal plate 7 is formed on the guide roll 1.
1 and pinch rolls (not shown). For this cooling, a jet type cooler and a closed type cooler are used together.

The jet cooler has a temperature near the meniscus 2 of the molten metal 10.
A plurality of fin rolls 17, 17' are provided in opposition to the back surfaces of the belts 5, 5' of No. 4, respectively, so as to be in contact with each other.
A plurality of annular grooves 12 are formed in parallel over the entire width of the belt on the outer periphery of the tension pulleys 2 and 2', and each of the coiled cooling water jet pipes 13 is installed.

In addition, the hermetic cooler has airtight box-shaped cooling pads 41 and 41' fixed to the base 18 so as to face each other on the back side of the belt in the casting area 25 below the meniscus, and a horizontal partition wall 28a, an intermediate Partition wall 28
b, there are multiple chambers in the vertical direction (42 in the case of Figure 1)
The belt side wall 44 is provided with a cooling water supply slit 37 and a cooling water drainage slit 36 extending in the belt width direction. A plurality of vertical partition walls 45 are provided on the surface to form grooves 46 having a rectangular cross section, and a cooling water supply pipe 33 and a cooling water discharge pipe 34 are connected to a wall 47 on the opposite side.

This twin-belt continuous casting machine injects molten metal 10 between a pair of belts 5 and 5' from a tundish 9, and injects cooling water from a jet pipe 13 onto the back of the belt near the meniscus of the molten metal. The molten metal 10 is cooled through the belt, the back side of the belt is supported by the fin rolls 17, the molten metal 10 moves downward while forming a solidified shell, and then enters the cooling pads 41, 41'. Here, the cooling water flowing out from the slits 36 of the cooling pads 41, 41' and rising along the grooves 46 having a rectangular cross section applies a large pressing force to the belt, making it possible to follow the static pressure of the molten metal. , the solidified shell is further cooled to form a thin slab 7, which is passed through guide rolls 11 and pinch rolls (not shown).
is pulled downward through. In this case, the cooling water in the meniscus portion is collected through the return pipe 34 from the slit 37 at the top of the cooling pads 41, 41', and the cooling water flowing down the back of the belt is collected by the drive pulley as in the conventional cooler described above. 3, 3' to the return line 23.

(Effects of the Invention) As described in detail above, the present invention is a twin-belt continuous casting apparatus equipped with a jet cooler with fin rolls and a closed cooler, in which the static pressure of the molten metal is low in the vicinity of the meniscus. Since the cooling is a jet type, it is easy to balance the cooling water pressure so that it does not become higher than the static pressure of the molten metal in that part, and it is easy to balance the cooling water pressure so that it does not become higher than the static pressure of the molten metal in this part. bulge can be suppressed. Furthermore, since a closed cooler is used in the downstream casting area where the static pressure of the molten metal is high, the cooling water pressure acting on the back surface of the belt in this area can be easily followed and balanced. As a result, accidents such as breakouts can be prevented, and the local cooling water pressure imbalance against the belt can be suppressed, making it possible to maintain the belt flat. It can improve surface quality and productivity, and significantly extend belt life.

A vertical bulkhead is provided on the surface of the side wall of the cooling pad facing the belt to form a rectangular vertical groove for flowing cooling water, and the cooling water is allowed to flow upward in the vertical groove for effective cooling. Furthermore, by running the belt in contact with the surface of the vertical partition wall, it is possible to easily follow and balance the high static pressure of the molten metal downstream of the meniscus portion.

[Brief explanation of the drawing]

1 and 2 are side cross-sectional views of a twin-belt continuous casting machine that is one embodiment of the present invention; FIG. 2 is a view taken along the line A-A in FIG. 1; FIGS. 3 and 4 is a side cross-sectional view of a twin-belt continuous casting machine equipped with a conventional jet cooler; Figure 4 is a view taken along the line B-B in Figure 3; Figures 5 to 7 are a conventional closed-type cooler. 6 is a partially enlarged view of FIG. 5, and FIG. 7 is a view taken along the line C--C in FIG. 5.

Claims (1)

[Scope of Claims] 1. A casting machine comprising a pair of endless belts for casting that run downward at an interval corresponding to the thickness of the thin metal sheet to be manufactured, and a means for cooling the belts, and a means for cooling the belts. In a twin-belt continuous casting machine that cools the dropped molten metal on the belt surface to form a solidified shell and continuously takes out thin metal sheets downward, a rotatable shell is placed on the back of the belt near the meniscus where the static pressure of the molten metal is low. A jet cooler consisting of a pair of fin rolls and a number of pairs of cooling water jet tubes arranged in parallel in the belt width direction is installed on the back of the belt in the casting area where molten metal static pressure is high below the meniscus. A twin-belt type continuous casting characterized by having a closed cooler equipped with a pair of closed box-shaped cooling pads arranged in multiple stages adjacent to each other in the vertical direction, each having an extending slit for supplying cooling water and a slit for discharging cooling water. Machine. 2 The cooling pad has a compartment formed by a first wall facing the belt, a second wall located behind the wall, and two adjacent horizontal partitions, and the tip of the horizontal partition is connected to the belt. A horizontal intermediate partition wall is provided between adjacent horizontal partition walls to divide the partition into upper and lower parts, forming a lower cooling water supply chamber and an upper cooling water discharge chamber. A cooling water supply pipe and a cooling water discharge pipe are connected to the rear of the second wall, and a large number of vertical partitions are provided on the belt-side surface of the first wall to form vertical grooves between the partitions. The lower end of the first wall and the horizontal partition form a cooling water supply slit, the upper end of the first wall and the horizontal partition form a cooling water discharge slit, and the two 2. The twin-belt continuous casting machine according to claim 1, wherein the upper and lower ends of the horizontal partition wall and the first wall are shaped so that the slits are inclined upward toward the belt.