DE10236368A1 - Method and device for continuous casting and direct shaping of a metal strand, in particular a casting strand made of steel materials - Google Patents

Abstract

A method and a continuous casting device for the direct shaping of a metal, in particular a casting strand (1) made of steel materials, any strand format (1d), works in such a way that the casting strand (1) is only co-located in the longitudinal sections (6) by liquid coolant (4) inside the liquid casting strand (1) is cooled and that the casting strand (1) in a transition area (7) in front of, in and / or behind a bending-straightening unit (8) by isolating the outer surface (1b) in temperature, in Essentially without liquid coolant (4), is further evened out by zone-wise heat radiation, and that the casting strand (1) on a dynamically variable reduction section (9) due to the compressive strength measured on individual deformation rollers (10) or roller segments (11), depending on the location applicable compressive force is deformed.

Description

The invention relates to a method and a device for continuous casting and immediate deformation of a metal, especially a casting strand Steel materials that are rectangular, block, pre-profile, billet or round format, after the continuous casting mold in a curved strand guide and with liquid coolant cooled secondarily and to a uniform temperature field in the Strand cross section is prepared for the deformation process regulated.

In general, when casting various types of steel and Dimensions or formats in the secondary cooling focus on the Strand shell growth and in a deformation zone on the position of the swamp tip directed. It is known, for example, from EP 0 804 981, the casting strand in the Squeeze the deformation section so far that the desired final thickness arises. To do this, however, it is necessary to determine the position of the swamp tip from which is applied from the deformation force lying on a wedge surface. On however, such a procedure is relatively crude and takes no account of the condition of the expected structure. The cause lies in the insufficient Heat distribution due to disadvantageous cooling and even strand support uneven heat dissipation from the strand cross-section. A vote of Secondary cooling to the strand support also does not take place. Around Improving conditions is in the unpublished German Patent application 100 51 959.8 has been proposed, the secondary cooling in their geometric design of the solidification profile of the casting strand on the following Adjust the length of the casting strand in each case analogously. Also the Strand support depending on the solidification profile of the casting strand on the respective following route length is reduced analogously. The corner areas of the Casting section cross-section less cooled than that with increasing route length Middle ranges. The spray jets are implemented in the process Secondary cooling with its spray angle adapted to the strand shell thickness in such a way that a smaller spray angle is assigned to a narrowing sump width. By these measures will already be a significant leveling out of temperature reached in the strand cross-section over layers of the strand cross-section.

With this level of knowledge, the inventor did not have the aforementioned Pre-published patent application further recognized that the process execution of the so-called soft reduction of the casting strand must still be optimized. This The underlying knowledge is that large deformation resistances are caused by unfavorable Temperature distribution in the cast billet or in the cast pre-profile with different ductility different deformation resistance, cause different strains and thus lead to cracks.

An improvement in the internal quality of casting strands with different Cross-sectional shapes and dimensions, especially with regard to positive segregations, Core porosity and core loosening requires a reduction process in the Ender congealing area. The previous procedure, e.g. B. at Billet cross sections, causes a circular solidification with circular isotherms in the Cross-section that occurs in the area of the bending-straightening driver. Because with such Temperature distribution only a reduction in the core is possible, only one mechanically influenced final solidification reached. However, the results are not satisfactory and subject to very strong fluctuations. The reason is that the Area of final solidification is very difficult to grasp.

The object of the invention is to provide the necessary temperature distribution in the To produce casting strand and thus optimize the deformation process and to achieve a usable structure of final solidification at the end.

The object is achieved according to the invention in that the casting strand is cooled by liquid coolant only in the longitudinal sections in which the Casting strand in cross section is predominantly liquid that the casting strand in one Transition area in front of, in and / or behind a bending / straightening unit by insulation the respective heat radiating outer surface in temperature, in essentially without liquid coolant, further by zone-wise heat radiation is evened out and that the casting strand on a dynamically variable Reduction distance due to a single deformation rollers or roller segments measured compressive strength, depending on the locally applicable compressive force, is deformed. The advantages are a better preparation for the deformation process Pouring or cooling process with a modified solidification or Temperature profile in the strand cross-section and a reduction process with continuous or variable course of reduction, which leads to a largely error-free structure of the Lead to final solidification.

The deformation process can be further optimized by the Temperature field is formed from elliptical, horizontally lying isotherms.

This also creates an advantageous differentiated requirement created that the temperature image evenly in the transverse and longitudinal directions of the Core area is formed in the strand cross section.

Such a mode of operation is further supported by the fact that the casting strand is open the dynamically variable reduction section in the core area in transverse and Longitudinal direction is compressed.

The lengths of the. Play an important role in cooling the casting strand Side edges of a polygonal strand cross section. It is therefore of considerable importance Meaning that the deformation depending on the strand format, the Strand dimensions and / or the casting speed is made.

Basically, the deformation on the deformation line can be done according to two systems be carried out by deforming by point pressing over individual Deformation rollers or by approximate surface pressing over roller segments is made.

A further embodiment of the method in the case of surface pressing is that when deforming over roller segments for different steel grades different conicity when applying the role segments are used.

Another very important part of the invention comes from the control or Regulation, the measurement and control technology of the deformation process. That at the beginning For this purpose, the designated method provides for regulation in such a way that several Roller segments in normal position or with constant taper or with progressive Taper or with variable taper, what by regulating can be adjusted. After that, depending on the determined resistance to deformation be deformed.

The continuous or variable course of reduction is also supported by that compacting the core area of the casting strand by grasping its Deformation resistance and / or the strand path is regulated.

Then a less mechanically influenced final solidification is achieved that when deforming approximately horizontal layers in the strand cross-section, which have the same isotherms, are compressed.

A form-maintaining measure is still that the Cast strand at least during the deformation by on both side surfaces adjacent support rollers are supported and guided.

This can result in a distribution of the total deformation energy supplied that the rate of the reduction process is set to 0 to 14 mm / m becomes.

The generic method for continuous casting with direct In terms of control technology, deformation is designed so that the current Deformation rate on the respective temperature of the cast strand and / or on the Casting speed is adjusted by using the individual deformation rollers or The deformation resistance on the individual roller segments is continuous is measured and the position of the sump tip based on the respective contact force determined and the coolant volume, the contact force, the casting speed and / or the extension speed of the deformed cast strand can be regulated.

Fixed baseline values can still be obtained by Deformation roll or each roll segment first one in a fixed Ratio related deformation rate is assigned.

The generic device for continuous casting with direct Deformation is designed so that the curved strand guide with the Spray device for liquid coolant largely without liquid coolant working, predominantly dry area is connected as insulation against the dissipation of radiant heat, specifically surrounding the casting strand and that an upstream, covering the area of the bending-straightening unit or downstream reduction section, from individual, hydraulically adjustable Deformation rollers or from several hydraulically adjustable roller segments existing, is provided.

A correction option when hiking the solidification cone tip can also can be absorbed by the fact that in the strand running direction next to one or more fixed bending-straightening units arranged roller segments in Strand direction or are displaceable in the opposite direction.

Different deformation forces can occur within the roller segments be applied by each reduction roller segment at least two pairs of rollers has, of which at least one adjustable deformation roller with a piston Cylinder unit is equipped.

The different deformation forces can also be generated by the fact that with a rigidly arranged sub-deformation roller pair or a rigid one Lower roller segment the upper, adjustable deformation roller or the upper, adjustable roller segment each with two in a row on the center line Piston-cylinder arranged or arranged in pairs outside the center line Units per pair of rollers are equipped.

Another measure for an advantageous deformation path is thereby achieved that the role division on a role segment as a narrow division in the Range 150 to 450 mm is selected.

It is also proposed that in the field of radiation isolation arranged bending-directional units also against heat radiation by the Cast strand are insulated.

In the drawing, embodiments of the invention for the method and Device with the deformation path shown, which is explained in more detail below become.

Show it:

Fig. 1 is a side view of a continuous casting, for example. Billet formats,

Fig. 2 is an in-plane deformation compared with elliptical temperature field in the steady-state operation,

Fig. 3 is a perspective view of a section of a comparative change in shape with an elliptical temperature field after the first pass in the deformation path,

Fig. 4 shows a first system of the soft reduction with individual forming rollers,

Fig. 5 shows a second system of the deformation distance of roller segments,

Fig. 6-9 different conicity employment of roller segments,

Fig. 10 is a side view with a plurality of bending-straightening units and with the deformation path,

Fig. 11, the deformation distance in an alternative embodiment with individual driven forming rollers,

FIG. 12A is a side view of another alternative embodiment of the bending straightening units and the roller segments;

FIG. 13A, a deformation stand in the normal position,

FIG. 13B, a deformation stand in drive position and

Fig. 13C, the deformation scaffold with an insulation.

In Fig. 1 is an example of a continuous casting device for a billet strand format 1 d of a cast strand 1 is shown. The strand cross-section 1 a could, however, also be a rectangular, a block, a pre-profile or a round format.

The liquid steel material is cooled via a continuous casting mold 2 in a (curved) strand guide 3 with liquid coolant 4 , for example water, and is regulated in a controlled manner to a uniform temperature field 5 in the strand cross section 1 a (cf. also FIG. 2). This creates a liquid-cooled longitudinal section 6 with a solid shell and a liquid core area 1 c.

The curved strand guide 3 with a spray device 4 a for the liquid coolant 4 is followed by a largely dry region 24 that works largely without liquid coolant 4 and serves as insulation 25 against the dissipation of radiant heat, specifically surrounding the casting strand 1 , the possible Insulation length in the longitudinal area indicated by arrows, depending on the strand format 1 d, the dimensions, the casting speed and the like. Like parameters is obtained. The dry area 24 can, for example, as shown, extend over the transition area 7, liquid 1, to the bending-straightening unit 8 with an upstream or downstream reduction section 9 . The reduction section 9 consists of individual, hydraulically adjustable deformation rollers 10 or a plurality of hydraulically adjustable roller segments 11 , as can be seen in FIG. 1.

The method based on the continuous casting apparatus for liquid steel materials explained above is now carried out in such a way ( FIGS. 2 and 3) that the casting strand 1 is used by the liquid coolant 4 only in liquid-cooled longitudinal sections 6 , in which the casting strand in cross section 1 a predominantly is liquid or still liquid. In a transition area 7 , in front of, in and / or behind the bending-straightening unit 8 , the heat-radiating outer surface 1 b is insulated in temperature, essentially without the liquid coolant 4 , which results in zone-by-zone heat radiation of colder cross-sectional parts, such as z. B. the corner edges 1 f, less cooled and / or supported than other cross-section parts connected to the still hot or liquid core area 1 c. As a result, the heat distribution in the strand cross section 1 a is evened out. The temperature field 5 arises with elliptical, essentially horizontal isotherms 12 ( FIGS. 2 and 3).

The casting strand 1 is deformed on the basis of this improved temperature distribution on a dynamically variable reduction section 9 and on the basis of a compressive strength measured via the individual shaping rollers 10 or one or more roller segments 11 , depending on the locally applicable compressive force.

The temperature field 5 ( FIG. 2) is formed uniformly in the transverse and longitudinal directions 1 e of the core region 1 c in the strand cross section 1 a.

Due to the isotherms 12 , the casting strand 1 on the dynamically variable reduction section 9 in the core area 1 c can be compressed in the transverse and longitudinal directions 1 e ( FIGS. 4 and 5). The deformation is carried out as a function of the strand format 1 d, the strand dimensions 14 and / or the respective casting speed in the longitudinal direction 13 . The shaping can be carried out by line pressing ( FIG. 4) over individual shaping rollers 10 or by approximate surface pressing over several roller segments 11 ( FIG. 5). The core area 1 c is compressed to a bottom tip 1 g. When deforming via roller segments 11 , different conicalities 15 can be used for different steel grades by appropriately positioning the roller segments 11 .

In Figs. 6 to 9 such examples of different tapers 15 are shown.

Fig. 6 shows the "normal" position 16 of the roller segments 11, that the taper is 0 °. Nevertheless, compression takes place. In Fig. 7 a constant taper 17 is set for all roller segments 11. On the other hand, FIG. 8 shows a changing taper angle in the sense of progressive taper 18 from roller segment 11 to the next roller segment 11 . It is also possible to regulate a variable conicity 19 depending on the position of the sump tip 1 g according to FIG. 9.

The compression of the core area 1 c (FIGS . 4 and 5) of the casting strand 1 via the pressure cone 1 h is first regulated by detecting the relevant deformation resistance and / or a strand path 20 covered (path detection). It is particularly expedient here the formation of the temperature field is uniform 5 of the core region 1 c in the transverse and longitudinal direction 1 e. This results in so-called optimized isotherms 12 . The isotherms 12 run particularly flat. The resistance to deformation can be measured, for example, under a single deformation roller 10 by measuring the hydraulic pressure in a hydraulic line or another hydraulic component.

In the transverse direction 1 e of the strand cross section 1 a, approximately horizontal layers 21 , which have the same isotherms 12 , are advantageously compacted (see FIGS . 2 and 3). When the core porosities are compacted, existing segregations can be eliminated at the same time. During compaction, the warmer and therefore softer layer 21 yields.

As shown in Fig. 12B, are expediently arranged during deformation on both outer surfaces 1 b adjacent support rollers 22 b do not allow a width of the cast strand 1 on its outer surface 1. The rate of the reduction process can be set to (currently) 0 to 14 mm per running meter of casting strand 1 and regulated.

The control process for soft reduction also takes place: The current deformation rate is matched to the respective temperature of the casting strand 1 and / or to the (set) casting speed (for example 3.2 m / min). For this purpose, the resistance to deformation (for example via the hydraulic pressure) is continuously measured on the individual deformation rollers 10 or on the individual roller segments 11 . The position of the sump tip 1 g is determined on the basis of the respectively determined contact force and, for example, the volume of the sprayed coolant 4 , the contact force, the casting speed and / or the extension speed of the deformed casting strand 1 are regulated so that the sump tip 1 g is in a desired position within the dynamic, variable reduction section 9 thus arrives. In this case, each individual deformation roller 10 or each roller segment 11 can first be assigned a deformation rate in a fixed ratio in accordance with the conicity system of FIGS. 6 to 9.

Referring to FIGS. 10 to 13C, the essential components of the deformation section 10 are shown.

In FIG. 10, in the strand running direction 23, in addition to one or more fixed bending-straightening units 8, there are several roller segments 11 on a common base plate 26 . The base plate 26 with the bending-straightening units 8 and the (four) roller segments 11 shown can be moved back and forth in the region of a changed position of the sump tip 1 and is accordingly connected to the control system.

Each of the (six) reduction roller segments 11 is equipped with at least two pairs of rollers 11 a. At least one adjustable deformation roller 10 is equipped with a piston-cylinder unit 27 .

As shown in FIGS. 12A and 12B, wherein a rigid lower roller deformation pair engagable roller segment 11 can 11a or a rigid sub-roller segment 11, the upper, adjustable deforming roller 10 or the upper, respectively arranged by means of two on a center line 28 one after the other or Piston-cylinder units 27 arranged in pairs outside the center line 28 are provided.

The roller division 29 ( FIGS. 4 and 5) on a roller segment 11 is selected as a narrow division in the range from 200 to 450 mm with a roller diameter of 230 mm (roller segment 11 ) or 500 mm (individual deformation roller 10 ).

Such a single roller segment 11 for a billet format is shown in FIGS. 13A, 13B and 13C. In Fig. 13A, the drive 30 and the pair of rollers 11 a is in the normal position. In Fig. 13B, the pair of rollers 11 a and the drive 30 in the drive position are shown. The insulation 25 in the area of the reduction section 9 can be seen in FIG. 13C.

The invention can also advantageously be used for the entire range of steel grades, such as for stainless steels, quality steels and stainless steels. LIST OF REFERENCES 1 cast strand
1 a strand cross section
1 b outer surface
1 c core area
1 d strand format
1 e transverse and / or longitudinal direction
1 f corner edges
1 g sump tip
1 h pressure cone
2 continuous casting mold
3 (curved) strand guide
4 liquid coolant
4 a spraying device
5 temperature field, temperature image
6 liquid-cooled longitudinal section
7 transition area
8 bending-straightening unit
9 dynamically variable reduction section
10 Deformation roller
11 roller segment
11 a pair of rollers
12 isotherm
13 longitudinal direction
14 strand dimension
15 different conicities
16 normal position
17 constant taper
18 progressive taper
19 variable conicity
20 strandweg
21 horizontal layer of the same temperature
22 support rollers
23 strand running direction
24 dry area
25 isolation
26 base plate
27 piston-cylinder unit
28 center line
29 Role division
30 drive

Claims (20)

1. A method for continuous casting and direct shaping of a metal, in particular a casting strand ( 1 ) made of steel materials, which has a rectangular, block, pre-profile, billet or round format, after the continuous casting mold ( 2 ) in a curved strand guide ( 3 ) guided and secondarily cooled with liquid coolant ( 4 ) and prepared for a uniform temperature field ( 5 ) in the strand cross section ( 1 a) for the shaping operation, characterized in that the casting strand ( 1 ) is only in the longitudinal sections by liquid coolant ( 4 ) ( 6 ) is cooled, in which the casting strand ( 1 ) is predominantly liquid in cross section ( 1 a), that the casting strand ( 1 ) in a transition region ( 7 ) in front of, in and / or behind a bending-straightening unit ( 8 ) by isolating the respective heat-radiating outer surface ( 1 b) in temperature, essentially without liquid coolant ( 4 ), further by zone-wise heat radiation v is evened out and that the casting strand ( 1 ) is deformed on a dynamically variable reduction section ( 9 ) on the basis of a compressive strength measured via individual shaping rollers ( 10 ) or roller segments ( 11 ), depending on the locally applicable compressive force. 2. The method according to claim 1, characterized in that the temperature field ( 5 ) from elliptical, horizontally lying isotherms ( 12 ) is formed. 3. The method according to any one of claims 1 or 2, characterized in that the temperature image ( 5 ) is formed uniformly in the transverse and longitudinal directions ( 1 e) of the core region ( 1 c) in the strand cross section ( 1 a). 4. The method according to any one of claims 1 to 3, characterized in that the casting strand ( 1 ) on the dynamically variable reduction section ( 9 ) in the core area ( 1 c) is compressed in the transverse and longitudinal directions ( 1 e). 5. The method according to any one of claims 1 to 4, characterized in that the shaping is carried out as a function of the strand format ( 1 d), the strand dimensions ( 14 ) and / or the casting speed. 6. The method according to any one of claims 1 to 5, characterized in that the shaping is carried out by point pressing over individual shaping rollers ( 10 ) or by approximate surface pressing over roller segments ( 11 ). 7. The method according to claim 6, characterized in that when deforming over roller segments ( 11 ) for different steel grades different conicity ( 15 ) are used when starting the roller segments ( 11 ). 8. The method according to any one of claims 1 to 7, characterized in that a plurality of roller segments ( 11 ) in the normal position ( 16 ) or with constant taper ( 17 ) or with progressive taper ( 18 ) or with variable taper ( 19 ) are employed , 9. The method according to any one of claims 1 to 8, characterized in that the compression of the core region ( 1 c) of the casting strand ( 1 ) is controlled by detecting its resistance to deformation and / or the strand path ( 20 ). 10. The method according to any one of claims 1 to 9, characterized in that when deforming approximately horizontal layers ( 21 ) in the strand cross-section ( 1 a), which have the same isotherms ( 12 ), are compressed. 11. A method according to any one of claims 1 to 10, characterized in that the cast strand (1) is supported at least adjacent support rollers (22) during forming by on both outer faces (1 b) and guided. 12. The method according to any one of claims 1 to 11, characterized, that the rate of the reduction process is set to 0 to 14 mm / m. 13. A method for continuous casting and direct shaping of a metal, in particular a casting strand ( 1 ) made of steel materials, which has a polygonal format or a round format, guided after the continuous casting mold ( 2 ) in a curved strand guide ( 3 ) and with liquid Coolant ( 4 ) is cooled secondarily and prepared in a controlled manner for a uniform temperature field ( 5 ) in the strand cross section ( 1 a) for the deformation operation, characterized in that the instantaneous deformation rate is matched to the respective temperature of the casting strand ( 1 ) and / or to the casting speed is determined by continuously measuring the deformation resistance on the individual deformation rollers ( 10 ) or on the individual roller segments ( 11 ) and determining the position of the sump tip ( 1 g) on the basis of the respective contact force and the coolant volume, the contact force, the casting speed and / or the extension speed of the deformed casting strand ( 1 ) to be regulated. 14. The method according to claim 13, characterized in that each deformation roller ( 10 ) or each roller segment ( 11 ) is initially assigned a deformation rate which is in a fixed ratio. 15. Device for continuous casting with direct deformation of a metal, in particular a casting strand ( 1 ) made of steel materials, the rectangular, block, pre-profile, billet or round format ( 1 d), with one in the strand running direction ( 23 ) after Continuous casting mold ( 2 ) curved strand guide ( 3 ) and a spray device ( 4 a) for liquid coolant ( 4 ), a bending-straightening unit ( 8 ) and a control device for a uniform temperature field ( 5 ) in the strand cross section ( 1 a) are provided , characterized in that a largely dry area ( 24 ) which functions largely without liquid coolant ( 4 ) and is connected as insulation ( 25 ) is connected to the curved strand guide ( 3 ) with the spray device ( 4 a) for liquid coolant ( 4 ) against the dissipation of radiant heat, specifically surrounding the casting strand ( 1 ), and that an upstream or downstream covering the area of the bending / straightening unit ( 8 ) held reduction section ( 9 ), consisting of individual, hydraulically adjustable deformation rollers ( 10 ) or of several hydraulically adjustable roller segments ( 11 ) is provided. 16. The apparatus according to claim 15, characterized in that in the strand running direction ( 23 ) next to one or more fixed bending-straightening units ( 8 ) arranged roller segments ( 11 ) in the strand running direction ( 23 ) or are displaceable in the opposite direction. 17. Device according to one of claims 15 or 16, characterized in that each reduction roller segment ( 11 ) has at least two pairs of rollers ( 11 a), of which at least one adjustable deformation roller ( 10 ) with a piston-cylinder unit ( 27 ) is equipped. 18. Device according to one of claims 15 to 17, characterized in that in the case of a rigidly arranged lower deformation roller pair ( 11 a) or a rigid lower roller segment ( 11 ), the upper, adjustable deformation roller ( 10 ) or the upper, adjustable Roller segment ( 11 ) are each equipped with two piston-cylinder units ( 27 ) arranged one behind the other on the center line ( 28 ) or in pairs outside the center line ( 28 ) per pair of rollers ( 11 a). 19. Device according to one of claims 15 to 18, characterized in that the roller division ( 29 ) on a roller segment ( 11 ) is selected as a narrow division in the range 150 to 450 mm. 20. Device according to one of claims 14 to 19, characterized in that in the region of the radiation insulation ( 25 ) arranged bending-directing units ( 8 ) are also insulated against heat radiation from the casting strand ( 1 ).