CN106289037B - A kind of continuous casting steel billet shell thickness eddy current detection method - Google Patents
A kind of continuous casting steel billet shell thickness eddy current detection method Download PDFInfo
- Publication number
- CN106289037B CN106289037B CN201610577344.8A CN201610577344A CN106289037B CN 106289037 B CN106289037 B CN 106289037B CN 201610577344 A CN201610577344 A CN 201610577344A CN 106289037 B CN106289037 B CN 106289037B
- Authority
- CN
- China
- Prior art keywords
- thickness
- continuous casting
- steel billet
- eddy current
- steel
- 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.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
- G01B7/06—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness for measuring thickness
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Continuous Casting (AREA)
Abstract
The invention discloses a kind of continuous casting steel billet shell thickness eddy current detection methods, belong to continuous casting steel billet detection technique field.Purpose be in order to solve the prior art measure continuous casting and solidifying shell thickness deficiency, provide it is a kind of by inside steel billet according to corresponding to temperature conductivity be layered, the method for measuring continuous casting steel billet shell thickness with multifrequency electric eddy current measurement method.This method is specially：Casting billet surface in continuous cast mold exit places current vortex sensor, sensor is mutual inductance differential type, current vortex sensor carries out mixing excitation by digital frequency synthesizer, multiple and different frequency signals of excitation are mixed by adder, measuring signal passes through the amplification of signal conditioning circuit, filtering, in the correlator computing cross-correlation is carried out with the reference signal of different frequency respectively, by Signal separator and carry out the width phase separation for being vortexed impedance signal, the signal separated is acquired and converts, it is transferred to the processing that computer carries out data, obtain the thickness of continuous casting steel billet green shell.
Description
Technical field
Present invention relates particularly to a kind of continuous casting steel billet shell thickness eddy current detection methods, belong to continuous casting steel billet detection technique
Field.
Background technology
In continuous casting of iron and steel production process, measured by the online non-destructive testing of the thickness of solidified slab shell in secondary in crystallizer exit and
Control has carried out efficient detection in time, to improve continuous casting for the uniformity of bleed-out and shell thickness in continuous casting production process
The quality of production of steel billet improves continuous casting automatization level, is embodied in following two aspects：Detection crystallizer exit in real time
Shell thickness bears the static pressure ability of molten steel, prevents that bleed-out production accident occurs in casting process；Online non-destructive testing solidifies base
Thickness of the shell variation tendency, with the intensity of cooling of on-line control secondary cooling water, closed-loop control secondary cooling water cooling water inflow.
Since the site environment of continuous casting is severe, the influence of high temperature heat radiation, cooling water spray, dust etc., Er Qie
There is solid phase area, two-phase section, liquid phase regions for the green shell in crystallizer exit.These factors determine the online nothing of thickness of continuous casting shell
Damaging testing requirements can the long-term operation of energy in high temperature, high water mist environment.
At present, thickness of solidified slab shell in secondary detection method mainly has experiment mensuration, numerical model method, strain to pass in casting process
Feel the three classes such as detection method.It tests and mainly uses method of powder actuated shot in mensuration, the steel nail of sulfur-bearing tracer is injected into continuous casting in two cold-zones
Base determines thickness of solidified slab shell in secondary and liquid phase using sufur printing analysis, pattern of the low power detection nailing in strand solid phase, liquid phase region
Acupuncture point is set, this experimental method technology maturation, and precision is high, and visual result is reliable, but is belonged to offline and damaged detection, and work is measured
Amount is big.Green shell mensuration is punctured, solidified shell is pierced through in secondary cooling area for continuous casting, so that not solidified liquid steel flow is gone out, then to solidification
Shell thickness carries out on-line checking, and this detection method belongs to destructive detection, and execute-in-place is difficult.Bulge method is to pass through
The position of continuous casting billet bulge is detected to determine wick-containing position, the measurement method is intuitive, and device is simple, but can only rough estimate wick-containing
Terminal position.According to using radiographic source is bored, radiographic source mainly is detected across ray after continuous casting billet by geiger counter for radiation method
Intensity changes to detect the thickness of solidified shell, and this method technical thought is feasible, but the radioactive pollution of radioactive source is to human body
It affects with environment.Numerical model method is to be based on one-dimensional or two dimensional unsteady heat transfer governing equation, uses finite element
Difference Calculation method calculates inner temperature of continuous casting stock field, and then determines continuous casting billet internal morphology, and this method is at low cost, but model is asked
It solves precision and depends on accurate boundary condition, but the continuous casting of unstable state determines and is difficult to determine accurate boundary condition, together
When model to calculate convergence time long, it is difficult to the variation of the online thickness of solidified slab shell in secondary of prediction in real time.Stain measuring technology passes through in continuous casting
Foil resistance foil gauge is installed in base correlation fan-shaped section, determines that continuous casting billet solidifies by monitoring dependent variable variation catastrophe point on-line
The position of end, this method reliability, sensibility are poor, but by live hyperthermia radiation, two cold-zone water mists, fan-shaped section or working roll
The influences such as stress complexity, test result is less reproducible, can not be promoted and applied in industrial site.
The importance of solidified shell based on crystallizer exit, its thickness of accurate characterization and uniformity connect optimization
Crystallizer technique and equipment are cast, continuous casting billet quality is improved and continuous casting efficiency is most important.At present both at home and abroad for solidification base
Thickness of the shell detection method is all without fundamentally solving industrial site application problem.
Invention content
Therefore, the above-mentioned deficiency that continuous casting and solidifying shell thickness is measured for the prior art, the present invention is intended to provide a kind of company
Cast steel base shell thickness eddy current detection method.The present invention can effectively overcome the surface high-temp at continuous casting scene to radiate, water mist
The influence of the adverse circumstances such as bad border is suitble to measure the thin sheet continuous casting requirement of strand different surfaces temperature, different cast steel grades respectively.
The principle of this method is according to continuous casting steel billet surface temperature on curie point, and the resistivity of billet material is with temperature
Degree variation, and when steel is molten into liquid, 2-3 times when transition its resistivity is solid-state occurs for its resistivity, therefore can be by steel
Base is divided into three layers according to resistivity, solidification layer, solid-liquid layer and layer liquid, and then uses current vortex technology, measures solidification layer
Thickness.
The purpose of this programme is realized by following scheme：
Casting billet surface in continuous cast mold exit places current vortex sensor, and sensor is mutual inductance differential type.Electric whirlpool
Flow sensor carries out mixing excitation by digital frequency synthesizer, and three different frequency signals of excitation are carried out by adder
Mixing, amplification, filtering of the measuring signal by signal conditioning circuit, the ginseng with three different frequencies respectively in three correlators
It examines signal and carries out computing cross-correlation, by Signal separator and carry out the width phase separation for being vortexed impedance signal, the signal warp separated
Acquisition and conversion are transferred to the processing that computer carries out data.The data procedures of computer disposal are as follows：When calibration, first
The temperature field pre-established by using finite element emulation software and electromagnetic field couples measurement model carry out analogue simulation calibration, obtain
Obtain measurement data and layer thickness relation curve.Solidification layer, another hot steel plate is replaced to replace solid-liquid with the hot steel plate of Varying-thickness again
Layer, molten steel is layer liquid, and measured data are completed by least-squares algorithm to solidified layer thickness and solid-liquid layer measurement data
Fitting amendment, obtain measure inverting mathematical model.When measurement, measurement data is brought measurement inverting mathematical model into and be can be obtained
The thickness of continuous casting steel billet green shell.
Further, in the method current vortex sensor the casting billet surface being placed on apart from continuous cast mold exit
The positions 2mm.
Further, digital frequency synthesizer is AD9959 digital frequency synthesizers in the method.
Further, in the method 700HZ is actuated in the parameter setting of the eddy-current coils of current vortex sensor
To 12KHZ, inside radius 12mm, outer radius is 17mm to 19mm, is highly 4mm, and former pair side the number of turns is 60 circles.
Further, the method for building up of measurement model is by finite element emulation software ANSYS to crystallizer exit
Strand carries out temperature field and carries out simulation calculating according to formula one and boundary condition, and calculating can obtain strand internal temperature gradient point
Cloth cloud atlas, in conjunction with the chemical composition of steel grade and the calculation formula two of solid-liquid phase line temperature, it can be deduced that the solidus temperature of steel grade
Value and liquidus, strand parameter is when calculating：
Crystallizer wall thickness：20mm, effective length：1000mm, casting speed：2-5.5m/min, pouring temperature：1547 DEG C,
Slab thickness：50mm.
The coefficient of heat conduction (w/m. DEG C) of λ-material, C-specific heat (J/Kg. DEG C), ρ-density (Kg/m in formula3), τ-casting
Base setting time (s), LfMolten steel solidification latent heat (J/kg).
T l=Tf∑ Δ Ti% (formula two)
In formula：TlFor solid-liquid phase line temperature, TfIt is 1% element i not to be added in iron fusing point is made to reduce for steel grade fusing point, Δ T
Value.
According to simulation calculation, required measurement range is determined.Select measurand for thin plate strand, slab thickness is ranging from
20-100 millimeters, ranging from 5-20 millimeters of range of shell thickness.It is varied with temperature according to the electromagnetic property of metal, continuous cast mold
Base surface temperature is higher than Curie temperature at lower exit port, and when steel is molten into liquid, the characteristic of transition occurs for resistivity, by steel
Base is corresponding with material temperature according to resistivity, and the strand in continuous cast mold exit is layered.
The process for carrying out emulation calibration in the method to measurement model specifically includes：
Step 1：Data processing is carried out using the impedance value that phase place mutually cuts algorithm different to three groups in MATLAB；
Step 2：Change the thickness of solidified shell layer, remaining two layers thickness respective change, repetition step 1 is multiple, obtains
Multiple-plate nominal data is surveyed to multifrequency；The corresponding experiment curv of different frequency and mathematical model are obtained by least square method.
Mathematical model such as formula three
Wherein ufiFor the corresponding voltage value of measuring signal phase under different frequency.αi,βi,χiPass through multi-group data and minimum
Square law obtains, diFor layer thickness.Then solving equations obtain thickness inverse model such as formula four
Step 3：It is measured with two layers of hot steel plate of known thickness and molten steel composition shell thickness and is substituted measurand, only changed
The thickness of the thickness of two-layered steel plates, molten steel remains unchanged, and the measuring system described in scheme obtains sensor measurement signal three not
The corresponding amplitude of same frequency and phase, are modified measurement model.
The beneficial effects of the present invention are：The present invention applies multifrequency current vortex technology in continuous casting steel billet thickness measuring, excellent
Point be can high temperature, more water mists continuous casting environment under, the concreting thickness of non-contacting on-line measurement continuous casting billet, specifically
It is embodied in the following：
1, using high temperature resistant type platypelloid type excitation coil, coil is mutual inductance differential form, and texture of coil is tungsten, insulation
Moppinged on one side while coiling using ceramic paint, the additional water-cooled jacket of coil can effectively overcome the surface high-temp spoke at continuous casting scene
It penetrates, the influence of the adverse circumstances such as water mist environment, while ensuring high-temperature metal surface reliable work of the eddy current coil at 1000 DEG C or more
Make.
2, the resistivity of material inside the strand in crystallizer exit corresponding to temperature is layered for the first time, is utilized
Current vortex multifrequency mensuration obtains shell thickness, makes more simple and clear inside strand, and solidified shell thickness measuring can be made more smart
It is accurate.
3, it using finite element emulation software, to temperature field analysis in continuous casting billet, obtains shell thickness below crystallizer and measures
Range.It is required to devise probe coil size, structure and driving frequency range according to the measurement range, more there is specific aim,
It makes the measurement in the bad border slab thickness of continuous casting high temperature, there is more feasible scheme.
4, continuous-cast blank thickness of the shell is measured using multifrequency multi-layered conductive structure thickness measuring for the first time so that multifrequency Eddy
Etection theory is applied to be verified in hot environment practice.
Description of the drawings
Strand cross-section temperature isogram under Fig. 1 pulling rates V=4.5m/min
Fig. 2 is strand interior laminate layer schematic diagram in continuous cast mold exit of the present invention.
Fig. 3 is continuous-cast blank multi-layer board vortex sensor measuring schematic diagram of the present invention.
Fig. 4 is that schematic diagram is arranged in thickness of solidified slab shell in secondary electric eddy current measurement device of the present invention.
Fig. 5 is that frequency is under 4kHZ excitations in the present invention, the penetration depth schematic diagram of current vortex.
Fig. 6 is high-temperature probe water-cooled jacket outline drawing of the present invention.
Fig. 7 is the schematic diagram calculation that finite element emulation software of the present invention carries out simulated calibration.
Fig. 8 is the graph of relation of thickness and voltage change under different frequency of the present invention.
Fig. 9 is the measuring system general principles block diagram of the method for the present invention.
Specific implementation mode
Description of specific embodiments of the present invention below in conjunction with the accompanying drawings：
The thickness of on-line measurement continuous cast mold of the present invention exit solidified shell, eddy current coil of the invention are the companies of measurement
The thickness for casting the solidification strand in crystallizer exit carries out autonomous Design due to the particularity of object to eddy current coil.
It is solid-state area, solid-liquid two-phase region, liquid phase region inside strand, the thickness in these sections is to be difficult to when strand has just gone out continuous cast mold
It measures.Firstly the need of the range for knowing shell thickness, probe and measuring system are designed according to measurement range.
Temperature field is carried out according to formula one and a system to the strand in crystallizer exit by finite element emulation software ANSYS
Row boundary condition carries out simulation calculating, and calculating can obtain strand internal temperature gradient cloud charts as shown in Figure 1, in conjunction with steel grade
Chemical composition and solid-liquid phase line temperature calculation formula two, it can be deduced that the solidus temperature values and liquidus temperature of steel grade
Value.Strand parameter is as shown in table 1 when calculating.
Table 1
| Crystallizer wall thickness | Effective length | Casting speed | Pouring temperature | Slab thickness |
| 20mm | 1000mm | 2-5.5m/min | 1547℃ | 50mm |
The coefficient of heat conduction (w/m. DEG C) of λ-material, C-specific heat (J/Kg. DEG C), ρ-density (Kg/m in formula3), τ-casting
Base setting time (s), LfMolten steel solidification latent heat (J/kg).
T l=Tf∑ Δ Ti% formula two
In formula：TlFor solid-liquid phase line temperature, TfIt is 1% element i not to be added in iron fusing point is made to reduce for steel grade fusing point, Δ T
Value.
According to simulation calculation, required measurement range is determined.Select measurand for thin plate strand, slab thickness is ranging from
20-100 millimeters, ranging from 5-20 millimeters of range of shell thickness.
It is varied with temperature according to the electromagnetic property of metal, continuous cast mold lower exit port ejection surface temperature is higher than Curie's temperature
Degree, and when steel is molten into liquid, the characteristic of transition occurs for resistivity, and steel billet is corresponding with material temperature according to resistivity,
The strand in continuous cast mold exit can be made to be layered, for institute's established model as shown in Fig. 2, wherein 4 be solid-state area, 5 be solid-liquid two
Phase region, 6 be liquid phase region.
Sensor model is established on detection object model, institute's established model is as shown in Figure 3.Wherein, R1For coil inside radius,
R2It is eddy current coil height for coil outer radius, D, H is lift-off distance, t1Plate layer thickness, t are removed for solid-state2For solid-liquid two-phase region
Thickness, t3For the thickness of liquid phase region.Sensor optimization calculating is carried out on the mold.
Result of calculation support by the placement location of current vortex sensor as shown in figure 4, in Fig. 41 be tundish, 2 for crystallization
Device, 3 be current vortex sensor.Show that vortex density can expire when lift-off distance is 2mm by finite element emulation software ANSYS
Sufficient measurement request.Therefore current vortex sensor 3 be placed on away from below at continuous cast mold 2 away from the positions casting billet surface 2mm at.
According to the particularity of measured target and the correlation theory of EDDY CURRENT, with finite element emulation software and impedance analysis
Method emulates eddy current coil, so that eddy current coil can be with the efficiency of the thickness of on-line checking solidified shell and eddy-current coils
It can be optimal.
F is the master drive frequency of eddy current coil in formula, and ρ is magnetic conductivity, and μ is relative permeability, and d is skin depth, and R is line
Enclose inside radius.
Eddy-current coils master drive frequency and coil inside radius can be obtained based on formula five, formula six, with above-mentioned two
On the basis of factor, finite element stimulation is carried out to the outer radius of eddy current coil, height and the number of turns respectively, calculates obtained knot
Fruit data are imported into MATLAB, are analyzed it processing by MATLAB, have been finally obtained being actuated to for eddy-current coils
700HZ to 12KHZ, inside radius 12mm, outer radius are 17mm to 19mm, are highly 4mm, and former pair side the number of turns, which is 60 circles, to be obtained
Maximal efficiency is obtained, finite element simulation skin depth is as shown in Figure 5.
For the present invention in order to be suitable for the environment such as continuous casting scene high temperature, more water mists, excitation coil coiling used uses high temperature resistant
Tungsten filament and ceramic paint be wound with screw type, the probing shell of sensor uses the metal shell with water cooling effect, spy
Head shell water cooling design is as shown in Figure 6.
First finite element emulation software is used to carry out simulated calibration, then utilize hot steel plate and liquid molten steel to measurement model into
Row is corrected.
In multi frequency detection, current vortex sensor is encouraged with the signal of three frequency Waveform compositions, since superposition is former
Coil linear system ought to be used, so the impedance variations popped one's head under mixed frequency excitation are hindered under each frequency independent drive
The linear synthesis of resistance.Its effect controls same probe with three independent eddy-current instruments, then by the output of three instruments
Addition is the same, therefore in finite element simulation, and coil is deactivated using three individual frequencies.
Step 1：Different driving frequencies will produce different impedance values, and three groups of different driving frequencies will will produce three
The different impedance value of group carries out data processing in MATLAB using the impedance value that phase place mutually cuts algorithm different to three groups；
Step 2：Change the thickness of solidified shell layer, remaining two layers thickness respective change, repetition step 1 is multiple, obtains
Multiple-plate nominal data is surveyed to multifrequency；The corresponding experiment curv of different frequency and mathematical model are obtained by least square method.
Mathematical model such as formula three
Wherein ufiFor the corresponding voltage value of measuring signal phase under different frequency.αi,βi,χiPass through multi-group data and minimum
Square law obtains, diFor layer thickness.The thickness of upper two layers need to only be obtained.Then it is such as public to obtain thickness inverse model for solving equations
Formula four
The Computing Principle of simulated calibration is carried out as shown in fig. 7, in figure, due to casting billet surface temperature using finite element emulation software
Degree is higher than curie point, relative permeability μiIt is 1, conductivity is corresponded to according to temperature, and coil is mutual inductance differential type.Probe coil is joined
Number:r1,r2Probe coil internal diameter and outer diameter, (12-l1)-probe length；l1Lift-off；Material electric conductivity:σ1,σ2,…,σm,
σm+1,σm+2；Material relative permeability:μ1,μ2,…,μm,μm+1,μm+2Each directions layer intersection z are sat:z1,z2,…,zm,z1+m,zi
=-(dm+dm-1,…di+2+di+1), i=1,2,3 ... m-1, dm+dm-1,…di+2+di+1The thickness of each layer.
Step 3：It is measured with two layers of hot steel plate of known thickness and molten steel composition shell thickness and is substituted measurand, only changed
The thickness of the thickness of two-layered steel plates, molten steel remains unchanged, and the measuring system described in scheme obtains sensor measurement signal three not
The corresponding amplitude of same frequency and phase, are modified measurement model, thickness and voltage change under finally obtained different frequency
The relation curve of value is as shown in Figure 8.
The thickness schematic diagram of eddy current coil on-line measurement solidified shell of the present invention, as shown in Figure 9.It is encouraged by multiple-frequency signal
Source AD9959, eddy current probe coil, signal processing circuit, correlator, signal acquisition and conversion and computer composition.
Current vortex sensor needs three different driving frequencies simultaneously to test coil of eddy current into row energization.Therefore, by
The pumping signal for the three road different frequencies that AD9959 is generated must be mixed by adder, to meet multifrequency simultaneously to whirlpool
Detection coil is flowed into row energization, and the design completes the mixed of different frequency signals using the summation operation circuit in the same direction of principle of stacking
Frequently.
Simple signal excitation is measured for shell thickness cannot achieve, traditional Impedance Analysis can only inhibit one
Disturbing factor.Therefore, it is desirable to which the information for obtaining more examined workpieces is needed with multiple frequencies to current vortex sensor into row energization.
Three layers of conductive structure thickness measure are then needed with the sinusoidal signal mixing frequency excitation mode of three different frequencies, and must assure that each
Pumping signal can penetrate shell thickness, therefore can be wrapped the vortex response signal of frequency alias using three quadricorrelators
The information separation contained, obtains the direct current signal under single frequency excitation.
The thickness of on-line measurement solidified shell of the present invention is such be measured：In continuous cast mold exit distance
Above-mentioned current vortex sensor is placed at casting billet surface 2mm, current vortex sensor carries out mixing excitation by AD9959, and three are not
With frequency be mixed by adder, measure end signal by signal conditioning circuit amplification, filtering, in the correlator into
Capable computing cross-correlation realizes the separation of different frequency signals and is vortexed the width phase separation of impedance signal, separates
Signal is acquired and converts, and is finally transferred to the processing that computer carries out data.
It is measured with two layers of hot steel plate of known thickness and molten steel composition shell thickness and is substituted measurand, sensed described in Fig. 9
Device and measuring system obtain data.In the data that computer is handled, the measurement model to emulating calibration in advance is modified,
Obtain practical measurement model.
When measuring, the sensor and measuring system acquisition measured value, which bring measurement model into, can calculate solidified shell thickness
Degree.When steel grade changes, need to re-scale.
In order to improve measurement accuracy, being layered in steel billet further to segment, but measurement frequency need to add more multi-frequency, measure
Speed will reduce.This problem needs to compromise in calibration to be considered.
The above is the preferred embodiment of the present invention, it is noted that for those skilled in the art
For, without departing from the principles of the present invention, it can also make several improvements and retouch, these improvements and modifications
It should be regarded as protection scope of the present invention.
Claims (7)
1. a kind of continuous casting steel billet shell thickness eddy current detection method, which is characterized in that the method is：Go out in continuous cast mold
Casting billet surface at mouthful places current vortex sensor, and sensor is mutual inductance differential type, and current vortex sensor is closed by numerical frequency
It grows up to be a useful person and carries out mixing excitation, three different frequency signals of excitation are mixed by adder, and measuring signal passes through signal
Amplification, the filtering of modulate circuit, computing cross-correlation is carried out in three correlators with the reference signal of three different frequencies respectively,
By Signal separator and the width phase separation for being vortexed impedance signal is carried out, the signal separated is acquired and converts, and is transferred to calculating
Machine carries out the processing of data, and the data procedures of computer disposal are as follows：When calibration, first by using finite element emulation software
The temperature field pre-established and electromagnetic field couples measurement model carry out analogue simulation calibration, obtain measurement data and layer thickness relationship
Curve, then replace solidification layer, another hot steel plate to replace solid-liquid layer with the hot steel plate of Varying-thickness, molten steel is layer liquid, measured
Data by least-squares algorithm, complete the amendment of the fitting to solidified layer thickness and solid-liquid layer measurement data, measured
Inverting mathematical model, when measurement, measurement data, which is brought into, measures the thickness that inverting mathematical model can be obtained continuous casting steel billet green shell.
2. continuous casting steel billet shell thickness eddy current detection method as described in claim 1, which is characterized in that electric in the method
The positions casting billet surface 2mm of eddy current sensor being placed on apart from continuous cast mold exit.
3. continuous casting steel billet shell thickness eddy current detection method as described in claim 1, which is characterized in that number in the method
Word frequency synthesizer is AD9959 digital frequency synthesizers.
4. continuous casting steel billet shell thickness eddy current detection method as described in claim 1, which is characterized in that in the method
The parameter of the eddy-current coils of current vortex sensor is set as, and is actuated to 700HZ to 12KHZ, inside radius 12mm, and outer radius is
17mm to 19mm is highly 4mm, and former pair side the number of turns is 60 circles.
5. continuous casting steel billet shell thickness eddy current detection method as described in claim 1, which is characterized in that surveyed in the method
The method for building up for measuring model is to carry out temperature field according to public affairs to the strand in crystallizer exit by finite element emulation software ANSYS
Formula one and boundary condition carry out simulation calculating, and calculating can obtain strand internal temperature gradient cloud charts, in conjunction with the change of steel grade
It studies point and the calculation formula two of solid-liquid phase line temperature, it can be deduced that the solidus temperature values and liquidus of steel grade, meter
Strand parameter is when calculation：
Crystallizer wall thickness：20mm, effective length：1000mm, casting speed：2-5.5m/min, pouring temperature：1547 DEG C, strand
Thickness：50mm,
The coefficient of heat conduction of λ-material, unit in formula：DEG C, w/m. C-compares heat unit：DEG C, J/Kg. ρ-density unit：Kg/m3,
τ-casting blank solidification chronomere：s,LfMolten steel solidification latent heat unit：J/kg,
Tl=Tf∑ Δ Ti% formula two
In formula：TlFor solid-liquid phase line temperature, TfIt is that 1% element i is not added in iron to make fusing point decreasing value for steel grade fusing point, Δ T,
According to simulation calculation, required measurement range is determined, select measurand for thin plate strand, slab thickness ranging from 20-
100 millimeters, ranging from 5-20 millimeters of range of shell thickness is varied with temperature according to the electromagnetic property of metal, under continuous cast mold
Square exit base surface temperature is higher than Curie temperature, and when steel is molten into liquid, the characteristic of transition occurs for resistivity, by steel billet
It is corresponding with material temperature according to resistivity, the strand in continuous cast mold exit is layered.
6. continuous casting steel billet shell thickness eddy current detection method as claimed in claim 5, which is characterized in that right in the method
The process that measurement model carries out emulation calibration specifically includes：
Step 1：It is mutually cut algorithm using phase place in MATLAB and three groups of different impedance values of corresponding three frequencies is carried out
Data processing,
Step 2：Change casting speed, the thickness of solidified shell changes correspondingly, remaining two layers thickness consequently also becomes, and repeats to walk
Rapid one, it obtains multifrequency and surveys multiple-plate calibration curve.
7. continuous casting steel billet shell thickness eddy current detection method as claimed in claim 6, which is characterized in that used in the method
The hot steel plate of known thickness and molten steel composition shell thickness measure and substitute measurand, only change the thickness of steel plate, the thickness of molten steel
It remains unchanged, measurement model is modified.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610577344.8A CN106289037B (en) | 2016-07-19 | 2016-07-19 | A kind of continuous casting steel billet shell thickness eddy current detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610577344.8A CN106289037B (en) | 2016-07-19 | 2016-07-19 | A kind of continuous casting steel billet shell thickness eddy current detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106289037A CN106289037A (en) | 2017-01-04 |
| CN106289037B true CN106289037B (en) | 2018-09-07 |
Family
ID=57651821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610577344.8A Active CN106289037B (en) | 2016-07-19 | 2016-07-19 | A kind of continuous casting steel billet shell thickness eddy current detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106289037B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107063142B (en) * | 2017-05-04 | 2019-09-10 | 盐城工学院 | A kind of sheet billet continuous casting thickness of solidified slab shell in secondary detection system |
| JP7355250B2 (en) * | 2020-08-12 | 2023-10-03 | Ｊｆｅスチール株式会社 | Continuous steel casting method and steel test solidification device |
| CN112179261B (en) * | 2020-09-24 | 2022-09-23 | 桂林理工大学 | Method for detecting thickness of steel rail decarburized layer based on electromagnetic response |
| CN115994461B (en) * | 2022-11-29 | 2023-06-30 | 北华航天工业学院 | Finite element simulation method for influence of defects on impedance in magnetic leakage-vortex composite detection |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101162171A (en) * | 2007-11-28 | 2008-04-16 | 重庆大学 | Method for measuring surface temperature of high-temperature casting billet within water fog medium |
| CN101992281A (en) * | 2009-08-25 | 2011-03-30 | 鞍钢股份有限公司 | Method and device for measuring thickness of continuous casting shell |
| CN102029368A (en) * | 2010-12-25 | 2011-04-27 | 大连理工大学 | Method for online detecting solid-liquid phase fraction and solidified tail end of secondary cooling zone of continuous casting blank |
| CN103386472A (en) * | 2013-08-05 | 2013-11-13 | 中冶南方工程技术有限公司 | Method and device of obtaining safe thickness of outlet shell of crystallizer for continuous casting |
| CN103852000A (en) * | 2014-03-24 | 2014-06-11 | 电子科技大学 | Method and device for detecting thickness of multi-layer conductive coating through vortex |
| CN104384469A (en) * | 2014-12-16 | 2015-03-04 | 东北大学 | Prediction system and method for thickness of initially solidified shell in continuous steel casting crystallizer |
-
2016
- 2016-07-19 CN CN201610577344.8A patent/CN106289037B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101162171A (en) * | 2007-11-28 | 2008-04-16 | 重庆大学 | Method for measuring surface temperature of high-temperature casting billet within water fog medium |
| CN101992281A (en) * | 2009-08-25 | 2011-03-30 | 鞍钢股份有限公司 | Method and device for measuring thickness of continuous casting shell |
| CN102029368A (en) * | 2010-12-25 | 2011-04-27 | 大连理工大学 | Method for online detecting solid-liquid phase fraction and solidified tail end of secondary cooling zone of continuous casting blank |
| CN103386472A (en) * | 2013-08-05 | 2013-11-13 | 中冶南方工程技术有限公司 | Method and device of obtaining safe thickness of outlet shell of crystallizer for continuous casting |
| CN103386472B (en) * | 2013-08-05 | 2016-03-02 | 中冶南方工程技术有限公司 | A kind of acquisition methods of continuous cast mold outlet base shell safe thickness and device |
| CN103852000A (en) * | 2014-03-24 | 2014-06-11 | 电子科技大学 | Method and device for detecting thickness of multi-layer conductive coating through vortex |
| CN104384469A (en) * | 2014-12-16 | 2015-03-04 | 东北大学 | Prediction system and method for thickness of initially solidified shell in continuous steel casting crystallizer |
| CN104384469B (en) * | 2014-12-16 | 2016-04-20 | 东北大学 | The prognoses system of initial set shell thickness and method in a kind of steel continuous casting crystallizer |
Non-Patent Citations (1)
| Title |
|---|
| 基于涡流无损检测技术的导电涂层厚度检测方法研究;张德俊;《中国优秀硕士学位论文全文数据库信息科技Ⅰ辑》;20160315(第03期);摘要、"点涡流传感器有限元建模"部分、"基体上多涂层厚度检测方法研究"部分，图3-1，图3-10 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106289037A (en) | 2017-01-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106289037B (en) | A kind of continuous casting steel billet shell thickness eddy current detection method | |
| EP0349528B1 (en) | A method and measuring system for contactless measuring the values of magnitudes relating to electrically conductive materials | |
| CN104493121B (en) | A kind of solidification end position online test method of bloom continuous casting production process | |
| JP6489061B2 (en) | Thinning detection system, thinning detection method | |
| KR100768395B1 (en) | Method for detecting solidification completion position of continuous casting cast piece, detector, and method for producing continuous casting cast piece | |
| CN104964659B (en) | High temperature resistant type thickness of solidified slab shell in secondary electromagnetic acoustic sweep frequency detection method and device | |
| CN103247357A (en) | Online nondestructive testing method of multilayer sleeve structure eccentricity of internal ITER (International Thermonuclear Experimental Reactor) coil | |
| EP2409114B1 (en) | A method and an apparatus for measuring the thickness of a metal layer provided on a metal object | |
| CN201653588U (en) | Temperature measuring device used for concrete track slabs and test blocks and maintenance device | |
| MX2011004335A (en) | Method and apparatus for a non contact metal sensing device. | |
| Thomas et al. | Monitoring of meniscus thermal phenomena with thermocouples in continuous casting of steel | |
| CN108680607B (en) | Pipeline crack corrosion monitoring method based on multidirectional alternating current potential drop | |
| CN204381333U (en) | One solidifies detection system based on hyperacoustic steel billet | |
| US11892285B2 (en) | Thickness measurement using a pulsed eddy current system | |
| ITUB20154095A1 (en) | MAGNETIC SYSTEM | |
| US3899651A (en) | Method and apparatus for control of weld temperature in a high frequency electric resistance welded pipe mill | |
| JPH0242402B2 (en) | ||
| SE462998B (en) | PROCEDURE AND DEVICE FOR DETERMINATION OF THE CONDITION OF THE INSULATION OF A PREPARATION MADE FROM ELECTRICALLY CONDUCTIVE MATERIAL, COVERED WITH AN ELECTRIC INSULATION AND PROVIDED IN AN ELECTRICALLY CONDUCTIVE MEDIUM | |
| Terekhin et al. | Evaluating specific electrical conductivity of two-layered nonmagnetic objects by pulsed eddy-current method | |
| Vidoni et al. | Profile strip casting with inline hot rolling: Numerical simulations for the process chain design | |
| EP3335000B1 (en) | Device and method for the hot measuring, during rolling, of a size of metal profiles | |
| SU905443A1 (en) | Method of measuring fluid inflow curve profile | |
| Gille | The electrical potential method and its application to non-destructive testing | |
| JPS59151003A (en) | Method for measuring thickness of solidified layer | |
| Rao et al. | Electromagnetic modelling of sheet-like bodies by the combined-loop version of the transient pulse induction method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |