EP0903192A1 - Verbesserungen beim Giessen - Google Patents

Verbesserungen beim Giessen Download PDF

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Publication number
EP0903192A1
EP0903192A1 EP98307619A EP98307619A EP0903192A1 EP 0903192 A1 EP0903192 A1 EP 0903192A1 EP 98307619 A EP98307619 A EP 98307619A EP 98307619 A EP98307619 A EP 98307619A EP 0903192 A1 EP0903192 A1 EP 0903192A1
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EP
European Patent Office
Prior art keywords
strand
rollers
stage
volume
casting
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.)
Withdrawn
Application number
EP98307619A
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English (en)
French (fr)
Inventor
Robert Graham
Robert Perry
Neil Hutcheon
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.)
Kvaerner Clecim Continuous Casting Ltd
Kvaerner Metals Continuous Casting Ltd
Original Assignee
Kvaerner Clecim Continuous Casting Ltd
Kvaerner Metals Continuous Casting 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 GBGB9719837.8A external-priority patent/GB9719837D0/en
Application filed by Kvaerner Clecim Continuous Casting Ltd, Kvaerner Metals Continuous Casting Ltd filed Critical Kvaerner Clecim Continuous Casting Ltd
Publication of EP0903192A1 publication Critical patent/EP0903192A1/de
Withdrawn legal-status Critical Current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
    • B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands

Definitions

  • This invention concerns improvements in and relating to casting, particularly, but not exclusively to methods and apparatus for manipulating strand thickness by a sequential rolling process, including the location of such changes and / or timing of such changes, for instance when ending a casting cycle.
  • Liquid core reduction allows a slab to be formed of a suitable size for subsequent rolling whilst allowing a meniscus with a larger surface area than would otherwise be possible in the mould.
  • the liquid core reduction stage involves a series of rollers with decreasing spacing, which, as a consequence, reduce the separation between the solidified skins and squeeze the liquid core out.
  • the position of this liquid core reduction stage along the strand pass line is fixed.
  • the present invention seeks to overcome these problems by manipulating the position of rollers in the initial rolling stage of a sequential rolling process.
  • Soft reduction is used to improve internal quality and properties of the cast product.
  • An important criteria, particularly affecting internal quality of high carbon steels is the extent of central segregation and porosity. High segregation results in nonuniform properties across the thickness of the finished product which may be detrimental to the weldability and resistance to hydrogen induced cracking (HIC). Segregation arises during the final stages of solidification. As the steel solidifies, the volume change due to phase transformation generates voids within the strand. The reduced pressure within the voids creates a liquid flow or suction of liquid into the voids.
  • the liquid steel may become enriched with alloying elements such as carbon, manganese, phosphorous, sulphur and the like. It is this enriched solution that fills the voids generated by the shrinkage producing an undesirable segregated structure.
  • Soft reduction seeks to provide a solidification bridge or barrier which restricts liquid flow and so the voids cannot be re-filled.
  • the present invention additionally seeks to overcome these problems with the positioning of soft reduction, and this fully addresses the problems associated with central segregation and porosity by manipulating the position of the rollers in the final (solidification) rolling stage of a sequential rolling process.
  • a method of casting the method involving a moulding stage for forming a partially solidified strand with a molten core, the partially solidified strand passing to a roller stage on leaving the moulding stage, the method comprising, at least during a portion of a casting cycle :-
  • the volume of the strand between the rollers in that portion may be increased.
  • Such a method may be used in liquid core reduction to lower the level of the meniscus with in the solidifying strand.
  • Such a method may be used in dynamic soft reduction to move the location of the soft reduction zone away from the moulding stage / along the direction of travel of the strand.
  • the volume of the strand between the rollers in that portion may be decreased.
  • Such a method may be used in liquid core reduction to increase the level of the meniscus within the moulding stage.
  • Such a method may be used in dynamic soft reduction to move the location of the soft reduction zone towards the moulding stage / against the direction of travel of the strand.
  • the further portion in such a case is provided closer to the moulding stage than the first portion.
  • the further portion of the rolling stage may be a different portion of the rolling stage to the first portion and/or the first portion subsequent to its change in volume.
  • a moulding stage for forming a partially solidified strand with a molten core, the partially solidified strand passing to a roller stage on leaving the moulding stage, the method comprising, at least during a portion of a casting cycle :-
  • the increase in volume is provided by increasing the separation of one or more rollers on one side of the strand from one or more rollers on the other side of the strand.
  • all of the rollers are increased to a predetermined equivalent separation.
  • the separation conforms to the equivalent dimension of the mould outlet and / or the initial rolling stage outlet.
  • the further portion of the rolling stage with a reduced separation is a different portion to the first portion / increased volume portion and is provided further, in the direction of travel of the strand, than the first portion / increased volume portion.
  • the further portion of the rolling stage may be defined with separations between rollers equivalent to those provided in the initial reduced separation portion.
  • the separation of the initial rollers of this portion are configured to the adjoining rollers of the increased volume portion.
  • the last rollers on this reduced portion configured to the separation of adjoining rollers of subsequent portions.
  • substantially parallel rollers are provided in subsequent portions of the rolling stage.
  • the method further comprises decreasing the volume of the strand between the rollers in the further portion of the rolling stage with a reduced separation between rollers. Most preferably it still further provides, providing a yet further portion of the rolling stage with a reduced separation between rollers. The method may still further provide increasing the volume of the strand between still further portions of the rolling stage and/or providing still further portions of the rolling stage with a reduced separation.
  • the increase in volume of the strand between rollers and/or the provision of further portions of the rolling stage with a reduced separation may be provided by varying blocks of rollers simultaneously or by varying one or more rollers in a sequential manner.
  • the gradual movement of the increased volume portion and/or reduced separation portion down a line of rollers is envisaged.
  • a moulding stage for forming a partially solidified strand with a molten core, the partially solidified strand passing to a roller stage on leaving the moulding stage, the method comprising, at least during a portion of a casting cycle :-
  • the decrease in volume of the strand between the rollers generates an increased volume of material in the moulding stage.
  • the decrease of volume may therefore give a rise in the level of molten material in the moulding stage.
  • the method provides for the advancement of the strand with the rollers in the decreased volume position.
  • the portion with a reducing separation is provided before the level of molten material reaches the outlet of the mould.
  • the reducing separation portion is provided in an equivalent configuration to the initial reduced separation portion, most preferably in the same portion of the rolling stage.
  • the separation of the initial rollers of this portion are configured to the adjoining rollers of the preceding portion.
  • the last rollers of this reduced portion configured to the separation of adjoining rollers of the subsequent portion.
  • substantially parallel rollers are provided in subsequent portions of the rolling stage.
  • a moulding stage for forming a partially solidified strand with a molten core, the partially solidified strand passing to a roller stage on leaving the moulding stage, the method comprising, at least during a portion of a casting cycle :-
  • the invention including third and fourth aspects of the invention, may also be provided with the following features and / or options.
  • the decrease in volume of the strand between the rollers is preferably provided by reducing the separation of one or more rollers relative to one or more rollers on the other side of the strand.
  • a reduction between opposing pairs of rollers is provided.
  • all of the rollers are reduced to an equivalent separation. It is preferred that this separation be substantially equivalent to the corresponding dimension of the desired strand product.
  • a first portion of the rolling stage with a reducing separation between rollers is provided by increasing the separation between one or more rollers in that portion.
  • the rollers are moved apart to a decreasing degree in the direction of strand travel.
  • the decrease in volume of the strand between rollers and/or the provision of further portions of the rolling stage with a reduced separation may be provided by varying blocks of rollers simultaneously or by varying one or more rollers in a sequential manner.
  • the method provides a strand which is of equivalent thickness throughout its length.
  • the relative positions of rollers in the non-reducing separation portion are maintained constant throughout.
  • a moulding stage for forming a partially solidified strand with a molten core, the partially solidified strand passing to a roller stage on leaving the moulding stage, the method comprising, at least during a portion of a casting cycle :-
  • the first and/or second and/or third and / or fourth and / or fifth aspects of the invention may further include the following possibilities, options and features.
  • the portion of the rolling stage with a reduced separation is initially provided in proximity to the mould outlet, for instance for liquid core reduction.
  • the reduced separation is provided by decreasing the separation between rollers in the direction of strand travel.
  • the reduction in separation may occur in a linear or non-linear manner.
  • the rate of reduction of separation may be reduced at the start and/or end part of the portion compared with the mid part of that portion.
  • pairs of opposing rollers are provided.
  • rollers on one side of the strand are provided in a line, parallel to the direction of travel of the strand.
  • the rollers on one side of the strand are inclined relative to the direction of travel of the strand.
  • the change in position is provided by moving one or more rollers on one side of the strand, the rollers on the other side of the strand remain in position.
  • all the rollers forming the portion of reduced separation are varied to an equivalent separation.
  • the separation may correspond to the corresponding separation of the mould outlet or to the corresponding separation of the desired product.
  • the portion of the rolling stage subsequently provided with a reducing separation is provided with the same configuration as the first reduced separation portion.
  • the moulding stage may involve linear or curved mould or a mould incorporating both linear and curved portions.
  • a mould incorporating a funnel portion may be provided.
  • the rolling stage or one or more portions thereof may be provided in a linear configuration and/or in a non-linear (eg curved) configuration and/or in a combination of such configurations. It is preferred that a first portion of the rolling stage after the moulding stage be provided in a linear configuration. Preferably this portion is followed by a bending portion, with most preferably subsequent further linear and / or non-linear portions being provided.
  • the method of the present invention may be used shortly before final solidification, for instance in a final set of rollers of a sequential rolling process in order to reduce strand thickness (a method referred to hereinafter as "soft reduction").
  • Soft reduction may be achieved by any of the variations in roller separation and volume described hereinbefore.
  • soft reduction may be achieved by providing a tapered roller gap or a variable, roller gap in the area of final solidification which serves to compensate for slab shrinkage and alleviate the aforementioned disadvantages.
  • the position of the tapered roller gap and / or its variation may be dynamically controlled.
  • the extent of soft reduction required to compensate for strand shrinkage is dependent upon steel composition and initial strand thickness. It may be typically of the order of 2% of strand thickness.
  • the liquid steel flow between the solidified dendrites is restricted after about 0.8 solid fraction has been reached.
  • the voids or pores do not refill but simply become re-shaped on reduction.
  • the rolling loads become significantly greater when the strand becomes solid.
  • applying the method of soft reduction before the strand centre has attained some solidification may limit the observed improvement in segregation.
  • Soft reduction is, therefore, more efficient when used over the preferred solidification range of about 0.3 to 0.8 fraction solid.
  • the length of the soft reduction zone may, however, be dependent on the rate of soft reduction. If the rate of reduction at each roller or taper (mm/m) is too great, excessive loads and strains may be experienced at the liquid-solid interface leading to internal cracking.
  • the optimum characteristics of the soft reduction zone are preferably determined by or according to the cooling/solidification rate of the strand and strain limits of the steel being cast. Preferably mathematical modelling may be performed to establish a suitable location and / or length of the soft reduction zone. For 0.3 to 0.8 fraction solid, reduction rates of around 0.6 to 1.5 mm/m may be utilised.
  • the length and location of the appropriate soft reduction zone at any point in time may be accurately determined with the aid of heat transference solidification calculations, in order to derive optimum benefit from the strand reduction.
  • a computer thermal model is used to assess machine layout, secondary cooling and solidification for a range of casting conditions.
  • the process models may be advantageously used to determine optimum soft reduction characteristics, such as length, location, route, etc.
  • the final solidification position and therefore optimum soft reduction zone may vary.
  • the dynamic soft reduction system described hereinafter allows soft reduction to be advantageously variably applied over some or all segments.
  • the form of the dynamic soft reduction varies with varying conditions and / or with time.
  • soft reduction may be applied as a heavy line taper over the full support length. Both systems provide for effective soft reduction although a dynamic system is preferred to ensure that optimised reduction rates may be consistently applied.
  • the benefits of dynamic soft reduction may be optimised by applying dynamic spray control and thermal tracking.
  • Cooling may be provided at one or more portions of the rolling stage, for instance in liquid core reduction and / or soft reduction.
  • the level of cooling may be varied over time to control the amount and hence level of the molten core. Spray cooling applied to a part of the strand having a molten core is preferred.
  • the shape of the solidification point across the width of the strand (the sump profile). This is mainly influenced by the position and cooling intensity of the secondary cooling system. An even sump profile or "U-shape" is preferred to ensure that soft reduction is applied in the correct position over most of the slab width.
  • the required withdrawal force may be calculated according to the resistances acting on the strand resisting it moving through the machine.
  • the resistances include friction due to the mould and roller bearings, as well as slab straightening forces, roller eccentricities and misalignment, etc.
  • soft reduction or even excessive drive roller pressures
  • significant rolling forces on the strand are created. These forces increase the withdrawal resistance and thus the required torque of the motors within the casting machine.
  • Sufficient drive capability must be made available to allow withdrawal of the strand.
  • the effect of increased loading due to soft reduction on strand guide segments require that further checks are made to inter alia segment frames, drive rollers and non-drive rollers, roller bearings, roller gap settings and packers, segment drive torques and segment drive motor suitability.
  • the casting machine thickness position is normally set by equipment units arranged along the ferro-static length of the casting apparatus from the mould, through the top zone, bender and segments.
  • the setting of these units is normally achieved by clamping frames together hydraulically onto thickness packs.
  • one advantageous apparatus for liquid core reduction or soft reduction comprises setting packers for adjusting the roller gap.
  • the segments which may be typically used for soft reduction may be calculated from or predetermined based upon, the steel grade to be cast and steady state casting speed.
  • the method of the invention therefore further comprises a step in which the roller gaps are adjusted by static clamping onto preset packers. Subsequent segments are set to the new roller gaps.
  • the location may be optimised to the predicted steady state casting conditions.
  • an apparatus comprising remotely operable means for adjusting the rollers dynamically, for example hydraulic means or electromechanical means coupled with a dynamic control system.
  • Preferred dynamic control systems for the hydraulic means are, for example, pulse systems using standard valves or servo or high gain proportional valve systems.
  • Each of these may advantageously use a sensor transducer or similar device at each cylinder to dynamically feedback the signal of the strand position. Due to its location, it may be desirable to instal the system in a pull-down cylinder or a separate piggy-back type cylinder (e.g. an air cylinder).
  • a control device (such as a digital controller) may be used and may be linked to a host computer.
  • the advantage of the pulse system using standards valves is that it may be adapted to suit new and existing machinery.
  • the servo system on the other hand may use high gain proportional valves which are less demanding than a true servo valve and may be adaptable to existing hydraulic systems (typically in conjunction with filtration means).
  • the present invention provides a casting apparatus comprising remotely operable means for dynamically or statically adjusting one or more rollers.
  • the apparatus comprises a position sensor for determining the position of one or more rollers.
  • a hydraulic cylinder is mounted to the equipment frame and arranged with a dynamic control system and digital controllers.
  • the strand may be tracked with conditions set by a process control computer and set points down-loaded for optimum roller gap setting to the digital controllers that control the movement of fluid through the control valves which in turn move each hydraulic cylinder and set the roller gap.
  • Feedback for the roller gap may be taken from a sensor transducer or the like monitoring the cylinder stroke movement and thus the roller gap.
  • the method of soft reduction is carried out dynamically by including a step in which one or more rollers is adjusted dynamically.
  • this advantageously involves the automatic adjustment of individual roller gaps to suit the location of final solidification.
  • Dynamic soft reduction may therefore usefully compensate for non-steady state casting conditions. That is to say, during casting, the slab speed varies depending upon conditions and casting practice with the result that the solidification point of liquid metal may move up or down the machine length. It will be appreciated, therefore, that to achieve maximum flexibility for strand roller gap adjustment during casting and to meet the conditions for soft reduction, an apparatus that may respond dynamically and be capable of accurately positioning and setting the roller gap is preferred.
  • Thermal tracking provides real time thermal modelling of the cast product with calculations of slab surface temperature, shell thickness and solidification position, etc. To ensure the necessary accuracy, the modelling should have grade dependent thermal and physical properties and spray zone dependent heat transfer coefficients. Such a model may provide calculated slab temperatures and shell thicknesses throughout the casting machine. Numerous real time variables may be inputted into the thermal tracking model including steel grade, casting temperatures, section size, casting speed, mould cooling water flow rates and temperature rises, and spray cooling water flow rates. Thermal tracking model results may be used to provide inputs into the dynamic liquid core reduction and soft reduction control systems to ensure that optimum strand thickness reduction rates and positions are correctly applied in relation to calculated solidification position.
  • liquid core reduction and soft reduction may be performed dynamically in new casting machines or by retro-fitting appropriate means to existing machines.
  • the benefits of the apparatus of the invention are that liquid core reduction allows thinner sections to pass to the rolling mill therefore less power is required during rolling.
  • liquid core reduction takes place in the top zone and bender segment.
  • Soft reduction gives enhanced quality off the casting machine for certain grades of material.
  • the soft reduction stage typically takes place downstream of the top zone and bender system in segments 1 to 5 and segments 6 to 7. Reduction over each unit will typically be 2 millimetres.
  • Continuous casting of metal typically involves the introduction into a mould 3 of molten material 5, the molten material partially solidifying therein to form a strand 6 comprising a solidified thin skin 7 and a molten core 9.
  • the molten material 5 introduced into the mould 3 forms a skin 7 of increasing thickness as the temperature drops for the skin and solidification occurs. However, by the time the strand 6 exits the mould 3 it still possesses a sizeable liquid core 9.
  • Reduction of the strand 6 towards a more desirable thickness X can be achieved in the initial rolling stage 13 using liquid core reduction by pushing one or both of the skins 7 towards the other.
  • pairs of cylindrical rollers 15 are provided with one set provided in a straight line, along the pass line, and with the other set tapering towards the first so as to gradually decrease the separation distance.
  • the opposing solidified skins 7 are brought together and the liquid core 9 is squeezed out.
  • this squeezing process leads to a flow of material upwards within the core.
  • a 90mm gap on exiting the mould may well be reduced to a 70mm strand in such a stage.
  • the liquid core reduction (LCR) unit 22, bender stage 24 and rolling stages are all opened to the width of strand corresponding to the mould outlet 26.
  • LCR liquid core reduction
  • bender stage 24 and rolling stages are all opened to the width of strand corresponding to the mould outlet 26.
  • a dummy strand is inserted with the drive rollers 28 being sequentially moved into grip the thin main length 30 and drive the dummy bar upwards.
  • the dummy bar has an enlarged head portion 32 to block the mould and thinner subsequent portion 30 corresponding to the desired eventual slab thickness.
  • casting can be started by introducing molten material 34 into the mould 36.
  • the strand drives 28 can be started and the strand withdrawn from the mould 36.
  • the LCR unit and bender rollers are set at a fully open separation to accommodate the dummy bar and the cast strand attached to it, representation 3.
  • the LCR unit rollers can be reduced in separation to give the desired squeezing effect to reduce the strand 40 down to the desired thickness, representation 4.
  • a tapered stage is thus provided.
  • the present invention aims to solve this problem and increase the effective length of the useable product obtained.
  • the casting process is in a steady state with molten material 60 being introduced to the mould 62, withdrawn through LCR unit 64 to reduce its thickness and processed in subsequent benders and other stages.
  • representation 14 Following the stoppage of material being fed to the mould, representation 14, the level 66 in the mould starts to drop, representation 15.
  • rollers in the LCR unit 64 are opened to a width corresponding to that of the mould outlet, representation 16.
  • This increase in volume 68 of the LCR unit results in a depression in the level of still molten core so leading to a crater 70 in the top of the strand.
  • the rollers of the bender stage 72 are opened to the full width and the rollers of the first segment 76 are increased in separation to provide a gradual taper down to the desired slab thickness.
  • an increase in volume is provided with a consequential reduction of the level of the molten core relative to the solidified skins, whilst still achieving a reduction of the slab thickness down to the desired level, representation 19.
  • representation 26 steady state casting is occurring with a LCR unit thickness reduction stage 80.
  • representation 27 the level 82 of molten material in the mould drops, representations 28 and 29.
  • rollers of the LCR unit 80 are opened to their tapered squeezing configuration once more providing an increased volume 86 between the skins and leading to cratering 88 of the strand end.
  • the strand end then passes into the LCR stage and is reduced in thickness down to the desired extent, but without overflow of the molten core as the increased volume is sufficient to accommodate the up flow of molten material, representation 32.
  • Both embodiments of the invention described hereinabove therefore, involve varying the internal volume of the slab so as to ensure that the molten core is always below the end level of the strand. In this way spillage is avoided. The crater in the meniscus will vary, it will not completely disappear.
  • the invention therefore, allows a large meniscus area to be employed in the mould whilst achieving products of the desired, reduced thickness. Furthermore this is achieved whilst minimising loss of material in an undesirable product form at the end of any casting strand procedure.
  • Figure 6 illustrates schematically a typical casting machine comprising mould 600 and top zone 601, bender 602 and segment sections 603a and 603b.
  • Section 603a represents segments a to e and section 603b represents segments f to g.
  • the adjustment of the segments is normally achieved by clamping frames together, hydraulically, onto thickness packs.
  • dynamic hydraulic means allow the roller gap in these segments to be advantageously adjusted during casting.
  • the casting methods of the invention may use any one of the following combination of steps:
  • liquid core reduction is to reduce the strand thickness (roller gap) from say 150 millimetres to 125 millimetres. This may be achieved by setting the entry dimension of the top zone segment to 150 millimetres and tapering through to the exit bender segment dimension at 125 millimetres. This tapering reduction of the roller gap is performed at a controlled rate by hydraulic cylinders, finally clamping onto hard packs. Throughout the operation, a sensor monitors the position of the cylinder stroke and thus the roller gap position.
  • step 3 liquid core reduction is achieved as follows:
  • Soft reduction may be achieved in segments a to e (603a and f to g (603b) and in conjunction with or separately to liquid core reduction to control the final solidification of the casting machine.
  • roller gap position control is achieved through hydraulic cylinders.
  • Packers used in the case of an existing damping method are removed and roller gap adjustment is made dynamic.
  • FIGS 8a and 8b a typical strand segment is illustrated for use in the method and apparatus of the invention.
  • the main valve manifolds 801 are located outside the spray chamber area 802 adjacent to the equipment with hard piping and hoses to a valve block 803 on each hydraulic cylinder 804 in the spray chamber area 802. Adjusting the hydraulics allows the roller gap 806 to be varied.
  • Figure 9 illustrates a schematic representation of the progress of a soft reduction method with the roller positions indicated for a soft reduction taper 902 in a soft reduction zone 903 as compared with a rigid line taper 904 which addresses contraction due to cooling only.
  • Figure 10 shows examples of thermal modelling and calculation of fraction solids.
  • the upper results shows the increase in shell thickness for fraction solids ranging from 0.0 (liquidus line) through to 1.0 (solidus line).
  • the lower result shows the increase in fraction solid at the centre of the slab versus distance from meniscus. This shows that the optimum soft reduction position of typically 0.3 to 0.8fs occurs at say 8.4 to 10 metres from the meniscus. This is within the third (c) and fourth (d) curved support segments.
  • the appropriate location under steady state can be determined and based on suitable monitoring the appropriate locations with process variations can be determined.
  • Roller gap configurations for a soft reduction process are under a variety of conditions are shown in the resolutions of Figure 11.
  • the formats 1 to 8 show the final solidification point (apex of the liquid core) at various positions along the machine length.
  • Set points down-loaded from the process control computer tracking systems are sent to the position control digital controllers and to the hydraulic cylinders for roller gap setting according to where this solidification point is determined as occurring.
  • Sensor transducers are used to monitor the roller gap position and provide feedback to the control system.
  • FIG. 12 A preferred embodiment of the apparatus for setting and / or controlling a roller gap is illustrated in Figure 12.
  • the apparatus comprises a hydraulic cylinder 1301 with a sensor transducer 1302 which are mounted to the equipment frame, together with position control valves 1303 and digital controllers 1304. Power for the hydraulics is taken from the main machine system. As casting commences, the strand is tracked with conditions set by the process control computer 1305 and set points down-loaded for setting the optimum roller gap. This is achieved using position control digital controllers that control the movement of fluid through the control valves which in turn move each hydraulic cylinder and set the roller gap. Feedback for the roller gap is taken from the sensor transducer 302 monitoring the cylinder stroke movement 1306 and thus the roller gap.
  • the apparatus is designed to control the setting of roller gaps for the following equipment:
  • Entry and exit hydraulic cylinders are arranged at the corners of each unit as shown (as numeral 1401 in Figure 13a and 13b and as numeral 1501 in 14a and 14b).
  • the top zone roller gap is controlled at the exit side by two hydraulic cylinders and pivots at the entry side where the roller gap is fixed.
  • the bender and segments are controlled at the entry and exit side by two hydraulic cylinders on each side (ie by providing independent roller gap movement and setting).
  • Figure 14b shows the segment roller gap pivot movement in the open position as compared to the tapering position of Figure 14a.
  • Dynamic liquid core reduction with dynamic soft reduction allows dynamic positioning of all strand containment units below the mould. Set points for roller gaps are automatically controlled to maximise accuracy.
  • the control system includes dynamic spray control and on-line thermal tracking together with an apparatus for roller gap setting.
  • Static liquid core reduction with dynamic soft reduction allows static positioning of the top zone and bender by clamping onto preset thickness packers and dynamic positioning of soft reduction for the segments.
  • the most cost effective method of setting the strand roller gap is to include line taper by static clamping onto a preset packer thickness and adjusting these packers between casts if required. This system ensures that some degree of soft reduction (albeit at a reduced rate) is always applied without requiring complex control systems and dynamic movements.
  • Table 2 summarises the various alternatives relating to liquid core reduction and soft reduction giving indications of likely effects on product quality.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
EP98307619A 1997-09-18 1998-09-18 Verbesserungen beim Giessen Withdrawn EP0903192A1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB9719837 1997-09-18
GBGB9719837.8A GB9719837D0 (en) 1997-09-18 1997-09-18 Improvements in and relating to casting
GB9815798 1998-07-21
GBGB9815798.5A GB9815798D0 (en) 1997-09-18 1998-07-21 Improvements in and relating to casting

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EP0903192A1 true EP0903192A1 (de) 1999-03-24

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1050355A2 (de) * 1999-05-07 2000-11-08 Sms Schloemann-Siemag Aktiengesellschaft Verfahren und Vorrichtung zum Herstellen von stranggegossenen Stahlerzeugnissen
EP1238727A2 (de) * 2001-02-15 2002-09-11 Thyssen Krupp AG Verfahren zum Herstellen von metallischen Bändern mit Abschnitten unterschiedlicher Materialeigenschaften
WO2003070399A1 (de) * 2002-02-22 2003-08-28 Sms Demag Aktiengesellschaft Verfahren und vorrichtung zum stranggiessen und unmittelbaren verformen eines metall-, insbesondere eines giessstrangs aus stahlwerkstoffen
WO2005068109A1 (de) * 2004-01-20 2005-07-28 Sms Demag Ag Verfahren und einrichtung zum bestimmen der lage der sumpfspitze im giessstrang beim stranggiessen von flüssigen metallen, insbesondere von flüssigen stahlwerkstoffen
KR101018661B1 (ko) * 2002-02-22 2011-03-04 에스엠에스 지마크 악티엔게젤샤프트 강 재료의 주조 빌렛을 연속 주조하여 직접 성형하는 방법 및 장치
AT512214A1 (de) * 2011-12-05 2013-06-15 Siemens Vai Metals Tech Gmbh Prozesstechnische massnahmen in einer stranggiessmaschine bei giessstart, bei giessende und bei der herstellung eines übergangsstücks

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01170566A (ja) * 1987-12-26 1989-07-05 Kawasaki Steel Corp 連続鋳造における鋳片の大圧下方法
EP0611610A1 (de) * 1993-02-16 1994-08-24 Voest-Alpine Industrieanlagenbau Gmbh Verfahren zum Herstellen eines Bandes, Vorstreifens oder einer Bramme
DE4436328A1 (de) * 1993-10-14 1995-04-20 Voest Alpine Ind Anlagen Verfahren und Anlage zum Stranggießen
EP0730924A1 (de) * 1994-07-29 1996-09-11 Sumitomo Metal Industries, Ltd. Verfahren zum kontinuierlichen giessen für dünnes gussstück und vorrichtung
WO1997014522A1 (fr) * 1995-10-18 1997-04-24 Sumitomo Metal Industries, Ltd. Procede de coulage continu et appareil s'y rapportant

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01170566A (ja) * 1987-12-26 1989-07-05 Kawasaki Steel Corp 連続鋳造における鋳片の大圧下方法
EP0611610A1 (de) * 1993-02-16 1994-08-24 Voest-Alpine Industrieanlagenbau Gmbh Verfahren zum Herstellen eines Bandes, Vorstreifens oder einer Bramme
DE4436328A1 (de) * 1993-10-14 1995-04-20 Voest Alpine Ind Anlagen Verfahren und Anlage zum Stranggießen
EP0730924A1 (de) * 1994-07-29 1996-09-11 Sumitomo Metal Industries, Ltd. Verfahren zum kontinuierlichen giessen für dünnes gussstück und vorrichtung
WO1997014522A1 (fr) * 1995-10-18 1997-04-24 Sumitomo Metal Industries, Ltd. Procede de coulage continu et appareil s'y rapportant

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 013, no. 441 (M - 876) 4 October 1989 (1989-10-04) *

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1050355A2 (de) * 1999-05-07 2000-11-08 Sms Schloemann-Siemag Aktiengesellschaft Verfahren und Vorrichtung zum Herstellen von stranggegossenen Stahlerzeugnissen
EP1050355A3 (de) * 1999-05-07 2001-03-28 Sms Schloemann-Siemag Aktiengesellschaft Verfahren und Vorrichtung zum Herstellen von stranggegossenen Stahlerzeugnissen
KR100707785B1 (ko) * 1999-05-07 2007-04-13 에스엠에스 데마그 악티엔게젤샤프트 연속적인 주물을 제조하는 방법 및 장치
EP1238727A2 (de) * 2001-02-15 2002-09-11 Thyssen Krupp AG Verfahren zum Herstellen von metallischen Bändern mit Abschnitten unterschiedlicher Materialeigenschaften
EP1238727A3 (de) * 2001-02-15 2003-01-22 Thyssen Krupp Stahl AG Verfahren zum Herstellen von metallischen Bändern mit Abschnitten unterschiedlicher Materialeigenschaften
US7121323B2 (en) 2002-02-22 2006-10-17 Sms Demag Ag Method and device for the continuous casting and direct shaping of a metal strand, in particular a steel cast strand
WO2003070399A1 (de) * 2002-02-22 2003-08-28 Sms Demag Aktiengesellschaft Verfahren und vorrichtung zum stranggiessen und unmittelbaren verformen eines metall-, insbesondere eines giessstrangs aus stahlwerkstoffen
KR101018661B1 (ko) * 2002-02-22 2011-03-04 에스엠에스 지마크 악티엔게젤샤프트 강 재료의 주조 빌렛을 연속 주조하여 직접 성형하는 방법 및 장치
WO2005068109A1 (de) * 2004-01-20 2005-07-28 Sms Demag Ag Verfahren und einrichtung zum bestimmen der lage der sumpfspitze im giessstrang beim stranggiessen von flüssigen metallen, insbesondere von flüssigen stahlwerkstoffen
CN100409975C (zh) * 2004-01-20 2008-08-13 Sms迪马格股份公司 用于确定连铸坯中凝固末端的位置的方法和装置
US8006743B2 (en) 2004-01-20 2011-08-30 Sms Siemag Ag Method and device for determining the position of the solidification point
AT512214A1 (de) * 2011-12-05 2013-06-15 Siemens Vai Metals Tech Gmbh Prozesstechnische massnahmen in einer stranggiessmaschine bei giessstart, bei giessende und bei der herstellung eines übergangsstücks
AT512214B1 (de) * 2011-12-05 2015-04-15 Siemens Vai Metals Tech Gmbh Prozesstechnische massnahmen in einer stranggiessmaschine bei giessstart, bei giessende und bei der herstellung eines übergangsstücks
US9254520B2 (en) 2011-12-05 2016-02-09 Siemens Vai Metals Technologies Gmbh Process engineering measures in a continuous casting machine at the start of casting, at the end of casting and when producing a transitional piece

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