CN102029368A - Method for online detecting solid-liquid phase fraction and solidified tail end of secondary cooling zone of continuous casting blank - Google Patents
Method for online detecting solid-liquid phase fraction and solidified tail end of secondary cooling zone of continuous casting blank Download PDFInfo
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- CN102029368A CN102029368A CN2010106058582A CN201010605858A CN102029368A CN 102029368 A CN102029368 A CN 102029368A CN 2010106058582 A CN2010106058582 A CN 2010106058582A CN 201010605858 A CN201010605858 A CN 201010605858A CN 102029368 A CN102029368 A CN 102029368A
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Abstract
The invention relates to a method for online detecting a solid-liquid phase fraction and a solidified tail end of a secondary cooling zone of a continuous casting blank, belonging to an online detection method in the field of metallurgy continuous casting. The detection method comprises the steps of: applying indirect excitation to a casting blank in secondary cooling zone solidification by using one vibration frequency and one vibration amplitude through a measuring device installed on a casting machine, transmitting a sensor measuring value obtained through feedback to a developed model analysis system, and figuring out a solid-liquid phase fraction and the position of the solidified tail end of the secondary cooling zone of the continuous casting blank. The detection method has the advantage of being capable of improving the solid-liquid fraction of the casting blank and the detection accuracy of the liquid core solidification tail end by adopting an online direct measuring mode and using a method of measuring instead of calculating. Equipment of the method has short reconstruction period and low input cost and is more convenient for later-stage maintenance; and the position of the solidification tail end of the casting blank can be determined under the condition of constant pull speed steady-state pouring, and the solid-liquid phase fractions and the positions of the solidified tail end of the casting blank in different positions can be more accurately and quantitatively given.
Description
Technical field
The present invention relates to the method for a kind of online detection continuous casting billet two cold-zone solid-liquid phase fractions and solidification end, belong to a kind of online test method in metallurgical continuous casting field.
Background technology
Along with the continuous development of modern industrial technology, also more and more higher to the quality requirement of steel products, and in continuous casting was produced, generally all can there be defectives such as center segregation, center porosity and implosion in strand inside, thereby has influenced slab quality.The method that improves the efficient and cost-effective of internal soundness is to adopt continuous casting gently to depress technology.Continuous casting is gently depressed technology and promptly the continuous casting billet that does not solidify is fully suitably depressed, be that a kind of to melt that metallurgical casting solidifies with elastic-plastic deformation be the technology of one, its depress effect and suitable depressing position closely related, and suitable depressing position is by the solid-liquid phase fraction of strand and solidification end determining positions.
At present, the solidification end position determines it is to obtain by finding the solution based on the computation model in strand temperature field mostly.This method based on numerical computations need constantly be adjusted some special parameter artificially at different steel grades, casting machine and pouring condition; And computation model is on certain hypothesis basis, ignored promptly that the part physical condition sets up down, the setting value of its boundary condition that adopts and input parameter, some also may be quite different with actual conditions, therefore, determine that by the The model calculation in temperature field may there be bigger deviation in the position of casting blank solidification end sometimes, has bigger uncertainty.
In patent CN101035639A, disclose and be used for metal is determined liquid core end when especially the steel material carries out continuous casting a kind of method.This invention is installed in a pair of piston-hydraulic cylinder-unit that has measurement mechanism in the fan-shaped section, position sensor is integrated in the hydraulic cylinder nominal position by hydraulic valve regulator solution cylinder pressure and exerting pressure accordingly.The feedback information of comparison position value and power value is calculated the position of liquid core end.If will realize more high-precision measurement, to install then how group is right by piston-hydraulic cylinder-unit that a pair of independently piston-hydraulic cylinder-unit is formed at least.The method will be carried out the hardware modification of upper frame and underframe to fan-shaped section, and not only transformation process is wasted time and energy, and the cost of servo-hydraulic system is higher, and the supply of oil circuit and the maintenance in later stage also all are very important problems.
A kind of solidified tail end of liquid core of continuous casting billet method for determining position is also disclosed in patent CN101890488A.This invention is provided with force cell in the junction of continuous casting machine fan-shaped segment frames and clamping cylinder, measure and be recorded in the pressure of the entrance and exit of each sector-segment frames in the casting process, the sudden change situation of each sector-segment frames entrance and exit pressure relatively draws the residing position of solidified tail end of liquid core when changing according to pulling rate.The method can only be judged the approximate range that solidified tail end of liquid core is in certain number fan-shaped section qualitatively, and will analyze and be prerequisite extract to become data under the pulling rate situation.And in conjunction with the actual conditions at continuous casting scene, opening the stage of watering except ladle had the specific change pulling rate situation appearance with the cast stage of being near completion, strand all can be in the situation of stable state cast, be that pulling rate does not change, simultaneously, the cooling water Quench that causes for fear of pulling rate sudden change and the quality of strand is caused harmful effect also can be avoided the change of pulling rate as far as possible.Certainly, when running into the signal prompt of latent defects such as bleed-out early warning, also have the situation that becomes pulling rate and occur, but this has very big uncertainty.
Summary of the invention
The present invention provides the detection method of a kind of online detection continuous casting billet two cold-zone solid-liquid phase fractions and solidification end thereof in order to overcome problems of the prior art.
This detection method should be determined the liquid phase fraction and the final freezing point of strand in the casting process, provide more accurate technique parameter for gently depressing technology, thereby further reduce the mass defects such as component segregation of strand, when improving the strand quality of production, also lay the foundation for the deep exploitation of high-speed continuous casting technology.
Technical scheme of the present invention is: step 1, by the measurement mechanism that is installed on the casting machine strand in solidify two cold-zones is shaken frequently and amplitude applies indirect excitation with certain; Step 2, the sensor signal value that feedback is obtained pass to the model analysis system of exploitation; Step 3, draw the solid-liquid phase fraction of continuous casting billet in two cold-zones in conjunction with the solid-liquid phase fraction computing formula of strand in two cold-zones; Step 4, be that the basis draws equivalent shell thickness d ' and the solidification end position discreet value L ' of continuous casting billet in two cold-zones with the The above results; Step 5, by equivalent shell thickness d ' and casting blank solidification square root law draw casting blank solidification COEFFICIENT K based on actual measurement '; Step 6, by based on the casting blank solidification COEFFICIENT K of actual measurement ' and the experience coagulation factor K of throwing steel grade
0Weighting is handled and is obtained comprehensive coagulation factor K; Step 7, send comprehensive coagulation factor K to target component numerical computations module and algorithm correcting module, determine solid-liquid phase fraction and the solidification end position of strand in two cold-zones.
Effect of the present invention and benefit are: this detection method adopts the mode of online direct measurement to determine the solid-liquid phase fraction and the final freezing point of strand in the casting process, replaces Calculation Method with measuring, and can further improve the accuracy of detection of solidified tail end of liquid core.The scrap build cycle of the present invention is short, input cost is low, later maintenance is comparatively convenient; The position of casting blank solidification end can be under the constant stable state pouring condition of pulling rate, determined, and solid-liquid phase fraction and the solidification end position of strand can be provided more accurately quantitatively at the diverse location place.
Description of drawings
Fig. 1 is the on-line detecting system schematic diagram of continuous casting billet two cold-zone solid-liquid phase fractions and solidification end thereof;
Fig. 2 is the measuring system entire block diagram;
Fig. 3 is the definite schematic diagram of shell thickness situation of change and solidification end position in certain steel grade casting cycle.
The specific embodiment
Fig. 1 is the on-line detecting system schematic diagram of continuous casting billet two cold-zone solid-liquid phase fractions and solidification end thereof.Molten steel flows into tundish 2 by ladle 1, by the requirement of casting process, the molten steel in the tundish 2 is assigned in the crystallizer 3 of conticaster again.Molten steel is constantly by water mold, pulls out from the crystallizer below after being frozen into solid-state base shell, enters secondary cooling zone through No. 0 fan-shaped section foot roller section 4a.In two cold-zones the casting billet surface that has the liquid core is forced cooling, the solidification process of strand is quickened in the spray effect by cooling water, and the fan-shaped section of two cold-zones is made up of segmental arc, aligning section and horizontal segment.Wherein segmental arc comprises No. 1 fan-shaped section 4b and No. 2 fan-shaped section 4c, and the aligning section comprises No. 3 fan-shaped section 4d and No. 4 fan-shaped section 4e, and No. 5 fan-shaped section 4f, No. 6 fan-shaped section 4g, No. 7 fan-shaped section 4h and No. 8 fan-shaped section 4i are horizontal segment.
Principle of the present invention is: along with constantly scattering and disappearing of outside water-cooled and strand self heat, strand 5 will solidify gradually, and inner liquid core zone will be more and more littler.And the liquid core thickness difference of strand inside, the damping effect of its generation is different.Measuring system of the present invention just is being based on this principle exploitation.
Fig. 2 has provided the detection schematic diagram of measuring system.Measuring system 6 comprises hardware detection system 7 and model analysis system 8.By sensing measurement system, the pumping signal that power source system is produced feeds back to model analysis system 8, calculates to pass to after the information such as the solid-liquid phase fraction of continuous casting billet and solidification end position 5a thereof to show that output system finishes visual output.
Fig. 3 has provided the definite schematic diagram of shell thickness situation of change and solidification end position in certain steel grade casting cycle.Curve A is represented the situation of change of pulling rate among the figure, and curve B changes the situation of change of shell thickness, and 5a is the solidified tail end of liquid core position.
The present invention can at first utilize the empirical model method to judge the approximate region scope of strand solidified tail end of liquid core position 5a under the casting machine work pulling rate.The square root law computing formula of casting blank solidification is:
In the formula: d
0Be thickness of solidified slab shell in secondary, mm;
K
0Be the experience coagulation factor of this strand steel grade, mm/min
0.5
L is the distance of solidified tail end of liquid core apart from meniscus, m;
V is a casting speed, m/min.
Formula can calculate the casting blank shell thickness that has solidified under certain type of cooling and pulling rate thus, and then can be in the hope of the approximate region scope of the solidified tail end of liquid core position 5a of casting machine under different casting.Determine the fan-shaped section area code that contained according to this scope, the hardware detection device is installed near the fan-shaped section of solidification end position, can further reduce the hardware cost input at these.
Be that example describes the position of how specifically determining continuous casting billet two cold-zone solid-liquid phase fractions and solidification end thereof with certain steel mill's mild steel below.Casting blank cross-section size is 2260mm * 220mm, adopts circular-arc type continuous casting machine to carry out the single current casting.Consider the practical operation situation of on-the-spot casting machine, its work pulling rate generally between 0.85m/min～1.1m/min, in conjunction with the square root law computing formula of casting blank solidification, the experience coagulation factor K of this steel grade here
0=27mm/min
0.5The position 5a that then can extrapolate the strand solidified tail end of liquid core locates about distance crystallizer meniscus 14.11m to 18.26m greatly, corresponding casting machine position is between No. 4 fan-shaped section 4e and No. 5 fan-shaped section 4f, therefore can measuring system of the present invention be installed in these two fan-shaped section.
When strand is cast with certain stable state pulling rate, the hardware detection system 7 that is installed on No. 4 fan-shaped section 4e and No. 5 fan-shaped section 4f is started working, checkout gear is respectively 14.89m and 17.11m apart from the distance of crystallizer meniscus, by sensing measurement system feedback signal is passed to model analysis system 8.The model analysis system just can obtain the solid-liquid phase fraction of strand in two cold-zones based on following formula.
In the formula:
Fraction solid for strand;
Calculating and can get by analytical system, is 0.759 apart from the fraction solid at crystallizer meniscus 14.89m place, is that the equivalent shell thickness of 0.825, two position is respectively 83.6mm and 88.2mm apart from the fraction solid at crystallizer meniscus 17.11m place.And then obtain casting blank solidification COEFFICIENT K ' be 19.2 mm/min based on actual measurement
0.5, with the experience coagulation factor K of this steel grade
0It is 20.6 mm/min that the weighting processing can get the comprehensive coagulation factor K of strand
0.5Send this value to target component numerical computations module and algorithm correcting module, draw solidified tail end of liquid core position 5a at distance crystallizer meniscus 20.46 ± 0.22m place, strand solid-liquid phase fraction that obtains like this and solidification end position thereof just can provide more accurate guide parameters for dynamically gently depressing with the solidification end electromagnetic agitating technology.
Claims (2)
1. the method for online detection continuous casting billet two cold-zone solid-liquid phase fractions and solidification end is characterized in that described employing the following step:
(1) by the measurement mechanism that is installed on the casting machine strand in solidify two cold-zones is shaken frequently and amplitude applies indirect excitation with certain;
(2) sensor signal value that feedback is obtained passes to the model analysis system of exploitation;
(3) draw the solid-liquid phase fraction of continuous casting billet in conjunction with the solid-liquid phase fraction computing formula of strand in two cold-zones in two cold-zones;
(4) be that the basis draws equivalent shell thickness d ' and the solidification end position discreet value of continuous casting billet in two cold-zones with the The above results
L′；
(5) by equivalent shell thickness d ' and casting blank solidification square root law draw casting blank solidification COEFFICIENT K based on actual measurement ';
(6) by based on the casting blank solidification COEFFICIENT K of actual measurement ' and the experience coagulation factor K of throwing steel grade
0Weighting is handled and is obtained comprehensive coagulation factor K;
(7) send comprehensive coagulation factor K to target component numerical computations module and algorithm correcting module, determine solid-liquid phase fraction and the solidification end position of strand in two cold-zones.
2. press the method for claim 1 described a kind of online detection continuous casting billet two cold-zone solid-liquid phase fractions and solidification end, it is characterized in that: described strand in the solid-liquid phase fraction computing formula of two cold-zones is
,
,
In the formula:
Fraction solid for strand;
The driving frequency that applies for measuring system;
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102492882A (en) * | 2011-12-05 | 2012-06-13 | 大连理工大学 | Capture and conversion rule for simulation of solidified microstructure of magnesium alloy |
| CN102554170A (en) * | 2012-03-27 | 2012-07-11 | 大连理工大学 | Method for detecting solid-liquid phase fractions of continuous casting blanks in secondary cooling zone on line |
| CN104540616A (en) * | 2012-07-05 | 2015-04-22 | 丹尼尔和科菲森梅克尼齐有限公司 | Method for determining a stretch of casting line including the closing position of the liquid cone of a continuously cast metal product |
| CN106289037A (en) * | 2016-07-19 | 2017-01-04 | 内蒙古科技大学 | A kind of continuous casting steel billet shell thickness eddy current detection method |
| CN112784367A (en) * | 2020-12-10 | 2021-05-11 | 江阴兴澄特种钢铁有限公司 | Method for calculating thickness of blank shell at position of continuous casting roller row and solidification tail end of casting machine |
| CN114905020A (en) * | 2022-05-16 | 2022-08-16 | 北京科技大学 | Method for correcting solidification heat transfer model in continuous casting process |
-
2010
- 2010-12-25 CN CN2010106058582A patent/CN102029368A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102492882A (en) * | 2011-12-05 | 2012-06-13 | 大连理工大学 | Capture and conversion rule for simulation of solidified microstructure of magnesium alloy |
| CN102554170A (en) * | 2012-03-27 | 2012-07-11 | 大连理工大学 | Method for detecting solid-liquid phase fractions of continuous casting blanks in secondary cooling zone on line |
| CN102554170B (en) * | 2012-03-27 | 2013-10-30 | 大连理工大学 | Method for detecting solid-liquid phase fractions of continuous casting blanks in secondary cooling zone on line |
| CN104540616A (en) * | 2012-07-05 | 2015-04-22 | 丹尼尔和科菲森梅克尼齐有限公司 | Method for determining a stretch of casting line including the closing position of the liquid cone of a continuously cast metal product |
| CN104540616B (en) * | 2012-07-05 | 2016-08-17 | 丹尼尔和科菲森梅克尼齐有限公司 | The method determining one section of foudry line of the make position of the liquid cone including continuously cast metal product |
| CN106289037A (en) * | 2016-07-19 | 2017-01-04 | 内蒙古科技大学 | A kind of continuous casting steel billet shell thickness eddy current detection method |
| CN106289037B (en) * | 2016-07-19 | 2018-09-07 | 内蒙古科技大学 | A kind of continuous casting steel billet shell thickness eddy current detection method |
| CN112784367A (en) * | 2020-12-10 | 2021-05-11 | 江阴兴澄特种钢铁有限公司 | Method for calculating thickness of blank shell at position of continuous casting roller row and solidification tail end of casting machine |
| CN114905020A (en) * | 2022-05-16 | 2022-08-16 | 北京科技大学 | Method for correcting solidification heat transfer model in continuous casting process |
| CN114905020B (en) * | 2022-05-16 | 2022-12-27 | 北京科技大学 | Method for correcting solidification heat transfer model in continuous casting process |
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Application publication date: 20110427 |