WO1999012675A1 - Continuous casting of metal slabs - Google Patents

Continuous casting of metal slabs Download PDF

Info

Publication number
WO1999012675A1
WO1999012675A1 PCT/GB1997/002374 GB9702374W WO9912675A1 WO 1999012675 A1 WO1999012675 A1 WO 1999012675A1 GB 9702374 W GB9702374 W GB 9702374W WO 9912675 A1 WO9912675 A1 WO 9912675A1
Authority
WO
WIPO (PCT)
Prior art keywords
faces
pair
strand
mould
flat
Prior art date
Application number
PCT/GB1997/002374
Other languages
French (fr)
Inventor
John Huddart Watters
Original Assignee
Davy Distington Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Davy Distington Limited filed Critical Davy Distington Limited
Priority to AU41258/97A priority Critical patent/AU4125897A/en
Priority to PCT/GB1997/002374 priority patent/WO1999012675A1/en
Publication of WO1999012675A1 publication Critical patent/WO1999012675A1/en

Links

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
    • B22D11/009—Continuous casting of metals, i.e. casting in indefinite lengths of work of special cross-section, e.g. I-beams, U-profiles
    • 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
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/0406—Moulds with special profile
    • 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

  • This invention relates to a method of producing a metal slab and to a continuous casting
  • a slight taper is usually introduced in the direction of casting to counteract steel shrinkage during solidification. If the process is not optimised then cast slabs can suffer from defects of guttering where the slab thickness is reduced immediately adjacent to the slab corners. Additionally slab edge bulging is a frequent defect often leading to internal cracking of the solidified structure.
  • the slab contains a liquid core during reduction and the solidified shell of the slab can be relatively thin.
  • a method of producing a metal slab comprises continuously casting a metal strand in a continuous casting mould, said strand having a first pair of faces which are flat and are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form, and before the strand is fully solidified, applying
  • each of the faces of the second pair of faces is convenient for each of the faces of the second pair of faces to have its portion of
  • the concave portions and the chamfered portions of the faces of the second pair distort outwardly so that the second pair of faces are substantially flat, mutually parallel and are at 90° to the first pair of faces.
  • a continuous casting mould has a mould passage which when the mould is in use produces a metal strand having a first pair of faces which are flat and are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form.
  • the mould passage is shaped so that each of the faces of the second pair has
  • Figure 1 is a plan view of a continuous casting mould
  • Figure 2 is a perspective view of part of the mould of Figure 1
  • Figures 3a - 3c show successive changes in the cross section of a metal slab produced by
  • a mould (Fig 1) for the continuous casting of steel slabs comprises four cooled copper plates forming a cavity for the primary shell solidification.
  • Two broad face copper plates (1) are clamped against two end face copper plates (2) to form a cavity in which the initial slab solidified shell shape is formed prior to withdrawal continuously from the mould.
  • the mould will be of a
  • Slab width change can be carried out during casting by moving the end plates (2) by drives (3) within the confines of the broad face plates (1).
  • the copper mould end plates (2) have a profiled shape consisting of triangular portions (4) which form an edge chamfer with the broad face plates, and a convex curved face (5) having a radius of curvature proportional to the slab thickness, both of which will present a cooling surface to the liquid metal and provide further shell support and cooling in the mould.
  • edge chamfers will continue down the length of the mould end plate whereas the end face curvature may vary down the length.
  • Figure 2 shows the chamfered/profiled copper mould end plate (2).
  • the plate will be cooled by water which is passed along either slots or holes (6) in the copper back face.
  • the profiled shape of the end plate may be either as machined copper or coated for wear
  • mould end plate edge chamfers (4) which produce chamfered corners on the newly formed slab shell in the continuous slab casting mould and the mould end plate curved face (5) will give a concave shape to the cast slab edge which will eliminate the need for below mould
  • the shell comprises a shell (7) surrounding a non-solidified core (8).
  • the shell has a
  • the mould end plate curved face (5) gives a concave shape to the cast slab edge as it leaves the mould which will reduce internal corner cracks normally associated with slab edge bulging, reduce gutter on the slab broad faces giving improved slab quality during finish rolling
  • the mould end plate curved face (5) together with chamfers (4) will give a slab edge profile such that during reduction of thickness with a liquid core immediately after the mould, the slab comers will rotate thus minimising internal and external strain and limiting final convexity of

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Abstract

A method of producing a metal slab comprises continuously casting a metal strand in a continuous casting mould having two broad face plates (1) and two end plates (2), the latter being shaped so that each of one pair of faces (10) of the strand includes a portion (11) of concave form, and before the strand is fully solidified, applying rolling forces to the other pair of faces (9) to reduce the thickness of the strand to the required thickness and to cause the concave portions (11) to distort outwardly so that that pair of faces (10) becomes substantially flat and mutually parallel. Conveniently, each concave portion (11) is flanked on either side by a chamfered corner portion (12) which also distort outwardly upon the application of rolling forces to the faces (9) so that the faces (10) become substantially flat, mutually parallel and are at 90° to the other pair of faces (9).

Description

CONTINUOUS CASTING OF METAL SLABS
This invention relates to a method of producing a metal slab and to a continuous casting
mould which is used in said method.
In the continuous casting of steel slabs it is usual to cast into a water cooled mould having a generally rectangular cross section at the mould exit. Sometimes simple chamfers are added at the corners and sometimes for thinner slabs the mould cross section thickness is enlarged at mid wide side to allow better access for the refractory tube through which molten steel is introduced.
A slight taper is usually introduced in the direction of casting to counteract steel shrinkage during solidification. If the process is not optimised then cast slabs can suffer from defects of guttering where the slab thickness is reduced immediately adjacent to the slab corners. Additionally slab edge bulging is a frequent defect often leading to internal cracking of the solidified structure.
It is desirable for the fully solidified slab thickness to be reduced in order to minimise the process steps and extent of plant utilised for subsequent rolling of the slab to strip or plate product. It is however desirable to maintain a larger thickness at the mould to provide more
favourable liquid steel meniscus conditions which in turn influences the surface quality of the cast
slab. One way to reconcile these two desirable features is to reduce the thickness of the strand
below the mould but before the slab is fully solidified. In this case the slab contains a liquid core during reduction and the solidified shell of the slab can be relatively thin. Shell buckling and
consequent cracks in the solidifying structure is a significant risk in applying this type of reduction.
It is an object of the present invention to provide a method of producing a metal slab
which includes continuously casting a metal strand which produces a slab in which shell buckling
is at least reduced if not completely overcome.
According to a first aspect of the invention a method of producing a metal slab comprises continuously casting a metal strand in a continuous casting mould, said strand having a first pair of faces which are flat and are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form, and before the strand is fully solidified, applying
rolling forces to said first pair of faces to reduce the thickness of the strand to the thickness of the required slab and to cause the concave portions of the second pair of faces to distort outwardly so that the second pair of faces are substantially flat and mutually parallel.
It is convenient for each of the faces of the second pair of faces to have its portion of
concave form to be flanked on either side by a chamfered corner portion. After the application of the rolling forces to the first pair of faces, the concave portions and the chamfered portions of the faces of the second pair distort outwardly so that the second pair of faces are substantially flat, mutually parallel and are at 90° to the first pair of faces.
According to a second aspect of the present invention a continuous casting mould has a mould passage which when the mould is in use produces a metal strand having a first pair of faces which are flat and are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form.
Conveniently the mould passage is shaped so that each of the faces of the second pair has
its portion of concave form flanked on either side by a chamfered corner portion .
In order that the invention may be more readily understood it will now be described, by
way of example only, with reference to the accompanying drawings in which:
Figure 1 is a plan view of a continuous casting mould;
Figure 2 is a perspective view of part of the mould of Figure 1, and
Figures 3a - 3c show successive changes in the cross section of a metal slab produced by
the method of the invention.
A mould (Fig 1) for the continuous casting of steel slabs comprises four cooled copper plates forming a cavity for the primary shell solidification. Two broad face copper plates (1) are clamped against two end face copper plates (2) to form a cavity in which the initial slab solidified shell shape is formed prior to withdrawal continuously from the mould. The mould will be of a
length sufficient to ensure adequate shell thickness at the exit for the required slab withdrawal speed. Slab width change can be carried out during casting by moving the end plates (2) by drives (3) within the confines of the broad face plates (1).
The copper mould end plates (2) have a profiled shape consisting of triangular portions (4) which form an edge chamfer with the broad face plates, and a convex curved face (5) having a radius of curvature proportional to the slab thickness, both of which will present a cooling surface to the liquid metal and provide further shell support and cooling in the mould.
The edge chamfers will continue down the length of the mould end plate whereas the end face curvature may vary down the length.
Figure 2 shows the chamfered/profiled copper mould end plate (2). The plate will be cooled by water which is passed along either slots or holes (6) in the copper back face. The profiled shape of the end plate may be either as machined copper or coated for wear
resistance.
The mould end plate edge chamfers (4) which produce chamfered corners on the newly formed slab shell in the continuous slab casting mould and the mould end plate curved face (5) will give a concave shape to the cast slab edge which will eliminate the need for below mould
edge support.
The cross-section of the strand as it emerges from the mould is shown at Figure 3a. It
can be seen that it comprises a shell (7) surrounding a non-solidified core (8). The shell has a
first pair of flat substantially parallel faces (9) and a second pair of faces (10) each of which
includes a concave portion (11) flanked by a chamfered corner (12) at each side where it adjoins the faces (9).
The mould end plate curved face (5) gives a concave shape to the cast slab edge as it leaves the mould which will reduce internal corner cracks normally associated with slab edge bulging, reduce gutter on the slab broad faces giving improved slab quality during finish rolling
while also retaining the ability to slab width change during casting.
After leaving the mould the shell (7), before becoming fully solidified, is subject to reduction in thickness by rolling applied to the faces (9). This may be brought about by a progressive reduction in the gap in the support roller path below the mould. A reduction in the cross-section is shown in Figure 3b. As the section is reduced then the previously solidified edges rotate until the edge face is
approximately flat and the chamfers are flattened in proportion to the amount of reduction. See Fig. 3 c.
The mould end plate curved face (5) together with chamfers (4) will give a slab edge profile such that during reduction of thickness with a liquid core immediately after the mould, the slab comers will rotate thus minimising internal and external strain and limiting final convexity of
edge during heavy reduction of 5-40 per cent.
With a lighter reduction however, the concave portions will rotate to give new flat edge
faces, which retain some corner chamfer.

Claims

1. A method of producing a metal slab comprising continuously casting a metal strand
in a continuous casting mould, said strand having a first pair of faces which are flat and are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form, and before the strand is fully solidified, applying rolling forces to said first pair of faces to reduce the thickness of the strand to the thickness of the required slab and to cause the concave portions of the second pair of faces to distort outwardly so that the second pair of faces
are substantially flat and mutually parallel, characterized in that each of the faces of the second pair of faces has its portion of concave form flanked on either side by a chamfered corner portion.
2. A method as in Claim 1 , wherein after the application of the rolling forces to the first pair of faces, the concave portions and the chamfered portions of the faces of the second pair distort outwardly so that the second pair_of faces are substantially flat, mutually parallel and are at 90° to the first pair of faces.
3. A continuous casting mould having a mould passage which when the mould is in use produces a metal strand having a first pair of faces which are flat and are substantially parallel to
each other and a second pair of faces each of which includes a portion of concave form, characterized in that the mould passage is shaped so that each of the faces of the second pair has
its portion of concave form flanked on either side by a chamfered corner portion .
4 A method of producing a metal slab substantially as hereinbefore described with
reference to the accompanying drawings.
5 A continuous casting mould substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings. AMENDED CLAIMS
[received by the International Bureau on 15 July 1998 (15.07.98); original claims 1 - 3 amended ; remaining claims unchanged
(1 page)]
1. A method of producing a metal slab comprising continuously casting a metal strand
in a continuous casting mould, said strand having a first pair of faces which are flat and~are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form, and before the strand is fully solidified, applying rolling forces to said first pair of faces to reduce the thickness of the strand to the thickness of the required slab and to cause the concave portions of the second pair of faces to distort outwardly so that the second pair of faces are substantially flat and mutually parallel, characterized in that each of the faces of the second pair of faces has its portion of concave form flanked on either side by a flat chamfered corner portion.
2. A method as in Claim 1, wherein after the application of the rolling forces to the first pair of faces, the concave portions and the flat chamfered corner portions of the faces of the second pair distort outwardly so that the second pair of faces are substantially flat, mutually
parallel and are at 90° to the first pair of faces. 3. A continuous casting mould having a mould passage which when the mould is in use
produces a metal strand having a first pair of faces which are flat and are substantially parallel to each other and a second pair of faces each of which includes a portion of concave form,
characterized in that the mould passage is shaped so that each of the faces of the second pair has
its portion of concave form flanked on either side by a flat chamfered corner portion .
4. A method of producing a metal slab substantially as hereinbefore described with
reference to the accompanying drawings.
5. A continuous casting mould substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.
PCT/GB1997/002374 1997-09-05 1997-09-05 Continuous casting of metal slabs WO1999012675A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU41258/97A AU4125897A (en) 1997-09-05 1997-09-05 Continuous casting of metal slabs
PCT/GB1997/002374 WO1999012675A1 (en) 1997-09-05 1997-09-05 Continuous casting of metal slabs

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB1997/002374 WO1999012675A1 (en) 1997-09-05 1997-09-05 Continuous casting of metal slabs

Publications (1)

Publication Number Publication Date
WO1999012675A1 true WO1999012675A1 (en) 1999-03-18

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Application Number Title Priority Date Filing Date
PCT/GB1997/002374 WO1999012675A1 (en) 1997-09-05 1997-09-05 Continuous casting of metal slabs

Country Status (2)

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AU (1) AU4125897A (en)
WO (1) WO1999012675A1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10314460A1 (en) * 2003-03-28 2004-10-21 Sms Demag Ag Continuous casting device with a continuous casting mold for casting liquid metals, in particular steel materials
DE102007054911A1 (en) 2007-11-15 2009-05-20 Thyssenkrupp Steel Ag Width adjustable mold
WO2011039083A1 (en) 2009-09-29 2011-04-07 Siemens Vai Metals Technologies Gmbh Continuous casting die
DE102012207786A1 (en) 2012-05-10 2013-11-14 Sms Siemag Ag Continuous casting mold comprises number of mold walls, which form casting surface with their inner sides, where inner side is provided with a profile, such that the inner side has non-planar shape and central region adjoining side region
JP2015128776A (en) * 2014-01-06 2015-07-16 三島光産株式会社 Continuous casting mold
CN108339955A (en) * 2018-01-22 2018-07-31 上海东震冶金工程技术有限公司 Strand arc chord angle molding machine
CN110252981A (en) * 2019-06-10 2019-09-20 邢台钢铁有限责任公司 Mitigate the continuous casting process of bearing steel bloom internal soundness defect
EP3795273A4 (en) * 2018-05-14 2021-03-24 Posco Mold

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1508802A1 (en) * 1965-07-08 1969-11-06 Tsnii Tchneroy Metallourgiy I Mold for the continuous casting of semi-finished products with a thick cross-section
GB1333154A (en) * 1971-02-01 1973-10-10 Rossi I Continuous casting methods and apparatus
GB1400811A (en) * 1971-11-18 1975-07-23 Rossi I Continuous casting method
US3978909A (en) * 1974-01-02 1976-09-07 Allis-Chalmers Corporation Mold with convex sidewalls for continuous casting machines
JPS52117234A (en) * 1976-03-29 1977-10-01 Hitachi Ltd Continuous casting method of slab
SU908490A1 (en) * 1980-03-31 1982-02-28 Предприятие П/Я Р-6762 Mould
GB2311029A (en) * 1996-03-11 1997-09-17 Davy Distington Ltd Continuous casting of metal slabs with concave faces

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1508802A1 (en) * 1965-07-08 1969-11-06 Tsnii Tchneroy Metallourgiy I Mold for the continuous casting of semi-finished products with a thick cross-section
GB1333154A (en) * 1971-02-01 1973-10-10 Rossi I Continuous casting methods and apparatus
GB1400811A (en) * 1971-11-18 1975-07-23 Rossi I Continuous casting method
US3978909A (en) * 1974-01-02 1976-09-07 Allis-Chalmers Corporation Mold with convex sidewalls for continuous casting machines
JPS52117234A (en) * 1976-03-29 1977-10-01 Hitachi Ltd Continuous casting method of slab
SU908490A1 (en) * 1980-03-31 1982-02-28 Предприятие П/Я Р-6762 Mould
GB2311029A (en) * 1996-03-11 1997-09-17 Davy Distington Ltd Continuous casting of metal slabs with concave faces

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 7745, Derwent World Patents Index; Class M22, AN 77-80486Y, XP002063354 *
DATABASE WPI Section Ch Week 8251, Derwent World Patents Index; Class M22, AN 82-11295J, XP002063353 *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10314460A1 (en) * 2003-03-28 2004-10-21 Sms Demag Ag Continuous casting device with a continuous casting mold for casting liquid metals, in particular steel materials
DE10314460B4 (en) * 2003-03-28 2006-04-20 Sms Demag Ag Method and continuous casting apparatus with a continuous casting mold for the casting of liquid metals, in particular of steel materials
DE102007054911A1 (en) 2007-11-15 2009-05-20 Thyssenkrupp Steel Ag Width adjustable mold
WO2009062968A2 (en) * 2007-11-15 2009-05-22 Thyssenkrupp Steel Ag Mould of adjustable width
WO2009062968A3 (en) * 2007-11-15 2009-07-30 Thyssenkrupp Steel Ag Mould of adjustable width
DE102007054911B4 (en) * 2007-11-15 2015-02-05 Thyssenkrupp Steel Europe Ag Width-adjustable mold and method for producing a hot strip
CN102686336A (en) * 2009-09-29 2012-09-19 西门子Vai金属科技有限责任公司 Continuous casting die
WO2011039083A1 (en) 2009-09-29 2011-04-07 Siemens Vai Metals Technologies Gmbh Continuous casting die
DE102012207786A1 (en) 2012-05-10 2013-11-14 Sms Siemag Ag Continuous casting mold comprises number of mold walls, which form casting surface with their inner sides, where inner side is provided with a profile, such that the inner side has non-planar shape and central region adjoining side region
JP2015128776A (en) * 2014-01-06 2015-07-16 三島光産株式会社 Continuous casting mold
CN108339955A (en) * 2018-01-22 2018-07-31 上海东震冶金工程技术有限公司 Strand arc chord angle molding machine
CN108339955B (en) * 2018-01-22 2019-10-22 上海东震冶金工程技术有限公司 Slab arc chord angle molding machine
EP3795273A4 (en) * 2018-05-14 2021-03-24 Posco Mold
CN110252981A (en) * 2019-06-10 2019-09-20 邢台钢铁有限责任公司 Mitigate the continuous casting process of bearing steel bloom internal soundness defect

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