US20020189783A1 - Continuous casting apparatus with soft reduction - Google Patents
Continuous casting apparatus with soft reduction Download PDFInfo
- Publication number
- US20020189783A1 US20020189783A1 US09/884,710 US88471001A US2002189783A1 US 20020189783 A1 US20020189783 A1 US 20020189783A1 US 88471001 A US88471001 A US 88471001A US 2002189783 A1 US2002189783 A1 US 2002189783A1
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- United States
- Prior art keywords
- support
- assemblies
- strand
- mold
- reducing member
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- 238000009749 continuous casting Methods 0.000 title claims abstract description 12
- 230000009467 reduction Effects 0.000 title claims description 35
- 238000005096 rolling process Methods 0.000 claims abstract description 68
- 230000000712 assembly Effects 0.000 claims description 33
- 238000000429 assembly Methods 0.000 claims description 33
- 238000005266 casting Methods 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 16
- 239000012809 cooling fluid Substances 0.000 claims description 10
- 238000004873 anchoring Methods 0.000 claims description 8
- 230000000284 resting effect Effects 0.000 claims description 8
- 230000000694 effects Effects 0.000 claims description 7
- 239000012768 molten material Substances 0.000 claims description 6
- 239000007788 liquid Substances 0.000 abstract description 4
- 239000000969 carrier Substances 0.000 description 24
- 229910000831 Steel Inorganic materials 0.000 description 13
- 239000010959 steel Substances 0.000 description 13
- 239000007787 solid Substances 0.000 description 12
- 230000007246 mechanism Effects 0.000 description 10
- 238000007711 solidification Methods 0.000 description 4
- 230000008023 solidification Effects 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 239000000498 cooling water Substances 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229910001208 Crucible steel Inorganic materials 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
Definitions
- the invention relates to continuous casting.
- Apparatus for the continuous casting of steel typically include a mold having a generally vertical casting passage.
- the casting passage is open at the top and bottom, and a stream of molten steel is directed into the top of the passage.
- the molten steel partially solidifies in the mold to form a continuously cast strand consisting of a solidified outer shell and a molten core.
- the strand is withdrawn from the bottom of the casting passage and conveyed along a path which curves to the horizontal. As the strand travels along such path, the strand is cooled and the molten core solidifies progressively. Once the strand has solidified throughout the cross section thereof, the strand is cut into sections.
- solid fraction arises from the fact that steel generally does not undergo a direct transformation from liquid to solid when cooled. Instead, there is a temperature range between liquidus and solidus where the steel is in a so-called “mushy” state. In this state, the steel is neither completely solid nor completely liquid but is a mixture of solid and liquid. The proportion of solid in the mixture is indicated by a percentage referred to as the “solid fraction”.
- Each of the rolling stands includes an upper module containing a movable roller, and a hydraulic unit for moving the roller towards and away from a second roller in a lower module.
- the upper module of each rolling stand is supported on four columns of its own, and two of the columns face one another across the path of the strand at a first location of the path while two face one another across the path of the strand at a second location of the path.
- the rollers of neighboring rolling stands are spaced from each other by a relatively large distance which typically is at least 1 meter. Although it is desirable for the rollers to be closer to one another, the adjoining columns of two neighboring rolling stands prevent the distance between the stands from being reduced.
- the solidification rate of a continuously cast strand can vary significantly depending upon a number of factors such as the type of steel being cast, the degree of superheat and the casting speed. When the distance between neighboring rolling stands is large, this can result in a situation where only one of the rolling stands, or possibly none of the rolling stands, acts on the portion of the strand having a solid fraction of 20 percent to 85 percent, i.e., on the portion of the strand which is suitable for soft reduction. In this case, little or none of the benefit of soft reduction is achieved.
- the apparatus comprises a mold designed to form a continuously cast strand from molten material, at least one support and at least two assemblies operable substantially independently of one another to effect a dimensional reduction of a strand formed in the mold.
- Each of the assemblies includes a supporting part which rests on the support, and each of the assemblies further includes another part which extends downward from the respective supporting part and comprises at least one reducing member for effecting a dimensional reduction of a strand formed in the mold.
- the support can constitute or resemble a column while the reduction assemblies can constitute rolling stands.
- two assemblies for effecting a dimensional reduction of a continuously cast strand share a support thereby allowing a second support between the assemblies to be eliminated. This enables the assemblies to be placed closer to one another than before.
- Another aspect of the invention resides in a method of operating a continuous casting apparatus.
- the method comprises the steps of providing a mold designed to form a continuously cast strand from molten material, installing the mold at a casting location and providing two assemblies operable substantially independently of one another to effect a dimensional reduction of a continuously cast strand.
- the method further comprises the step of placing the assemblies on a support at a reduction location spaced from the casting location so that a supporting part of each assembly rests on the support and a second part of each assembly extends downward from the respective supporting part.
- the second part of each assembly includes a reducing member for effecting a dimensional reduction of a strand formed in the mold.
- Each of the assemblies is preferably placed on the support substantially independently of the other assembly.
- the method can additionally comprise the step of fixing the assemblies to the support with a fixing element which urges both of the assemblies towards the support.
- the method may also include the steps of forming a partially solidified continuously cast strand in the mold, and subjecting the partially solidified strand to a dimensional reduction in at least one of the assemblies.
- the reducing member of this assembly can comprise a roll and the subjecting step can then involve rolling the partially solidified strand.
- At least one of the reducing assemblies can include an additional reducing member which is arranged to cooperate with the other reducing member of such assembly to effect a dimensional reduction of a strand formed in said mold.
- the method can here comprise the step of anchoring the additional reducing member to the support for the reducing assemblies.
- the method may further comprise the steps of providing a hollow anchoring member having an upper side and a lower side separated by a gap, passing the support through the upper side, and resting the support on the lower side.
- the method may further comprise the steps of providing an additional support, bridging the two supports with a pipe, and introducing a cooling fluid into the supports from the pipe.
- FIG. 1 is a schematic sectional side view of a continuous casting apparatus in accordance with the invention.
- FIG. 2 is a side view showing certain details of rolling stands constituting part of the apparatus of FIG. 1.
- FIG. 3 is a sectional view in the direction of the arrows III-III of FIG. 2.
- FIG. 4 is a fragmentary sectional view in the direction of the arrows IV-IV of FIG. 2 but without counterweights and drive units forming part of the rolling stands.
- FIG. 5 is a fragmentary sectional view in the direction of the arrows V-V of FIG. 4.
- FIG. 6 is a fragmentary sectional view in the direction of the arrows VI-VI of FIG. 4.
- the numeral 10 generally identifies a continuous caster or casting apparatus according to the invention.
- the caster 10 is of the type typically used to cast steel, and this type of apparatus is generally designed to produce billets, blooms or slabs which are square or rectangular products differing primarily in cross-sectional size.
- the caster 10 is assumed to be capable of casting steel into multiple product types and product sizes, and the products generated by the caster 10 can be converted into special bar quality and/or rails. Examples of products which can be made by the caster 10 are blooms, billets and rounds.
- the caster 10 includes a cooled, generally vertical continuous casting mold 12 having a generally vertical casting passage 14 .
- the casting passage 14 which is here curved but could also be straight, has an open upper end 14 a and an open lower end 14 b .
- the upper end 14 a constitutes an inlet end of the casting passage 14 while the lower end 14 b constitutes an outlet end of the casting passage 14 .
- a curved roller apron 16 which includes a row of rollers 16 a and another row of rollers 16 b situated opposite the roller row 16 a .
- a series of rolling stands or reduction assemblies 18 each of which comprises an upper roller or reducing member 18 a and a lower roller or reducing member 18 b .
- the lower rollers 18 b are mounted for rotation at fixed locations while the upper rollers 18 a are movable towards and away from the respective lower rollers 18 b by individual hydraulic units 20 forming part of the rolling stands 18 .
- the rolling stands 18 are designed to subject the strand 18 to soft reduction.
- a pinch roll and final straightening mechanism 22 with an upper roller 22 a and two lower rollers 22 b and 22 c .
- the lower rollers 22 b , 22 c are mounted for rotation at fixed locations whereas the upper roller 22 a , which is situated opposite the lower roller 22 c , is movable towards and away from the roller 22 c by a hydraulic unit not shown in FIG. 1.
- the rolling stands 18 together with the pinch roll and final straightening mechanism 22 , constitute a straightener/withdrawal unit with soft reduction capability.
- the straightener/withdrawal unit 18 , 22 is followed by a runout table 24 which includes a row of rollers 24 a.
- the pinch roll and final straightening mechanism 22 can be eliminated.
- the rolling stands 18 carry out withdrawal and straightening as well as soft reduction.
- the mold 12 , roller apron 16 , rolling stands 18 , pinch roll and final straightening mechanism 22 and runout table 24 define a path, indicated by the arrow P, which curves from the mold 12 to the pinch roll and final straightening mechanism 22 and then becomes straight and horizontal.
- the portion of the path P from the mold 12 to the rolling stands 18 constitutes a segment of a circle, and this portion of the path P has an inner radius which is tangent to the roller apron rollers 16 a and an outer radius which is tangent to the roller apron rollers 16 b.
- the outlet end 14 b of the casting passage 14 is closed by a non-illustrated dummy bar which is gripped by the pinch roll and final straightening mechanism 22 .
- a stream or jet 26 of molten material is then teemed into the inlet end 14 a of the casting passage 14 .
- the molten material which is here assumed to be steel, solidifies partially in the casting passage 14 to establish a connection with the dummy bar and to form a continuously cast strand 28 which is releasably attached to the dummy bar.
- the strand 28 comprises a shell or skin 28 a of solidified steel and a core 28 b of molten steel confined within the shell 28 a.
- the dummy bar is withdrawn from the casting passage 14 along the path P by the pinch roll and final straightening mechanism 22 .
- the dummy bar which pulls the strand 28 behind it, is disconnected from the strand 28 and stored once the strand 28 reaches the pinch roll and final straightening mechanism 22 . Thereafter, the pinch roll and final straightening mechanism 22 acts directly on the strand 28 to convey the latter along the path P.
- the strand 28 is conveyed continuously along the path P at a predetermined rate commonly referred to as the casting speed.
- the molten steel from the ladle and tundish is teemed continuously into the casting passage 14 at a rate matched to the casting speed.
- the strand 28 As the strand 28 travels through the roller apron 16 , the strand 28 is cooled by non-illustrated water sprays. Consequently, the strand 28 solidifies progressively along the roller apron 16 with the shell 28 a increasing in thickness and the core 28 b decreasing in thickness. Upon reaching the rolling stands 18 , the strand 28 is subjected to a soft reduction which can involve a reduction of 1 mm to 5 mm in the thickness of the strand 28 in each rolling stand 18 .
- the cross section of the strand 28 preferably has a solid fraction of at least 20 percent and, depending upon the operator of the caster 10 , no more than 70 percent or 85 percent when undergoing soft reduction.
- the strand 28 After leaving the rolling stands 18 , the strand 28 passes through the pinch roll and final straightening mechanism 22 which straightens the strand 28 .
- the strand 28 which has now solidified throughout, then moves onto the runout table 24 where the strand 28 is cut into sections by non-illustrated traveling cutting torches.
- the soft reduction of the strand 28 improves the quality of the strand 28 . For example, it has been found that soft reduction decreases segregation and porosity.
- each of the rolling stands 18 includes an upper module 30 containing the respective upper roller 18 a and a lower module 32 containing the respective lower roller 18 b .
- the lower modules 32 are fixed to a bottom frame 34 which sits on a subbase 36 and is connected thereto by clamping bolts 38 .
- the subbase 36 sits on a foundation 40 .
- the subbase 36 is provided with anchoring elements 42 which penetrate the foundation 40 and help to prevent shifting of the subbase 36 relative to the same.
- Foundation bolts 44 serve to secure the subbase 36 to the foundation 40 .
- each upper module 30 further contains a counterweight 46 , a drive unit 48 for rotating the upper roller 18 a , and the respective hydraulic unit 20 for moving the upper roller 18 a towards and away from the lower roller 18 b .
- Every drive unit 48 comprises a motor 48 a and a gear box 48 b.
- Each upper module 30 includes a main carrier or supporting part 50 and an auxiliary carrier 52 below the main carrier 50 .
- the counterweight 46 and the drive unit 48 are fixed to opposite sides of the auxiliary carrier 52 while the upper roller 18 a is suspended therefrom.
- the main carrier 50 and auxiliary carrier 52 can be in the form of box beams.
- each upper module 30 is provided with a vertical central passage 54 .
- the hydraulic unit 20 of each upper module 30 comprises a cylinder 56 and a cylinder rod 58 which projects from the cylinder 56 .
- the cylinder 56 of each hydraulic unit 20 rests on top of the respective main carrier 50 and is secured to the carrier 50 by four threaded bolts or fastening elements 60 which screw into square nuts 62 .
- the cylinder rod 58 of each hydraulic unit 20 extends downward from the cylinder 56 through the respective central passage 54 , and the end of the cylinder rod 58 remote from the cylinder 56 is threaded.
- a coupling device 64 is fixed to the top of each auxiliary carrier 52 , and each coupling device 64 is formed with a blind bore which is aligned with the respective central passage 54 .
- the blind bore is threaded, and the threaded end of the cylinder rod 58 of the respective hydraulic unit 20 is screwed into the blind bore. Consequently, as the cylinder rod 58 of an upper module 30 is extended, the corresponding auxiliary carrier 52 and upper roller 18 a move away from the respective main carrier 50 and towards the respective lower roller 18 b . Conversely, as the cylinder rod 58 is retracted, the corresponding auxiliary carrier 52 and upper roller 18 a move towards the respective main carrier 50 and away from the respective lower roller 18 b.
- each rolling stand is supported on four columns of its own. Two of the columns face one another across the path of the strand at a first location of the path and two face one another across the path of the strand at a second location of the path.
- the rollers of neighboring rolling stands are spaced from each other by a relatively large distance, which is typically at least 1 meter, and the adjoining columns of two neighboring rolling stands prevent the distance between the rolling stands from being reduced.
- One object of the invention is to position the rolling stands 18 closer to one another. To this end, the upper modules 30 of two neighboring rolling stands 18 rest on and are fixed to a common pair of columns or carrying members 66 .
- the columns 66 are mounted on the bottom frame 34 of the continuous casting apparatus 10 .
- the bottom frame 34 includes parallel box beams or anchoring members 68 each having two side plates 68 a and 68 b which are separated by a gap.
- Each of the box beams 68 further has an upper plate 68 c and a lower plate 68 d which are likewise separated by a gap and bridge the respective side plates 68 a , 68 b .
- the side plates 68 a of the box beams 68 face the path P of the strand 28 .
- the columns 66 pass through the upper plates 68 c and rest on the lower plates 68 d , and the columns 66 are secured to the upper plates 68 c and the lower plates 68 d , e.g., by welding.
- the columns 66 are hollow to permit circulation of cooling water therethrough and can be in the form of circular tubing.
- a plate 70 is located inside each column 66 a short distance below the top of the respective column 66 and closes the column 66 .
- the plates 70 prevent the cooling water flowing in the columns 66 from escaping through the tops of the columns 66 .
- the columns 66 are arranged in pairs with the columns 66 of each pair being situated directly opposite one another on opposite sides of the path P of the strand 28 . As shown in FIG. 3, the columns 66 of each pair are connected to each other by a lower pipe 72 a disposed near the bottoms of the columns 66 and by an upper pipe 72 b disposed near the tops of the columns 66 .
- the lower pipes 72 a are located between the box beams 68 of the bottom frame 34 and connect to the columns 66 through openings in the side plates 68 a .
- the pipes 72 a , 72 b function to distribute a cooling fluid, typically water, to the columns 66 and also to stiffen the columns 66 .
- a plate 74 is fixed to the top of each column 66 , e.g., by welding, and the main carriers 50 of the upper modules 30 rest on the plates 74 .
- Two columns 66 disposed directly opposite one another on opposite sides of the path P of the strand 28 are situated between neighboring ones of the rolling stands 18 , and the upper modules 30 of neighboring rolling stands 18 are both carried by the two columns 66 between such rolling stands 18 .
- the upper modules 30 of neighboring rolling stands 18 share the columns 66 located between these rolling stands 18 .
- FIG. 6 shows the main carrier 50 of an upper module 30 resting on two columns 66 located directly opposite each other on opposite sides of the path P of the strand 28 .
- the plate 74 at the top of each column 66 has a portion 74 a which projects laterally from the respective column 66 towards the other of the two columns 66 .
- the main carrier 50 is fixed to each of the two columns 66 by a bolt or fastening element 76 which passes through the main carrier 50 and through the projecting portion 74 a of the respective plate 74 .
- Each of the bolts 76 has a head 76 a which bears against the upper side of the respective main carrier 50 , and each of the bolts 76 further has a threaded end which projects from the respective plate 74 .
- a nut 78 is screwed onto the threaded end of each of the bolts 76 .
- each of the main carriers 50 is provided with two parallel pipe sections 80 a and two parallel pipe sections 80 b .
- the pipe sections 80 a are disposed side-by-side as are the pipe sections 80 b .
- the pipe sections 80 a , 80 b run in the direction of the path P of the strand 28 , and the pipe sections 80 a in each main carrier 50 are located upstream of the central passage 54 for the respective hydraulic unit 20 while the pipe sections 80 b are located downstream of the central passage 54 .
- the axis of each pipe section 80 a lies on a line with the axis of one of the pipe sections 80 b.
- Each of the pipe sections 80 a , 80 b has an open end 82 to allow access to the interior of the respective pipe section 80 a , 80 b .
- the square nuts 62 which screw onto the bolts 60 holding the hydraulic units 20 on the main carriers 50 , are located inside the pipe sections 80 a , 80 b.
- cooling fluid is supplied to each of the main carriers 50 by way of an inlet pipe 84 . After circulating through the respective main carrier 50 , the cooling fluid flows out of the main carrier 50 via an outlet pipe 86 .
- FIG. 6 shows that flow passages 88 for the cooling fluid are machined into the pipe sections 80 a , 80 b.
- each of the two main carriers 50 resting on a column 66 is secured to such column 66 by a discrete bolt 76 .
- FIGS. 2, 4 and 5 illustrate that, in addition, the two main carriers 50 resting on a column 66 are secured to such column 66 by a common threaded bolt or fastening element 90 , i.e., a bolt or fastening element 90 acting on both of the main carriers 50 .
- the two main carriers 50 resting on a column 66 define two gaps 92 which are disposed directly opposite one another on opposite sides of the path P of the strand 28 .
- the main carriers 50 have outer sides 94 which face away from the path P, and each of the gaps 92 has an open end at the outer sides 94 of the respective main carriers 50 .
- the gaps 92 which are located above and centered with reference to the respective columns 66 , extend inward from the outer sides 94 to locations overlying the plates 70 inside the columns 66 .
- the widths of the gaps 92 are slightly larger than the diameters of the bolts 90 , and the bolts 90 extend through the gaps 92 and pass through the plates 74 fixed to the tops of the columns 66 .
- FIG. 5 which further shows that the bolts 90 have heads 90 a disposed above the main carriers 50 .
- the ends of the bolts 90 remote from the heads 90 a are located in the spaces between the plates 74 on the tops of the columns 66 and the plates 70 inside the columns 66 . Nuts 96 are screwed onto these ends of the bolts 90 .
- each bolt 90 functions to secure the two main carriers 50 resting on a column 66 to the respective column 66 .
- each of the plates 74 fixed to the tops of the columns 66 have outer edges 100 which face away from the main carriers 50 .
- Each of the plates 74 is provided with a slot or cutout 102 which is in alignment with, and can have the same width as, the respective gap 92 .
- the slots 102 extend inward from the respective outer edges 100 and terminate at the same locations as the gaps 92 , that is, at locations overlying the plates 70 inside the columns 66 .
- the wall of each column 66 is formed with a non-illustrated opening which is in register with the respective slot 102 and extends downward from the slot 102 to the level of the plate 70 inside the respective column 66 .
- the nut 98 is screwed onto the respective bolt 90 followed by the nut 96 .
- the distance between the nuts 96 , 98 is adjusted so that it exceeds the distance between the bottom surface of the respective plate 74 and the top surfaces of the respective main carriers 50 .
- the bolt 90 is then inserted in the respective slot 102 and moved inward through the aligned gap 92 and the non-illustrated opening in the column 66 so that the nut 96 enters the space between the plate 74 on top of the column 66 and the plate 70 inside the column 66 .
- the nut 98 is tightened.
- a guide plate 104 for the strand 28 is mounted on each of the columns 66 .
- the guide plates 104 face the path P of the strand 28 and prevent excessive sideways shifting of the latter.
- two additional guide plates 106 are fixed to each of the columns 66 . While the guide plates 104 for the strand 28 project from the respective columns 66 at right angles to the path P of the strand 28 , the additional guide plates 106 project from the respective columns 66 parallel to the path P. Two additional guide plates 106 are mounted on each column 66 , and one of the additional guide plates 106 extends upstream of the path P from the column 66 whereas the second of the additional guide plates 106 extends downstream of the path P.
- Each of the auxiliary carriers 52 is located between four of the columns 66 and, hence, between four of the additional guide plates 106 .
- the main function of the additional guide plates 106 is to guide the auxiliary carriers 52 and the upper rollers 18 a as these move towards and away from the lower rollers 18 b .
- each of the auxiliary carriers 52 is equipped with four guide members 108 , and each guide member 108 includes a pair of wear plates which embrace a respective additional guide plate 106 .
- FIG. 2 shows that each of the additional guide plates 106 has a relatively narrow upper portion 106 a , a wider lower portion 106 b and a portion 106 c of variable width between the upper portion 106 a and the lower portion 106 b .
- the auxiliary carriers 52 and upper rollers 18 a move along the upper portions 106 a while the lower modules 32 containing the lower rollers 18 b sit at the levels of the lower portions 106 b.
- Each of the lower modules 32 is located between four of the columns 66 and, therefore, between the lower portions 106 b of four of the additional guide plates 106 .
- Each of the lower modules 32 is equipped with four extensions 110 in the form of plates (only two of the extensions 110 are visible for each lower module 32 ), and each extension 110 projects towards and overlaps a respective lower portion 106 b .
- the extensions 110 lie against the lower portions 106 b of the additional guide plates 106 and are fixed to the lower portions 106 b by bolts or fastening elements 112 . This arrangement enables stiffness to be increased.
- Each of the rolling stands 18 can be withdrawn from the apparatus 10 and mounted in the apparatus 10 independently of the other rolling stands 18 , that is, without moving the other rolling stands 18 .
- the bolts 90 and the bolts 76 holding the respective main carrier 50 on the respective columns 66 are removed.
- the upper module 30 of the rolling stand 18 is then lifted off the columns 66 .
- the bolts 112 connecting the lower module 32 of the respective rolling stand 18 to such columns 66 are likewise removed, and the lower module 32 is thereupon lifted from the bottom frame 34 . It is possible to tie a lower module 32 to the respective upper module 30 by way of straps or the like so that the lower module 32 can be lifted from the apparatus 10 together with the upper module 30 .
- the apparatus 10 is shown as having six rolling stands 18 , the number of rolling stands 18 may be smaller or larger than six. It is preferred for the apparatus 10 to have 3 to 9 rolling stands 18 .
- hollow or tubular columns 66 makes it possible to circulate a cooling fluid through the columns 66 . Furthermore, as opposed to columns of solid cross section, the tubular columns 66 permit the weight of the apparatus 10 to be reduced.
- the stiffness of the rolling stands 18 may be increased.
- the pipes 72 a , 72 b connecting two opposite columns 66 to one another allow the stiffness to be enhanced while, at the same time, providing a means for supplying a cooling fluid to and/or removing a cooling fluid from the columns 66 .
- a further increase in stiffness can be achieved by the attachment of the lower modules 32 to the columns 66 via the extensions 110 and the bolts 112 .
- the bolts 90 make it possible to simplify mounting of the main carriers 50 on and removal of the main carriers 50 from the columns 66 .
- each bolt 90 holds two neighboring main carriers 50 on a column 66 , the number of bolts which must be tightened or removed to assemble or disassemble the rolling stands 18 can be reduced.
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Abstract
Description
- 1. Field of the Invention
- The invention relates to continuous casting.
- 2. Description of the Prior Art
- Apparatus for the continuous casting of steel typically include a mold having a generally vertical casting passage. The casting passage is open at the top and bottom, and a stream of molten steel is directed into the top of the passage. The molten steel partially solidifies in the mold to form a continuously cast strand consisting of a solidified outer shell and a molten core. The strand is withdrawn from the bottom of the casting passage and conveyed along a path which curves to the horizontal. As the strand travels along such path, the strand is cooled and the molten core solidifies progressively. Once the strand has solidified throughout the cross section thereof, the strand is cut into sections.
- It has been found that the internal quality of a fully solidified strand is improved when the strand undergoes a small amount of rolling before solidification is complete. This rolling, which is referred to as soft reduction, is carried out while the cross section of the strand has a solid fraction of 20 percent to 85 percent.
- The term “solid fraction” arises from the fact that steel generally does not undergo a direct transformation from liquid to solid when cooled. Instead, there is a temperature range between liquidus and solidus where the steel is in a so-called “mushy” state. In this state, the steel is neither completely solid nor completely liquid but is a mixture of solid and liquid. The proportion of solid in the mixture is indicated by a percentage referred to as the “solid fraction”.
- Rolling of the strand during soft reduction takes place in a series of rolling stands or assemblies which are located next to one another along the path of the strand. Each of the rolling stands includes an upper module containing a movable roller, and a hydraulic unit for moving the roller towards and away from a second roller in a lower module. The upper module of each rolling stand is supported on four columns of its own, and two of the columns face one another across the path of the strand at a first location of the path while two face one another across the path of the strand at a second location of the path.
- The rollers of neighboring rolling stands are spaced from each other by a relatively large distance which typically is at least 1 meter. Although it is desirable for the rollers to be closer to one another, the adjoining columns of two neighboring rolling stands prevent the distance between the stands from being reduced.
- The solidification rate of a continuously cast strand can vary significantly depending upon a number of factors such as the type of steel being cast, the degree of superheat and the casting speed. When the distance between neighboring rolling stands is large, this can result in a situation where only one of the rolling stands, or possibly none of the rolling stands, acts on the portion of the strand having a solid fraction of 20 percent to 85 percent, i.e., on the portion of the strand which is suitable for soft reduction. In this case, little or none of the benefit of soft reduction is achieved.
- It is an object of the invention to reduce the spacing between reduction devices.
- The preceding object, as well as others which will become apparent as the description proceeds, are achieved by the invention.
- One aspect of the invention resides in a continuous casting apparatus. The apparatus comprises a mold designed to form a continuously cast strand from molten material, at least one support and at least two assemblies operable substantially independently of one another to effect a dimensional reduction of a strand formed in the mold. Each of the assemblies includes a supporting part which rests on the support, and each of the assemblies further includes another part which extends downward from the respective supporting part and comprises at least one reducing member for effecting a dimensional reduction of a strand formed in the mold. By way of example, the support can constitute or resemble a column while the reduction assemblies can constitute rolling stands.
- In accordance with the invention, two assemblies for effecting a dimensional reduction of a continuously cast strand share a support thereby allowing a second support between the assemblies to be eliminated. This enables the assemblies to be placed closer to one another than before.
- Another aspect of the invention resides in a method of operating a continuous casting apparatus. The method comprises the steps of providing a mold designed to form a continuously cast strand from molten material, installing the mold at a casting location and providing two assemblies operable substantially independently of one another to effect a dimensional reduction of a continuously cast strand. The method further comprises the step of placing the assemblies on a support at a reduction location spaced from the casting location so that a supporting part of each assembly rests on the support and a second part of each assembly extends downward from the respective supporting part. The second part of each assembly includes a reducing member for effecting a dimensional reduction of a strand formed in the mold. Each of the assemblies is preferably placed on the support substantially independently of the other assembly.
- The method can additionally comprise the step of fixing the assemblies to the support with a fixing element which urges both of the assemblies towards the support.
- The method may also include the steps of forming a partially solidified continuously cast strand in the mold, and subjecting the partially solidified strand to a dimensional reduction in at least one of the assemblies. The reducing member of this assembly can comprise a roll and the subjecting step can then involve rolling the partially solidified strand.
- At least one of the reducing assemblies can include an additional reducing member which is arranged to cooperate with the other reducing member of such assembly to effect a dimensional reduction of a strand formed in said mold. The method can here comprise the step of anchoring the additional reducing member to the support for the reducing assemblies.
- The method may further comprise the steps of providing a hollow anchoring member having an upper side and a lower side separated by a gap, passing the support through the upper side, and resting the support on the lower side.
- The method may further comprise the steps of providing an additional support, bridging the two supports with a pipe, and introducing a cooling fluid into the supports from the pipe.
- Additional features and advantages of the invention will be forthcoming from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings.
- FIG. 1 is a schematic sectional side view of a continuous casting apparatus in accordance with the invention.
- FIG. 2 is a side view showing certain details of rolling stands constituting part of the apparatus of FIG. 1.
- FIG. 3 is a sectional view in the direction of the arrows III-III of FIG. 2.
- FIG. 4 is a fragmentary sectional view in the direction of the arrows IV-IV of FIG. 2 but without counterweights and drive units forming part of the rolling stands.
- FIG. 5 is a fragmentary sectional view in the direction of the arrows V-V of FIG. 4.
- FIG. 6 is a fragmentary sectional view in the direction of the arrows VI-VI of FIG. 4.
- Referring to FIG. 1, the
numeral 10 generally identifies a continuous caster or casting apparatus according to the invention. Thecaster 10 is of the type typically used to cast steel, and this type of apparatus is generally designed to produce billets, blooms or slabs which are square or rectangular products differing primarily in cross-sectional size. Thecaster 10 is assumed to be capable of casting steel into multiple product types and product sizes, and the products generated by thecaster 10 can be converted into special bar quality and/or rails. Examples of products which can be made by thecaster 10 are blooms, billets and rounds. - The
caster 10 includes a cooled, generally verticalcontinuous casting mold 12 having a generallyvertical casting passage 14. Thecasting passage 14, which is here curved but could also be straight, has an openupper end 14 a and an open lower end 14 b. Theupper end 14 a constitutes an inlet end of thecasting passage 14 while the lower end 14 b constitutes an outlet end of thecasting passage 14. - Below the
mold 12 is acurved roller apron 16 which includes a row of rollers 16 a and another row ofrollers 16 b situated opposite the roller row 16 a. At the end of theroller apron 16 remote from themold 12 is a series of rolling stands orreduction assemblies 18 each of which comprises an upper roller or reducingmember 18 a and a lower roller or reducingmember 18 b. Thelower rollers 18 b are mounted for rotation at fixed locations while theupper rollers 18 a are movable towards and away from the respectivelower rollers 18 b by individualhydraulic units 20 forming part of the rolling stands 18. The rolling stands 18 are designed to subject thestrand 18 to soft reduction. - Following the rolling stands18, as considered in a direction away from the
mold 12, is a pinch roll andfinal straightening mechanism 22 with an upper roller 22 a and twolower rollers 22 b and 22 c. Thelower rollers 22 b,22 c are mounted for rotation at fixed locations whereas the upper roller 22 a, which is situated opposite the lower roller 22 c, is movable towards and away from the roller 22 c by a hydraulic unit not shown in FIG. 1. The rolling stands 18, together with the pinch roll andfinal straightening mechanism 22, constitute a straightener/withdrawal unit with soft reduction capability. The straightener/withdrawal unit - The pinch roll and
final straightening mechanism 22 can be eliminated. Thus, it is possible to design thecaster 10 such that the rolling stands 18 carry out withdrawal and straightening as well as soft reduction. - The
mold 12,roller apron 16, rolling stands 18, pinch roll andfinal straightening mechanism 22 and runout table 24 define a path, indicated by the arrow P, which curves from themold 12 to the pinch roll andfinal straightening mechanism 22 and then becomes straight and horizontal. The portion of the path P from themold 12 to the rolling stands 18 constitutes a segment of a circle, and this portion of the path P has an inner radius which is tangent to the roller apron rollers 16 a and an outer radius which is tangent to theroller apron rollers 16 b. - At the start of a casting operation, the outlet end14 b of the
casting passage 14 is closed by a non-illustrated dummy bar which is gripped by the pinch roll andfinal straightening mechanism 22. A stream orjet 26 of molten material is then teemed into the inlet end 14 a of thecasting passage 14. The molten material, which is here assumed to be steel, solidifies partially in thecasting passage 14 to establish a connection with the dummy bar and to form a continuously caststrand 28 which is releasably attached to the dummy bar. Thestrand 28 comprises a shell orskin 28 a of solidified steel and a core 28 b of molten steel confined within theshell 28 a. - The dummy bar is withdrawn from the
casting passage 14 along the path P by the pinch roll andfinal straightening mechanism 22. The dummy bar, which pulls thestrand 28 behind it, is disconnected from thestrand 28 and stored once thestrand 28 reaches the pinch roll andfinal straightening mechanism 22. Thereafter, the pinch roll andfinal straightening mechanism 22 acts directly on thestrand 28 to convey the latter along the path P. - The
strand 28 is conveyed continuously along the path P at a predetermined rate commonly referred to as the casting speed. The molten steel from the ladle and tundish is teemed continuously into thecasting passage 14 at a rate matched to the casting speed. - As the
strand 28 travels through theroller apron 16, thestrand 28 is cooled by non-illustrated water sprays. Consequently, thestrand 28 solidifies progressively along theroller apron 16 with theshell 28 a increasing in thickness and the core 28 b decreasing in thickness. Upon reaching the rolling stands 18, thestrand 28 is subjected to a soft reduction which can involve a reduction of 1 mm to 5 mm in the thickness of thestrand 28 in each rollingstand 18. The cross section of thestrand 28 preferably has a solid fraction of at least 20 percent and, depending upon the operator of thecaster 10, no more than 70 percent or 85 percent when undergoing soft reduction. - After leaving the rolling stands18, the
strand 28 passes through the pinch roll andfinal straightening mechanism 22 which straightens thestrand 28. Thestrand 28, which has now solidified throughout, then moves onto the runout table 24 where thestrand 28 is cut into sections by non-illustrated traveling cutting torches. - The soft reduction of the
strand 28 improves the quality of thestrand 28. For example, it has been found that soft reduction decreases segregation and porosity. - Referring to FIGS. 2 and 3, each of the rolling stands18 includes an
upper module 30 containing the respectiveupper roller 18 a and alower module 32 containing the respectivelower roller 18 b. Thelower modules 32 are fixed to abottom frame 34 which sits on asubbase 36 and is connected thereto by clampingbolts 38. Thesubbase 36, in turn, sits on a foundation 40. Thesubbase 36 is provided with anchoringelements 42 which penetrate the foundation 40 and help to prevent shifting of thesubbase 36 relative to the same.Foundation bolts 44 serve to secure thesubbase 36 to the foundation 40. - In addition to the respective
upper roller 18 a, eachupper module 30 further contains a counterweight 46, adrive unit 48 for rotating theupper roller 18 a, and the respectivehydraulic unit 20 for moving theupper roller 18 a towards and away from thelower roller 18 b. Everydrive unit 48 comprises a motor 48 a and agear box 48 b. - Each
upper module 30 includes a main carrier or supportingpart 50 and anauxiliary carrier 52 below themain carrier 50. The counterweight 46 and thedrive unit 48 are fixed to opposite sides of theauxiliary carrier 52 while theupper roller 18 a is suspended therefrom. Themain carrier 50 andauxiliary carrier 52 can be in the form of box beams. - Considering FIG. 4 in conjunction with FIGS. 2 and 3, each
upper module 30 is provided with a verticalcentral passage 54. Thehydraulic unit 20 of eachupper module 30 comprises acylinder 56 and a cylinder rod 58 which projects from thecylinder 56. Thecylinder 56 of eachhydraulic unit 20 rests on top of the respectivemain carrier 50 and is secured to thecarrier 50 by four threaded bolts orfastening elements 60 which screw into square nuts 62. The cylinder rod 58 of eachhydraulic unit 20 extends downward from thecylinder 56 through the respectivecentral passage 54, and the end of the cylinder rod 58 remote from thecylinder 56 is threaded. - A
coupling device 64 is fixed to the top of eachauxiliary carrier 52, and eachcoupling device 64 is formed with a blind bore which is aligned with the respectivecentral passage 54. The blind bore is threaded, and the threaded end of the cylinder rod 58 of the respectivehydraulic unit 20 is screwed into the blind bore. Consequently, as the cylinder rod 58 of anupper module 30 is extended, the correspondingauxiliary carrier 52 andupper roller 18 a move away from the respectivemain carrier 50 and towards the respectivelower roller 18 b. Conversely, as the cylinder rod 58 is retracted, the correspondingauxiliary carrier 52 andupper roller 18 a move towards the respectivemain carrier 50 and away from the respectivelower roller 18 b. - In conventional continuous casting apparatus, the upper module of each rolling stand is supported on four columns of its own. Two of the columns face one another across the path of the strand at a first location of the path and two face one another across the path of the strand at a second location of the path. The rollers of neighboring rolling stands are spaced from each other by a relatively large distance, which is typically at least 1 meter, and the adjoining columns of two neighboring rolling stands prevent the distance between the rolling stands from being reduced.
- .With widely spaced rolling stands, there is a good likelihood that little or none of the advantage of soft reduction will be achieved. The reason is that the solidification rate of a continuously cast strand can vary significantly depending upon a number of factors such as the type of steel being cast, the degree of superheat and the casting speed. Thus, when the distance between neighboring rolling stands is large, this variation in solidification rate can result in a situation where only one of the rolling stands, or possibly none of the rolling stands, acts on the portion of the strand having a solid fraction of 20 percent to 85 percent, i.e., on the portion of the strand which is suitable for soft reduction.
- One object of the invention is to position the rolling stands18 closer to one another. To this end, the
upper modules 30 of two neighboring rolling stands 18 rest on and are fixed to a common pair of columns or carryingmembers 66. - The
columns 66 are mounted on thebottom frame 34 of thecontinuous casting apparatus 10. As seen in FIG. 3, thebottom frame 34 includes parallel box beams or anchoringmembers 68 each having twoside plates box beams 68 further has an upper plate 68 c and alower plate 68 d which are likewise separated by a gap and bridge therespective side plates side plates 68 a of thebox beams 68 face the path P of thestrand 28. Thecolumns 66 pass through the upper plates 68 c and rest on thelower plates 68 d, and thecolumns 66 are secured to the upper plates 68 c and thelower plates 68 d, e.g., by welding. - As illustrated in FIG. 5, the
columns 66 are hollow to permit circulation of cooling water therethrough and can be in the form of circular tubing. Aplate 70 is located inside each column 66 a short distance below the top of therespective column 66 and closes thecolumn 66. Theplates 70 prevent the cooling water flowing in thecolumns 66 from escaping through the tops of thecolumns 66. - The
columns 66 are arranged in pairs with thecolumns 66 of each pair being situated directly opposite one another on opposite sides of the path P of thestrand 28. As shown in FIG. 3, thecolumns 66 of each pair are connected to each other by a lower pipe 72 a disposed near the bottoms of thecolumns 66 and by an upper pipe 72 b disposed near the tops of thecolumns 66. The lower pipes 72 a are located between thebox beams 68 of thebottom frame 34 and connect to thecolumns 66 through openings in theside plates 68 a. The pipes 72 a,72 b function to distribute a cooling fluid, typically water, to thecolumns 66 and also to stiffen thecolumns 66. - As seen in FIGS.2-6, a
plate 74 is fixed to the top of eachcolumn 66, e.g., by welding, and themain carriers 50 of theupper modules 30 rest on theplates 74. Twocolumns 66 disposed directly opposite one another on opposite sides of the path P of thestrand 28 are situated between neighboring ones of the rolling stands 18, and theupper modules 30 of neighboring rolling stands 18 are both carried by the twocolumns 66 between such rolling stands 18. In other words, theupper modules 30 of neighboring rolling stands 18 share thecolumns 66 located between these rolling stands 18. - FIG. 6 shows the
main carrier 50 of anupper module 30 resting on twocolumns 66 located directly opposite each other on opposite sides of the path P of thestrand 28. As illustrated in FIG. 6, theplate 74 at the top of eachcolumn 66 has a portion 74 a which projects laterally from therespective column 66 towards the other of the twocolumns 66. Themain carrier 50 is fixed to each of the twocolumns 66 by a bolt orfastening element 76 which passes through themain carrier 50 and through the projecting portion 74 a of therespective plate 74. Each of thebolts 76 has a head 76 a which bears against the upper side of the respectivemain carrier 50, and each of thebolts 76 further has a threaded end which projects from therespective plate 74. Anut 78 is screwed onto the threaded end of each of thebolts 76. - Referring to FIG. 4 together with FIG. 6, each of the
main carriers 50 is provided with twoparallel pipe sections 80 a and two parallel pipe sections 80 b. Thepipe sections 80 a are disposed side-by-side as are the pipe sections 80 b. Thepipe sections 80 a,80 b run in the direction of the path P of thestrand 28, and thepipe sections 80 a in eachmain carrier 50 are located upstream of thecentral passage 54 for the respectivehydraulic unit 20 while the pipe sections 80 b are located downstream of thecentral passage 54. In each of themain carriers 50, the axis of eachpipe section 80 a lies on a line with the axis of one of the pipe sections 80 b. - Each of the
pipe sections 80 a,80 b has anopen end 82 to allow access to the interior of therespective pipe section 80 a,80 b. The square nuts 62, which screw onto thebolts 60 holding thehydraulic units 20 on themain carriers 50, are located inside thepipe sections 80 a,80 b. - As seen in FIG. 4, cooling fluid is supplied to each of the
main carriers 50 by way of aninlet pipe 84. After circulating through the respectivemain carrier 50, the cooling fluid flows out of themain carrier 50 via an outlet pipe 86. FIG. 6 shows that flowpassages 88 for the cooling fluid are machined into thepipe sections 80 a,80 b. - As outlined earlier, each of the two
main carriers 50 resting on acolumn 66 is secured tosuch column 66 by adiscrete bolt 76. FIGS. 2, 4 and 5 illustrate that, in addition, the twomain carriers 50 resting on acolumn 66 are secured tosuch column 66 by a common threaded bolt orfastening element 90, i.e., a bolt orfastening element 90 acting on both of themain carriers 50. - Considering FIGS. 4 and 5, the two
main carriers 50 resting on acolumn 66 define two gaps 92 which are disposed directly opposite one another on opposite sides of the path P of thestrand 28. Themain carriers 50 haveouter sides 94 which face away from the path P, and each of the gaps 92 has an open end at theouter sides 94 of the respectivemain carriers 50. The gaps 92, which are located above and centered with reference to therespective columns 66, extend inward from theouter sides 94 to locations overlying theplates 70 inside thecolumns 66. - The widths of the gaps92 are slightly larger than the diameters of the
bolts 90, and thebolts 90 extend through the gaps 92 and pass through theplates 74 fixed to the tops of thecolumns 66. This is shown in FIG. 5 which further shows that thebolts 90 have heads 90 a disposed above themain carriers 50. The ends of thebolts 90 remote from the heads 90 a are located in the spaces between theplates 74 on the tops of thecolumns 66 and theplates 70 inside thecolumns 66.Nuts 96 are screwed onto these ends of thebolts 90. - With reference still to FIG. 5, the heads90 a of the
bolts 90 bear againstnuts 98 screwed onto thebolts 90. Each of the nuts 98, in turn, bears against the tops of the twomain carriers 50 defining the gap 92 which receives therespective bolt 90. Hence, eachbolt 90 functions to secure the twomain carriers 50 resting on acolumn 66 to therespective column 66. - Turning to FIG. 4 again, the
plates 74 fixed to the tops of thecolumns 66 haveouter edges 100 which face away from themain carriers 50. Each of theplates 74 is provided with a slot orcutout 102 which is in alignment with, and can have the same width as, the respective gap 92. Theslots 102 extend inward from the respectiveouter edges 100 and terminate at the same locations as the gaps 92, that is, at locations overlying theplates 70 inside thecolumns 66. The wall of eachcolumn 66 is formed with a non-illustrated opening which is in register with therespective slot 102 and extends downward from theslot 102 to the level of theplate 70 inside therespective column 66. - To fix two neighboring
main carriers 50 to acolumn 66, thenut 98 is screwed onto therespective bolt 90 followed by thenut 96. With reference to FIG. 5 once more, the distance between the nuts 96,98 is adjusted so that it exceeds the distance between the bottom surface of therespective plate 74 and the top surfaces of the respectivemain carriers 50. Thebolt 90 is then inserted in therespective slot 102 and moved inward through the aligned gap 92 and the non-illustrated opening in thecolumn 66 so that thenut 96 enters the space between theplate 74 on top of thecolumn 66 and theplate 70 inside thecolumn 66. Once thebolt 90 has arrived at its desired position, thenut 98 is tightened. - As illustrated in FIG. 3, a
guide plate 104 for thestrand 28 is mounted on each of thecolumns 66. Theguide plates 104 face the path P of thestrand 28 and prevent excessive sideways shifting of the latter. - Referring to FIG. 2 in conjunction with FIG. 3, two
additional guide plates 106 are fixed to each of thecolumns 66. While theguide plates 104 for thestrand 28 project from therespective columns 66 at right angles to the path P of thestrand 28, theadditional guide plates 106 project from therespective columns 66 parallel to the path P. Twoadditional guide plates 106 are mounted on eachcolumn 66, and one of theadditional guide plates 106 extends upstream of the path P from thecolumn 66 whereas the second of theadditional guide plates 106 extends downstream of the path P. - Each of the
auxiliary carriers 52 is located between four of thecolumns 66 and, hence, between four of theadditional guide plates 106. The main function of theadditional guide plates 106 is to guide theauxiliary carriers 52 and theupper rollers 18 a as these move towards and away from thelower rollers 18 b. To this end, each of theauxiliary carriers 52 is equipped with fourguide members 108, and eachguide member 108 includes a pair of wear plates which embrace a respectiveadditional guide plate 106. - FIG. 2 shows that each of the
additional guide plates 106 has a relatively narrow upper portion 106 a, a wider lower portion 106 b and a portion 106 c of variable width between the upper portion 106 a and the lower portion 106 b. Theauxiliary carriers 52 andupper rollers 18 a move along the upper portions 106 a while thelower modules 32 containing thelower rollers 18 b sit at the levels of the lower portions 106 b. - Each of the
lower modules 32 is located between four of thecolumns 66 and, therefore, between the lower portions 106 b of four of theadditional guide plates 106. Each of thelower modules 32 is equipped with fourextensions 110 in the form of plates (only two of theextensions 110 are visible for each lower module 32), and eachextension 110 projects towards and overlaps a respective lower portion 106 b. Theextensions 110 lie against the lower portions 106 b of theadditional guide plates 106 and are fixed to the lower portions 106 b by bolts or fastening elements 112. This arrangement enables stiffness to be increased. - Each of the rolling stands18 can be withdrawn from the
apparatus 10 and mounted in theapparatus 10 independently of the other rolling stands 18, that is, without moving the other rolling stands 18. To withdraw a rollingstand 18 from theapparatus 10, thebolts 90 and thebolts 76 holding the respectivemain carrier 50 on therespective columns 66 are removed. Theupper module 30 of the rollingstand 18 is then lifted off thecolumns 66. The bolts 112 connecting thelower module 32 of the respective rolling stand 18 tosuch columns 66 are likewise removed, and thelower module 32 is thereupon lifted from thebottom frame 34. It is possible to tie alower module 32 to the respectiveupper module 30 by way of straps or the like so that thelower module 32 can be lifted from theapparatus 10 together with theupper module 30. - When a rolling
stand 18 is to be mounted in theapparatus 10, the respectivelower module 32 is lowered onto thebottom frame 34 and attached to therespective columns 66 by the bolts 112. Subsequently, theupper module 30 of the rollingstand 18 is lowered into theapparatus 10 so that the respectivemain carrier 50 comes to rest on thecolumns 66. Once themain carrier 50 has been properly positioned on thecolumns 66, themain carrier 50 is secured to thecolumns 66 via thebolts - It is possible to tie a
lower module 32 to the respectiveupper module 30 by way of straps or the like so that thelower module 32 can be lifted from or placed in theapparatus 10 together with theupper module 30. - Although the
apparatus 10 is shown as having six rolling stands 18, the number of rolling stands 18 may be smaller or larger than six. It is preferred for theapparatus 10 to have 3 to 9 rolling stands 18. - By mounting the
upper modules 30 of two neighboring rolling stands 18 on a common pair ofcolumns 66, it becomes possible to reduce the distance between the rolling stands 18 from 1 meter or more to 800 millimeters or less. This decreases the likelihood that none of the rolling stands 18 will act on the portion of thestrand 28 which is suitable for soft reduction, i.e., the portion of thestrand 28 having a solid fraction of 20 percent to 85 percent. Moreover, if the nature of thestrand 28 is such that a certain number of rolling stands of a prior art apparatus would act on the portion of thestrand 28 suitable for soft reduction, the smaller rolling stand spacing in theapparatus 10 of the invention may allow a greater number of the rolling stands 18 to act on such portion of thestrand 28. - The use of hollow or
tubular columns 66 makes it possible to circulate a cooling fluid through thecolumns 66. Furthermore, as opposed to columns of solid cross section, thetubular columns 66 permit the weight of theapparatus 10 to be reduced. - By employing
box beams 68 for thebottom frame 34 and passing thecolumns 66 through the upper plates 68 c of thebox beams 68 so that thecolumns 66 rest on thelower plates 68 d, the stiffness of the rolling stands 18 may be increased. The pipes 72 a,72 b connecting twoopposite columns 66 to one another allow the stiffness to be enhanced while, at the same time, providing a means for supplying a cooling fluid to and/or removing a cooling fluid from thecolumns 66. A further increase in stiffness can be achieved by the attachment of thelower modules 32 to thecolumns 66 via theextensions 110 and the bolts 112. - The
bolts 90 make it possible to simplify mounting of themain carriers 50 on and removal of themain carriers 50 from thecolumns 66. Thus, since eachbolt 90 holds two neighboringmain carriers 50 on acolumn 66, the number of bolts which must be tightened or removed to assemble or disassemble the rolling stands 18 can be reduced. - Various modifications are possible within the meaning and range of equivalence of the appended claims.
Claims (21)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US09/884,710 US20020189783A1 (en) | 2001-06-19 | 2001-06-19 | Continuous casting apparatus with soft reduction |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/884,710 US20020189783A1 (en) | 2001-06-19 | 2001-06-19 | Continuous casting apparatus with soft reduction |
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US20020189783A1 true US20020189783A1 (en) | 2002-12-19 |
Family
ID=25385208
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US09/884,710 Abandoned US20020189783A1 (en) | 2001-06-19 | 2001-06-19 | Continuous casting apparatus with soft reduction |
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US (1) | US20020189783A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010158719A (en) * | 2008-12-10 | 2010-07-22 | Jfe Steel Corp | Method for manufacturing continuously cast slab |
CN102000789A (en) * | 2010-12-08 | 2011-04-06 | 中冶连铸技术工程股份有限公司 | Continuous casting machine and small square billet soft reduction device |
CN105880496A (en) * | 2016-04-29 | 2016-08-24 | 马鞍山尚元冶金科技有限公司 | Digitalized crystallizer-free beam blank continuous caster |
CN110871265A (en) * | 2018-08-31 | 2020-03-10 | 宝山钢铁股份有限公司 | Soft reduction method for combination of flat roll and convex roll of continuous casting bloom |
KR20200036551A (en) * | 2018-09-28 | 2020-04-07 | 주식회사 포스코 | dummy and casting method using the same |
-
2001
- 2001-06-19 US US09/884,710 patent/US20020189783A1/en not_active Abandoned
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010158719A (en) * | 2008-12-10 | 2010-07-22 | Jfe Steel Corp | Method for manufacturing continuously cast slab |
CN102000789A (en) * | 2010-12-08 | 2011-04-06 | 中冶连铸技术工程股份有限公司 | Continuous casting machine and small square billet soft reduction device |
CN105880496A (en) * | 2016-04-29 | 2016-08-24 | 马鞍山尚元冶金科技有限公司 | Digitalized crystallizer-free beam blank continuous caster |
CN110871265A (en) * | 2018-08-31 | 2020-03-10 | 宝山钢铁股份有限公司 | Soft reduction method for combination of flat roll and convex roll of continuous casting bloom |
KR20200036551A (en) * | 2018-09-28 | 2020-04-07 | 주식회사 포스코 | dummy and casting method using the same |
KR102156714B1 (en) * | 2018-09-28 | 2020-09-16 | 주식회사 포스코 | dummy and casting method using the same |
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