Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/14—Closures
  • B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
  • B22D41/38—Means for operating the sliding gate
• • 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
  • B22D11/10—Supplying or treating molten metal
• • 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
  • B22D11/16—Controlling or regulating processes or operations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D37/00—Controlling or regulating the pouring of molten metal from a casting melt-holding vessel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/14—Closures
  • B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
  • B22D41/28—Plates therefor

Definitions

• the main object of the present invention is a systematic method making it possible to objectively decide whether a refractory plate of a drawer obturator used for controlling the flow of a liquid metal during the pouring of said metal from an upper container to a lower container can be reused or must be discarded.
• the invention relates to a device provided for this purpose.
• Most drawer shutters include a set of refractory plates, each provided with at least one pouring orifice, inserted in a mechanism allowing relative movement of the plates while ensuring their compression so that the jet of liquid metal can flow more or less easily through the openings of adjacent plates depending on the throttling rate of the openings.
• the relative movement of the plates takes place according to a movement of linear translation, rotation or any other trajectory.
• the relative movement of the plates is generally ensured by the force exerted by a jack (hydraulic, pneumatic or electromechanical) or also by a motorized drive system.
• the throttling rate of the plates is constantly adjusted so as to keep the casting conditions (flow rate, height of metal in the lower container, etc.) within the appropriate limits.
• Such slide shutters can be used for casting from an oven to a pocket or a converter, from a converter to a pocket or from a pocket to a distribution basin.
• the present invention relates to these different possibilities. For the sake of brevity, however, it will mainly be described in the context of casting from a ladle to a distribution basin.
• the refractory plates are subjected to numerous and severe stresses which, in the long run, are responsible for their wear.
• these are thermal stresses (high casting temperature), chemical stresses (composition of the cast metal, slag), mechanical stresses (strangulation intensity, relative number of displacements, etc.), thermomechanical stresses (thermal shock) , etc.
• certain events and incidents that occurred during casting operations can have a preponderant impact on the state of the refractory plates.
• This visual inspection is carried out at a so-called "preparation” area (metallurgical vessels) where the metallurgical vessels are arranged so that access to the drawer shutter is easy. It will be noted that this preparation zone is often distant from the casting zone where the casting operations proper are practiced so that, practically, very little information is exchanged between operators of these different zones.
• the present invention therefore relates to a method for objectively deciding whether a refractory plate of a drawer obturator used for the control of the flow of a liquid metal during the pouring of said metal from an upper container to a lower container can be reused or must be discarded.
• the method according to the invention is characterized in that the decision to reuse or reject the refractory plate is based on a set of parameters determined, calculated or measured during successive uses of the plate which are then compared , at the time of decision-making, at threshold values.
• the threshold values are determined according to the local conditions of use; for example, depending on the installation itself, the casting process, the quality of liquid metal poured and the acceptable safety margin.
• the parameters determined, measured or calculated during casting are representative of the actual wear of the plates and take account of the history of the plates by integrating the data relating to the various events and incidents which may have occurred during their use.
• This method incorporates a certain number of quantities which are normally available in casting installations (weight of metal in the upper container for example).
• the method is based on an instant determination of the wear of the plates.
• the method determines the wear of the throttling lips of the plates by calculating the difference between the measured throttling rate of the shutter and the throttling rate calculated by the laws of physics. This difference in throttling rate can be compared to a threshold value beyond which a decision to reject the plates must be made.
• the theoretical throttling rate can also be easily calculated as follows.
• this passage section corresponds to a theoretical throttling rate.
• the difference between the measured and theoretical throttle rate values provides a measure of wear.
• the difference in throttling rate can be expressed in terms of length corresponding to the worn part of the lips of the plates. We can then compare this length to a maximum length beyond which the plates must be spread.
• the method assesses the wear of the throttle lips by calculating the difference between the actual flow calculated for an instantaneous position of the shutter measured by a device suitable for an instantaneous ferrostatic pressure calculated as a function of the instantaneous weight of metal and the geometry inside of the upper container at a given moment, for a given pouring hole diameter (new plates or used plates) and the same flow rate calculated by the laws of physics.
• This difference in flow rate can also be compared to a threshold value beyond which a decision to reject the plates must be made.
• the method evaluates the radial wear of the plate orifices by calculating the difference between the actual flow rate measured when the shutter is open at full jet, at instantaneous ferrostatic pressure calculated as a function of the instantaneous weight of metal and the inner geometry of the upper container at that time, and the flow calculated by the laws of physics under the same conditions. This difference in flow rate can also be compared to a threshold value beyond which a decision to reject the plate must be made.
• the method can take into account the energy (hydraulic pressure or electric current) consumed for the sliding of the movable plate.
• This measurement gives an image of the roughness of the sliding surface of the movable plate with respect to the fixed plate or fixed plates (i.e., an image of the wear of the contact surface of the plates) and of the mechanical state of the system or, more generally, an image of the alteration of the relative displacement characteristics of the plates.
• a plate rejection or plate and shutter inspection threshold may be considered.
• the method incorporates the time of use of the plates in wear condition.
• account is taken of the time which has elapsed during which the refractory plates have actually been subject to wear.
• it is necessary to deduce from the total casting time, the total closing time and the total opening time insofar as, in these two positions, the plates undergo little or no wear.
• the method according to the invention therefore comprises a step of comparing the time of use of the plate in wear condition with a threshold value.
• the number of relative movements (linear or rotary) made by the plates is counted. This number of movements can also be compared to a threshold value beyond which a decision to reject the plate must be made.
• the accuracy of the decision is improved by integrating the times associated with the incidents. It can be observed that in the event of an unnatural opening of a metallurgical container which requires recourse to the devastating action of a blowtorch, the number of blowtorches required and therefore the intensity and the duration of the uncorking process under action of the torch - and therefore the wear of the resulting plates - are directly proportional to the time during which the orifice of the plate remained blocked.
• the method takes into account an infiltration of liquid metal between the plates (which can be associated with the fact that the shutter being completely closed, a residual metal flow exists). In the case of a serious incident which could jeopardize the installation, the method gives a signal for the immediate removal of the refractories.
• each of the events or incidents is assigned a severity index.
• the decision method integrates two or more of the embodiments (and their variants) set out above: as soon as one of the values compared to its corresponding threshold value is exceeded, a decision to reject the plate is made.
• one can also decide to provide a "zone of indecision" corresponding to a situation in which no threshold value has been exceeded, but in which one would approach these values for at least two of the parameters.
• the invention relates to a device intended for the implementation of the method described above. It is therefore a decision-making device for reuse or rejection of a refractory plate of a slide valve used for controlling the flow of a liquid metal during the pouring of said metal from an upper container.
• the apparatus comprising an input unit connected to sensors, detectors or counters for the introduction of selected quantities, a unit for memorizing threshold values, a calculation unit capable of performing different operations on the quantities introduced via the input unit and compare the quantities or the results of said operations on these quantities with threshold values and an output unit capable of emitting a signal corresponding to the reuse or rejection decision.
• the device also stores the different quantities linked to a set of plates during its successive uses.
• each set of plates is clearly identified. This can be done by identifying the set of plates using, for example, bar codes.
• the set of plates When the set of plates is introduced into the slide valve mounted on a given casting container, the set of plates no longer being visible, it therefore becomes necessary to also identify this container unequivocally so that ( thanks to a link between the identifiers of the set of plates and of the pouring container) the information relating to a set of plates can be retrieved from the identifier of the upper container.
• the different units of the device can be distant from each other; as the pouring area can be moved away from the preparation area. Therefore, it is also advantageous for the signal transmissions between the different units to be carried out by a computer network, telephony or over the air.
• Figure 1 a schematic version of the method according to the invention applied to a continuous casting ladle of steel provided with a hydraulically operated slide valve.
• the storage step in this case consists in entering into the storage unit the various threshold values which have been retained. For example, the values of the casting time, number of relative movements and wear of the lips beyond which a rejection decision must be made or beyond which a visual inspection is recommended are set.
• the coefficients linked to the incidents are also fixed at this stage, as well as, if necessary, the severity indices. These values can be entered manually, but preferably the device retrieves them from a library, taking into account the local conditions of use.
• the static acquisition step consists of introducing via the input unit of the system the information relating to the pocket (internal geometry) and to the set of plates (history) to be the subject of the decision.
• the dynamic acquisition step comprises the acquisition, during all the casting operations, of the different values of the parameters selected. For example, the pouring time of the bag during emptying, the instantaneous weight of the bag, the number of movements, the hydraulic pressure of the jack, the instantaneous position of the end of the jack, etc.
• the calculation step comprises the calculation of the different values which are not acquired directly by the system, but which it is possible to determine from the acquired values.
• the processing step comprises the determination of the various incidents (blockage, clogging, infiltration) from the quantities acquired beforehand.
• the comparison step consists in comparing the quantities thus determined or the quantities acquired with the threshold values contained in the storage unit. These last four steps are repeated throughout the emptying of the bag.
• the last decision step is implemented.
• the system emits a signal (visual or audible) corresponding either to a decision to reject or to reuse or to a recommendation to carry out the visual inspection.
• Figure 2 there is shown schematically a device for the implementation of this method. There is shown a pocket 1 in the casting zone. The pocket is fitted with a linear or rotary drawer shutter 2 and is connected to a decision-making device 4 by a connection 3.
• the device 4 itself comprises a storage unit, one (or more) unit (s) ) acquisition, calculation, processing and exit. Finally, the device 4 is connected to an output device 6 (here represented by a traffic light) by a connection 5.
• the connection represented here by a line can be carried out by wiring, radio or other means.
• the outlet device 6 will be located in the bag preparation area.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Carbon Steel Or Casting Steel Manufacturing (AREA)
• Sliding Valves (AREA)
• Operating, Guiding And Securing Of Roll- Type Closing Members (AREA)
• Specific Sealing Or Ventilating Devices For Doors And Windows (AREA)
• Furnace Charging Or Discharging (AREA)
• Processing Of Solid Wastes (AREA)
• Gasification And Melting Of Waste (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (2)

Family

ID=34072705

Family Applications (1)

Country Status (16)

Families Citing this family (6)

Family Cites Families (20)

• 2004
  • 2004-07-20 CA CA2532890A patent/CA2532890C/fr not_active Expired - Fee Related
  • 2004-07-20 AU AU2004257357A patent/AU2004257357B2/en not_active Ceased
  • 2004-07-20 RU RU2006102431/02A patent/RU2352436C2/ru not_active IP Right Cessation
  • 2004-07-20 KR KR1020067001441A patent/KR101068604B1/ko not_active Expired - Fee Related
  • 2004-07-20 CN CNB2004800209952A patent/CN100376345C/zh not_active Expired - Fee Related
  • 2004-07-20 BR BRPI0412865-6A patent/BRPI0412865A/pt not_active Application Discontinuation
  • 2004-07-20 EP EP04737689A patent/EP1654083B1/de not_active Revoked
  • 2004-07-20 ZA ZA200600119A patent/ZA200600119B/xx unknown
  • 2004-07-20 MX MXPA06000783A patent/MXPA06000783A/es active IP Right Grant
  • 2004-07-20 JP JP2006520634A patent/JP2006528070A/ja active Pending
  • 2004-07-20 WO PCT/BE2004/000106 patent/WO2005007325A1/fr not_active Ceased
  • 2004-07-20 DE DE602004003712T patent/DE602004003712T2/de not_active Expired - Lifetime
  • 2004-07-20 UA UAA200600979A patent/UA81333C2/uk unknown
  • 2004-07-20 ES ES04737689T patent/ES2274460T3/es not_active Expired - Lifetime
  • 2004-07-20 AT AT04737689T patent/ATE347956T1/de active
  • 2004-07-20 US US10/565,480 patent/US7487820B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events