JP3291265B2 - Mold for continuous casting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting machine used for producing a rectangular parallelepiped metal ingot used as a material for producing a rolled coil such as a copper alloy by a continuous casting method or a semi-continuous casting method. More specifically, the present invention relates to a rectangular frame-shaped mold composed of a pair of long side mold walls facing front and back and a pair of short side mold walls facing left and right.

[0002]

2. Description of the Related Art According to a continuous casting machine, a molten metal poured into a mold from above is solidified by primary cooling, and a slab having a solidified shell formed on a surface thereof is moved downward from the mold at a predetermined speed ( (Casting speed) by continuous withdrawal, and secondary cooling of the slabs drawn from the mold,
A rectangular ingot is obtained. At this time, in the mold, the volume of the solidified shell part shrinks due to the progress of the solidification of the molten metal (formation of the solidified shell) and the decrease in temperature (growth of the solidified shell) as compared with the volume when the liquid phase was in the liquid phase. I do. Shrinkage in the vertical direction, which is the casting direction, occurs remarkably on the lower side of the mold because the high-temperature molten metal is injected from above the mold. In addition, the cross-sectional shape (shape of a cross-section orthogonal to the drawing direction (casting direction) from the mold) of a metal ingot used as a material for manufacturing a rolled coil has a longer side direction width than a shorter side direction width. Since it has a rather long rectangular shape (for example, 1260 mm × 190 mm), shrinkage in the direction (horizontal direction) perpendicular to the casting direction increases on the short side, and is hardly recognized on the long side.

[0003] Therefore, when using a mold in which the long side mold wall and the short side mold wall are both parallel, separation from the short side mold wall occurs due to solidification shrinkage of the slab at the lower side of the mold. A void that is an adiabatic space is generated between the mold wall and the solidified shell, and the solidified shell portion corresponding to the void is re-melted, so-called a sweat band is generated, and the finally obtained ingot has a surface defect. It will be.

In view of the above, there has been proposed a mold in which both short-side mold walls are tapered so that the distance between the opposite mold walls is gradually reduced downward so as to avoid the generation of voids due to shrinkage. ing.

[0005]

However, shrinkage in the mold does not always occur under the same conditions, and the amount of shrinkage varies. The progress of solidification in the mold changes from moment to moment due to variations in the type of lubricant (flux), usage, consumption, changes in tapping temperature, molten metal components, primary cooling capacity, and the like. Therefore, even if the short side mold wall is tapered, the generation of the above-described void cannot be reliably prevented. In addition, when the shrinkage is smaller than the taper of the short side mold wall, serious problems such as poor drawing of the slab and breakout (restrictive breakout) occur. For example, in order to ensure casting stability (equalization of shell formation, promotion of lubrication of molten flux, etc.), the mold is generally subjected to an oscillation for vertically oscillating the mold. Among them, during the upward movement, a tensile force acts on the initially solidified shell of the meniscus portion, and there is a possibility that the shell may be broken, that is, restrictive breakout may occur.

[0006] The present invention has been made in view of the above-mentioned points, and a continuous casting or high-quality ingot having no surface defects without forming a gap between the short side mold wall and the solidified shell. It is an object of the present invention to provide a practical mold that can be semi-continuously cast.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a rectangular frame-shaped mold composed of a pair of long-side mold walls facing each other in front and back and a pair of short-side mold walls facing left and right. The side mold wall is supported so that it can swing left and right within a certain range around the upper end, and both short side mold walls are coiled in the opposite direction.
It is proposed to be biased by a spring .

According to this structure, the taper amount of each short side mold wall automatically changes in accordance with the amount of shrinkage in the mold, so that the slab surface is always in close contact with the short side mold wall. No voids are generated, and the occurrence of a sweating phenomenon (partial melting) is reliably prevented, and no draw-out from the mold or breakout occurs.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
It will be described based on.

FIGS. 1 to 5 show an example of a continuous casting machine for obtaining a rectangular parallelepiped ingot such as a copper alloy, in which a mold 1 having a cavity having a rectangular cross section and cooling devices 7 and 8 are provided. Have.

As shown in FIGS. 1 to 4, the mold 1 includes a pair of long side mold walls 2 and 2 facing each other and a pair of long side mold walls 2 and 2 facing each other.
A pair of short side mold wall machines 3 and 3 located between and facing left and right
And support mechanisms 4 and 4 for supporting each short side mold wall 3 so as to be able to swing right and left within a certain range around the upper end thereof, and an urging mechanism for urging both short side mold walls 3 and 3 in opposite directions. 5,5.

As shown in FIGS. 1 and 2, both long side mold walls 2 and 2 have a rectangular structure composed of main body portions 21 and 21 and wall surfaces 22 and 22 such as copper plates adhered to opposing surfaces thereof. And
By connecting the left and right ends of the main body portions 21 and 21 with the connecting machine frames 6 and 6, the main body portions 21 and 21 are held parallel to the vertical direction (casting direction).

As shown in FIGS. 1 to 3, both short-side mold walls 3 and 3 have a rectangular structure composed of main bodies 31 and 31 and wall surfaces 32 and 32 such as copper plates adhered to opposing surfaces thereof. And is disposed between the wall surfaces 22, 22 of both long side mold walls 2, 2.

Each support mechanism 4 is, as shown in FIGS.
A first bracket 41 fixed to the upper end of the main body 31 of the short side mold wall 3, a second bracket 42 fixed to the lower end of the main body 31, and attached to upper and lower ends of the coupling machine frame 6. First and second support rods 4 extending horizontally in the horizontal direction
3, 44. The distal end of the first support rod 43 is pivotally attached to the first bracket 41 by a first horizontal pin 45, and supports the short side mold wall 3 so as to be swingable in the left-right direction about the first horizontal pin 45. ing. The second support rod 44 and the second bracket 42 are connected by engaging a second horizontal pin 47 fixed to the second bracket 42 with an elongated hole 46 formed at the tip of the second support rod 44. Thus, the swing range of the short side mold wall 3 is regulated. The long hole 46 has an arc shape centered on the first horizontal pin 45, and its length is set such that the short side mold wall 3 can swing a predetermined amount in the left-right direction with respect to the vertical line. . As shown in FIG. 3, the amount of swing θ of the short side mold wall 3 in the direction in which the short side mold wall 3 approaches the opposed short side mold wall 3 (the angle of inclination of the wall surface portion 32 with respect to the vertical line, hereinafter referred to as “taper amount”) is The maximum value is obtained when the second horizontal pin 47 abuts on the end of the elongated hole 46 on the distal end side of the second support rod 44. The maximum taper amount is appropriately set according to casting conditions (melt properties, cooling conditions, shrinkage amount of the molten and solidified shell, etc.). In this example, the second support rod 44 is formed as a screw shaft, and is supported by the connecting machine frame 6 via a suitable screw feed mechanism 49 so as to be able to advance and retreat in the axial direction. It is devised so that it can be adjusted. That is, the second support rod 44
By operating the screw in the direction of the short side mold wall, the maximum taper amount can be increased, and by operating the screw in the opposite direction, the maximum taper amount can be reduced.

A molten metal inlet 11 as an upper end opening and a slab outlet 12 as a lower end opening of the mold 1 are rectangular.
The widths To and Te in the short side direction and the width Wo in the long side direction of the molten metal injection port 11 are kept constant irrespective of the swing of the short side mold walls 3 and 3. Width We
Is changed by the swing of the short side mold walls 3. For example,
Assuming that the taper amount θ of both short side mold walls 3, 3 is minimized (θ = 0 °), the wall surfaces 32, 32 as opposing end surfaces are in a parallel state along the vertical direction, and the width of the slab withdrawal port 12 in the long side direction. W
e is maximized. That is, the molten metal inlet 11 and the slab outlet 12 have the same rectangular shape. When the two short-side mold walls 3 and 3 swing in the facing direction from this state, as shown in FIG. 4, the wall portions 32 and 32 have an inverted C-shape in which the distance between the facing walls gradually decreases downward, and The width We of the drawing port 12 in the long side direction decreases. When the taper amount θ becomes the maximum, as shown in FIG. 3, the long side width We of the slab outlet 12 becomes the minimum. The shape of the molten metal inlet 11 is set according to the shape of the slab to be cast. In this example, Wo = 1260 mm and To = 190 mm.

Each urging mechanism 5 is, as shown in FIGS.
The second support rod 44 is formed as a screw shaft, and a coil spring 52 is interposed between a spring receiver 51 screwed to the second support rod 44 and the second bracket 42 so that the short side mold wall 3 has a taper amount θ. Are urged to increase.
As shown in FIG. 3, the short side mold wall 3 is biased and held at a position where the taper amount θ is maximum at the start of casting. The spring force of the coil spring 52 can be freely changed and adjusted by screwing the spring receiver 51 in the left-right direction.

As shown in FIGS. 2 to 5, the cooling device is drawn from a primary cooling mechanism 7 for cooling the molten metal 9 injected into the mold 1 from a molten metal inlet 11 and a slab outlet 12 of the mold 1. And a secondary cooling mechanism 8 for cooling the slab 91.

The primary cooling mechanism 7 is provided in the mold 1, as shown in FIG.
1 and 31 are configured as hollow water-cooled jackets, and the cooling water 71 is continuously supplied into the main body portions 21 and 31 to cool the wall surfaces 22 and 32, thereby cooling the molten metal 8 in the mold 1 ( (Primary cooling). The inside of each of the main bodies 21 and 31 is provided with a water supply port 7 opened at the lower end thereof.
It is partitioned so as to form a series of circulating water passages 77 communicating with the second and drain ports 73.

As shown in FIGS. 2 to 5, the secondary cooling mechanism 8 is disposed at a position immediately below the slab outlet 12, and the surface 9 on each long side of the slab 91 drawn from the mold 1.
2 comprises a plurality of long side nozzles 82 for spraying the cooling water 81 and a plurality of short side nozzles 83 for spraying the cooling water 81 to each short side surface 93 of the cast piece 91.

The long-side nozzles 82 are arranged side by side at equal intervals in the horizontal direction (left-right direction) so as to face each long-side surface 92 of the slab 91 drawn from the mold 1. Zone control is performed so that the amount of water sprayed on the long side surface 92 gradually decreases from the center of the slab to the end of the slab.
That is, as shown in FIG. 2 and FIG.
The zone to be cooled is the first in the center of the slab in the lateral direction.
It is divided into a zone to be cooled A, a third zone to be cooled C at the end of the slab, and a second zone to be cooled B which is an intermediate zone between them, and a plurality of zones provided to face the first zone to be cooled A. The first long side nozzles 82a, the plurality of second long side nozzles 82b provided facing the second cooled zone B, and the plurality of first nozzles provided facing the third cooled zone C. The long-side nozzles 82c are connected to the cooling water supply passage 86 via respective flow controllers (flow control valves and the like) 84a, 84b, 84c, respectively. And the flow controller 84
a, 84b, 84c, each first long side nozzle 82a
Each of the second long side nozzles 82
b, the amount of water sprayed from each first long side nozzle 82b is smaller than the amount of water sprayed from each third long side nozzle 82c, and the amount of water sprayed from each third long side nozzle 82c is smaller than the amount of water sprayed from each second long side nozzle 82b. The amount of water sprayed from the long-side nozzles 82 is zone-controlled to minimize the amount of water sprayed.

The amount of water sprayed from each of the third long side nozzles 82c is preferably substantially the same as the amount of water sprayed from each of the short side nozzles 83. In this example, as shown in FIG. 5, six first long side nozzles 82a.
, Eight second long side nozzles 82b, four third long side nozzles 82c, and two short side nozzles 83, and spray from the first long side nozzles 82a. Water volume: 1
0 l / min, the amount of spray water from each second long side nozzle 82b: 8 l / min, and the amount of spray water from each third long side nozzle 82c and each short side nozzle 83: 4 l / min. The flow controller 85 for controlling the amount of spray water of the short-side nozzles 83 is used as the flow controller 84c for the third long-side nozzles 82c because the amount of spray water is the same as described above. It may be.

According to the continuous casting machine configured as described above, the molten metal 9 injected into the mold 1 from the molten metal injection port 11 is cooled by the cooling water 7 circulating in the main bodies 21 and 31 of the mold walls 2 and 3.
The cast slab 91, which has been primarily cooled and solidified by the slab 1 to form a solidified shell, is sequentially pulled out from the slab draw-out port 12 of the mold 1 and is secondarily cooled by the secondary cooling mechanism 8 and further tertiary if necessary. It is cooled (immersed in a water tank or the like) to obtain a rectangular solid ingot.

At this time, the contraction due to solidification is caused by the long side surface 9.
2, a gap is generated between the short side surface 93 and the short side mold wall 3 due to solidification shrinkage. However, in the above-described mold 1, the short side surface 9
3 shrinks, the taper amount θ of each short side mold wall 3 automatically increases and decreases following the contraction, and the short side mold wall 3 comes into close contact with the short side surface 93. For example, in the early stage of casting, the amount of shrinkage is small because only primary cooling is performed. However, when secondary cooling (and further tertiary cooling) is performed as the casting proceeds, the amount of shrinkage of the short side surface 93 increases. . In such a case, the short-side mold wall 3 is urged and oscillated toward the short-side surface 93 by the coil spring 52 to come into close contact with the short-side surface 93, thereby preventing the generation of a gap. Conversely, when the amount of shrinkage decreases, the short side mold wall 3 swings in a direction to reduce the taper amount θ against the coil spring 52, and does not compress the slab 91 in the mold 1 more than necessary. The short side mold wall 3 is in close contact with the short side surface 93. The lowering of the slab 91 in the early stage of forging is smoothly performed by such swinging of the short side mold wall 3 (swinging in a direction in which the taper amount θ is reduced).

As described above, the short-side mold walls 3 and 3 are automatically oscillatingly displaced in accordance with a change in the casting state such as shrinkage of the short-side surface 92. In addition to being reliably prevented, the slab 91 can be smoothly pulled out of the mold 1 without any problem such as breakout. Therefore, a high-quality ingot without surface defects such as sweat bands can be obtained.

The slab 91 drawn from the mold 1 is secondarily cooled and further solidified.
According to the conventional secondary cooling method of uniformly cooling the surface of the casting 1 with water, the surface temperature of the slab 91 becomes uneven. That is, the temperature distribution in the slab 91 drawn from the mold 1 is not constant, and the central portion in the longitudinal direction has a higher temperature than the end portion. Therefore, when the surface of the slab 1 is cooled with a uniform amount of cooling water, the cooling temperature becomes uneven, and the growth of the solidified shell (increase in shell thickness) becomes uneven. As a result, cracks, dents and cavities occur in the slab 91. In particular, the water cooling action on the long side surface 92 and the short side surface 9
In the corner portion of the slab 1 which receives both the water cooling action and the water cooling action 3, supercooling occurs, and deformation such as cracks and dents occurs. However, according to the secondary cooling mechanism 8 described above, the amount of cooling water sprayed from each of the long-side nozzles 82 to the long-side surface 92 is maximized in the first cooled zone A at the center, and the amount of cooling water at the end is reduced. Minimized in the third cooled zone C,
In the zone to be cooled B, the amount of intermediate water between the zones A and C is sprayed. That is, the amount of water sprayed from each long side nozzle 82 is controlled so that the slab surface is cooled to a uniform temperature in accordance with the temperature distribution of the slab 1. Therefore, the amount of water sprayed from each of the third long side nozzles 82c in the third cooled zone C is reduced by each of the short side nozzles 83.
The surface of the slab 1 is cooled to a uniform temperature. As a result, generation of cracks and cavities due to secondary cooling is prevented, and a very high quality ingot without defects is obtained.

It should be noted that the present invention is not limited to the above-described embodiment, but can be appropriately improved and changed without departing from the basic principle of the present invention. For example, the support mechanism 4 of each short side mold wall 3 includes support rods 43 and 44.
May be configured so that both can be advanced and retracted in the axial direction, so that the opposing interval between the two short-side mold walls 3 can be changed and adjusted according to a desired slab shape (long-side direction width). . The number of zones to be cooled can be arbitrarily set according to the width of the slab 91 in the long side direction. Further, the present invention is not only for obtaining an ingot of a non-ferrous metal such as a copper alloy,
Of course, it can be applied to the case of obtaining an ingot of steel or the like, but in particular, to obtain an ingot having a rectangular cross section in which the ratio between the width in the long side direction and the width in the short side direction is larger than a certain degree. Suitable in some cases.

[0027]

As can be easily understood from the above description, in the mold of the continuous casting machine of the present invention, since both short side mold walls are urged to swing in opposite directions, Since the short side mold wall automatically swings in accordance with the drawing or shrinkage change of the slab in the mold, the slab is always solidified in close contact with the mold and smoothly drawn out of the mold.
Therefore, according to the present invention, it is possible to obtain a high-quality metal ingot without surface defects without causing problems such as generation of a sweat band, poor pulling out from a mold, and breakout.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a continuous casting machine provided with a mold according to the present invention.

FIG. 2 is a rear view of the same.

FIG. 3 is a vertical sectional front view taken along the line III-III in FIG. 1;

FIG. 4 is a longitudinal sectional front view corresponding to FIG. 3, showing a state different from FIG. 3;

5 is a cross-sectional plan view showing a secondary cooling state of the slab (the cross section is along the line VV in FIG. 4).

[Explanation of symbols]

REFERENCE SIGNS LIST 1 mold, 2 long mold wall, 3 short mold wall, 4 support mechanism, 5 urging mechanism, 7 primary cooling mechanism, 8 secondary cooling mechanism, 9 molten metal, 11 molten metal injection Inlet, 12: slab outlet, 52: coil spring, 71, 81: cooling water,
82a: first long side nozzle, 82b: second long side nozzle, 82c: third long side nozzle, 83: short side nozzle,
84a, 84b, 84c, 85 ... flow rate controller, 91 ... cast piece, 92 ... long side surface, 93 ... short side surface, A ... first cooled zone, B ... second cooled zone, C ... 3 Zone to be cooled, θ: taper amount of short side mold wall.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B22D 11/05 B22D 11/04 311 B22D 11/051 B22D 11/053 B22D 11/16 105 B22D 11/16 106

Claims (1)

(57) [Claims] 1. A rectangular frame-shaped mold comprising a pair of long side mold walls facing front and back and a pair of short side mold walls facing left and right, each short side mold wall being centered on its upper end. The slab is slidably supported in a certain range, and both short side mold walls are urged by coil springs in the opposite direction.
The short side mold wall automatically follows the drawer and shrinkage changes
A mold for a continuous casting machine, which is configured to swing .