CA1156423A - Controlling the continuous casting of metals - Google Patents
Controlling the continuous casting of metalsInfo
- Publication number
- CA1156423A CA1156423A CA000319690A CA319690A CA1156423A CA 1156423 A CA1156423 A CA 1156423A CA 000319690 A CA000319690 A CA 000319690A CA 319690 A CA319690 A CA 319690A CA 1156423 A CA1156423 A CA 1156423A
- Authority
- CA
- Canada
- Prior art keywords
- signal
- mould
- continuous casting
- casting
- predetermined value
- 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
Links
- 238000009749 continuous casting Methods 0.000 title claims abstract description 93
- 239000002184 metal Substances 0.000 title claims description 27
- 229910052751 metal Inorganic materials 0.000 title claims description 27
- 150000002739 metals Chemical class 0.000 title description 4
- 238000005266 casting Methods 0.000 claims abstract description 116
- 239000000463 material Substances 0.000 claims abstract description 47
- 229910001338 liquidmetal Inorganic materials 0.000 claims abstract description 31
- 239000000470 constituent Substances 0.000 claims abstract description 13
- 206010000117 Abnormal behaviour Diseases 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 57
- 230000006870 function Effects 0.000 claims description 31
- 230000004044 response Effects 0.000 claims description 29
- 230000002123 temporal effect Effects 0.000 claims description 25
- 230000010355 oscillation Effects 0.000 claims description 20
- 230000004907 flux Effects 0.000 claims description 17
- 230000033228 biological regulation Effects 0.000 claims description 15
- 238000010586 diagram Methods 0.000 claims description 10
- 230000001276 controlling effect Effects 0.000 claims description 8
- 238000005507 spraying Methods 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 230000003542 behavioural effect Effects 0.000 claims description 3
- 239000012809 cooling fluid Substances 0.000 claims description 3
- 230000001419 dependent effect Effects 0.000 claims description 3
- 238000011161 development Methods 0.000 claims description 3
- 238000007654 immersion Methods 0.000 claims description 3
- 230000001105 regulatory effect Effects 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 239000000725 suspension Substances 0.000 claims description 3
- 230000005856 abnormality Effects 0.000 claims 2
- 238000001514 detection method Methods 0.000 claims 1
- 238000012544 monitoring process Methods 0.000 claims 1
- 239000000843 powder Substances 0.000 description 33
- 229910000831 Steel Inorganic materials 0.000 description 22
- 239000010959 steel Substances 0.000 description 22
- 230000007547 defect Effects 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- 239000000314 lubricant Substances 0.000 description 6
- 230000002159 abnormal effect Effects 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000007792 addition Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 101150087426 Gnal gene Proteins 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229920000136 polysorbate Polymers 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- RZVAJINKPMORJF-UHFFFAOYSA-N Acetaminophen Chemical compound CC(=O)NC1=CC=C(O)C=C1 RZVAJINKPMORJF-UHFFFAOYSA-N 0.000 description 1
- 229910018125 Al-Si Inorganic materials 0.000 description 1
- 229910018520 Al—Si Inorganic materials 0.000 description 1
- 229910000655 Killed steel Inorganic materials 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000000332 continued effect Effects 0.000 description 1
- 230000002844 continuous effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- BTCSSZJGUNDROE-UHFFFAOYSA-N gamma-aminobutyric acid Chemical compound NCCCC(O)=O BTCSSZJGUNDROE-UHFFFAOYSA-N 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002674 ointment Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- SYOKIDBDQMKNDQ-XWTIBIIYSA-N vildagliptin Chemical compound C1C(O)(C2)CC(C3)CC1CC32NCC(=O)N1CCC[C@H]1C#N SYOKIDBDQMKNDQ-XWTIBIIYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- 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
- B22D11/07—Lubricating the moulds
-
- 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
- B22D11/168—Controlling or regulating processes or operations for adjusting the mould size or mould taper
-
- 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
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
- B22D11/208—Controlling or regulating processes or operations for removing cast stock for aligning the guide rolls
Abstract
A B S T R A C T
A signal S representing the frictional forces arising ?etween the strand and the mould during a continuous casting operation is provided by selecting according to at least two frequency bands, e.g. 0.2 to 3 Hz and 3 to 10 Hz, the constituents of a signal, e.g.
from a mould-movement sensor, representing the frictional forces. The signal S is preferably a signal representing the ratio of the demodulated constituents. Any abnormal behavior of at least one Or a plurality of continuous casting factors, particularly those related to the covering, material on the liquid metal, is detected by comparing the signal S with an analog-type reference signal considered as ideal for satisfactory casting.
The abnormal behaviour is corrected by modifying the factor concerned so that the signal S comes as close as possible to the reference signal.
A signal S representing the frictional forces arising ?etween the strand and the mould during a continuous casting operation is provided by selecting according to at least two frequency bands, e.g. 0.2 to 3 Hz and 3 to 10 Hz, the constituents of a signal, e.g.
from a mould-movement sensor, representing the frictional forces. The signal S is preferably a signal representing the ratio of the demodulated constituents. Any abnormal behavior of at least one Or a plurality of continuous casting factors, particularly those related to the covering, material on the liquid metal, is detected by comparing the signal S with an analog-type reference signal considered as ideal for satisfactory casting.
The abnormal behaviour is corrected by modifying the factor concerned so that the signal S comes as close as possible to the reference signal.
Description
1 ~ 5B~2 3 "~ON'I'L~ OLLING 'l'~:Ih (:~OrT'.l'Il~`llJ()lJS C~A~ MG OF M~æ'l'AI.,S"
'L`he present inven-liion relates to a rnethod and app~rat-us f;or controllin~ the continuous castirig of a metal. ~he descrip-tion which follows is based on the I specific case of the continuous casting of steel, but this is simply given as an example, as the inventicn ¦ relates to the continuous casting o~ metals in general.
It is well known that the process of continuous castin~ of steel is highly complex, in particular in the case of the continuous casting of strands of large cross-¦ 10 sections, and that a large number of factors are taken ¦ into account when determining the optimum conditions for continuous casting operations.
Amongst the aspec-ts of continuous casting which should in particular be taken into account in a control ¦ 15 process are the level and the temperature of the liquid ¦ metal in the basket, the position of the nozzle in the ~ould, the level of the liquid metal in the mould, the selection, the type, and the quantity of the covering 1 powder, bonding of the strand, the casting speed, ¦ 20 oscillationiof the mould, the conicity of the mould faces, the heat exchange wlth respect to the mould and I the first spraying zones at the exit of the mould, and lastly the regulation of the rollers at the base of the continuous casting mould.
~he following is an account of tthe effect of the above factors on working co~ditl ns for continuous casting 1, , ' '~
I
1 1$~3 f ~tc~l I-t is well known t-hat, in theS contimlo-us crl-Jting~
of steel, in p~lrticular when cas-ting strands ha-rlny;
large cross-sections, the upper surfacc of the strand is covered with a covering material of suitable composition during casting. This material plays a multiple role, in par-ticular -to ensure, with respec~
to the air, adequate thermal insulation of the upper surface of the strand and protection against oxidation, ! 10 to capture imp~rities in the steel, and to act as a 3 lubricant be-tween the s-trand and the mould~ to best ensure heat transfer from the strand to the mould, whilst accommodating oscillations of the mould.
i When this covering material is applied to the 15 surface of the strand during continuous casting, it mav have physical aggregation states which vary i~nensely, such as powder, paste, fibres, or flexible or rigid geometrical shapes, acoording to the extent to which it ~ ; is processed.
Z 20 In the particular case of powder, this is in general composed of CaO, S02, A1303, with a flux such as, for example, CaF2, K20, Na20, and in most cases a, with proportions depending on the features of the strand to be cast and the casting conditions. ~he permanen-t contact of this material with the continuously renewed metal is most often obtained by a suitable configuration of the end of the casting nozzls, by which some at least
'L`he present inven-liion relates to a rnethod and app~rat-us f;or controllin~ the continuous castirig of a metal. ~he descrip-tion which follows is based on the I specific case of the continuous casting of steel, but this is simply given as an example, as the inventicn ¦ relates to the continuous casting o~ metals in general.
It is well known that the process of continuous castin~ of steel is highly complex, in particular in the case of the continuous casting of strands of large cross-¦ 10 sections, and that a large number of factors are taken ¦ into account when determining the optimum conditions for continuous casting operations.
Amongst the aspec-ts of continuous casting which should in particular be taken into account in a control ¦ 15 process are the level and the temperature of the liquid ¦ metal in the basket, the position of the nozzle in the ~ould, the level of the liquid metal in the mould, the selection, the type, and the quantity of the covering 1 powder, bonding of the strand, the casting speed, ¦ 20 oscillationiof the mould, the conicity of the mould faces, the heat exchange wlth respect to the mould and I the first spraying zones at the exit of the mould, and lastly the regulation of the rollers at the base of the continuous casting mould.
~he following is an account of tthe effect of the above factors on working co~ditl ns for continuous casting 1, , ' '~
I
1 1$~3 f ~tc~l I-t is well known t-hat, in theS contimlo-us crl-Jting~
of steel, in p~lrticular when cas-ting strands ha-rlny;
large cross-sections, the upper surfacc of the strand is covered with a covering material of suitable composition during casting. This material plays a multiple role, in par-ticular -to ensure, with respec~
to the air, adequate thermal insulation of the upper surface of the strand and protection against oxidation, ! 10 to capture imp~rities in the steel, and to act as a 3 lubricant be-tween the s-trand and the mould~ to best ensure heat transfer from the strand to the mould, whilst accommodating oscillations of the mould.
i When this covering material is applied to the 15 surface of the strand during continuous casting, it mav have physical aggregation states which vary i~nensely, such as powder, paste, fibres, or flexible or rigid geometrical shapes, acoording to the extent to which it ~ ; is processed.
Z 20 In the particular case of powder, this is in general composed of CaO, S02, A1303, with a flux such as, for example, CaF2, K20, Na20, and in most cases a, with proportions depending on the features of the strand to be cast and the casting conditions. ~he permanen-t contact of this material with the continuously renewed metal is most often obtained by a suitable configuration of the end of the casting nozzls, by which some at least
2 3 of the Metal which is passLng 1;hrough it is co~tinuou~sly directad towards thi-; material. 'l~lis covering powder can be prepared in variou3 ways. Some powders are syn-thetic mixtures of various pre-powdered constituer.ts, whereas others are prepared by a premelting operation of a mixture of suitable constituents, followed by powdering.
Moreover, the powders obtained in this way can be formed ~, into various shapes.
~ Recent experiments have shown ~hat not only the J 10 chemical and mineralogical composition, and -thé treatments for preparing these powders (mixing, melting, powdering, addition of binder) have a very great effect on the continuously cast product, but also the shaping of these covering powders, e.g. if they have the form of sticks, 15 cubes, or other geometrical shapes, has a certain effect on the properties of the product obtained by continuous ~ casting.
¦ Control of the casting process is normally carried out by observing the behaviour and appearance of the ¦ 20~ surface of the strand during cooling from the point at ¦ which the strand emerges from -the spraying zone of the continu~ous casting machine. However, this method has the ~ drawback that certain faults, due perhaps to the selection i~ of an inedequate covering powder or to deterioration of j 25 the covering powder, are only discovered at a late stage, ! and that the measures designed to prevent them are subject to a delay before being effective. ~his means -that lt is very dif-ficul-t ~o avoid quite consideI,able sections of: t~.Le cas t str~lcl occasiona'lly ~eing re jected or a-t least downgraded.
~, ~aking into account the above considerations, it is possible to see the advantage of having a means of '' controlling the adequa-te selection of ~he covering powder in terms of the casting condi-tions and the ~ composition of the steel, and furthermore of ensuring ¦ ~ that this con-trol is continuous in order to detect all faults as quickly as possible during casting and to enable a remedy to be quickly applied.
' It is known that certain problems may arise when i the steel passing through the casting nozzle and contacted , with the covering powder has a ternperature which is too I - 15 low or too high. In the first case, the metal may block or at least restrict the flow from the casting nozzles and in addition may not have enough calorific energy to melt the covering powder with which it is contacted; if it is insufficiently melted, the powder can ~either absorb the impurities which separate from the steel nor carry out its function of lubrica~t.
~,he level of the liquid metal in the basket, must , also be regula-ted; if it becomes too low, the impurities in the covering powder in the baske-t are drawn into the mould and contaminate the continuously cast strand. The position of the casting nozzle, in particular centering and depth of lmmersion has, as is known, a considerable 4.
I
; 4 2 3 eEfect on -the path which -the llquid metal follows in the mould and thexefore on the efficienc~ of -the effect of -the covering powder. Verlficat:ion of the position of this nozzle is at present usuall~ carried out by inspecting the strand during cooling from the point at I which the strand emerges froM the spraying zone of the ,1 casting machine, and is carried out for a number of castings in order that empirical rules may be established.
However, -this method has the drawback that faults due to 10 incorrect positioning of the nozzle are only detected at a late stage and that measures designed to correct the nozzle are subject to some delay before taking effect.
~his does not prevént sometimes quite considerable sections of the strand being rejected or at least down-15 graded and in addition it does not enable rupture of the surface of the strand, as a result of incorrect positioning J of the nozzle~ to be anticipated. ~his demonstrates the advantage o~ having continuous control of the position of the nozzle, in particular a-t the moment of casting, 20 and a control which ensures that it is maintained or I moved into the optimum position as required.
j ~ It is important to maintain the level of the upper surface of the liquid metal in the mould as constant as ~i possible, in particular to avoid certain surface defects 25 in the strand. ~hese arise for example when the flow of ¦ covering material, as well as the lubricant film, are I subject ~o alternate stresses due to the reciprocating .....
1 iL5~A23 movem~rl~ oL the m~t~l SUl'f'aC~'~ If~ t i.s stretched too far al.ong the mould wall by a dccrease or an increase in the level o~ the metal, the fll7n tears. Va:riation in the metal level may also cause rupture of -the strand as a resul-t of slag borders being included.
~ he determination of the steel level in the mould in addi-tion enables the flow for the cast;ng nozzle to be controlled~
Normally the position of the upper surface of the metal in the mould is monitored op-tically or by means of level detectors, such as radioactive pick-ups; these various conventional methods all ha.ve their own advantages ; and disadvantages.
i It is known that continuous casting conditions are 1 15 largely dependent on the quantity of covering powder used I ~ during casting. ~he absence of lubricant, as a result of the depletion of the covering powder, may give rise to ` fissures in the strand surface, resulting from a frictional èffort which is too large being exerted by the mechanical handling means, in particular for withdrawing the strand. Moreover, excessive lubricant may disturb the casting conditions, cause casting malfunctions, and ~ r harm the quality of the strand.
It can be seen from the preceding r escription that it would be advantageous to be able to continuously dose the quantity of covering powder applied during continuous casting and to do this in terms of the casting , 6~
4 ~ 3 .
t conditions and the composition of the steel, in order to restrlct, as stated above, the size of the rejected sections.
Another very important aspect of continuous casting ~i 5 of the strand is the risk of the steel bonding to the ! \ mould. ~his phenomenon may result in the deterioration of the strand surface and sometiraes even rupture of the ~; ~ . . . .
skin. It can therefore be seen that it is extremely useful to have a rapid information means continuously analysing this phenomenon.
~he casting speed, that is the speed at which the ~1 continuous cast strand is withdrawn from the mould, also has a considerable effect on the quality of the product j obtained. An incorrect selection of speed may cause ¦ 15 fissures and other defects superficially and i~ternally, ` and may even give rise to rupture.
It can easily be seen that the factors relating to oscillation of the mould such as the frequency, the ` amplitude, or the shape, effect the surface quality of the continuously cast product.
Quite an important cause of the appearance of defects or even rupture in the continuous cast strand is incorrect tapering of the faces of the continuous ~ casting mould. An insufficiently conical arrangement 1 25 Of the faces of the mould results in the formation of a skin which is unable to resist the mechanical stresses appli~d to the strand, and can thus give rise to rupture;
' furthermo:re, an arr~gernent which :is too conical give, rise to strand-mould friction which is too lar~e, resulting irl a skin having many surface defes-t~. It goes withou-t saying that the conditions for -regula-ting 5~ the conicity of the faces of the ingot rnould vary according to -the casting conditions and the composition of the steel. It is importan-t, for this reason, to ensure for each casting operation and each type of steel suitable regulation of this conicity, which will avold 10 all these defects.
¦ It is known that an important problem in the ¦ continuous casting of metals lies in evaluating the heat I excha~ge between the strand and the mould during solidification. It is in fact very important to trace ~¦ 15 continuously the variations of heat exchange between the ¦ strand and the mould, in order to be able to take rapidaction if a defect is detected. ~rom this estimation of the-heat flux between the strand and the mould, the I solidification of the strand may easily be traced, and t 20 thus the risks of defects appearing may be ~nticipated, particularly surface defects such as rupture during casting. Knowledge of the heat flux between the strand and the mould also enables one to determine the mechanical stresses of thermal origin to which the mould is subject 25 and in particular to anticipate any abnormal increase of the temperature of the mould which ~ould prove detrimental i to the mould.
.
~ eat e~charl~e betwoen the rnould anrl th,e strand i,5 curIently monitored by mea,;uring -the ternperclture ~rsriation between the input ~nd t-he ou-tput of th,e cooling water for the mould~ or by means of thermocouples incorporatsd in the mould. However, -these two methods have drawbacks, in particular requiring complex calculations for determining continuously, the value of the hea-t flux, from ternperature measurements taking into account the heat transfer parameters which are linked to the particular specific conditions for each casting operation and lor each continuously cast metal, and in addition the quite considerable response time between the time at which the variation of the hea-t flux occurs and the time at which it is detected by means of temperature measurements.
With respect to the second method in particular, this has in addition the serlous drawback of weakening the mould as a result of the introduction of thermocouples, which decreases its mechanical strength.
~ hese conditions show that it would be advantageous to have a-process, for continuously controlling the heat flux between the strand and the continuous casting mould, which does not have the above drawbacks~
Regulation of the rollers at the base of the mould effects the quality of the cast product by the bias of forces which these rollers-exert on the cast edge, particularly in terms of clamping, determined by their distance apart. For this reason it i~ very advantageous to ha~Te a means of determining adequate regulation of , 9~
, ' ' .
!
1 ~5~42;3 the posi~ion and in par-ticular th~ (listarce apfJ.r t oi the rollers at the base of -the mould (in p~-cticlllar as regulation varies accord;ng to the type of cas-ting operation and the composi-tion of the steel), in order to prevent surface defects due to the effect of the base rollers.
~ he present invention is based on the unexpected disco-very -that -there is a cause to effect relationship between, on the one hand, the frictional forces which exist be-tween the strand and the mould during a I continuous casting operation and, on the other hand, i certain factors such as:
~ - the level of the liguid metal in the casting basket, ;~ - the temperature of the liguid metal in the casting `, 15 basket, ;~ - the position of the casting nozzle in the mould, - the level of the liguid metal in the mould, - the type of covering material, - the amount of covering materlal, - the bonding of the strand, - the;casting speed, - factors concerning oscillations of the mould, such as gulding suspension, and freguency.
- the conicity of the facas of the mould, ,25 - the heat exchange in the mould and at the first Ispraying zones at the exit of the mould.
- regulation of the base rollers of -the mould.
10.
Moreover, the powders obtained in this way can be formed ~, into various shapes.
~ Recent experiments have shown ~hat not only the J 10 chemical and mineralogical composition, and -thé treatments for preparing these powders (mixing, melting, powdering, addition of binder) have a very great effect on the continuously cast product, but also the shaping of these covering powders, e.g. if they have the form of sticks, 15 cubes, or other geometrical shapes, has a certain effect on the properties of the product obtained by continuous ~ casting.
¦ Control of the casting process is normally carried out by observing the behaviour and appearance of the ¦ 20~ surface of the strand during cooling from the point at ¦ which the strand emerges from -the spraying zone of the continu~ous casting machine. However, this method has the ~ drawback that certain faults, due perhaps to the selection i~ of an inedequate covering powder or to deterioration of j 25 the covering powder, are only discovered at a late stage, ! and that the measures designed to prevent them are subject to a delay before being effective. ~his means -that lt is very dif-ficul-t ~o avoid quite consideI,able sections of: t~.Le cas t str~lcl occasiona'lly ~eing re jected or a-t least downgraded.
~, ~aking into account the above considerations, it is possible to see the advantage of having a means of '' controlling the adequa-te selection of ~he covering powder in terms of the casting condi-tions and the ~ composition of the steel, and furthermore of ensuring ¦ ~ that this con-trol is continuous in order to detect all faults as quickly as possible during casting and to enable a remedy to be quickly applied.
' It is known that certain problems may arise when i the steel passing through the casting nozzle and contacted , with the covering powder has a ternperature which is too I - 15 low or too high. In the first case, the metal may block or at least restrict the flow from the casting nozzles and in addition may not have enough calorific energy to melt the covering powder with which it is contacted; if it is insufficiently melted, the powder can ~either absorb the impurities which separate from the steel nor carry out its function of lubrica~t.
~,he level of the liquid metal in the basket, must , also be regula-ted; if it becomes too low, the impurities in the covering powder in the baske-t are drawn into the mould and contaminate the continuously cast strand. The position of the casting nozzle, in particular centering and depth of lmmersion has, as is known, a considerable 4.
I
; 4 2 3 eEfect on -the path which -the llquid metal follows in the mould and thexefore on the efficienc~ of -the effect of -the covering powder. Verlficat:ion of the position of this nozzle is at present usuall~ carried out by inspecting the strand during cooling from the point at I which the strand emerges froM the spraying zone of the ,1 casting machine, and is carried out for a number of castings in order that empirical rules may be established.
However, -this method has the drawback that faults due to 10 incorrect positioning of the nozzle are only detected at a late stage and that measures designed to correct the nozzle are subject to some delay before taking effect.
~his does not prevént sometimes quite considerable sections of the strand being rejected or at least down-15 graded and in addition it does not enable rupture of the surface of the strand, as a result of incorrect positioning J of the nozzle~ to be anticipated. ~his demonstrates the advantage o~ having continuous control of the position of the nozzle, in particular a-t the moment of casting, 20 and a control which ensures that it is maintained or I moved into the optimum position as required.
j ~ It is important to maintain the level of the upper surface of the liquid metal in the mould as constant as ~i possible, in particular to avoid certain surface defects 25 in the strand. ~hese arise for example when the flow of ¦ covering material, as well as the lubricant film, are I subject ~o alternate stresses due to the reciprocating .....
1 iL5~A23 movem~rl~ oL the m~t~l SUl'f'aC~'~ If~ t i.s stretched too far al.ong the mould wall by a dccrease or an increase in the level o~ the metal, the fll7n tears. Va:riation in the metal level may also cause rupture of -the strand as a resul-t of slag borders being included.
~ he determination of the steel level in the mould in addi-tion enables the flow for the cast;ng nozzle to be controlled~
Normally the position of the upper surface of the metal in the mould is monitored op-tically or by means of level detectors, such as radioactive pick-ups; these various conventional methods all ha.ve their own advantages ; and disadvantages.
i It is known that continuous casting conditions are 1 15 largely dependent on the quantity of covering powder used I ~ during casting. ~he absence of lubricant, as a result of the depletion of the covering powder, may give rise to ` fissures in the strand surface, resulting from a frictional èffort which is too large being exerted by the mechanical handling means, in particular for withdrawing the strand. Moreover, excessive lubricant may disturb the casting conditions, cause casting malfunctions, and ~ r harm the quality of the strand.
It can be seen from the preceding r escription that it would be advantageous to be able to continuously dose the quantity of covering powder applied during continuous casting and to do this in terms of the casting , 6~
4 ~ 3 .
t conditions and the composition of the steel, in order to restrlct, as stated above, the size of the rejected sections.
Another very important aspect of continuous casting ~i 5 of the strand is the risk of the steel bonding to the ! \ mould. ~his phenomenon may result in the deterioration of the strand surface and sometiraes even rupture of the ~; ~ . . . .
skin. It can therefore be seen that it is extremely useful to have a rapid information means continuously analysing this phenomenon.
~he casting speed, that is the speed at which the ~1 continuous cast strand is withdrawn from the mould, also has a considerable effect on the quality of the product j obtained. An incorrect selection of speed may cause ¦ 15 fissures and other defects superficially and i~ternally, ` and may even give rise to rupture.
It can easily be seen that the factors relating to oscillation of the mould such as the frequency, the ` amplitude, or the shape, effect the surface quality of the continuously cast product.
Quite an important cause of the appearance of defects or even rupture in the continuous cast strand is incorrect tapering of the faces of the continuous ~ casting mould. An insufficiently conical arrangement 1 25 Of the faces of the mould results in the formation of a skin which is unable to resist the mechanical stresses appli~d to the strand, and can thus give rise to rupture;
' furthermo:re, an arr~gernent which :is too conical give, rise to strand-mould friction which is too lar~e, resulting irl a skin having many surface defes-t~. It goes withou-t saying that the conditions for -regula-ting 5~ the conicity of the faces of the ingot rnould vary according to -the casting conditions and the composition of the steel. It is importan-t, for this reason, to ensure for each casting operation and each type of steel suitable regulation of this conicity, which will avold 10 all these defects.
¦ It is known that an important problem in the ¦ continuous casting of metals lies in evaluating the heat I excha~ge between the strand and the mould during solidification. It is in fact very important to trace ~¦ 15 continuously the variations of heat exchange between the ¦ strand and the mould, in order to be able to take rapidaction if a defect is detected. ~rom this estimation of the-heat flux between the strand and the mould, the I solidification of the strand may easily be traced, and t 20 thus the risks of defects appearing may be ~nticipated, particularly surface defects such as rupture during casting. Knowledge of the heat flux between the strand and the mould also enables one to determine the mechanical stresses of thermal origin to which the mould is subject 25 and in particular to anticipate any abnormal increase of the temperature of the mould which ~ould prove detrimental i to the mould.
.
~ eat e~charl~e betwoen the rnould anrl th,e strand i,5 curIently monitored by mea,;uring -the ternperclture ~rsriation between the input ~nd t-he ou-tput of th,e cooling water for the mould~ or by means of thermocouples incorporatsd in the mould. However, -these two methods have drawbacks, in particular requiring complex calculations for determining continuously, the value of the hea-t flux, from ternperature measurements taking into account the heat transfer parameters which are linked to the particular specific conditions for each casting operation and lor each continuously cast metal, and in addition the quite considerable response time between the time at which the variation of the hea-t flux occurs and the time at which it is detected by means of temperature measurements.
With respect to the second method in particular, this has in addition the serlous drawback of weakening the mould as a result of the introduction of thermocouples, which decreases its mechanical strength.
~ hese conditions show that it would be advantageous to have a-process, for continuously controlling the heat flux between the strand and the continuous casting mould, which does not have the above drawbacks~
Regulation of the rollers at the base of the mould effects the quality of the cast product by the bias of forces which these rollers-exert on the cast edge, particularly in terms of clamping, determined by their distance apart. For this reason it i~ very advantageous to ha~Te a means of determining adequate regulation of , 9~
, ' ' .
!
1 ~5~42;3 the posi~ion and in par-ticular th~ (listarce apfJ.r t oi the rollers at the base of -the mould (in p~-cticlllar as regulation varies accord;ng to the type of cas-ting operation and the composi-tion of the steel), in order to prevent surface defects due to the effect of the base rollers.
~ he present invention is based on the unexpected disco-very -that -there is a cause to effect relationship between, on the one hand, the frictional forces which exist be-tween the strand and the mould during a I continuous casting operation and, on the other hand, i certain factors such as:
~ - the level of the liguid metal in the casting basket, ;~ - the temperature of the liguid metal in the casting `, 15 basket, ;~ - the position of the casting nozzle in the mould, - the level of the liguid metal in the mould, - the type of covering material, - the amount of covering materlal, - the bonding of the strand, - the;casting speed, - factors concerning oscillations of the mould, such as gulding suspension, and freguency.
- the conicity of the facas of the mould, ,25 - the heat exchange in the mould and at the first Ispraying zones at the exit of the mould.
- regulation of the base rollers of -the mould.
10.
3 ~ 3 , j (~his li.st; i.s not made in any par-ticul~r order and the terms used have the mean.i.ngs given -to them by the con.-text of the preceding descriptlon.) ~hese factors . may be taken in isolation or combined in any number in several groups, as the various factors may occur ~ simultaneously.
'! ~ Accordingly, the present invention provides a control 3 method in which a measured signal S is continuously ~ compared, this signal representing the frictional forces ;~ 10 which arise between the strand and the mould during a 3 eontinuous casting operation and obtained by selécting, according to at least two frequency bands, thé constituents of the signal represen.ting the above friction forces, w~th a predetermined analog-type reference signal; as a 15 result of this comparison operation, the abnormal behaviour of one or several of the continuous casting . factors is detected, such as:
- the level and the temperature of the liquid metal in . the casting basket, 20 - the position of the casting nozzle in the mould, - the.type and amount of covering material, ~: - bonding of the s-trand, ¦ . - the casting speed, - factors concerning oscillations of the mould, such . 25 as guiding, suspension, and frequency, - - the conicity of the mould faces, - factors relating to regulation of the heat flux in 11 .
'! ~ Accordingly, the present invention provides a control 3 method in which a measured signal S is continuously ~ compared, this signal representing the frictional forces ;~ 10 which arise between the strand and the mould during a 3 eontinuous casting operation and obtained by selécting, according to at least two frequency bands, thé constituents of the signal represen.ting the above friction forces, w~th a predetermined analog-type reference signal; as a 15 result of this comparison operation, the abnormal behaviour of one or several of the continuous casting . factors is detected, such as:
- the level and the temperature of the liquid metal in . the casting basket, 20 - the position of the casting nozzle in the mould, - the.type and amount of covering material, ~: - bonding of the s-trand, ¦ . - the casting speed, - factors concerning oscillations of the mould, such . 25 as guiding, suspension, and frequency, - - the conicity of the mould faces, - factors relating to regulation of the heat flux in 11 .
4 2 3 the mou:Ld and at the f'ir,-t s~)r1ying zon~cJ ;k lt~ ex1t~
such as pressl1Ie an(l rate oL' flow of' t~e coolirlg fluid, - regulation of the rollers at the base of` the mou]d, ~ 5 and one or several of the actors are modified, simultaneously or in sequence, in particular those factors mentioned above, so that the measured signal is as close as possible to the predetermined re erence , signal which is considered ideal for satisfactory casting.
; 10 As a result of the method according to the invention, behavioural differences of one or several of the a~ove factors may be measured from tne predetermined behavoiur ; of the same factors resulting from previous castings of a similar type which were considered satisfactory.
In -the conventional control system for continuous casting, the determination of the abnormal character of the behaviour of one or several of the above factors is I carried out by direct determination using a technique known ~ se. ~his direct determination may advantageously be used additionally in the presen-t method.
In the case of the invention, the de-termina-tion of the abnormal character of the behaviour of one or several of the above factors may comprise t,he observation of a predetermined reference signal Si, with i - 0, .....
; 25 n, if n parameters are considered, the signal varying accordlng to the parame-ter in question.
It goes without saying that a re erence signal may be used which has been predetermined during one or i ~ severa.:l. pri.o.c castirlg ope.Latiorls having sirnilar ¦ characteristi.cs.
I ~he signal :representing the frictional forces is jl preferably measured by the shift of movements of the mould, for example its accelerations, which does not exclude a measu~ement of the friction forces by means of another physical ma~ni;ude which would be dependent on it.
In order to avoid any ambigui-ty with respect to the meaning of the terms "measured signal" and "reference signal" 7 precise details are given as follows. ~he terms "measured signal" and "reference signal" designate both continuous and discontinuous recordin~s of the friction forces, and even numerical values whlch represent the friction forces which act on a determined length of `1 the strand.
In order to make the object of the invention more comprehensible, various applications of the method I adapted to the case of certain continuous casting factors ~¦ 20 are given below wlth explanations; the different methods ~¦ of use~are given in an order which may be considered j preferable if they are all to be achieved, but this order j is not formally laid down.
he variation of the level of -the llquid metal ln the casting basket is monitored by observing the development of a signal S; if the measured signal S is.
13.
h:ighe-c ~harl or equa~ o a p-~edfterrrli.r~e(l v.rllue L~o~ it can be seen thal the level. of the met;al i..5 not belo~r a fi~ed -thresho:Ld; i:E -this is the case, r,leans suitable ~or increasing this above the predeterrnined threshold are actuated; the upper surface of the liquid metal may then be cleaned and fresh covering powder ma-y finally be added to the liqu~.d metal. After an interval which is a function of -the temporal constant of response to the beginning o:E casting and if the measured signal S has ' 10 again dropped below the predetermined value S0, the continuous casting operation is continued; otherwise another casting factor is tested~
~ According to another embodiment of the method according ! to the inven-tion~ which may be combined with any other embodiment, if the measured signal ~ is higher than or c~e~/~e~/
equal to a ~Y~ value S1 and if the temperature of the liquid metal in the casting basket - to be ~
~,ç c er7~Q ~ ~ec~
-~eF~e~ - is not between ~ - A and ~C + B or equal to these values (~C being an ideal predetermined temperature value, and A and B being constants which are functions ~ . of the characteristics of -the continuous casting plant -. and the t~pe of steel cast), observation is made to establish whether the tempera-t~re of the liquid metal is higher than ~ + B. If this is the case, the upper ; 25 surface of the liqui.d metal may for example be cleaned .
' .and then covering materi.al of higher viscosity added. -1L~. ~
1 ~ 2 3 I, After an inte:rvaL which is a flmctiorl of ~he ter~poral i constc~nt of response o:` the corltinuous cas-tin~.plant and I if the meas~red si.gnal S has agai.n become lower than or equal to S1, -the con-tinuous castirlg operation is continued;
if not, ano-ther cas-ting factor i,s tested. If on the other hand the temperature ~ is no-t higher than ~ -~ B
¦ and is therefore lower than ~ - A, subsequen-t measures are undertaken such as cleaning of the upper surface of the liquid metal and the addition of covering material of a lower viScosit~J. AIter an interval which is a ~ - function of the -temporal constan-t of response of the ;~, continuous casting plant and if -the measured signal S
has again become lower than S1 the continuous casting operation is con-tinued, if not, another casting factor is tested.
. Examp].e In the case of casting Al-Si medium killed steel (format 1,90Q x 200 mm and casting speed 0.8m/min) the ¦ ~ following relationship was es.tablished between the ¦ 20 variation (~) with respec-t to the casting -temperature . required (1,535~) and the variation of the measured signal ~ S%) i ~ TC _ _ a s%
_ 5 15 ~ - 15 45 ¦ According to a first variant of the method according 1 5~
~ ~S6~23 to the invention a syi5 tem l:o:r detexmi.nin~-; trle tempera~ ~ e of -the con-tinuously cast meta:l. is connecl~ed by a feedback loop to a hea-ti.ng or cooling sy.Citem which regulates the temperature of the liqu.id me-tal in, for examp].e, a casting ladle or in an intermediate con-talner such as a hea-ting basket.
- - According to ano-ther ernbodiment~ if the measured signal S is higher than or eq-ual to a prede-termined value S2 and if the values of the charac-teristic factors of the centering and depth of immersion of the nozzle are ' not correct, these factors are adequately adjusted.
! After an interval which is a function of the temporal 3 constant of response of the con-tinuous casting plant ,' provided the meas~red signal S has again become lower i 15 than the value S2, the continuous casting operation is.
i continued; if no-t9 another casting factor is tested.
Aecording to another embodiment, if the measured signal S is higher than or equal to a predetermined alue S3 and if the level of the liquid metal in the continuous casting mould is not between a prede-termined minimum-maximum interval, the level is ad.ju.sted accordingly. After an interval which i.s a function of the temporal constant of response of the con-tinuous casting plant provided the measured signal S has again become lower than the value S3, the casting operation is continued; if not, another casting factor is tested.
16.
,~
4 ~ 3 .
f:irst Variar.Lt of the abvve rnethod consi~ts in ~ that the information obtained with respect to the level l of l~quid metal in the mould is sent by means of a feed-3 back loop to a system for controlling the rnetal flow.T 5 A second variant of the above method consis-ts in j that the information obtained with respect to the level ¦ of liquid metal in the mould is sen-t by means of a feed-back loop to a system for controlling the speed of with-I drawal of the continuously cast strand.
¦ 10 According to another embodiment, if the measuredsignal S is higher th&n or ~qual to a prédetermined - value S4 and if the selection of the covering material . is not correct, the surface of the liquid metal in the mould is then cleaned &nd suitable covering material is added. After an interval which is a function of the temporal constant of response of the continuous casting plan~, if the signal measured S has again become lower than the value ~4, the continuous casting operation is continued; if not, another casting factor is tested.
¦ 20 According to another embodiment, if ~he measured signa~ S is higher th&n or equal to a predetermined i value S5 and if the amount of covering material on the T upper surface of the liquid metal in the mould is not within a predetermined interval, observation is made.to esta~lish whether there lS excess or insufficient covering material and the quantity of covering material is adjusted accordingly. Af-ter &~ interval which is a fu~lction of the 17.
L 2 ~
temporaL constant of re-;porl~3e of' the cont:lnuous casiting plant, if the measured signa] $ has again, becoJ~e lower than the predetermined value S5, -the continuous castin~
operation is continued; if no-t;, another cas-ting fac-tor is tested.
A first variant of the above method consists in that a curve C i8 used as a predetermined reference signal, this curve having relative extrema in a system of axes ' having an abscissa the amount of covering material 3, 10 introduced per unit of time into the mould and as ordinate the reference signal value S5, -this curve defining an interval of values on the axis of the abscissae so that ~ it includes the extremum wh~ch correspon~s to ,the smallest j value of the amount of covering material introduced per l 15 unit of time, this value corresponding to a signal value ;I representing the satisfactory friction conditions. ~his smallest value is defined arbitrarily in each case in terms of the particular condi-tions of the casting in - question, for example the size of' the strarld, the t~pe of strand, and the features of the plan-t, using for example the data provided by the constructor or previous knowledge, whether empirical or no-t, which is known to be valid for the plant in question.
Another variant of the above method consists in that the comparison operation is followed by the emission of a signal indicating whether the amount of covering 18.
I
t '.
materia:L actually introduced per u~llt of t:ime and correspo:ndi.ng to the value of the signal actually ¦ measured is inside or outside -the limi-ts of thé interval defined by -the abscissa axisO
l 5 Another variant consists in that the regulation sf ¦ the amo~nt of covering material added to the rnould is carried out colitinuously by means of a feedback loop.
According to another embodiment, if.the measured I signal S is higher than or equal to a predetermined value S6, the surface of the liquid metal in the mould ! iS subsequently cleaned and then.supplied with a different ;~ covering material selscted so that it has one or several ¦ physicochemical properties different from the first, so l that ths measured signal is brought as close as possible ¦ 15 to the predetermined reference signal, as stated above, which is considered suited for successful casting; if this is not the case, another casting factor is tested.
¦ According to a variant of the above method, the physicochemical properties chosen should enable analysis ~ 20 of the manner and/or the degree of prefusion and/or the .1~ shaping of the covering material.
Another variant of the above method consists in ~ ~ that the changes in properties of the covering material j can be advantageously carried out con-tinuously and adequately by a return loop.
According to ano-ther embodiment, if the measured I signal S is higher than or equal. to a predetermined value ¦ S7 and if the appearance of the phenomenon of bonding - ~9.
of the steel is observcd, -the suL~ace Gf -tho liquid metal in the moulcl i.i3 subsequentl~ cleaned and i~pplied with covering material of a type differing frorrl that in use at the moment that bonding appear6d. Af:ter an interval which iiJ a ~unction of the tempora] constant of response of the continuous ca3ting plant, if the signal measured has again become lower than -the predeter-mined value S7, the continuous castlng ope~ation is continued. In the opposite case, that is i~ the measured signal S is still higher than or equal to the predetermined value S7 and ;f the phenomenon of bonding of the steel continues, the surface of the liquid metal in the mould is again cleaned, and covering ma-terial having a lower viscosity than the preceding material is added. If the bonding phenomenon continues, this operation is repeated until all the possible choices of covering material have been tried. After an interval which is a function of the temporal constant of response of the continuous casting ~ plant, if the measured signal S has again become lower than the predetermined value S7, the continuous casting operation is continued; if not, another casting factor ii3 tested.
According to another embodiment, if the measured signal S is higher than or equal to a predetermined value S8 a~d if the casting s~eed V is not equal to predetermined value Vc, Vc being the casting speed value 20.
,i !
~ ~5~23 !
considered ideal i'or the cJa,stirlgS in ~uestion, the cas-ting ; speed is adjus~e-l to the value V~. ~f'ter a-n intcrval I which is a function of the ternporal constarlt of response ! of the continuous casting plant and if the measured ! 5 signal S has again become lower than the predetermined value ~8~ the continuous castlng opera-tion is continued.
~ In the opposite case, that is if the measu~ed signal ~
-I is still higher than or equal to the predetermined value S8, the casting speed V is reduced by an arnount V1, which is a function of the technical features of the continuous casting plant and the particular conditions for the type of steel being cast, so that the risk of defects or even ~ rupture in the cast strand is limited; if not, another ¦ casting factor is tested.
In the accompan~ing drawings:
~igure 1 is a graph of the measured signal S (%) against the casting speed V (m/min);
Figure 2 is a similar graph~ showing the situation during normal casting and during abnormal casting ¦ 20 (rupture);
¦ Figure 3 is a logic diagram for -the control of a continuous casting plant; and Figure 4 is a block diagram of apparatus for use in 1 controlling a continuous casting plant.
¦ 25 A diagram giving the measured signal S in terms of the casting speed ma~ be set up taking into account the fi~ed values of the other casting factors and a speed . ', ~1 .
.
I' .. , -for the castjrLgr s-peed Vr, is choqerl cor-res-p(Jndin~!; to the~
rninimwn signa:L S which is compatib]c w-ith t'ne -technical requirements for -the cast:ina, i~l ques-tion.
~ 'igure 1, given as a norl-limi-ting e~a~r~ple 7 shows how -this particula-r application of the process accordingr to the present invention may be utilized. ~his graph has ~-n ordina-te 9 in conven-tional uni-ts (%), -the intensit~ of the signal S representing the fric-tional forces between the strand and the mould, and as a~Scissa,in metres/
minute, the casting speed; the resultant curve for a powder of a given composition and a strand of given characteristics is generally V-shaped; the area to be chosen for the casting speed lS that which surrounds -the Q, lowest point of the curve, which corresponds to the lowest frictional forces and in addition the best lubrication.
, ~he method according to the invention is therefore in keeping with the use of the above graph, which? in an absolutely unforseen manner, gave a minimum.
According to another embodiment, if the measured sïgnal S is higher than or equal to a predetermined value S~
~` and if the values of the oscillation factors of the mould ; are incorrect, the values of the osclllation factors of the mould are adjusted. After an interval which is a function of the temporal constant of response of the continuous casting plant, if the measured signal S has again become lower than the predetermined value S9, the continuous casting operation is continued. In the opposite case, that is if the signal S is still hlgher than or ~, . . .
$~23 .
equal ko the predetellmirled valus f,~, ano-ther castlng I factor is -tested.
i According -to another ernbodiment, if the measu~ed signal S i5 higher than or equal -to a predetermlned ~ 5 value S10 and if the adjustment of -the conicity of thej mould faces is incorrect, the conicity is suitably adjusted. After an in-terval ~hich is a function of the temporal constant o~ response of the continuous casting plant, if the measu-red signal ~ has again become lower than the predetermined value S10, the continuous j casting operation is continued; if notj another casting ¦ factor is tested.
As a non-limiting exa~ple of the possibilities of use of this application of the method according to the invention, curves which are characteristic of casting are given in ~igure 2, in which the levels of the measured signals are the ordinate and the casting speeds -are the abscissa. With respect to so-called "normal"
j casting operations, that is where an optimum conicity . ..
is used, "malfunctioning" casting operations have a q considerably increased signal level.
According to another embodiment, if the measured ; signal S is higher than or equal to a predetermined ! value S11 and if the factors relating to set-tings of the ¦ 25 heat flux in the mould and in the first spraying zones when the strand emerges, that is flow, pressure, and input temperature and heating of the cooling fluid, are , 23.
not set to p:rede-termi.ned values, the vllue~ of t;he above factors are adequately adjusted in order to give ag~.reerQent with the predetermined values. After an interval which is a function of the ternporal constarlt of response of the continuous casting plant~ if the measured signal S has . again become lower than the prede-termined value S11, t-he continuous cas-ting operation is continued; if not, another casting factor is tested.
According to a varian-t of tnis method, the pre~
determined values of the factors relating to heat flux i.n . the mould and in the first spraying zones are obtained ; from the study of heat fl.ux recordings in the mould and the first spra~ing zones in terms of the measured signal ~ ~ S and for continuous casting having similar characteris-;¦ 15 tics.
.~ Another variant of the method consists in that the operation for determining the heat flux between the strand : and the mould is followed by the use of a control loop by means of which one or several cas-ting factors ma~J be adequately adjusted so that the heat flux follow~s a determined ternporal development.
According to another embodiment,.which, similarly to those described above, may be applied singly or in combination with the others, if the measursd signal S is higher than or equal to a predetermined value S12 and if . the values of the factors relating to setting of the roLlers at the base of the mould, and in particular -their 2L~.
.
I, distance apart, are not e~lurll to pre(le-terrnined value~, t -these factors are adequa-te]y adjusted in orde-r to rnake 3~ them correspond. Af-ter an interval which is a func-tion of the temporal constant of response of the continuous cas-ting plant, if the rneasured signal S has again become lower than the predeterrnined value S12, the continuous casting operation is continued; if not, another casting factor is tested~
According to a variant of the method~ the pre-determined values of the factors relating to setting of ¦ - the rollers at the base of the mould, and in particular ~3 their distance apar-t, are obtained by means of recordings ¦ of the S signal values for these factors during similar ! casting operations.
~he opera-tions for recording, processing, and comparing the meas~lred signal with the reference signal, and the resultant regulating operations may be carried out totally or partially by automatic systems.
As a non-limiting example, Figure 3 ~hows the logic ! 20 diagram fo~ the control of a particular continuous ! casting plant; the operations are given as follows.
I ~he different signs and coefficients used in this diagram ¦ and in the following lis-t of operations have the following meaning: `
~ Measured signal (betwee: 0 and 100%) Si ~'hreshold signal (surface defects, rupture, etc.);
Particular case of -the example: Si = S0 for all i-25.
~'empor~l consta~lt oL re,pon,;e of t;he con-tir--uolls c;3skinp;
p~rln-t = 30 ,s.
= B = ~oa.
C~ Con-tinuous casting
such as pressl1Ie an(l rate oL' flow of' t~e coolirlg fluid, - regulation of the rollers at the base of` the mou]d, ~ 5 and one or several of the actors are modified, simultaneously or in sequence, in particular those factors mentioned above, so that the measured signal is as close as possible to the predetermined re erence , signal which is considered ideal for satisfactory casting.
; 10 As a result of the method according to the invention, behavioural differences of one or several of the a~ove factors may be measured from tne predetermined behavoiur ; of the same factors resulting from previous castings of a similar type which were considered satisfactory.
In -the conventional control system for continuous casting, the determination of the abnormal character of the behaviour of one or several of the above factors is I carried out by direct determination using a technique known ~ se. ~his direct determination may advantageously be used additionally in the presen-t method.
In the case of the invention, the de-termina-tion of the abnormal character of the behaviour of one or several of the above factors may comprise t,he observation of a predetermined reference signal Si, with i - 0, .....
; 25 n, if n parameters are considered, the signal varying accordlng to the parame-ter in question.
It goes without saying that a re erence signal may be used which has been predetermined during one or i ~ severa.:l. pri.o.c castirlg ope.Latiorls having sirnilar ¦ characteristi.cs.
I ~he signal :representing the frictional forces is jl preferably measured by the shift of movements of the mould, for example its accelerations, which does not exclude a measu~ement of the friction forces by means of another physical ma~ni;ude which would be dependent on it.
In order to avoid any ambigui-ty with respect to the meaning of the terms "measured signal" and "reference signal" 7 precise details are given as follows. ~he terms "measured signal" and "reference signal" designate both continuous and discontinuous recordin~s of the friction forces, and even numerical values whlch represent the friction forces which act on a determined length of `1 the strand.
In order to make the object of the invention more comprehensible, various applications of the method I adapted to the case of certain continuous casting factors ~¦ 20 are given below wlth explanations; the different methods ~¦ of use~are given in an order which may be considered j preferable if they are all to be achieved, but this order j is not formally laid down.
he variation of the level of -the llquid metal ln the casting basket is monitored by observing the development of a signal S; if the measured signal S is.
13.
h:ighe-c ~harl or equa~ o a p-~edfterrrli.r~e(l v.rllue L~o~ it can be seen thal the level. of the met;al i..5 not belo~r a fi~ed -thresho:Ld; i:E -this is the case, r,leans suitable ~or increasing this above the predeterrnined threshold are actuated; the upper surface of the liquid metal may then be cleaned and fresh covering powder ma-y finally be added to the liqu~.d metal. After an interval which is a function of -the temporal constant of response to the beginning o:E casting and if the measured signal S has ' 10 again dropped below the predetermined value S0, the continuous casting operation is continued; otherwise another casting factor is tested~
~ According to another embodiment of the method according ! to the inven-tion~ which may be combined with any other embodiment, if the measured signal ~ is higher than or c~e~/~e~/
equal to a ~Y~ value S1 and if the temperature of the liquid metal in the casting basket - to be ~
~,ç c er7~Q ~ ~ec~
-~eF~e~ - is not between ~ - A and ~C + B or equal to these values (~C being an ideal predetermined temperature value, and A and B being constants which are functions ~ . of the characteristics of -the continuous casting plant -. and the t~pe of steel cast), observation is made to establish whether the tempera-t~re of the liquid metal is higher than ~ + B. If this is the case, the upper ; 25 surface of the liqui.d metal may for example be cleaned .
' .and then covering materi.al of higher viscosity added. -1L~. ~
1 ~ 2 3 I, After an inte:rvaL which is a flmctiorl of ~he ter~poral i constc~nt of response o:` the corltinuous cas-tin~.plant and I if the meas~red si.gnal S has agai.n become lower than or equal to S1, -the con-tinuous castirlg operation is continued;
if not, ano-ther cas-ting factor i,s tested. If on the other hand the temperature ~ is no-t higher than ~ -~ B
¦ and is therefore lower than ~ - A, subsequen-t measures are undertaken such as cleaning of the upper surface of the liquid metal and the addition of covering material of a lower viScosit~J. AIter an interval which is a ~ - function of the -temporal constan-t of response of the ;~, continuous casting plant and if -the measured signal S
has again become lower than S1 the continuous casting operation is con-tinued, if not, another casting factor is tested.
. Examp].e In the case of casting Al-Si medium killed steel (format 1,90Q x 200 mm and casting speed 0.8m/min) the ¦ ~ following relationship was es.tablished between the ¦ 20 variation (~) with respec-t to the casting -temperature . required (1,535~) and the variation of the measured signal ~ S%) i ~ TC _ _ a s%
_ 5 15 ~ - 15 45 ¦ According to a first variant of the method according 1 5~
~ ~S6~23 to the invention a syi5 tem l:o:r detexmi.nin~-; trle tempera~ ~ e of -the con-tinuously cast meta:l. is connecl~ed by a feedback loop to a hea-ti.ng or cooling sy.Citem which regulates the temperature of the liqu.id me-tal in, for examp].e, a casting ladle or in an intermediate con-talner such as a hea-ting basket.
- - According to ano-ther ernbodiment~ if the measured signal S is higher than or eq-ual to a prede-termined value S2 and if the values of the charac-teristic factors of the centering and depth of immersion of the nozzle are ' not correct, these factors are adequately adjusted.
! After an interval which is a function of the temporal 3 constant of response of the con-tinuous casting plant ,' provided the meas~red signal S has again become lower i 15 than the value S2, the continuous casting operation is.
i continued; if no-t9 another casting factor is tested.
Aecording to another embodiment, if the measured signal S is higher than or equal to a predetermined alue S3 and if the level of the liquid metal in the continuous casting mould is not between a prede-termined minimum-maximum interval, the level is ad.ju.sted accordingly. After an interval which i.s a function of the temporal constant of response of the con-tinuous casting plant provided the measured signal S has again become lower than the value S3, the casting operation is continued; if not, another casting factor is tested.
16.
,~
4 ~ 3 .
f:irst Variar.Lt of the abvve rnethod consi~ts in ~ that the information obtained with respect to the level l of l~quid metal in the mould is sent by means of a feed-3 back loop to a system for controlling the rnetal flow.T 5 A second variant of the above method consis-ts in j that the information obtained with respect to the level ¦ of liquid metal in the mould is sen-t by means of a feed-back loop to a system for controlling the speed of with-I drawal of the continuously cast strand.
¦ 10 According to another embodiment, if the measuredsignal S is higher th&n or ~qual to a prédetermined - value S4 and if the selection of the covering material . is not correct, the surface of the liquid metal in the mould is then cleaned &nd suitable covering material is added. After an interval which is a function of the temporal constant of response of the continuous casting plan~, if the signal measured S has again become lower than the value ~4, the continuous casting operation is continued; if not, another casting factor is tested.
¦ 20 According to another embodiment, if ~he measured signa~ S is higher th&n or equal to a predetermined i value S5 and if the amount of covering material on the T upper surface of the liquid metal in the mould is not within a predetermined interval, observation is made.to esta~lish whether there lS excess or insufficient covering material and the quantity of covering material is adjusted accordingly. Af-ter &~ interval which is a fu~lction of the 17.
L 2 ~
temporaL constant of re-;porl~3e of' the cont:lnuous casiting plant, if the measured signa] $ has again, becoJ~e lower than the predetermined value S5, -the continuous castin~
operation is continued; if no-t;, another cas-ting fac-tor is tested.
A first variant of the above method consists in that a curve C i8 used as a predetermined reference signal, this curve having relative extrema in a system of axes ' having an abscissa the amount of covering material 3, 10 introduced per unit of time into the mould and as ordinate the reference signal value S5, -this curve defining an interval of values on the axis of the abscissae so that ~ it includes the extremum wh~ch correspon~s to ,the smallest j value of the amount of covering material introduced per l 15 unit of time, this value corresponding to a signal value ;I representing the satisfactory friction conditions. ~his smallest value is defined arbitrarily in each case in terms of the particular condi-tions of the casting in - question, for example the size of' the strarld, the t~pe of strand, and the features of the plan-t, using for example the data provided by the constructor or previous knowledge, whether empirical or no-t, which is known to be valid for the plant in question.
Another variant of the above method consists in that the comparison operation is followed by the emission of a signal indicating whether the amount of covering 18.
I
t '.
materia:L actually introduced per u~llt of t:ime and correspo:ndi.ng to the value of the signal actually ¦ measured is inside or outside -the limi-ts of thé interval defined by -the abscissa axisO
l 5 Another variant consists in that the regulation sf ¦ the amo~nt of covering material added to the rnould is carried out colitinuously by means of a feedback loop.
According to another embodiment, if.the measured I signal S is higher than or equal to a predetermined value S6, the surface of the liquid metal in the mould ! iS subsequently cleaned and then.supplied with a different ;~ covering material selscted so that it has one or several ¦ physicochemical properties different from the first, so l that ths measured signal is brought as close as possible ¦ 15 to the predetermined reference signal, as stated above, which is considered suited for successful casting; if this is not the case, another casting factor is tested.
¦ According to a variant of the above method, the physicochemical properties chosen should enable analysis ~ 20 of the manner and/or the degree of prefusion and/or the .1~ shaping of the covering material.
Another variant of the above method consists in ~ ~ that the changes in properties of the covering material j can be advantageously carried out con-tinuously and adequately by a return loop.
According to ano-ther embodiment, if the measured I signal S is higher than or equal. to a predetermined value ¦ S7 and if the appearance of the phenomenon of bonding - ~9.
of the steel is observcd, -the suL~ace Gf -tho liquid metal in the moulcl i.i3 subsequentl~ cleaned and i~pplied with covering material of a type differing frorrl that in use at the moment that bonding appear6d. Af:ter an interval which iiJ a ~unction of the tempora] constant of response of the continuous ca3ting plant, if the signal measured has again become lower than -the predeter-mined value S7, the continuous castlng ope~ation is continued. In the opposite case, that is i~ the measured signal S is still higher than or equal to the predetermined value S7 and ;f the phenomenon of bonding of the steel continues, the surface of the liquid metal in the mould is again cleaned, and covering ma-terial having a lower viscosity than the preceding material is added. If the bonding phenomenon continues, this operation is repeated until all the possible choices of covering material have been tried. After an interval which is a function of the temporal constant of response of the continuous casting ~ plant, if the measured signal S has again become lower than the predetermined value S7, the continuous casting operation is continued; if not, another casting factor ii3 tested.
According to another embodiment, if the measured signal S is higher than or equal to a predetermined value S8 a~d if the casting s~eed V is not equal to predetermined value Vc, Vc being the casting speed value 20.
,i !
~ ~5~23 !
considered ideal i'or the cJa,stirlgS in ~uestion, the cas-ting ; speed is adjus~e-l to the value V~. ~f'ter a-n intcrval I which is a function of the ternporal constarlt of response ! of the continuous casting plant and if the measured ! 5 signal S has again become lower than the predetermined value ~8~ the continuous castlng opera-tion is continued.
~ In the opposite case, that is if the measu~ed signal ~
-I is still higher than or equal to the predetermined value S8, the casting speed V is reduced by an arnount V1, which is a function of the technical features of the continuous casting plant and the particular conditions for the type of steel being cast, so that the risk of defects or even ~ rupture in the cast strand is limited; if not, another ¦ casting factor is tested.
In the accompan~ing drawings:
~igure 1 is a graph of the measured signal S (%) against the casting speed V (m/min);
Figure 2 is a similar graph~ showing the situation during normal casting and during abnormal casting ¦ 20 (rupture);
¦ Figure 3 is a logic diagram for -the control of a continuous casting plant; and Figure 4 is a block diagram of apparatus for use in 1 controlling a continuous casting plant.
¦ 25 A diagram giving the measured signal S in terms of the casting speed ma~ be set up taking into account the fi~ed values of the other casting factors and a speed . ', ~1 .
.
I' .. , -for the castjrLgr s-peed Vr, is choqerl cor-res-p(Jndin~!; to the~
rninimwn signa:L S which is compatib]c w-ith t'ne -technical requirements for -the cast:ina, i~l ques-tion.
~ 'igure 1, given as a norl-limi-ting e~a~r~ple 7 shows how -this particula-r application of the process accordingr to the present invention may be utilized. ~his graph has ~-n ordina-te 9 in conven-tional uni-ts (%), -the intensit~ of the signal S representing the fric-tional forces between the strand and the mould, and as a~Scissa,in metres/
minute, the casting speed; the resultant curve for a powder of a given composition and a strand of given characteristics is generally V-shaped; the area to be chosen for the casting speed lS that which surrounds -the Q, lowest point of the curve, which corresponds to the lowest frictional forces and in addition the best lubrication.
, ~he method according to the invention is therefore in keeping with the use of the above graph, which? in an absolutely unforseen manner, gave a minimum.
According to another embodiment, if the measured sïgnal S is higher than or equal to a predetermined value S~
~` and if the values of the oscillation factors of the mould ; are incorrect, the values of the osclllation factors of the mould are adjusted. After an interval which is a function of the temporal constant of response of the continuous casting plant, if the measured signal S has again become lower than the predetermined value S9, the continuous casting operation is continued. In the opposite case, that is if the signal S is still hlgher than or ~, . . .
$~23 .
equal ko the predetellmirled valus f,~, ano-ther castlng I factor is -tested.
i According -to another ernbodiment, if the measu~ed signal S i5 higher than or equal -to a predetermlned ~ 5 value S10 and if the adjustment of -the conicity of thej mould faces is incorrect, the conicity is suitably adjusted. After an in-terval ~hich is a function of the temporal constant o~ response of the continuous casting plant, if the measu-red signal ~ has again become lower than the predetermined value S10, the continuous j casting operation is continued; if notj another casting ¦ factor is tested.
As a non-limiting exa~ple of the possibilities of use of this application of the method according to the invention, curves which are characteristic of casting are given in ~igure 2, in which the levels of the measured signals are the ordinate and the casting speeds -are the abscissa. With respect to so-called "normal"
j casting operations, that is where an optimum conicity . ..
is used, "malfunctioning" casting operations have a q considerably increased signal level.
According to another embodiment, if the measured ; signal S is higher than or equal to a predetermined ! value S11 and if the factors relating to set-tings of the ¦ 25 heat flux in the mould and in the first spraying zones when the strand emerges, that is flow, pressure, and input temperature and heating of the cooling fluid, are , 23.
not set to p:rede-termi.ned values, the vllue~ of t;he above factors are adequately adjusted in order to give ag~.reerQent with the predetermined values. After an interval which is a function of the ternporal constarlt of response of the continuous casting plant~ if the measured signal S has . again become lower than the prede-termined value S11, t-he continuous cas-ting operation is continued; if not, another casting factor is tested.
According to a varian-t of tnis method, the pre~
determined values of the factors relating to heat flux i.n . the mould and in the first spraying zones are obtained ; from the study of heat fl.ux recordings in the mould and the first spra~ing zones in terms of the measured signal ~ ~ S and for continuous casting having similar characteris-;¦ 15 tics.
.~ Another variant of the method consists in that the operation for determining the heat flux between the strand : and the mould is followed by the use of a control loop by means of which one or several cas-ting factors ma~J be adequately adjusted so that the heat flux follow~s a determined ternporal development.
According to another embodiment,.which, similarly to those described above, may be applied singly or in combination with the others, if the measursd signal S is higher than or equal to a predetermined value S12 and if . the values of the factors relating to setting of the roLlers at the base of the mould, and in particular -their 2L~.
.
I, distance apart, are not e~lurll to pre(le-terrnined value~, t -these factors are adequa-te]y adjusted in orde-r to rnake 3~ them correspond. Af-ter an interval which is a func-tion of the temporal constant of response of the continuous cas-ting plant, if the rneasured signal S has again become lower than the predeterrnined value S12, the continuous casting operation is continued; if not, another casting factor is tested~
According to a variant of the method~ the pre-determined values of the factors relating to setting of ¦ - the rollers at the base of the mould, and in particular ~3 their distance apar-t, are obtained by means of recordings ¦ of the S signal values for these factors during similar ! casting operations.
~he opera-tions for recording, processing, and comparing the meas~lred signal with the reference signal, and the resultant regulating operations may be carried out totally or partially by automatic systems.
As a non-limiting example, Figure 3 ~hows the logic ! 20 diagram fo~ the control of a particular continuous ! casting plant; the operations are given as follows.
I ~he different signs and coefficients used in this diagram ¦ and in the following lis-t of operations have the following meaning: `
~ Measured signal (betwee: 0 and 100%) Si ~'hreshold signal (surface defects, rupture, etc.);
Particular case of -the example: Si = S0 for all i-25.
~'empor~l consta~lt oL re,pon,;e of t;he con-tir--uolls c;3skinp;
p~rln-t = 30 ,s.
= B = ~oa.
C~ Con-tinuous casting
5 Va Required casting speed V Casting speed (actua]) ~a ~9~ casting temperature (~) ~asting -temperatu~e (actual) YES ' .
' CO~RO~ PROCESS OPERA~IO~TS
1. S ,~ S
-' 2 Casting speed = Va?
3. Correct casting speed.
~ 15 4. S ~ SO after 30 s ?
`~1 5. Continue continuous casting.
' 6. Reduce speed by 20%: V = V~ - 0.20 Va.
i 7- is there bonding ?
j - 8. Make V = O (temporary pause in casting).
20 9. Glean, then use powder (same type) of a differeni;
batch (pallet).
! 10. Res-tar-t and move cas-ting gradually to Va.
S ~ SO after 30 s ?
12. Continue continuous casting 25 13- ~emperature of contimlous casting from ~c ~ 10C
to ~C + 10a~ that is ~a - 10C ~ ~ ~a -~ 10 ?
14-. aasting emperature higher than ~C + 10a~ tha-t is ~ ~a + 10 ?
1 ~ 1 2 ~
i i 1 15~ C~lean then apply rnore viscous powtler~
i 16. Cle~L-then apply more fluid powder, I 17- S~ S0 after 30 s ?
! 18. S~S0 after 30 s ?
19. Continue continuous ca,sting.
I 20. "
¦ 21. Steel level in basket too low 22. Correct steel level.
23. ~lean then re-apply powder of sarne type, using new powder.
¦ 24. S ~ S0 after 30 s ?
~ 25. Continue continuous casting.
¦ 26. Is powder suited to ca~sting conditions being used (predetermined type of powder)?
15 27- Clean, then apply correct powder, 28. S ~S0 after 30 s ?
29. Continue continuous casting.
30. Position, i.e. centering and/or depth of immersion of the nozzle is correct ?
¦ 20 31. Correct position of no~zle "
¦ 32~ S ~S0 after 30 s ?
¦ 33- Gontinue continuous casting.
34. Lubricant feed required and/or sufficient ?
I 35- Add lubricant and, in particular case, powder.
¦ 25 36~ S~ S0 after 30 s ?
37- Continue continuous casting.
38~ Is the oscillation frequenc~ of the mould correct ? 27 '1 2 3 39. Cor;rcc-t osc~Lla~,:i,oo f'requt,rlc~
40. S ~ SO (ir~ed~al;e ef.'fect~ with,out -ti~e de],a,y~
: 41. Continue conti,nuous casting~
42. Are -the rates of water flow ~Id./or pressure in the Mould and the fixst spra~Jing zones (base rollers) correc-t ?
43. Correct these flows and pressures.
. S ~SO af-ter 30 s ?
45. Continue contlnuous cas-ting.
46. Is th.e steel level in the mould correct ?
. Correct steel level by acting -~pon stopper/no~zle ' with baske-t slide valve and/or upon casting speed (withdrawal stand).
48. S ~ SO(immediate eff,'ec-t, without time delay)?
' 15 49. Continue continuous casting.
.~ 50. Cleanj'then apply powder ~same type) of a different batch (pallet).
' . 51. S ~ S0 after 30 s ?
. 52. Continue continuous casting.
20 53- Clean, then apply more fluid powder (different type).
54. ~ ~ S0 af.'ter 30 s ?
55. Continue continuous casting.
~' 56. Stop sequence (casting).
25 57- Exarnination of mould and related factors (state and adjustment) . - correct oscilla-tion?
- correct conicity ?
23.
4 2 ~
- corLect su,,perlsion (sprirlgs) 7 - correct guiding (plates) ?
base rollers (alignment, cooling) ?
- wear of mould walls ?
- mould spats suitably placed ?
58. ~asting speed.
~¦ 59. Strand bonding.
60. Steel temperature.
I 61. Basket level.
f 10 62. Powder check.- 6~. Nozzle positionO
64. Amount of covering powder.
65. Oscillatlon frequency.
66. Cooling fluid flow.
15 67. Level in mould.
~he selected factors and the sequence of operations as well as the values of vc7 A, B, Si and the temporal constant of response o~ the continuous casting plant are particular to the plant in question and are therefore only 7 20 given as an indication and not a rule.
Control apparatus which may be applied to a plant for contimlously casting metals cornprises:
(a) a sensor for the movements of the continuous castirg mould during the casting operation~
25 (b) electrical energy feed means for the sensor, (c) two electronic chains connected in parallel to the sensor output, the first enabling a signal solely linked to the movements due to the oscilla-tion 29.
provided b~J Ih.e mo-u:ld to ~he produced, and the second enabli.ng a signa:l. d.ependent on the aoove movements as well as -lhe friction between the s-trand and -the mould and -the withdrawa.l speed to be produced, . (d) a device enabling both. signals to be divided by each o-ther, which enables a new signal to be obtained, which has been found to represent the phenomenon in question, that is the ingot-ingot mould friction, in combination with -the extraction j speed.
According to a constructional embodiment of -this apparatus, the first chain compr:ises a band-pass filter , of 0~1 to 3 times -the oscillation .frequency of the mould, j 15 whereas the second chain comprises a band-pass filter of 3 to 1,000 times the oscillation frequency of the mould, preferably from 4 to 10 times this frequency.
~he diagram shown in ~igure 4, given as a non-limiti~-g example, enables the design of such apparatus to be envisaged, being a block diagram of such apparatus.
In this..block diagram, C represents t-he sensor for the mould movements, which is fed by an electrical supply 1.
~wo electronic chains connected in parallel to the output of the sensor C are composed as follows:
~ the first: an adjustable amplifier 6, a band-pass filter 7 of 0.2 to 3 Hz, a signal shunter 8 (which may be short-circuited), a demodulator 9 which may 3o.
t I ac-t on one o~ bo-th o~ the al-ternatiorl.q of.' the ! inP~t ~ignal, - the second: an adjustable amplifier 2, a band-1 pass filter 3 of ~-to 10 ~z, a signal shun-ter 4 j 5 (which may be sho:r.t-circui.ted), a demodulator 5 j which may act upon one or both of the alternations of the input signal, ~ a module 10 providing the quoti.ent of the output ~, signal from the demodulator 9 divided by the out-put signal from the demodulator 5, the value of the s~gnal quotient ~ S thus obtained being introduced into a display device or a recorder 11.
~he above diagram is completed by:
~ - a corrector circuit 12j cancelling the signal between ¦ . 15 casting operations, ¦ - a sub-assembl-y 13 enabling high and low alarms to ¦ be set off.
- , I
~ ~''"' ' . ' .
: . ~
31.
.' '.
' CO~RO~ PROCESS OPERA~IO~TS
1. S ,~ S
-' 2 Casting speed = Va?
3. Correct casting speed.
~ 15 4. S ~ SO after 30 s ?
`~1 5. Continue continuous casting.
' 6. Reduce speed by 20%: V = V~ - 0.20 Va.
i 7- is there bonding ?
j - 8. Make V = O (temporary pause in casting).
20 9. Glean, then use powder (same type) of a differeni;
batch (pallet).
! 10. Res-tar-t and move cas-ting gradually to Va.
S ~ SO after 30 s ?
12. Continue continuous casting 25 13- ~emperature of contimlous casting from ~c ~ 10C
to ~C + 10a~ that is ~a - 10C ~ ~ ~a -~ 10 ?
14-. aasting emperature higher than ~C + 10a~ tha-t is ~ ~a + 10 ?
1 ~ 1 2 ~
i i 1 15~ C~lean then apply rnore viscous powtler~
i 16. Cle~L-then apply more fluid powder, I 17- S~ S0 after 30 s ?
! 18. S~S0 after 30 s ?
19. Continue continuous ca,sting.
I 20. "
¦ 21. Steel level in basket too low 22. Correct steel level.
23. ~lean then re-apply powder of sarne type, using new powder.
¦ 24. S ~ S0 after 30 s ?
~ 25. Continue continuous casting.
¦ 26. Is powder suited to ca~sting conditions being used (predetermined type of powder)?
15 27- Clean, then apply correct powder, 28. S ~S0 after 30 s ?
29. Continue continuous casting.
30. Position, i.e. centering and/or depth of immersion of the nozzle is correct ?
¦ 20 31. Correct position of no~zle "
¦ 32~ S ~S0 after 30 s ?
¦ 33- Gontinue continuous casting.
34. Lubricant feed required and/or sufficient ?
I 35- Add lubricant and, in particular case, powder.
¦ 25 36~ S~ S0 after 30 s ?
37- Continue continuous casting.
38~ Is the oscillation frequenc~ of the mould correct ? 27 '1 2 3 39. Cor;rcc-t osc~Lla~,:i,oo f'requt,rlc~
40. S ~ SO (ir~ed~al;e ef.'fect~ with,out -ti~e de],a,y~
: 41. Continue conti,nuous casting~
42. Are -the rates of water flow ~Id./or pressure in the Mould and the fixst spra~Jing zones (base rollers) correc-t ?
43. Correct these flows and pressures.
. S ~SO af-ter 30 s ?
45. Continue contlnuous cas-ting.
46. Is th.e steel level in the mould correct ?
. Correct steel level by acting -~pon stopper/no~zle ' with baske-t slide valve and/or upon casting speed (withdrawal stand).
48. S ~ SO(immediate eff,'ec-t, without time delay)?
' 15 49. Continue continuous casting.
.~ 50. Cleanj'then apply powder ~same type) of a different batch (pallet).
' . 51. S ~ S0 after 30 s ?
. 52. Continue continuous casting.
20 53- Clean, then apply more fluid powder (different type).
54. ~ ~ S0 af.'ter 30 s ?
55. Continue continuous casting.
~' 56. Stop sequence (casting).
25 57- Exarnination of mould and related factors (state and adjustment) . - correct oscilla-tion?
- correct conicity ?
23.
4 2 ~
- corLect su,,perlsion (sprirlgs) 7 - correct guiding (plates) ?
base rollers (alignment, cooling) ?
- wear of mould walls ?
- mould spats suitably placed ?
58. ~asting speed.
~¦ 59. Strand bonding.
60. Steel temperature.
I 61. Basket level.
f 10 62. Powder check.- 6~. Nozzle positionO
64. Amount of covering powder.
65. Oscillatlon frequency.
66. Cooling fluid flow.
15 67. Level in mould.
~he selected factors and the sequence of operations as well as the values of vc7 A, B, Si and the temporal constant of response o~ the continuous casting plant are particular to the plant in question and are therefore only 7 20 given as an indication and not a rule.
Control apparatus which may be applied to a plant for contimlously casting metals cornprises:
(a) a sensor for the movements of the continuous castirg mould during the casting operation~
25 (b) electrical energy feed means for the sensor, (c) two electronic chains connected in parallel to the sensor output, the first enabling a signal solely linked to the movements due to the oscilla-tion 29.
provided b~J Ih.e mo-u:ld to ~he produced, and the second enabli.ng a signa:l. d.ependent on the aoove movements as well as -lhe friction between the s-trand and -the mould and -the withdrawa.l speed to be produced, . (d) a device enabling both. signals to be divided by each o-ther, which enables a new signal to be obtained, which has been found to represent the phenomenon in question, that is the ingot-ingot mould friction, in combination with -the extraction j speed.
According to a constructional embodiment of -this apparatus, the first chain compr:ises a band-pass filter , of 0~1 to 3 times -the oscillation .frequency of the mould, j 15 whereas the second chain comprises a band-pass filter of 3 to 1,000 times the oscillation frequency of the mould, preferably from 4 to 10 times this frequency.
~he diagram shown in ~igure 4, given as a non-limiti~-g example, enables the design of such apparatus to be envisaged, being a block diagram of such apparatus.
In this..block diagram, C represents t-he sensor for the mould movements, which is fed by an electrical supply 1.
~wo electronic chains connected in parallel to the output of the sensor C are composed as follows:
~ the first: an adjustable amplifier 6, a band-pass filter 7 of 0.2 to 3 Hz, a signal shunter 8 (which may be short-circuited), a demodulator 9 which may 3o.
t I ac-t on one o~ bo-th o~ the al-ternatiorl.q of.' the ! inP~t ~ignal, - the second: an adjustable amplifier 2, a band-1 pass filter 3 of ~-to 10 ~z, a signal shun-ter 4 j 5 (which may be sho:r.t-circui.ted), a demodulator 5 j which may act upon one or both of the alternations of the input signal, ~ a module 10 providing the quoti.ent of the output ~, signal from the demodulator 9 divided by the out-put signal from the demodulator 5, the value of the s~gnal quotient ~ S thus obtained being introduced into a display device or a recorder 11.
~he above diagram is completed by:
~ - a corrector circuit 12j cancelling the signal between ¦ . 15 casting operations, ¦ - a sub-assembl-y 13 enabling high and low alarms to ¦ be set off.
- , I
~ ~''"' ' . ' .
: . ~
31.
.' '.
Claims (33)
1. A method Or controlling the continuous casting of a metal strand, comprising the steps of sensing the movements of the continuous casting mould and providing a signal representing the said movements; selecting according to a first frequency band a first constituent of the said signal, the first constituent being solely linked to the oscillation imparted to the mould; selecting according to a second frequency band a second constituent of the said signal, the second constituent being dependent on the frictional forces arising between the strand and the mould as well as on the oscillation imparted to the mould; comparing the first and second constituents and producing a signal S that is a function of the comparison, the signal S representing the said frictional forces;
comparing the signal S with an analog-type reference signal to detect any abnormal behaviour of the casting operation;
and, so as to minimise any difference between the signal S and the reference signal, regulating at least one of the following continuous casting factors:
- the level of the liquid metal in the casting basket, - the temperature of the liquid metal in the casting basket, - the position Or the casting nozzle in the mould, - the type of covering material, - the amount of covering material, - bonding of the strand, - casting speed, - mould oscillation factors, such as guiding, suspension, and frequency, - conicity of the mould faces, - factors relating to regulation of the heat flux at the mould and the first spray-cooling zones when the strand emerges, - regulation of the base rollers of the mould.
comparing the signal S with an analog-type reference signal to detect any abnormal behaviour of the casting operation;
and, so as to minimise any difference between the signal S and the reference signal, regulating at least one of the following continuous casting factors:
- the level of the liquid metal in the casting basket, - the temperature of the liquid metal in the casting basket, - the position Or the casting nozzle in the mould, - the type of covering material, - the amount of covering material, - bonding of the strand, - casting speed, - mould oscillation factors, such as guiding, suspension, and frequency, - conicity of the mould faces, - factors relating to regulation of the heat flux at the mould and the first spray-cooling zones when the strand emerges, - regulation of the base rollers of the mould.
2. A method as claimed in claim 1, in which behavioural abnormality of at least one of the said factors is measured with respect to the behaviour of the same factor predetermined from previous casting operations which had similar characteristics and which were considered satisfactory.
3. A method as claimed in claim 1, in which the detection of abnormal behaviour of the casting operation is verified by direct determination of behavioural abnormality of at least one of the said factors.
4. A method as claimed in claim 1, in which the comparison of the first and second constituents comprises dividing one by the other.
5. A method as claimed in claim 1, in which the movements of the mould are sensed by an accelerometer.
6. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S0 and if the level of the liquid metal in the casting basket is below a predetermined threshold, means for raising the level above the threshold are actuated, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S0, the continuous casting operation is continued.
7. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S
and if the temperature T of the liquid metal in the casting basket is not between TC - A and TC + B, TC being a predetermined ideal value of the temperature T, and A and B being constants which are functions of the characteristics of the continuous casting plant and the type of metal cast, observation is made to establish whether T is higher than TC + B, and if so, the upper surface of the liquid metal is then cleaned of covering material and fresh covering material of a higher viscosity is added and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the value S1, the continuous casting operation is continued, but if the temperature T is not higher than TC + B and is therefore lower than TC - A, the upper surface of the liquid metal is then cleaned of covering material and fresh covering material of a lower viscosity is added and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the measured signal S has again become lower than S1, the continuous casting operation is continued.
and if the temperature T of the liquid metal in the casting basket is not between TC - A and TC + B, TC being a predetermined ideal value of the temperature T, and A and B being constants which are functions of the characteristics of the continuous casting plant and the type of metal cast, observation is made to establish whether T is higher than TC + B, and if so, the upper surface of the liquid metal is then cleaned of covering material and fresh covering material of a higher viscosity is added and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the value S1, the continuous casting operation is continued, but if the temperature T is not higher than TC + B and is therefore lower than TC - A, the upper surface of the liquid metal is then cleaned of covering material and fresh covering material of a lower viscosity is added and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the measured signal S has again become lower than S1, the continuous casting operation is continued.
8. A method as claimed in claim 7, in which a system for determining the temperature of the cast metal is connected in a feedback loop to a heating or cooling system which regulates the temperature of the liquid metal in a casting ladle or in an intermediate container such as a heating basket.
9. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S2 and if the values of the factors relating to centering and depth of immersion of the nozzle are incorrect, these values are adjusted accordingly and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the value S2, the continuous casting operation is continued.
10. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S3 and if the level or the liquid metal in the mould is not within a pre-determined minimum-maximum interval, the said level is adjusted until it becomes so, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the value S3, the continuous casting operation is continued.
11. A method as claimed in claim 109 in which the information obtained with respect to the level of the liquid metal in the mould is sent by means of a feedback loop to a system for controlling the metal flow.
12. A method as claimed in claim 10, in which the information obtained with respect to the level of the liquid metal in the mould is sent by means of a feed-back loop to a system for controlling the speed of withdrawal of the strand.
13. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S4 and if the selection of covering material is found to be incorrect, the surface of the liquid metal in the mould is cleaned and suitable covering material is added, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the signal S4, the continuous casting operation is continued.
14. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S5 and if the amount of covering material located on the upper surface of the liquid metal in the mould is not within a predetermined interval, observation is made to establish whether there is excess or insufficient covering material and the amount of covering material is adjusted accordingly, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S
has again become lower than the predetermined value S5, the continuous casting operation is continued.
has again become lower than the predetermined value S5, the continuous casting operation is continued.
15. A method as claimed in claim 14, in which the predetermined reference signal comprises a curve C
having relative extrema in a system of axes having the amount of covering material introduced into the mould per unit of time as the abscissa and the value of the reference signal S5 as the ordinate, an interval of values on the abscissa axis being defined for this curve such that it includes the extremum which corresponds to the smallest value of the amount of covering material introduced per unit of time, a value of the signal representing the frictional conditions considered satisfactory corresponding to this value.
having relative extrema in a system of axes having the amount of covering material introduced into the mould per unit of time as the abscissa and the value of the reference signal S5 as the ordinate, an interval of values on the abscissa axis being defined for this curve such that it includes the extremum which corresponds to the smallest value of the amount of covering material introduced per unit of time, a value of the signal representing the frictional conditions considered satisfactory corresponding to this value.
16. A method as claimed in claim 15, in which the comparison step is followed by the emission of a signal indicating whether the amount of covering material introduced per unit of time and corresponding to the value of the signal measured is inside or outside the limits of the interval defined on the abscissa axis.
17. A method as claimed in claim 16, in which regulation of the amount of covering material added to the mould is carried out continuously by means of a feedback loop.
18. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S6, the upper surface of the liquid metal in the mould is cleaned of covering material and fresh covering material is added, being of a different type and selected to provide at least one physico-chemical property modified with respect to the preceding material, so that the signal S comes as close as possible to the predetermined reference signal.
19. A method as claimed in claim 18, in which the said physico-chemical property is chosen from analysis of the manner and/or the degree of prefusion and/or the form of the covering material.
20. A method as claimed in claim 1, in which if -the signal S is higher than or equal to a predetermined value S7 and if the appearance of the phenomenon of bonding of the strand is observed, the surface of the liquid metal in the mould is cleaned of covering material and fresh covering material differing from that used at the time of appearance of the bonding is added, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predeter-mined value S7, the continuous casting operation is continued, but if the signal S is still higher than or equal to the predetermined value S7 and if the bonding phenomenon continues, the surface of the liquid metal in the mould is again cleaned and covering material of a lower viscosity than the preceding material of a added, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S7, the continuous casting operation is continued.
21. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S8 and if the casting speed V is not equal to a predetermined value VC, VC being a casting speed value considered ideal for the casting in question, the casting speed is adjusted to the value VC and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S8, the continuous casting operation is continued, but if the signal S is still higher than or equal to the predetermined value S8, the casting speed V is reduced by an amount V1 which is a function of the technical characteristics of the continuous casting plant and the particular conditions for the type of metal cast.
22. A method as claimed in claim 21, in which a diagram giving the signal S is drawn up in terms of the casting speed and this is effected by using fixed values for the other casting factors, and the speed corresponding to the S signal minimum compatible with the technical requirements for the casting in question is chosen as the casting speed VC.
23. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S9 and if the values of the oscillation factors of the mould are found to be incorrect, the values of the oscillation factors are corrected and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S9, the continuous casting operation is continued, but if the signal S
is still higher than or equal to the predetermined value S9, another casting factor is tested.
is still higher than or equal to the predetermined value S9, another casting factor is tested.
24. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S10 and if the setting of the conicity of the mould faces is found to be incorrect, the conicity is modified accordingly and, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S10, the continuous casting operation is continued.
25. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S11 and if the values of the factors relating to regulation of the heat flux in the mould and the first spraying zones when the strand emerges, that is the flow, the pressure, the input tem-perature, and the heating of a cooling fluid being sprayed, are not in accordance with predetermined values, the values of the said factors are adjusted accordingly in order to obtain agreement with the predetermined values, and then, after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S11, the continuous casting operation is continued.
26. A method as claimed in claim 25, in which the predetermined values of the factors relating to heat flux in the mould and the first spraying zones are obtained by analysing recordings of the heat flux in the mould and in the first spraying zones in terms of the signal S from continuous casting operations with similar characteristics.
27. A method as claimed in claim 25, in which the determination of the heat flux between the strand and the mould is followed by the use of a control loop by means of which at least one of the continuous casting factors can be adjusted accordingly so that the heat flux follows a given temporal development.
28. A method as claimed in claim 1, in which if the signal S is higher than or equal to a predetermined value S12 and if the factors relating to the regulation of the base rollers of the mould, in particular their distance apart, are not equal to predetermined values, these factors are modified in order to obtain this equality, and then after an interval which is a function of the temporal constant of response of the continuous casting plant, provided the signal S has again become lower than the predetermined value S12, the continuous casting operation is continued.
29. A method as claimed in claim 28, in which the predetermined values of the factors relating to regulations of the base rollers are obtained from recordings of the S signal values in terms of these factors during continuous casting operations with similar characteristics.
30. A method as claimed in claim 1, in which recordings, analysis, and comparison of the signal S with the reference signal, and the resultant modifying steps, are at least partially processed by an automatic system.
31. Apparatus for monitoring the continuous casting of a metal strand, comprising:
a) a sensor arranged to sense the movements of the continuous casting mould during the casting operation;
b) means for supplying the sensor with electrical energy;
c) two electronic circuits connected in parallel to the sensor output, one circuit comprising a band-pass filter and being arranged to produce a sensor output signal constituent solely linked to the oscillation imparted to the mould, the other circuit comprising a band-pass filter and being arranged to produce a sensor output signal constituent depending on the frictional forces arising between the strand and the mould, on the speed of withdrawal of the strand, and on the said oscillation;
d) a divider arranged to receive the two signal constituents and to produce a signal S representing the ratio of the two signal components and repre-senting the said frictional forces; and e) means for comparing the signal S with an analog-type reference signal.
a) a sensor arranged to sense the movements of the continuous casting mould during the casting operation;
b) means for supplying the sensor with electrical energy;
c) two electronic circuits connected in parallel to the sensor output, one circuit comprising a band-pass filter and being arranged to produce a sensor output signal constituent solely linked to the oscillation imparted to the mould, the other circuit comprising a band-pass filter and being arranged to produce a sensor output signal constituent depending on the frictional forces arising between the strand and the mould, on the speed of withdrawal of the strand, and on the said oscillation;
d) a divider arranged to receive the two signal constituents and to produce a signal S representing the ratio of the two signal components and repre-senting the said frictional forces; and e) means for comparing the signal S with an analog-type reference signal.
32. Apparatus as claimed in claim 31, in which the one circuit comprises a band-pass filter from 0.1 to 3 times the oscillation frequency given to the mould, the other circuit comprising a band-pass filter from 3 to 1,000 times the oscill-ation frequency given to the mould.
33. Apparatus as claimed in claim 31, which comprises a band-pass filter from 4 to 10 times the oscillation frequency given to the mould.
Applications Claiming Priority (22)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE6046316A BE863001A (en) | 1978-01-17 | 1978-01-17 | DEVICE FOR THE CONTROL OF THE CONTINUOUS METAL CASTING PROCESS. |
| BE6/46316 | 1978-01-17 | ||
| BE6046318A BE863041A (en) | 1978-01-18 | 1978-01-18 | PROCESS FOR PREDETERMINING THE OPTIMAL CONDITIONS FOR THE OPERATION OF A CONTINUOUS METAL CASTING PLANT |
| BE6/46318 | 1978-01-18 | ||
| BE6046533A BE869034A (en) | 1978-07-14 | 1978-07-14 | LINGOTIER OSCILLATION CONTROL PROCESS IN THE CONTINUOUS METAL CASTING |
| BE6046538A BE869039A (en) | 1978-07-14 | 1978-07-14 | METHOD FOR CHECKING THE ADJUSTMENT OF THE FOOT ROLLERS IN A CONTINUOUS METAL CASTING LINGOTIER |
| BE6/46535 | 1978-07-14 | ||
| BE6046537A BE869038A (en) | 1978-07-14 | 1978-07-14 | PROCESS FOR CHECKING AND ADJUSTING THE CONICITY OF THE FACES OF THE LINGOTIER IN THE CONTINUOUS CASTING OF THE METALS |
| BE6046535A BE869036A (en) | 1978-07-14 | 1978-07-14 | CONTINUOUS CAST METAL CASTING TEMPERATURE CONTROL PROCESS |
| BE6046536A BE869037A (en) | 1978-07-14 | 1978-07-14 | METAL LEVEL CONTROL METHOD IN CONTINUOUS METAL CASTING LINGOTIER |
| BE6/46538 | 1978-07-14 | ||
| BE6/46533 | 1978-07-14 | ||
| BE6/46537 | 1978-07-14 | ||
| BE6/46536 | 1978-07-14 | ||
| BE6/46568 | 1978-08-08 | ||
| BE6/46565 | 1978-08-08 | ||
| BE6046565A BE869618A (en) | 1978-08-08 | 1978-08-08 | CALORIFIC FLOW CONTROL PROCESS IN A CONTINUOUS METAL CASTING LINGOTIER |
| BE6046568A BE869620A (en) | 1978-08-08 | 1978-08-08 | METHOD OF CHECKING THE POSITION OF THE CONTINUOUS CASTING NOZZLE IN A CONTINUOUS METAL CASTING OPERATION |
| BE6/46573 | 1978-08-11 | ||
| BE6046573A BE869726A (en) | 1978-08-11 | 1978-08-11 | METHOD OF REGULATING THE ADDITION OF COVERING POWDER IN CONTINUOUS CASTING OF METALS |
| BE6/46572 | 1978-08-11 | ||
| BE6046572A BE869725A (en) | 1978-08-11 | 1978-08-11 | METHOD FOR CONTROL OF THE PHYSICO-CHEMICAL CHARACTERISTICS OF THE COVERING POWDER IN THE CONTINUOUS CASTING OF METALS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1156423A true CA1156423A (en) | 1983-11-08 |
Family
ID=27581398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000319690A Expired CA1156423A (en) | 1978-01-17 | 1979-01-16 | Controlling the continuous casting of metals |
Country Status (6)
| Country | Link |
|---|---|
| JP (2) | JPS54112338A (en) |
| CA (1) | CA1156423A (en) |
| DE (1) | DE2901407A1 (en) |
| GB (1) | GB2012637B (en) |
| IT (1) | IT1117559B (en) |
| LU (1) | LU80796A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2946843C2 (en) * | 1979-11-20 | 1984-02-09 | Vsesojuznyj naučno-issledovatel'skij institut avtomatizacii černoj metallurgii, Moskva | Device for the automatic control of the start-up operation of a continuous metal caster |
| CH649016A5 (en) * | 1980-03-13 | 1985-04-30 | Vnii Avtom Chernoi | Method for the automatic control of the conicity of the mould in a metal continuous-casting installation |
| WO1983002911A1 (en) * | 1982-02-24 | 1983-09-01 | Yaji, Motoyasu | Method of controlling continuous casting facility |
| DE19843033B4 (en) * | 1998-09-19 | 2017-11-09 | Sms Group Gmbh | Breakthrough detection method for a continuous casting mold |
| DE19915269A1 (en) * | 1999-04-03 | 2000-10-26 | Sms Demag Ag | Procedure for determining the friction between the continuous shell and the mold during continuous casting |
| JP4773796B2 (en) * | 2005-10-28 | 2011-09-14 | 昭和電工株式会社 | Aluminum alloy continuous casting rod, continuous casting rod casting method, continuous casting equipment |
| JP5565734B2 (en) * | 2011-04-05 | 2014-08-06 | 昭和電工株式会社 | Aluminum alloy continuous casting rod, continuous casting rod casting method, continuous casting equipment |
| CN107900296B (en) * | 2017-11-23 | 2024-05-07 | 燕山大学 | Non-sinusoidal vibration distributed control system of continuous casting crystallizer driven by servo motor |
| CN110479974B (en) * | 2018-03-27 | 2022-03-15 | 上海梅山钢铁股份有限公司 | Rapid slag changing method of automatic slag adding machine of continuous casting crystallizer |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1120641B (en) * | 1954-05-25 | 1961-12-28 | British Iron Steel Research | Method and device for casting metal |
| JPS5813260B2 (en) * | 1973-06-06 | 1983-03-12 | 川崎製鉄株式会社 | Igata no Shindo Hakeikanshi Ni Yoru Renzokuchi Yuzohou |
-
1979
- 1979-01-12 IT IT67061/79A patent/IT1117559B/en active
- 1979-01-15 DE DE19792901407 patent/DE2901407A1/en active Granted
- 1979-01-16 CA CA000319690A patent/CA1156423A/en not_active Expired
- 1979-01-16 JP JP381979A patent/JPS54112338A/en active Pending
- 1979-01-16 LU LU80796A patent/LU80796A1/en unknown
- 1979-01-17 GB GB791686A patent/GB2012637B/en not_active Expired
-
1985
- 1985-12-23 JP JP1985198192U patent/JPS6327892Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2901407A1 (en) | 1979-07-19 |
| JPS6327892Y2 (en) | 1988-07-27 |
| GB2012637B (en) | 1982-05-19 |
| JPS54112338A (en) | 1979-09-03 |
| IT1117559B (en) | 1986-02-17 |
| IT7967061A0 (en) | 1979-01-12 |
| LU80796A1 (en) | 1979-05-16 |
| JPS61117350U (en) | 1986-07-24 |
| GB2012637A (en) | 1979-08-01 |
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