EP0999000A1 - Apparatus for the adjustment of a continuous casting mould with curved interfaces - Google Patents

Abstract

Mold for continuous casting has narrow side walls with parallel straight lines and wide side walls in the adjusting region of the narrow side wall parts with straight lines, whose gradient in the thickness region continuously changes in the width region. The narrow side part to the outer side of the mold tapers in height as much as the wide side walls in the contrary position.

Description

The invention relates to a special embodiment of a multi-part Chill mold that is primarily used for thin slab continuous casting, but can also be significant in other continuous casting processes. The special one Design allows a width adjustment even in cases where so far this is not considered feasible.

For thin slab continuous casting of steel, Rossi in the DE-PS 887 990 proposed a certain form of a stationary mold. In this The question of whether the mold should be divided remained open. But especially adjustability of the slab width was not considered. Only in the In the 1990s, molds of this type were tried. It turned out that she after relatively minor modifications to the dimensions customary in other methods were quite operational. As a shortcoming, however, is today in the light of user requests to see that they are not like other mold types, especially the EP-PS 0 149 734, without significant changes to the recommended shape The slab width can be adjusted.

The mold according to DE-PS 887 990 has a funnel-shaped, enlarged pouring area to accommodate the pouring tube and narrow side walls that go from top to bottom have a constant width below, i.e. delimited by two parallel straight lines are. According to the proposal of DE-PS 887 990, the broad side walls run above of a certain height towards these ends increasingly upwards together, so that they have no parallel tangents in the width direction at these ends. This makes it difficult to adjust the width. It was therefore considered impracticable.

A solution to a similar problem was already given in DE-PS 35 01 442 in 1984. Here were the surfaces of the parting lines between two mold wall parts Levels. This forces some modifications in the mold form according to DE-PS 887 990 and also does not allow the production of constantly thick slabs.

The object of the invention presented here is, at least for a mold, considered the technically adequate form of the mold according to DE-PS 887 990 can be and has constant width narrow side walls, without the ends also the horizontal tangents parallel to one another on one of the broad side walls would be to create a safe adjustment of the slab width. If also the problem was preferably suggested by DE-PS 887 990 but to expect a very wide application of such an adjustment option, once it's known.

According to the invention it is proposed that the broad side walls in the desired adjustment range be designed so that they form surfaces that are everywhere in the casting direction Straight lines included, whose inclination in the thickness direction, however, in the width direction changes continuously. At the same time, both broad side walls or at least one of them is designed to be pivotable about the width axis at any height. Moves one now towards the inside of the mold with a relatively sharp edge provided narrow-side mold parts inwards or outwards, so by side Pressure on the two broad side walls always close the mold, whereby only the broad side walls or at least one of them around the width axis turns a little so that e.g. the width of the upper pouring area changes somewhat. This is done in such a way that when used in continuous slab casting usual sense, the width increases with greater width, what is also more of a technological advantage.

In another variant of the invention, one of the broad side walls is held. The narrow sides, which can then be twisted a little, lean against them are pressed from the other broad side wall.

Since at least one of the broad side walls is designed to be pivotable about a width axis must become. With this type of mold, it is no longer guaranteed that it is from a down a certain area with a constant rectangular cross-section gives. You can only make sure that there is always a rectangular cross-section at the outlet is present if you place the axis of rotation on the lower edge and if the broad side wall there is a straight line across the entire width. If you do not choose the axis of rotation at the lower end of the mold or leave a different contour of the broad side walls as a straight line, you can selectively concave and / or convex slab surfaces or even generate wavy ones.

The inclinations of the straight lines forming the wall surface should always be chosen so that the mold never gets narrower at the top than at the bottom. But that is always reachable.

If you want to make sure that e.g. to improve the sealing effect and / or to reduce it the wear caused by moving the narrow side walls in the joints must not fall below a certain minimum limit the two surfaces in contact are straight lines even in horizontal planes exhibit. This can be achieved by using the straight lines which are according to the invention creating the shape of the wide sidewalls requires that they all be through one transverse straight line and its inclination in the thickness direction with the latitude coordinate change linearly. The shape of the parting line on the narrow side parts the mold only has to be formed exactly according to the same principle. Geometric Conditional distance errors that occur when moving the narrow-side parts and thereby Conditional tilting of the broadside parts may occur in the parting line then with the usual dimensions of the mold in the area clearly below 1 µm, are therefore against all deformations, e.g. due to thermal expansion within the Narrow side parts arise and their differences already with thin slab casting a multiple of 10 µm, absolutely negligible.

Because the broad side walls can still run towards each other at the ends a continuation of the limitation into the outer, unused adjustment range after a relatively short distance to a narrow gap between the broad side walls or even lead to touching them, which must be avoided. Either you see a natural limitation of the adjustment range to this extent, or you can build at least one of the two mold broad side walls so that they itself consists of several parts, so that one part that is in the way, if necessary can remove.

All of this can still be generalized by the fact that, as generators of the Breitseltenwand surfaces do not choose straight lines, but any other curves and the narrow side walls with the same curve shape as a boundary to the broad sides designed. Of course, this also means that the constant is not used Width of the narrow side walls from top to bottom. But such a mold would also be closed in every position of the narrow side walls and at least linear tight. In the case of sufficiently high molds, such a shape is due to the shrinkage of the Strand shell may quite reasonable.

Of course, all of these principles also work, if for whatever reason anyway, not at the ends converging towards the outside, but from below horizontal tangents to the broad side walls diverging upwards wishes.

A vertical movement of the narrow side parts is particularly useful if if you have no narrow side surfaces limited in parallel.

Unfortunately, the construction described so far has to be changed a bit, because otherwise the casting would not be possible. If you guarantee that wants, at least in the casting phase, a cold strand that is naturally constant Cross-section has, in a mold part with an equally constant cross-section can rest while the first liquid material is poured. The The mold should be closed particularly tightly at the bottom. But that is with any one Position of the narrow side parts with a tilt depending on the position the broad side walls connected, which at least on the narrow sides from below straight lines containing upwards, which differ according to the invention are inclined.

1. Man fährt nur in der engsten Stellung an und sorgt dafür, daß in einem unteren Teil der Kokille nach innen hin dann nur senkrechte Geraden vorkommen. Diese Einschränkung ist sicherlich In einigen Fällen unzureichend.

2. Man sieht bei den Schmalseiten nach unten hin parallele Verlängerungen vor und preßt in der Angießphase von unten her Verlängerungen der Breitseiten-Teile gegen diese Schmalseiten-Verlängerungen und gegen die eigentlichen, nun oberen Kokillen-Breitseiten-Teile. Damit alles bei jedem Winkel paßt, müssen die Kokillen-Breitseiten-Teile und diese zwei Verlängerungsstücke eine zylinderförmige Trennfuge gemeinsam haben, die bei jeder Winkelstellung der Breitseiten-Teile 1, 2 exakt schließt. Die Verlängerungsstücke müssen als Anfahrhilfe gesehen werden und werden nach dem Angießen in der Regel entfernt. Sofern man diesen unteren Teil des Gesamt-Gießkastens ständig dort läßt, ist exakt die Form der in der DE-PS 887 990 Kokille erreicht, allerdings besteht die Kokille dann aus sechs und nicht nur aus vier Teilen. Das aber ist nach der Phase des Angießens voraussichtlich nicht mehr erforderlich.

There are two possible ways to remedy this disadvantage:

1. You only start in the narrowest position and ensure that only vertical lines appear in a lower part of the mold towards the inside. This limitation is certainly insufficient in some cases.

2. In the narrow sides, parallel extensions are provided downwards and in the casting phase, extensions of the broad side parts are pressed from below against these narrow side extensions and against the actual, now upper mold broad side parts. So that everything fits at every angle, the mold broadside parts and these two extension pieces must have a cylindrical parting line in common, which closes exactly at every angular position of the broadside parts 1, 2. The extension pieces must be seen as a starting aid and are usually removed after casting. Provided that this lower part of the overall casting box is always left there, the shape of the mold in DE-PS 887 990 is exactly achieved, however the mold then consists of six and not just four parts. However, this is probably no longer necessary after the pouring phase.

All of this is now explained using a few pictures:

Fig. 1, consisting of Fig. 1a and Fig. 1b, shows a view from above into an inventive Mold in which the mold parts only touch each other in a line, namely on the inside of the parts forming the narrow sides. Fig. 1a represents schematically one of the narrowest positions for which this mold would be suitable, Fig. 1b die furthest. One recognizes, although not quite easily in this representation, that the wide side walls 1 and 2 when moving the narrow side wall parts 3 and 4 turn, and this is indicated in these figures by the fact that in the sketch Fig. 1a still look down on the outer sides of the parts forming the broad side wall can, so that you can see the bottom edge, while these bottom edges in the Position of Fig. 1b are completely covered by the upper surfaces, so that only ever a dashed line has been drawn.

This effect becomes clearer if you look from the broad side, e.g. In Fig. 2 from the side of the narrow side part 3, on which the mold looks.

In Fig. 2 are a possible position of the mold In on the left, in the middle and on the right Side view. One can see the broadside parts 1 and 2 as well as the front one the narrow side parts 3, the other (4) is completely covered by this. The ends the broadside parts 1 and 2 cover, especially in the left and the middle Position, also part of the narrow side part 3. In the sketches is basically the start-up phase, the extension parts attached from below are also shown 5 and 6 sees that to illustrate the fact that they only exist at the beginning in the right sketch have been removed downwards and to the side.

3, consisting of FIGS. 3a and 3b, shows two positions again. In contrast to Fig. 1, however, the mold parts touch each other for longer Surfaces. For this, these surfaces must be horizontal across the entire adjustment range Straight lines exist. In Fig. 3, the entire half of a broad side surface was designed so that a diamond shape of the mold cross section is created, as in the DE-PS 887 990 was particularly recommended for the upper mold part.

Possible shapes for the narrow side parts can be seen in FIGS. 4 and 5:

Fig. 4 shows the narrow side part 3 in the usual three views. It can be like here have a constant cross-section from top to bottom, but the dimension must be a should be chosen small enough compared to b. With this narrow side part 3 would be a linear line for each broad side wall generated from straight lines in the casting direction Touch, i.e. closing the mold, guaranteed.

Fig. 5 shows how the narrow side part 3 is to be designed when you make a flat contact who wants to ensure narrow and broad side parts in the joints. The cross section would then have to go up from the lower rectangular cross section change continuously to the other trapezoidal, whereby here a is not arbitrary should be chosen, but to adapt to the slope of the broad sides would.

In Fig. 6 a mold is shown in the view from above, in which a particularly large adjustment range to be realized. If you look at the wall contour of the broadside part 1 to the left and the broadside part 2 to the right at the top of the If the mold is extended to the outside in the upper drawing, you can see that the would penetrate both mold walls above. Therefore in this position Part of the broad side wall can be removed if you want to reach this position. In the middle of the three positions shown, the missing part 7 fits part 1 and in accordance with Part 8 in Part 2 again, without the completed Would penetrate broad side walls. Finally, in the lower position Parts 7 and 8 then necessary portions of the broad side walls.

When applying the principle presented here to cases where the broad side walls on the narrow sides more or less parallel to each other at any height are, but still a twisted contact surface of the parts is necessary one can use this principle, e.g. one in the width direction to let the symmetrical mold change into another at the bottom. This opportunity for the currently in special cases, no immediate need can be identified, may become relevant. In general, a very large variety of shapes is more symmetrical in this sense adjustable as non-symmetrical outlet cross-sections. Fig. 7 illustrates this possibility in a top view for a skew-symmetrical one Outlet cross-section.

In Fig. 8 some forms are put together, which one applies the principle can reach as outlet cross sections.

Please note for all adjustments: For entry and exit cross sections the Mold, which is in relation to the plane formed from the casting direction and the thickness direction 8 are mirror-symmetrical, that is to say in FIG. 8 for all the ones shown on the left and the lower one In the right column, the narrow side parts 3 and 4 must also always be referenced move symmetrically on this level, otherwise the broad side walls will twist would. The same torsion is avoided with non-symmetrical systems a specially adapted driving style. Any positions of the narrow side parts independent of each other are not possible under any circumstances.

In the case of an arrangement according to FIG. 7, the two narrow side parts of FIG from the sketched position move only both to the right or both to the left and would have to maintain a certain speed ratio, which for these like for any other of the possible molds from the shape of the broad side wall contour would be fixed. This relationship would be fundamental for symmetrical profiles always 1: -1.

Claims (12)

Made of broad and narrow side wall parts as individual components and held together by lateral pressure on the broad side parts and closed mold for continuous casting, in particular thin slabs, with laterally displaceable narrow side parts, characterized in that the narrow side walls are delimited by preferably parallel straight lines and the broad side walls in the adjustment area of the narrow side parts in the casting direction are formed from straight lines everywhere, the inclination of which in the thickness direction changes continuously in the width direction, the narrow side part tapering towards the outside of the mold at any height at least as much as the broad side walls in the worst position. Chill mold according to claim 1, characterized in that the contact surfaces of the wide and narrow side parts in the adjustment range of the narrow side parts are both formed from straight lines whose inclination in the thickness direction is not only steady but constant in the width direction and in both parts in contact changes immediately, with all straight lines running through a transverse straight line, so that the contacting mold parts have a common contact surface in every position of the narrow side parts. Mold according to claim 1 or 2, characterized in that the narrow-side parts are guided non-rotatably in parallel and both broad-side parts are pressed against them. Chill mold according to claim 1 or 2, characterized in that one of the broad side parts is fixed, while the narrow side parts can rotate about a width axis and are pressed by pressure on the other broad side part with the fixed broad side part. Chill mold according to one of claims 1 to 4, characterized in that the lower edges of the broad side walls are at the same time their axes of rotation and in each case a continuous straight line. Chill mold according to one of claims 1 to 4, characterized in that the lower edges of the broad side walls are not continuous straight lines, so that the slab produced has a concave or a convex surface. Chill mold according to one of claims 1 to 6, characterized in that at least one broad side part on the left and / or right is divided one or more times, so that the adjustment range can be increased. Chill mold according to one of claims 1 to 7, characterized in that the outwardly directed horizontal tangents of both broad side walls do not increasingly converge towards the top, but increasingly diverge. Chill mold according to one of claims 1 to 8, characterized in that the narrow side parts are not only displaceable laterally but also in the casting direction. Chill mold according to one of claims 1 to 4 or 7 to 9, characterized in that the inclination of the straight line producing the broad side wall surfaces increases or decreases asymmetrically on both broad sides, if appropriate also only on one of the sides, the two broad side wall surfaces in the adjustment range at any height straight lines may be parallel to each other, but without those of a surface being parallel to each other. Chill mold according to one of claims 1 or 3 to 9, but characterized in that the generatrix of the broad side wall surfaces are not straight lines with inclination variable in the width direction in the thickness direction, but arbitrary curves that are rotated against each other in the width direction, and that the narrow side walls by the same curves are limited so that there is at least a linear contact of the mold parts with each position of the narrow side parts. Mold according to at least one of claims 1 to 11, characterized in that an extension of the narrow side walls (3, 4) and additional parts (5, 6) of the width side walls (1, 2) are provided at the lower end of the mold as an aid during casting.

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