ES2216414T3 - COQUILLA FOR CONTINUOUS METAL COLADA. - Google Patents

Abstract

Continuous casting mold has a tapered casting region having cooled wide side walls and narrow side walls. For creating regions with reduced deformation, the distance between the lateral limiting lines (7-7''') of the funnel region (6) and between the lines (8-8''') can be changed over one or more height sections of the funnel region.

Description

Shelf for continuous metal casting.

The invention relates to a shell for the continuous metal casting with a pouring region that presents refrigerated faces with wide faces and narrow faces, and that Narrow hopper-shaped in the casting direction to fit to the format of the casting bar.

The dimensions of the landfill region are determined primarily by the cross section of the casting rod, the dimensions of the casting tube and its depth of immersion in the broth.

Because of the hopper shaped conformation of the walls of wide faces, in the direction of laundry not only produces a narrowing but also a deformation of the cross section of the bar. As a result, imposed on the bar wrap, during circulation through a hopper shell, unlike in a laundry shell usual continuous with flat walls additional deformations that They can lead to failures.

It is known that by configuring the horizontal or vertical contour of the pouring region in the form of Hopper is possible a continuous casting shell, distribute of more advantageous the deformations imposed on the bar, for this mode act against the occurrence of product failures of wash.

Unlike in a usual shell with flat walls, in which the contraction of the bar is compensated by tilting the narrow faces, it has great importance of the narrowing of the section cross section of the shell in the casting direction on a shell Continuous casting with pouring region in the form of a hopper.

If through one or several segments in height the narrowing of the cross section of the shell is greater that bar contraction, are imposed on the bar wrap additional deformations Apart from this it is no longer guaranteed in this case a uniform contact between the bar wrap and wall of  coquilla Regions with a shell temperature are produced of excessively high or low bar, which increases the Probability of the occurrence of failures.

If the narrowing is excessively small, the Wrapped bar partially rises from the shell wall. The strong overheating in these regions produces high thermal stresses, which can lead to failures.

These failures are cracks, narrowings and / or structural failures. These failures are both more serious the more intensely a steel tends to a comparatively high contraction, during the development of the solidification and cooling of the bar wrap that shape.

EP 0 149 734 describes a shell with a hopper spill region that is reduced towards walls with narrow faces and in the direction of laundry, by triangular transition surfaces, to fit the format of the cast band. Through this you get an outline trapezoidal exterior of the pouring region.

To reduce the efforts to which the Wrapped bar and the wear of the shell, is proposed in the EP 0 230 886, rectangularly configure the contour of the lateral transition surfaces, being able to be these both flat and curved surfaces. In this case the contour Outside the pouring region represents a rectangle.

EP 0 268 910 also proposes to leave run the walls of wide faces, in the landfill region in a first segment in height, almost mutually parallel and make them return to the thickness of the casting format in a segment connected to it, reaching the first segment until below laundry level plane to adjust during the casting process, in the region of the first bar wrap formation. Of this mode wants to be guided without deformation the bar wrap still Fine below the wash level.

Document DE 39 07 351 A1 makes clear a proposal to form the horizontal contour of the inner wall of the pouring hopper of a shell through three arches circulars that make tangential mutual contact, whose radii are transform into the contour of the inner wall of the shell, gradually increasing in the direction of circulation of the bar. In this way the deformation of the bar is distributed metal casting between the longest possible path length, and avoid narrowing and cracking in the bar wrap The metal casting bar. You get a distribution the most possible uniform deformation of the bar wrap in a pouring region molded in this way, by means of which its radios increase by an equal or different factor in the direction of bar circulation. The outer contour of a region of Pouring of this type is a rectangle. The distance between lines, which join the tangential points starting at the edge upper of the shell until the exit of the hopper, remains invariable.

EP 0 552 501 makes clear a coquilla, whose hopper pouring region is determined by lateral circle arcs and, at tangential points, by arcs of central circle attached to them. To reduce the friction and wear as well as tensile stresses and flexion to which the bar wrap is subjected, the radii of the side circle arcs are constantly configured in a segment that reaches up to at least 100 mm down from the upper edge of the shell. In this segment the distance between the lines, which join the tangential points starting at the upper edge of the shell until the exit of the hopper while the outer contour of the pouring region It remains invariably rectangular.

Document DE 44 03 050 C describes a shell continuous casting to generate bars in roughing format, fine roughing, previous block and billet, which leads to high casting safety with casting speeds of up to 6 m / minute

Through the bulging shape of the shell, center the bar during casting in the shell, so that suppresses or dampens a lateral movement of the bar wrap towards one of the narrow faces (penduleo).

This symmetrical tour of the box of the Wrapped bar during casting in the shell leads to a uniform symmetric structure

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of the envelope of bar

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from its margin of temperature (isotherms)

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of the forces of extraction and

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of the burden of the bar wrapped,

even during a pendulum of the bar in the bar guidance region.

The document EP-B-0 419 570 makes a patent continuous casting shell with a hollow, which extends in longitudinal direction from one end on the input side to one end on the outlet side of the shell and whose cross-sectional area, located perpendicular to the longitudinal direction, it has two lateral regions almost rectangles that are separated from each other by a region central with almost constant width that is not reduced, increasing the central region in the longitudinal direction of the hollow space from its end on the entrance side, to form a casting region, the opposite walls of the casting region being curved, which they separate the lateral regions, and progressively growing the radii of curvature of the curved walls along at least a part of the longitudinal direction of the casting region.

Document DE 44 24 600 refers to a Continuous casting of fine grinding with better surface quality The shell is composed of two faces walls wide refrigerated, widened by the pouring side, as well as of two walls with narrow refrigerated faces. The relationship between maximum interior amplitude in the bath level region of the coquilla in the direction of thickness and the interior amplitude to the casting bar outlet, from the shell, is limited to one value between 1.3 and 1.5. The relationship between the length of the contour of the casting bar formed in the region of the level of the coquilla bath and the contour of the casting bar, when reaching the rectangular bottom shell segment does not exceed the ratio of the values for the linear contraction of the bar envelope between the equal planes of the shell, taking into account the cone of the walls of narrow faces during adjustment.

The state of the art can be summarized between other things in order that an outer contour rectangular of the region of the hopper is a particularity fundamental of coquillas with less load of the bar envelope and less wear of the shell in the hopper region. The creation of lateral regions without deformation of the hopper can lead to a variable distance between the lines, which delimit the regions of opposite curvature.

Starting from here the invention has imposed the task of indicating a hopper geometry of a shell that, in special during the formation of a steel bar wrap which tends to a comparatively greater contraction, with which achieve an even clearer reduction in the occurrence of failures in the roughing surface.

The invention is based on the experience gained from from multiple test casts, that when casting steels that tend to a comparatively high contraction in a shell with pouring region in the form of a hopper, whose horizontal contour it is formed by circle arcs that make mutual contact or is formed with the same radius, faults on the surface of roughing occurs almost exclusively in the central region of the hopper, corresponding to the horizontal contour path concave. From this it has been concluded that a reduction can be achieved of the appearance of faults on the surface of the bar, if reduces the load of the bar wrap in the central part of the hopper on account of the outer lateral regions.

The solution of the task is achieved with the invention by means of a configuration of the hopper geometry of a continuous casting shell corresponding to the particularities of claim 1. They are provided advantageous configurations corresponding to the subordinate claims.

For example a configuration of the invention provides that the horizontal contour of the hopper region is configured by circle arcs that make mutual contact tangential, with invariable or increasing radius.

Another configuration of the invention provides that the horizontal contour of the region of the present hopper, through one or more segments in height, a trigonometric path or polynomial. According to the invention, the vertical interior contour from the region of the hopper can present any route.

Other details and peculiarities of the invention of the following explanation of some examples of Execution represented in the drawings. Here they show:

Figure 1, in plan view, the region of pouring in the form of a single hopper hopper,

Figure 2 an interior view of a wall of wide faces with hopper-shaped pouring region,

Figure 3, in plan view, the path of horizontal contours of the I-III cutting planes shown in figure 2,

Figures 4, 5 other interior views of a wide-faced wall with hopper-shaped pouring region,

Figure 6 the vertical contour path for the cuts shown in figure 5 of the cutting planes V-IX,

Figure 7 another interior view of a wall of wide faces with hopper-shaped pouring region,

Figures 8-11 variations of length of the interior contours in the landfill region, both at different distances from the upper edge of the shell as from the center of the shell for wide-sided walls  represented in figures 2, 4, 5 and 7.

A continuous casting shell is composed, according to figure 1, of two walls with wide faces 1, 2 opposite and two walls of narrow faces 3, 4, arranged laterally between the walls of narrow faces 1, 2. The walls wide faces have a pouring region 6 in the form of a hopper arched that begins at the top edge of coquilla 5, which reduces towards narrow faces 3, 4 and, in the casting direction, to adapt to the casting bar.

Figure 2 shows the outer contour of the discharge region 7 - 7 '- 7' '- 7' '' - 7 '' '', which is configured such that in the upper segment B the distance is variable between lateral limiting lines 7 and 7 '' ''. According to the invention, in this region B the distance between lines 8 and 8 '' ', which delimit the regions of curvature opposed.

Figure 4 shows another configuration according to the invention of the pouring region in the form of a hopper. The lines 9 and 9 '' side limiters feature a curved path through the entire height A of the pouring region 6, such that the distance between these limiting lines is different in all horizons of the landfill region 6. At the same time also the lines 10 and 10 ', which delimit the regions of curvature opposed, they present a curved path such that it is variable the distance between them for the entire height A of the region pouring 6.

In figures 5 and 7 others have been represented two examples for the configuration according to the invention of the pouring region in the form of a hopper. The distance between the lines lateral limiters 11 and 11 'or 13 and 13' and lines 12 'and 12' 'or 14 and 14 ', which delimit the regions of opposite curvature, is variable in a part of the height A of the pouring region. To the contrary to the examples shown in figures 2 and 4, the pouring region narrows in the casting direction of such way, that its width is zero at its exit.

The advantages of the invention want represented based on four execution examples, which refer to the wide-face plates depicted in the figures, 2, 4, 5 and 7 of a shell, with the following parameters:

1,150 mm hopper width and 45 mm deep hopper on the upper edge of the center of the shell plate, 900 mm hopper length in the laundry address,

vertical interior contour in arc circle shape.

The horizontal interior contour of the plate wide faces represented in figure 2 is formed, in all the hopper height A, by three circle arcs that make contact tangential mutual whose radius is equal over each horizon. East radius is 1,848.06 mm above the upper edge.

The hopper width 7 - 7 '' '' is reduced in the casting direction, starting at the top edge 5 in a segment B 300 mm long, linearly 1,150 mm to 767.44 mm, and remains unchanged until the 7 '' exit of the region of discharge 6. The distance between the tangential points 8 - 8 '' 'is reduces in segment B correspondingly, linearly 575 mm to 383.72 mm and remains unchanged until the 7 '' exit of the discharge region 6.

Such a configuration of the region of the hopper makes it possible, in segment B, to keep the radius unchanged R of the inner horizontal contour of 1,848.06 mm. Figure 3 shows by way of example the horizontal interior contour on the upper edge of shell 5 and on three different horizons I, II and III.

As can be seen in figure 8, this way creates in the center of the upper segment of the landfill region in hopper shape, where the bar is especially tending to the appearance of surface faults, a region where produces no longitudinal variation of the horizontal contour during the transition from a horizon to a horizon located by below.

The fact that, at despite the lacking longitudinal variations, in the segment upper of the shell there is a narrowing of the region pouring in the casting direction, in the present case of 45 mm at 19.97 mm in the center of the shell. Variations longitudinal, which correspond to the narrowing of the pouring region, only occur in the upper segment of shell B in the lateral regions, where they are not critical for the bar wrap setting.

The horizontal interior contour of the plate wide faces depicted in figure 4 is characterized, to through the entire height of hopper A, by a route sine. With it the lateral contours 9 and 9 '' of the region of Poured 6 are segments in the form of a circle arc, whose tangents They run vertically at the height of the 9 'hopper outlet. The distance between the lateral limiting lines is reduced, from 1,150 mm above the upper edge of the shell 5 to 750 mm in the 9 'hopper outlet. The distance between lines 10 and 10 ', which delimit regions of opposite curvature, it is reduced from 575 mm to 375 mm.

The distribution of longitudinal variations in a region of molded pouring in this way it has been represented in figure 9. It can be seen that in this case the variations Longitudinals are not suppressed entirely in the center of the segment top of the hopper spill region, but in Comparison with lateral regions are clearly reduced.

The contour of the top edge 5 of the plate with wide faces represented in figure 5 is formed, according to to figure 3, by means of circle arcs that make mutual contact Tangential with a radius of 1,848.06 mm. Interior contours verticals V - IX according to figure 6 are formed by arc-shaped segments with a radius of 9,022.5 mm, which finally become the region of coquilla reduced to bar format. In this case the distance between the lateral limiting lines 11 and 11 'continuously, in such a way that at the hopper outlet the width of the hopper is zero. The same It is valid for the distance between the tangential points 12 'and 12 '', from a distance of C = 287.5 mm from the upper edge of coquilla 5. Up to this distance is invariable and amounts to 575 mm

Figure 6 shows the contours vertical interiors for longitudinal cuts V, VI, VII, VIII and IX shown in Figure 5.

From figure 10 it can be deduced that also in this configuration of the hopper spill region the longitudinal variations, during the transition of a horizon on the other, the longitudinal variations in the region are reduced upper central on account of the upper lateral regions.

The same applies to the wide-face plate represented in figure 7, which differs from that shown in the Figure 5 only by a sinusoidal path of the upper edge of coquilla 5. The corresponding longitudinal variations have been represented in figure 11.

The distributions mentioned in figures 8 a 11 of the longitudinal variations for hopper geometries shown in figures 2, 4, 5 and 7 confirm that with the invention it is possible, by selection according to the invention of the geometric parameters of the hopper spill region, reduce the deformation of the bar in the center of the upper region, which is especially critical for the formation of the bar wrap, and transfer it to the regions side of the hopper, where they are not critical for the formation of The bar wrap.

If the variation calculation is performed Longitudinal in the hopper region of the face plates widths represented in figures 2 and 3, regardless of the essential feature for the invention - the invariable distance between the outer boundary lines of the hopper and the lines that  they limit the concave and convex regions - it can be seen that in both cases the maximum value of the longitudinal variation in the Hopper region is in each case the same. Another advantage of the invention can also be seen that in the center of the region upper deformations are uniformly reduced over the lateral regions, without additional peaks of tension or deformation

Claims (7)

1. Continuous metal casting nozzle with a pouring region that has chilled faces with wide faces and narrow faces, and which narrows in the form of a hopper in the pouring direction to adapt to the casting bar format, characterized in that with in order to create regions with less deformation, both the distance between the lateral limiting lines (7 ') - (7''''), (9) - (9''), (11) - (11') or ( 13) - (13 ') of the hopper region (6) as the distance between the lines (8) - (8'''), (9) - (9 ''), (12 ') - (12'') or (14) - (14'), which delimit arcuate regions of opposite curvature or flat surfaces of different inclination, are reduced through one or more segments in height (A, B) of the hopper region in The laundry address. 2. Coquilla according to claim 1, characterized in that in the region of the hopper the vertical interior contours of the walls of wide faces do not run parallel to each other. 3. Coquilla according to claim 1, characterized in that the horizontal interior contour of the region of the hopper, through one or several segments in height (B), is formed by three arcs of circle that make tangential mutual contact. 4. Shell according to claim 1, characterized in that the radius R1 of these circle arcs that make tangential mutual contact remains unchanged through the height segment (s) (b). 5. Coquilla according to claim 1, characterized in that the horizontal interior contour of the region of the hopper, through one or several segments in height (B), has a trigonometric or polynomial path. 6. Coquilla according to claim 1, characterized in that the vertical interior contour of the region of the hopper, through one or several segments in width (V-IX), is configured by means of circle arcs that finally transform into the region of reduced shell to adapt to the bar format. 7. Shell according to claim 6, characterized in that the radius of the vertical inner contour R2 remains unchanged through one or more segments in width (V-IX).