EP1381482A1

EP1381482A1 - Method and device for the production of continuous casting input stock

Info

Publication number: EP1381482A1
Application number: EP02706775A
Authority: EP
Inventors: Hans Streubel; Jügen LEMKE; Ingo Schuster
Original assignee: SMS Demag AG
Current assignee: SMS Siemag AG
Priority date: 2001-04-21
Filing date: 2002-03-21
Publication date: 2004-01-21
Anticipated expiration: 2022-03-21
Also published as: DE10119550A1; DE50200636D1; TW520308B; WO2002085559A1; ATE270934T1; EP1381482B1

Abstract

The invention relates to a method for producing continuous casting input stock, especially for rolling metal profiles, especially steel profiles. The inventive method is characterized in that strands are cast in an ingot profile or a cast profile in a continuous casting plant and said strands are re-formed underneath the mould (5) or inside or below the strand guide in the region of the still liquid core using one or several pairs of rollers consisting of profiled, preferably axially and or radially adjustable rollers (3, 3) associated with a pre-shaping unit to create preliminary profiles.(4) which are finish rolled in a finish rolling process to form profiles having predetermined final dimensions. The invention also relates to a device for carrying out said method.

Description

Method and device for producing continuous casting material

The invention relates to a method for producing continuous casting primary material for rolling metal profiles, in particular for rolling steel profiles. The invention also relates to an apparatus for performing the method.

In profile rolling technology, pre-profiles cast close to the final dimensions are used in preparation for a finish rolling with final dimensions. Their development can be traced back to carrier rolling.

In the rolling mill technology, due to the minimum forming to be achieved, there is not so much the requirement for preliminary profiles as close to final dimensions as possible, but rather the requirement for a favorable mass distribution of the preliminary profiles with regard to the finished profiles to be rolled therefrom.

The well-known Liquid Core Reduction for reducing the strand thickness in thin slab casting shows that decreases of 25% and more are possible without loss of quality. When operating such systems, it was also possible to observe that locally higher acceptance levels without structural damage are quite possible.

The liquid core reduction (LCR) method known in the prior art provides a mode of operation in which the strand with a liquid core is reduced to a smaller thickness from the exit thickness from the mold of the continuous casting installation — distributed over several rollers. The strand solidifies below the wedge-shaped first segment of the strand guide in a strand guide that is conically adjusted to the shrinkage of the strand. LCR offers the possibility, in particular in the case of thin slab casting plants, not only to adapt the format width in the mold, but also to adapt the format thickness during casting according to the rolling program. The reduction of the format thickness and the return of the strand guide to the mold exit dimension is possible at any time within a sequence. The desired strand thickness is set by means of rollers either via hydraulic cylinders and stops, or continuously via position-controlled hydraulic cylinders.

In the prior art, both blocks and beam blanks are used as a preliminary profile in modern profile rolling mills. In addition to beams, beam blanks are also used to produce U-profiles, sheet piling and special profiles.

The use of blocks and beam blanks for profile rolling always requires a roughing unit, which can either consist of a breakdown stand or a duo roughing group. The greater the deviation of the cross-sectional geometry between roughing and intermediate profiles of a roughing group, the more calibers and passes are required for rolling the final dimensions in the finishing train.

The unpublished patent application with the official file number 100 11 689.2 describes a process for the continuous casting of slabs and, in particular, thin slabs, in a continuous casting installation with a strand guide, comprising strand guide segments that can be adjusted a short distance below a mold, in particular with pairs of rollers, whereby to reduce segregation and Core porosity of the casting strand in the area of residual solidification is reduced in thickness by adjusting the strand guide segments. The process is known as soft reduction.

In a known method according to DE 41 38 740 A1, a strand runs through a soft reduction section, at the start of which it has not yet solidified, but at the end of which it should be solidified, for which the casting speed is an essential operating parameter. In the area of end star thickness reduction, for example for thin slabs between 0.5 and 3 mm / m casting length. For this purpose, the pairs of rollers of individual segments in the soft reduction section are adjusted more closely beyond the shrinkage behavior of the strand in order to improve the internal strand quality in the area of residual solidification.

EP 0 834 364 A1 describes a method and a device for high-speed continuous casting plants with a reduction in strand thickness during solidification, the melt preferably being poured into an oscillating mold and the strand cross-section linearly over a minimum length of the strand guide directly below the mold, the so-called casting rolls, is reduced. There is then a further strand reduction via the remaining strand guidance, the so-called "soft reduction", up to a maximum of immediately before the final solidification or bottom tip. This procedural measure prescribes the deformation density of the reduction in cross section so that the critical deformation of the strand shell is not exceeded, taking into account the high casting speed and steel quality.

EP 0 177 796 B1 discloses a method for guiding and straightening a casting strand in the drawing and discharge area of a continuous sheet casting installation, wherein oppositely arranged rollers are held at a distance corresponding to the casting process by a spring force against the ferrostatic pressure of the casting strand. A cast strand area of increased strength is traced away, and when it passes between opposing rollers, the respective spring force is reduced by a small additional force. This proposal, namely to continuously adjust the clear distance or the mouth width via hydraulic cylinders with built-in inductive displacement measurement and servo valves, requires a computational or metrological determination of the position of the sump tip.

Starting from the above-mentioned prior art, the object of the invention is to develop a new method and a new device of pre-profiles using blocks or beam blanks that are cast close to their final dimensions. In this case, by means of a symmetrical or asymmetrical shaping of the strand shell, in contrast to rolling, a substantially more homogeneous shaping of the cast strand is to be achieved. The production of different pre-profiles for a profile rolling mill is also intended to significantly reduce the rolling effort for the final profiling in the finishing mill and thereby also save calibers.

To achieve the object, the invention provides, in a method of the type mentioned in the preamble of claim 1, that cast strands are cast in the continuous casting installation in the block profile or in another suitable casting profile (for example beam blank) and these are cast below the mold or within or below the strand guide in the area of its still liquid core using at least one pair of rollers for strand forming with profiled, preferably axially and / or radially adjustable rollers of a preforming unit to be preformed which are finished rolled in a finish rolling process to profiles with predetermined final dimensions , Furthermore, according to the invention, a simple and maintenance-friendly strand guide is created for a large number of different strand cross sections.

Advantageously, with the method according to the invention, an extruded profile with a liquid core, i.e. With the profile of a continuous casting mold and a correspondingly set strand guide in the passage through profiled and radially and axially adjustable rollers, a large number of different and also asymmetrical continuous casting profiles are produced as preliminary profiles.

In contrast to rolling, an asymmetrical shaping of the strand shell advantageously leads to a substantially more homogeneous shaping since the liquid core does not experience any compressive or tensile stresses.

Another advantage of the invention results from the higher number of different pre-profiles for a profile rolling mill, because this reduces the rolling effort. adorned and additionally saved caliber. When using asymmetrical pre-profiles, a more homogeneous forming is possible during rolling, so that the caliber and valve stress are significantly reduced and the service life is increased.

The strand is formed in stages with at least one pair of rollers. Experience has shown that the number of required roller pairs depends on the required profile cross-section. The forming can also be done using other adjustment means, e.g. adjustable profiled runners, which run along a predetermined path at the casting speed, lift off and return to the starting position at a higher speed.

Furthermore, the method according to the invention provides that a pre-profile is shaped in the preform unit in such a way that its cross-sectional shape and mass distribution are similar to the finished profile.

A further embodiment of the method according to the invention provides that the profiling of the rollers is designed such that their employment results in as many pre-profile dimensions as possible.

Furthermore, the method according to the invention provides that the casting of a cast strand into the preliminary profile is carried out with one or more pairs of rollers, the number of which depends on the profile cross section which can be specified in each case.

Care must be taken to ensure that a change in shape of the cast block or cast profile under the local influence of a pair of rollers is only carried out to such an extent that no damage to the strand shell is caused. Further refinements of the method according to the invention, in particular different pre-profile formats, are provided in accordance with the subclaims.

A device for producing continuous casting material for the rolling of metal profiles, in particular for the rolling of steel profiles, comprising a continuous casting system with a block or other suitable casting profile mold provides that below the mold or within or below the strand guide in the A preforming unit with at least one pair of rollers with profiled, preferably axially and / or radially adjustable rollers is arranged in the area of a still liquid core of a casting strand emerging from the mold in such a way that the rollers close the block or the casting profile as it passes through the preforming unit Form pre-profiles.

Details, features and advantages of the invention result from the following explanation of an embodiment shown schematically in the drawings. Show it:

Figure 1 in cross-section cast continuous profiles with a liquid core when reducing to profiles close to final dimensions;

FIG. 2 shows the forming of a cast strand according to the invention with several pairs of rollers,

3 shows a number of different pre-profiles which can be produced from a cast strand of a block or beam blank mold according to the invention,

FIG. 4 shows a device for producing continuous casting pre-profiles in accordance with the invention,

Figure 5 shows the principle of pre-profiling in a forming step. Figure 1, namely Figure 1 a to 1c shows work steps in the casting reduction of cast continuous casting profiles 4a, 4b, 4c to profiles close to the final dimensions between profile rollers 2a, 3a; 2b, 3b and 2c, 3c.

FIG. 2 shows the principle of pre-profiling a casting strand, for example from a block mold, as it passes through the pairs of rollers 2b / 3b, 2a / 3a. The rollers 2, 3 are profiled and press the strand shell against the ferrostatic internal pressure of the liquid core to a profile, similar to the profile cross section 4.1 in Fig. 3. Because the strand shell is still easily deformable compared to the liquid core, the process is not so much about a rolling process, but more about a spinning process. The number of required pairs of roles depends on the respective profile cross-section. The decrease in each pair of rolls must not be so great that the strand shell is damaged. In Fig. 2 the principle of pre-profiling between two pairs of rollers is shown purely by way of example.

First, the slightly smaller diameter roller pair 2b, 3b presses a flat concave groove 4, while the trailing roller pair 2a, 3a with a slightly larger diameter of its profiling 9 further reforms the concave shape according to the format 4.1 or 4.2 in FIG. 3. A zone of pure strand guidance can follow after the forming area. The pre-profiling of cast blocks or beam blanks with a still liquid core takes place in smaller steps, so that one can speak of a liquid core shaping during the pre-forming.

Figure 3 shows different continuous casting pre-profiles that can be produced by a liquid core shaping process. For example:

Beam blank formats with a large web thickness and a small incision depth for rolling double T profiles (cf. format 4.1). - Beam blank formats with different flange heights and widths, e.g. for rail rolling (see Format 4.2), - Beam blank formats with locally increased web thickness, e.g. for rolling groove profiles (see Format 4.3),

Beam blank formats with one-sided flange reduction enable, for example, U-profile rolling (see Format 4.4),

Blocks with a trapezoidal cross-section are suitable, for example, for rail rolling (see format 4.5 / 4.6 and 4.7),

Blocks with a slightly U-shaped cross-section are suitable, for example, for sheet piling (see Format 4.8),

Blocks with a slightly M or W-shaped cross section are also available

Sheet pile rolling suitable (see Format 4.9), - round profile e.g. for bar and wire rolling (see format 4.10),

Oval format e.g. for bar and wire rolling (see format

4.11).

FIG. 4 shows a device for producing continuous casting starting material according to the method of operation referred to as liquid core shaping (LCS), comprising a continuous casting installation with a block or beam blank mold 5.

A preforming unit 7 with profiled, axially and / or radially adjustable rollers 3 is arranged below the mold 5 or below a strand guide segment 6 'in the region of a still liquid core of the casting strand 1 emerging from the mold 5. The rollers 3 form the beam blank 1 as they pass through the preforming unit 7 into preforms 4 (cf. FIG. 3). Preferably, after the pre-forming unit (7), a self-supporting extrusion profile should be achieved that does not require any additional extrusion support. In the case of non-self-supporting extruded profiles, a further extruded guide segment 6 'is arranged after the preforming unit 7 and now has guide rollers with corresponding profiles, such as the initial profiling rollers 3 of the unit 7. In contrast, the strand guide segment 6 is smooth, non-profiled rollers 2. 5 shows the principle of pre-profiling the cast strand 1 in a forming step by means of the rollers 2a, 3a. Lateral guide rollers 8a, 8b give the flange of the preliminary profile lateral support.

Claims

claims

1. A process for the production of continuous casting material for rolling metal profiles, in particular steel profiles, characterized in that in a continuous casting system, cast strands are cast in the block or in another casting profile (for example beam blank) (1) and these are cast below the mold (5 ) or within or below the strand guide in the area of its still liquid core using one or more pairs of rollers with profiled rollers (2, 3), which can be adjusted axially and / or radially, of a preforming unit (7) to be preformed (4) are, which are finished rolled in a finish rolling process to profiles with predetermined final dimensions.

2. The method according to claim 1, characterized in that a pre-profile (4) in the pre-forming unit (7) is shaped such that it is similar to the finished profile in its cross-sectional shape and mass distribution.

3. The method according to claim 1 or 2, characterized in that the profiling of the rollers (3) is designed such that their employment results in as many pre-profile dimensions as possible.

4. The method according to one or more of claims 1 to 3, characterized in that the forming of a cast strand to the preliminary profile (4) with one or more pairs of rollers (3), preferably carried out in forming stages is, the number of which depends on the predeterminable profile cross-section (4i).

5. The method according to one or more of claims 1 to 4, characterized in that a change in shape of the cast block or the casting profile

(e.g. beam blank) (1) under the influence of a pair of rollers (2, 3) is only carried out to such an extent that no damage to the strand shell is caused.

6. The method according to one or more of claims 1 to 5, characterized in that the casting and / or setting parameters are set so that the cast strand is self-supporting after the pre-forming unit and therefore no strand support is required.

7. The method according to one or more of claims 1 to 6, characterized in that the roller profile is selected so that the cast strand is self-supporting after the pre-forming unit.

8. The method according to one or more of claims 1 to 7, characterized in that the cooling parameters are set before and / or in the pre-forming unit so that the temperature profile of the cast strand is not critical for the strand forming.

9. The method according to one or more of claims 1 to 8, characterized in that in a block or casting profile mold cast strands (1) by liquid core shaping (LCS) to beam blank pre-profiles (4.1 to 4.11) are formed.

10. The method according to claim 9, characterized in that the following pre-profile formats are generated by LCS forming: - With a large web thickness and a small incision depth, a pre-format

(4.1) e.g. a pre-format for T-profile rolling, with different flange heights and widths

(4.2) e.g. for the rail rolling, with a locally increased web thickness a pre-format (4.3) e.g. for the rolling of groove profiles, with one-sided flange reduction, a pre-format (4.4) e.g. for the

U-Profilwalzung,

Blocks with a trapezoidal cross-section (4.5 or 4a-4c) e.g. for the

Rail rolling - blocks with a trapezoidal cross-section (4.6, 4.7) e.g. for rail rolling,

Blocks with an approximately U-shaped cross-section (4.8) e.g. for sheet piling, blocks with approximately M or W-shaped cross-section (4.9) e.g. for sheet pile rolling,

Round profiles (4.10) or oval formats (4.11), e.g. for bar and wire rolling.

11. Device for producing continuous casting material, for rolling metal profiles, in particular steel profiles, comprising a

Continuous caster with a block or casting profile mold, characterized in that a preforming unit with a mold or die (1) emerging from the mold (5) below the mold (5) or inside or below the strand guide at least one pair of rollers with profiled, preferably axially and / or radially adjustable rollers (2, 3) is arranged in such a way that the rollers form the block or the cast profile (1) as they pass through the pre-forming unit (7) to form pre-profiles (4).

12. The apparatus according to claim 11, characterized in that the pre-forming unit (7) or the adjustable rollers (2, 3) are designed to be quickly exchangeable for adaptation to other pre-profiles (4).