US3924812A - Apparatus for supporting and guiding slab in the secondary cooling zone of continuous casting machine - Google Patents

Apparatus for supporting and guiding slab in the secondary cooling zone of continuous casting machine Download PDF

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Publication number
US3924812A
US3924812A US511268A US51126874A US3924812A US 3924812 A US3924812 A US 3924812A US 511268 A US511268 A US 511268A US 51126874 A US51126874 A US 51126874A US 3924812 A US3924812 A US 3924812A
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US
United States
Prior art keywords
slab
roller support
rollers
support structure
roller
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
US511268A
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English (en)
Inventor
Minoru Miura
Morio Kawasaki
Kantaro Sasaki
Yasuo Sugitani
Susumu Ishimura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
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
Priority claimed from JP48111037A external-priority patent/JPS5220169B2/ja
Priority claimed from JP12634273A external-priority patent/JPS5220170B2/ja
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Application granted granted Critical
Publication of US3924812A publication Critical patent/US3924812A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing
    • B22D11/1282—Vertical casting and curving the cast stock to the horizontal

Definitions

  • FIG. 5A FIG. 5B
  • FIG. 6 FIG. 50
  • FIG. 6A FIG 6B Patent Dec. 9,1975 Q Sheet 5 Of6 r .8. Patent Dec. 9, 1975 Sheet 6 of6 3,924,812
  • This invention relates to means for supporting and guiding continuously cast slab in the secondary cooling zone of a continuous casting machine and, more particularly, to such support and guide means which is pro- 1 vided with a liquid steel stirring means for improving the macroscopic and microscopic irregularities in the slab.
  • the continuous casting is usually carried out in the manner as shown in FIG. 1.
  • the liquid steel cast into a mold 3 forms a soldified shell 7 about several millimeters to millimeters in thickness within the mold, and is withdrawn by pinch rollers while accelerating the solidification in the secondary cooling zone by spraying water 9 ejected from the holes formed in cooling plates 4, openings formed in cooling grids and the gaps be tween rollers 5.
  • the thermal conductivity of which is low the solidification of the slab requires a long time, depending upon the thickness of the slab, and usually a long secondary cooling zone is required. Therefore, the conventional continuous casting equipment has a large height, so that a non-solidified portion subject to high static pressure of the liquid steel may be presented.
  • reference numeral 1 designates a submerged nozzle, numeral 2 powder, and numeral 6 non-solidified steel.
  • roller diameter has to be progressively increased according to the height from the meniscus, i.e., the static pressure of liquid steel, at a position where the static liquid steel pressure is high the distance between adjacent support points is large.
  • the slab passes through a succession of roller gaps it is locally subjected to repeated bulging and compression, so that its character would be extremely deteriorated due to such defects as concentration of certain components of the liquid steel at the position of final solidification and inner cracks.
  • the bulging 8 is related to the static pressure of the liquid steel and the roller gap as 8 (60/384) 4 (PF/Ed where E is Youngs modulus, d thickness of solidified steel, P static pressure, and l interroller distance. It will be seen from the equation that bulging is greater the greater the static pressure of the liquid steel and interroller distance. This phenomenon of bulging cannot be avoided in the roller apron system shown in FIG. I irrespective of the machine adjustment. It may be thought to substitute a cooling plate, cooling grid system or a walking beam system for the roller apron in the secondary cooling zone of FIG. 1.
  • the continuously cast slab produced with the set-up shown in FIG. 1 is subjected to forced cooling from its surface, so that the inner structure of the product differs from that of the ordinary ingots due to a greater cooling speed compared to the case of the ordinary ingots.
  • the type of steel or casting conditions may frequently produce the defects inherent in the continuously cast slab, such as inner cracks, mocroporosity and sharp segregation of molt components in a region of final solidification. These defects have adverse effects upon the quality of the final products, and various measures have been investigated. It is already known that the above effects can be reduced or eliminated by adequately stirring the nonsolidified steel in the secondary cooling zone.
  • the methods of causing a stirring phenomenon in the liquid steel through the outer shell or metal vessel include one, in which the stirring forces are provided electrically, that is, by means of electromagnetic induction, and one, in which current is directly passed in the liquid steel while simultaneously applying a magnetic field thereto.
  • a first object of the present invention is to provide means for supporting and guiding a slab in the secondary cooling zone, which permits to overcome the aforementioned drawbacks inherent in the prior art, and also which comprises a stationary roller support structure having a surface extending parallel to and spaced a constant distance from a corresponding surface of the slab and a plurality of rollers rolling over an endless surface of said roller support structure with the descent of the slab and adapted to process along the gap between said roller support structure and slab, each said roller having a diameter equal to relevant dimension of said gap.
  • a second object of the invention is to provide a device for supporting and guiding a slab in a continuous casting machine, which device comprises a liquid steel stirring means as well as a roller support and rollers.
  • FIG. 1 is a pictorial sectional view of a prior-art continuous casting machine
  • FIG. 2 is a pictorial sectional view of a continuous casting machine embodying the invention
  • FIGS. 2A to 3D show examples of the bulging prevention roller mechanism according to the invention
  • FIGS. 4A and 4B are fragmentary side views showing bearing portions of the bulging prevension roller mechamsm
  • FIGS. 4C and 4D are sectional views respectively taken along line A-A in FIG. 4A and line BB in FIG. 48;
  • FIGS. 5A to 5D are perspective views showing examples of the roller support structure according to the invention.
  • FIGS. 6A and 6B show, respectively in sectional view and side view, a cooling water spraying mechanism in the roller support structure
  • FIG. 7 is a pictorial sectional view of another embodiment of the apparatus for supporting and guiding a slab incorporating a liquid steel stirring means.
  • FIG. 8 is a perspective respesentation of the construction of the supporting and guiding apparatus shown in FIG. 7.
  • FIG. 2 shows an embodiment of the apparatus for supporting and guiding a slab according to the invention.
  • Liquid steel is poured through a submerged nozzle 1 provided in a turndish into a mold 3, and as the solidification of the steel proceeds the resultant slab 6 is with continuously drawn by pinch rollers 12.
  • the slab here is supported and guided in its progress through the secondary cooling zone by one or more pairs of stationary roller support structures 11 each having a surface extending parallel to and spaced a constant distance from a corresponding surface of the slab and carrying a plurality of rollers 10 extending at right angles to the direction of slab withdrawal and rolling over its endless surface.
  • the rollers 10 have the same diameter as the gap between the slab and their support 11 and roll along that gap, thereby supporting and guiding the slab.
  • the rollers are displaced in the direction of the slab withdrawal as they roll along the gap between the slab and roller support with the withdrawal of the slab, friction between roller and slab and between roller and roller support, and hence wear, is reduced.
  • the rollers belonging to each roller support are rotatably tied in the form of an endless row or band and are automatically fed back from the outlet on the side of the pinch rollers to the inlet on the side of the mold.
  • the apparatus for supporting and guiding a slab in the secondary cooling zone consists of a plurality of support sections. However, it may consist of a single support section as well. Also, while the above embodiment of the supporting and guiding means is provided over only part of the secondary cooling zone, it may provided along the entire secondary cooling zone as well.
  • rollers 10 for the prevention of bulging will now be discussed. Some arrangements of the examples are shown in FIGS. 3A to 3D and 4A to 4D.
  • rollers 10 each hav ing a length greater than the width of the slab are arranged in a row.
  • a plurality short rollers 10 are arranged end to end, and end-to-end arrangements of rollers are arranged in a row or rows with adjacent end-to-end roller arrangements flush with or staggered from each other.
  • These rollers may have their shafts 13 mounted in bearings 14 which are tied to one another, as shown in FIGS. 4A and 4B.
  • the bearing may be a metallic bearing as shown in FIG. 4C, or it may be a ball bearing with balls 16 as shown in FIG. 4D.
  • the diameter of the roller 10 may range from 10 to millimeters.
  • roller support 11 It is an important point of cooling by spraying water to obtain uniform cooling lest thermal stress should result due to the thermal cycle of sudden cooling. This may be achieved by arranging such that the slab surface other than the portions in contact with the bulging prevention rollers is uniformly subjected to the spray.
  • a number of spray nozzles 18 are provided on the roller support 11, whereby spray water can be issued from gaps between adjacent bulging prevention rollers 10. Each spray nozzle 18 here is screwed into a hole formed in the wall of the roller support 11.
  • FIG. 6B shows an alternative way of supplying the spray water.
  • the roller support consists of two halves, one of which is formed with a cooling water supply groove 20 for supplying the cooling water to be sprayed.
  • number of vertical slits or horizontal slits or both vertical and horizontal slits 21 for issuing the spray water are formed in the roller support 11.
  • FIGS. 7 and 8 show, respectively in pictorial sectional view and fragmentary perspective view, another embodiment of the apparatus for supporting and guiding a slab in the secondary cooling zone of a continuous casting machine according to the invention.
  • a liquid steel stirring means is incorporated.
  • the apparatus of this embodiment comprises a pair of roller support structures 1 1 each carrying a plurality of rollers 10 having a length greater than the width of the slab, the rollers 10 being rotatably tied to one another and extending at right angles to the direction of withdrawal of the slab.
  • each roller support 11 is provided with a built-in liquid steel stirring means 22.
  • FIG. 8 shows the construction of the roller support 11 in detail. As is shown, it has an inner space 23 for accommodating the liquid steel stirring means. The space 23 is defined by a plurality of guide bars 24 extending parallel to the direction of the slab withdrawal and guide bar supports 25 extending at right angles to the slab withdrawal direction.
  • the vertical guide bars and guide bar supports are assembled together with roller support keep bars 26 to form the frame of the roller support.
  • the guide bars 24 may extend parallel to the direction of the slab withdrawal.
  • the rollers 10 supporting the surface of the slab extend in a direction at right angles to the direction of the slab withdrawal and rotatably tied to one another to form an endless row or band surrounding the periphery of the roller support 11.
  • the rollers roll over the guide bars 24 due to frictions between them and slab 8 and also between them and guide bars 24, thereby supporting the surface of the slab so as to prevent the bulging.
  • the frictional resistance offered to the slab is substantially the same as in the case of the prior-art roller arrangements.
  • the rollers 10 roll in the direction of the slab withdrawal at a speed one half that of the slab. Since the rollers are tied into the form of an endless row so that they roll over the periphery of the roller support, they can be cyclically supplied to the gap between the slab and the roller support frame constituted by the guide bars at a constant interval.
  • the cooling water can be uniformly sprayed over the slab surface other than the portions in contact with the bulging prevention rollers 10, and it is possible to substantially eliminate thermal stress in the slab surface due to sudden cooling to obtain uniform cooling.
  • the roller support 11 which has a surface extending along the direction of the slab withdrawal, may be a block-like structure or a welded structure, or it may be a rectangular frame constituted by guide bars 24, guide bar supports 25 and roller support keep bars 26 as shown in FIG. 8.
  • the construction cost can be reduced compared to the conventional roller apron system.
  • one or more pairs of roller support structures each constituted by guide bars defining slit-like spaces and an inner space capable of accommodating a liquid steel stirring means, each said roller support structure carrying a roller arrange- 6 ment consisting of a plurality of rollers tied to one another such that they can roll over an endless peripheral surface of the support structure, are disposed in part of the secondary cooling zone, preferably after the roller apron, of a continuous casting machine incorporating liquid steel stirring means for supporting, pinching and guiding the slab in the secondary cooling zone.
  • An apparatus for supporting and guiding a slab in at least part of the secondary cooling zone of a continuous casting machine which comprises at least one pair of stationary roller support structures each having a surface spaced a constant distance from a corresponding surface of the slab being withdrawn, and rollers carried by said roller support structure and adapted to roll over an endless surface of said roller support structure with the descent of the slab, said rollers being adapted to proceed along the gap between the associated roller support structure and the slab, each said roller having a diameter equal to the relevant dimension of said gap, each said roller support structure having a number of cooling water spraying means, a cooling water supply duct extending within it and branch ducts connecting said respective spraying means and said cooling water supply duct, each said spraying means having its tip disposed on the inner side of the working surface of said roller support structure.
  • cooling water spraying means are nozzles.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Rolls And Other Rotary Bodies (AREA)
US511268A 1973-10-04 1974-10-02 Apparatus for supporting and guiding slab in the secondary cooling zone of continuous casting machine Expired - Lifetime US3924812A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP48111037A JPS5220169B2 (Direct) 1973-10-04 1973-10-04
JP12634273A JPS5220170B2 (Direct) 1973-11-12 1973-11-12

Publications (1)

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US3924812A true US3924812A (en) 1975-12-09

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US (1) US3924812A (Direct)
FR (1) FR2246336B1 (Direct)
GB (1) GB1481438A (Direct)
IT (1) IT1019455B (Direct)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4235280A (en) * 1979-01-22 1980-11-25 Concast Incorporated Spray nozzle for cooling a continuously cast strand
CN109093083A (zh) * 2018-09-28 2018-12-28 邢台钢铁有限责任公司 一种表面质量优化的连铸钢坯及其制造方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106938324B (zh) * 2016-01-05 2019-02-26 鞍钢股份有限公司 一种减少微合金化板坯角部裂纹的装置及方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3361367A (en) * 1964-12-18 1968-01-02 Vaillant Joh Kg Gas burner
US3589611A (en) * 1969-03-05 1971-06-29 John B Jones Jr Distributors for injecting fluids into vessels
US3617441A (en) * 1968-08-22 1971-11-02 United Board & Carton Corp Spray nozzle device for cleaning accumulations in suction roll openings
US3850241A (en) * 1972-07-24 1974-11-26 Chevron Res High pressure jet well cleaning
US3877510A (en) * 1973-01-16 1975-04-15 Concast Inc Apparatus for cooling a continuously cast strand incorporating coolant spray nozzles providing controlled spray pattern

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3361367A (en) * 1964-12-18 1968-01-02 Vaillant Joh Kg Gas burner
US3617441A (en) * 1968-08-22 1971-11-02 United Board & Carton Corp Spray nozzle device for cleaning accumulations in suction roll openings
US3589611A (en) * 1969-03-05 1971-06-29 John B Jones Jr Distributors for injecting fluids into vessels
US3850241A (en) * 1972-07-24 1974-11-26 Chevron Res High pressure jet well cleaning
US3877510A (en) * 1973-01-16 1975-04-15 Concast Inc Apparatus for cooling a continuously cast strand incorporating coolant spray nozzles providing controlled spray pattern

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4235280A (en) * 1979-01-22 1980-11-25 Concast Incorporated Spray nozzle for cooling a continuously cast strand
CN109093083A (zh) * 2018-09-28 2018-12-28 邢台钢铁有限责任公司 一种表面质量优化的连铸钢坯及其制造方法
CN109093083B (zh) * 2018-09-28 2020-09-01 邢台钢铁有限责任公司 一种表面质量优化的连铸钢坯及其制造方法

Also Published As

Publication number Publication date
IT1019455B (it) 1977-11-10
FR2246336A1 (Direct) 1975-05-02
DE2447504A1 (de) 1975-04-10
FR2246336B1 (Direct) 1979-09-28
GB1481438A (en) 1977-07-27
DE2447504B2 (de) 1977-06-30

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