CN107052292B - A kind of Hot Charging of Continuous Casting Slab tracking and calculating method calculated based on thermal physical property parameter distribution - Google Patents
A kind of Hot Charging of Continuous Casting Slab tracking and calculating method calculated based on thermal physical property parameter distribution Download PDFInfo
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Abstract
The present invention provides a kind of Hot Charging of Continuous Casting Slab tracking and calculating methods calculated based on thermal physical property parameter distribution, it is related to a kind of calculation method of online trace model, it is wide to solidified shell growth rhythm relationship at different location including obtaining the wide solidified shell growth rhythm and slab at 1/2 position of thermal physical property parameter, slab offline；Online heat tracking computation model is established the following steps are included: obtaining and reading in slab and initially cast condition and casting process information；Generate tracking cell；Choose thermal physical property parameter；Tracking cell, which solves, to be calculated；Non-homogeneous solidification front calculates；Judge tracking cell position.Calculation method provided by the invention is microcosmic and macroscopical unidirectional couplings, only consider influence of the thermal physical property parameter to macroscopical solidification and heat transfer, computational efficiency is substantially increased under the premise of ensureing computational accuracy, the shell thickness and measured value error of calculating are 5% or so, and the deviation of surface temperature value and measured value temperature can be controlled in ± 10 DEG C.
Description
Technical field
The present invention relates to a kind of calculation methods of online trace model, and in particular to a kind of based on thermal physical property parameter distribution
The Hot Charging of Continuous Casting Slab tracking and calculating method of calculation.
Background technique
The soft reduction technique of continuous casting billet solidifying end and weight Reduction Technology are to be effectively improved center segregation of casting blank and center is dredged
The main means of loose problem, and the precondition implemented under slighter compress and weight is the Accurate Prediction to solidification end position.Mesh
It is preceding that for the method that determines solidification end position to be mainly included in the calculating of line heat-tracking model, method of powder actuated shot, solidification end pressure anti-
Present detection method and at present electromagnetic acoustic detection method still under study for action.And most domestic enterprise locks into the condition limit of equipment
System generallys use the calculating of online heat-tracking model to predict solidification position.
The accuracy that physical parameter in online heat-tracking model calculates directly influences the accuracy of calculated result even
The convergence of calculating process.Wherein physical parameter mainly includes: phase fraction, thermal coefficient, specific heat capacity and density etc..It is general
The solid rate for generalling use Clyne TW et al. proposition to the calculating of solid rate in line heat-tracking model varies with temperature relational expression:And thermal coefficient is usually reduced to fixed value, generally 33W/ (kg DEG C).Density is generally also
Fixed value is taken, i.e., takes 7000kg/m in liquid phase region3, 7200kg/m is taken in two-phase section3, 7600kg/m is taken in solid phase area3。
Specific heat capacity is also usually chosen fixed value and is calculated, solid phase specific heat CS=669.44J/ (kg DEG C), two-phase section specific heat Cm=
772J/ (kg DEG C) and liquid phase specific heat Cl=824.64J/ (kg DEG C) is calculated.Although the mode of this selection is simple real
With, and certain parameters may have certain accuracy, but can not correctly reflect the company that physical parameter varies with temperature
Continuous property.
Some scholars propose using fully-coupled model, i.e., it is quasi- that microcosmic solute segregation couples the method calculated with macroscopic view heat transfer
Temperature field is really calculated, steps are as follows for the calculating of fully-coupled model:
Step 1: slab is divided into unit grid along the cross section in throwing direction using microtomy first, for entire
It is sliced in combination with boundary condition using the macroscopical solidification and heat transfer method of two dimension, such as finite element method, finite difference method calculating casting
In a calculating cycle, by macroscopical solidification and heat transfer model, temperature, cooling rate of each node etc. can be obtained in the solidification and heat transfer of base
Information；
Step 2: in a calculating cycle, according to information such as the temperature of each node, cooling rates, to each node location
Microcosmic solute segregation calculating is carried out, calculates solute segregation distribution and phase fraction at the node location, and according to phase fraction meter
Calculation obtains thermal physical property parameter required for macroscopical solidification and heat transfer such as thermal coefficient, specific heat capacity, density；
Step 3: bringing each node thermal physical property parameter into next macroscopical solidification and heat transfer calculating cycle, i.e. step 1, complete
Cycle calculations.
Since slab number of nodes is more, typically greater than 10000, therefore require to carry out in each calculating cycle
10000 times or more microcosmic solute segregations calculate；On the other hand, in order to guarantee that macro, micromodel is consistent in time scale
Property, general calculating cycle is all set as 0.01s, and the course of casting is typically greater than 30 minutes, therefore has needed in whole casting course
It is calculated at 180000 Macro-micro Couplings.Obviously, it under such huge calculation amount, can not be achieved in line computation.
Therefore, current online heat-tracking model: (1) it is most of to consider that thermal physical property parameter calculates, even if examining
Consider thermal physical property parameter, can not consider casting blank solidification in the process because carbon, silicon, manganese, phosphorus, element sulphur solute segregation are distributed different institutes
Caused physical parameter otherness；(2) the heat tracking on center line can only be considered in sheet billet continuous casting production process, it is unpredictable
Slab it is wide to non-homogeneous coagulating property, i.e., the wide shell growth speed difference to 1/2/ position, 1/4 position and 1/8 position
Property.
In view of the foregoing, the present invention provides one kind it can be considered that causing hot physical property to be joined because solute segregation is distributed difference
Number difference, and can predict the online hot tracking and calculating method of the non-homogeneous solidification law of slab.
Summary of the invention
In order to overcome the shortcomings of the prior art described above, the present invention provides one kind is calculated based on thermal physical property parameter distribution
Hot Charging of Continuous Casting Slab tracking and calculating method.
To achieve the goals above, the invention provides the following technical scheme:
A kind of Hot Charging of Continuous Casting Slab tracking and calculating method calculated based on thermal physical property parameter distribution, including obtain off-line data and build
Vertical slab is wide to the online heat tracking computation model in 1/2 position；
Obtaining off-line data includes the following contents:
The thermal physical property parameter of off-line calculation steel: steel under the conditions of using microcosmic SOLIDIFICATION MODEL to calculate different element segregation degree
Phase fraction calculates the thermal physical property parameter of steel based on the phase fraction, and the thermal physical property parameter includes thermal coefficient, density and specific heat
Hold, and in the database by thermal physical property parameter storage；
It is offline to obtain the wide solidified shell growth rhythm at 1/2 position of slab: to obtain slab using gross segregation detection
Wide slab on through-thickness at 1/2 position is segregated the regularity of distribution, and it is wide at 1/2 position in slab to form in steel element
The solidified shell growth rhythm of " slab thickness position-element segregation degree " simultaneously stores in the database；
It is offline that obtain slab wide to solidified shell growth rhythm relationship at different location: according to two-dimentional macroscopical solidification and heat transfer with
It is wide to 1/8 position, 1/4 position and wide to 1/2 position casting blank solidification base that microcosmic solute segregation unity couping computation model obtains slab
Shell growth rhythm relationship simultaneously stores in the database；
It is wide to the online heat tracking computation model in 1/2 position to establish slab, comprising the following steps:
It obtains and reads in slab and initially cast condition and casting process information: including slab size, composition of steel, pulling rate, mistake
Temperature, length of mould and amount of cooling water, crystallizer temperature difference between the inlet and outlet water, secondary cooling zone divides and the real-time water in each area；
It generates tracking cell: in one cycle, generating a new tracking cell, the tracking in crystallizer meniscus position
The solidification and heat transfer computation interval of unit is the solidification and heat transfer of the wide through-thickness on 1/2 position of slab, and single to the tracking
Member carries out the initialization of temperature and position；
Specifically, generating tracking cell using microtomy, microtomy, which refers to, divides entire slab streamline along throwing direction
For many a tracking cell, it is believed that streamline is made of the tracking cell of continuous " birth ".By " the base age " of tracking cell, initially
It is temperature, position, locating cooling zone, associated with the temperature field of unit by the primary condition such as water and process condition, thus make with
Track unit and time correlation turn to dynamic from static state.Each tracking cell indicates the temperature of a section on streamline throwing direction
Distribution, all tracking cell linkages get up to describe a dynamic temperature field；
It chooses thermal physical property parameter: in a tracking cell, initially cast condition and casting process of the slab being called to believe
It ceases and determines slab thickness position, select the corresponding element segregation degree of the thickness position in the database, and according to the element
Degree of segregation calls the corresponding thermal physical property parameter in the position in database；
Tracking cell, which solves, to be calculated: in one cycle, the thermal physical property parameter is called, to casting since mold liquid level
The wide all tracking cell into the entire strand of 1/2 position length of base complete a Temperature calculating；
Non-homogeneous solidification front calculates: growing rule by the wide solidified shell at 1/2 position of the slab obtained
Rule and the slab are wide to 1/8 position, 1/4 position and wide to 1/2 position casting blank solidification shell growth rule relationship, acquisition slab
The wide solidified shell growth rhythm to 1/4 and 1/8 position；
Judge tracking cell position: it is total that the casting overall length recorded when being generated according to tracking cell subtracts the casting at current time
The position that tracking cell reaches within this period is calculated in length, and position is saved in the attribute of the tracking cell, root
Boundary condition is chosen according to the tracking cell position, while judging the last one tracking cell position, if the last one
The position of tracking cell is more than casting machine length, that is, thinks that it removes air cooling zone, all properties of this tracking cell are eliminated, are deleted
Except tracking cell, otherwise continue next period calculating.
Preferably, the gross segregation detection uses in-situ study or drilling cuttings sampling analysis method.
Preferably, establish One-dimensional On-line heat tracking computation model and carry out the Temperature calculating, for described in each with
Track unit carries out solidification and heat transfer calculating, governing equation are as follows:
In formula, L is latent heat of solidification coefficient, and value is 2.72 × 105J/kg, ρ are the density of steel；C is the specific heat capacity of steel；k
For the thermal coefficient of steel；T is the node temperature of steel；fsFor the solid phase fraction of steel.
The beneficial effect provided by the invention calculated based on thermal physical property parameter distribution is: applying the present invention to dynamic draught
In system, press down system more accurate Temperature Distribution and curdled appearance can be supplied to.Dynamic draught system in this way can be with
Dynamic pressure process is completed by accurate curdled appearance, and it is cold to can specify reasonable two by accurate Temperature Distribution
Area's cooling system.The shell thickness and measured value error that the present invention calculates are 5% or so, the surface temperature value and measured value of calculating
The deviation of temperature can be controlled in ± 10 DEG C.
Method calculating provided by the invention is more quick, convenient, is mainly reflected in following three points:
(1) this method is microcosmic and macroscopical unidirectional couplings, i.e., only considers thermal physical property parameter to the shadow of macroscopical solidification and heat transfer
It rings, there is no need to consider that macro, micromodel time unification, settable time step 5s have broken the pact of time step 0.01s
Beam；
(2) this method establishes one-dimensional macroscopic solidification and heat transfer computation model, and number of nodes reduces two quantity than Two-Dimensional Heat
Grade；
(3) thermal physical property parameter is stored in database by this method, is combined in macroscopical solidification and heat transfer calculating process and is calculated position
The element segregation situation set calls directly corresponding thermal physical property parameter, and the micromodel calculating for eliminating magnanimity derives hot physical property again
The time of parameter.
Calculation method of the invention can fully consider that slab different location physical property is joined compared with conventional heat tracking computation model
Several otherness, to more accurately describe casting blank solidification process.
Detailed description of the invention
Fig. 1 is the microcosmic SOLIDIFICATION MODEL schematic diagram of the present invention；
Fig. 2 Q345b steel solidifies phase transformation figure；
Fig. 3 is online heat-tracking model flow diagram；
Influence of Fig. 4 carbon to model: (a) specific heat capacity, (b) thermal coefficient, (c) density (d) shell growth rule；
Fig. 5 is that the shell thickness for the different location that heat-tracking model of the present invention and traditional heat-tracking model calculate changes feelings
Condition；
Fig. 6 is in-situ study sample position；
Fig. 7 is the two-dimensional distribution of carbon element content；
Fig. 8 is the two-dimensional distribution of phosphorus element content；
Fig. 9 is the two-dimensional distribution of sulfur content.
Specific embodiment
With reference to the accompanying drawing, further description of the specific embodiments of the present invention.Following embodiment is only used for more
Technical solution of the present invention is clearly demonstrated, and not intended to limit the protection scope of the present invention.
Embodiment 1
The present invention provides a kind of Hot Charging of Continuous Casting Slab tracking and calculating methods calculated based on thermal physical property parameter distribution, including obtain
Off-line data and to establish slab wide to 1/2 position (slab is wide to center) online heat tracking computation model；
Obtaining off-line data includes the following contents:
(1) thermal physical property parameter of off-line calculation steel: under the conditions of the different element segregation degree of microcosmic SOLIDIFICATION MODEL calculating
The phase fraction of steel calculates the thermal physical property parameter of steel based on phase fraction, and thermal physical property parameter includes thermal coefficient, density and specific heat capacity,
And in the database by thermal physical property parameter storage, circular is as follows:
Step 1: establishing microcosmic SOLIDIFICATION MODEL based on regular hexagon dendrite cross section, calculates steel grade in process of setting
In each phase fraction, governing equation is as follows:
In formula,For solute concentration of the element i in solid phase, %；T is time, s；It is solute element i in solid phase
In diffusion coefficient, m2/s；
Steel grade each phase fraction in process of setting is calculated by microcosmic SOLIDIFICATION MODEL, that is, calculates separately the liquid of steel grade
Phase fraction fl, solid phase fraction fs, ferrite phase fraction fa, solid solution phase fraction fδWith austenite phase fraction fγ；
Step 2: each phase fraction of the steel grade obtained using step 1 in process of setting calculates the physical property ginseng of steel grade
Number, including thermal coefficient, density and specific heat capacity, formula are as follows:
K=(1-fl)ks+(1+m)flkl (2)
kl=35 (W/Km) (3)
In formula: k is the thermal coefficient of steel, W/Km；ksAnd klRespectively the convection conduct heat coefficient of steel grade and the thermally conductive system of liquid phase
Number, flFor the liquid phase fraction of steel grade, m is empirical, value 4；TlFor the liquidus temperature of steel grade, T is the node temperature of steel grade
Degree, wc、wSi、wMnCarbon content, silicone content and manganese content respectively in steel grade, %；
C=Cafa+Cδfδ+Cγfγ+Clfl (5)
Cδ=441.3942+0.17744236T (7)
Cγ=429.8495+0.01497T (8)
Cl=842.6157 (9)
In formula: C is the specific heat capacity of steel grade, J/ (kg DEG C)；Cl、Ca、CδAnd CγThe respectively liquid phase of steel grade, ferrite, solid
The specific heat of solution and austenite, J/ (kg DEG C)；fl、fa、fδAnd fγThe respectively liquid phase of steel grade, ferrite, solid solution and Ovshinsky
Body phase fraction；
ρ=ρlfl+ρδfδ+ργfγ (10)
ρl=7100-73wc-(0.8-0.09wc)(T-1550)(13)
In formula: ρ is the density of steel grade, kg/m3；wcFor the carbon content in steel grade, %；ρl、ρδAnd ργThe respectively liquid of steel grade
The density of phase, solid solution phase and austenite phase, kg/m3；
(2) the wide solidified shell growth rhythm at 1/2 position of slab is obtained offline: obtaining casting using gross segregation detection
The wide slab on through-thickness at 1/2 position of base is segregated the regularity of distribution, and it is wide at 1/2 position in slab to form in steel element
The solidified shell growth rhythm of " slab thickness position-element segregation degree " simultaneously stores in the database, in the present embodiment, macroscopic view
Segregation detection uses in-situ study method；
Specifically, measuring the wide solute segregation on 1/2 thickness of slab using in-situ study method, and by " slab thickness position
Set-element segregation degree " relationship store to database for call.Fig. 6 is in-situ study sample position, and Fig. 7 to Fig. 9 is respectively
The in-situ study testing result of carbon, phosphorus, element sulphur.
(3) need offline acquisition slab wide to solidified shell growth rhythm relationship at different location for sheet billet continuous casting: root
According to two-dimentional macroscopical solidification and heat transfer and microcosmic solute segregation unity couping computation model obtain slab it is wide to 1/8 position, 1/4 position with
It is wide to 1/2 position casting blank solidification shell growth rule relationship and store in the database, Fig. 5 gives Q345b steel, and pulling rate is
The solidification process of different location under the conditions of 0.83m/min pulling rate.
Solidification change relational expression using wide 1/8 position of face of MATLAB software regression fit and wide face center is as follows:
a1=1.324e+19
B1=34.58
C1=1.843
A2=2.405e+04
B2=69.19
C2=16.51
In formula: δ1/8、δcenterRespectively represent the shell thickness of 1/8 position and slab center, mm；X is represented away from bent moon
The value in face, a1, a2, b1, b2, c1 and c2 are the coefficient values that fitting obtains, by relational expression deposit database in line computation tune
With.
The above-mentioned data storage obtained offline in the database, is stayed in when line computation needs and is directly transferred.
As shown in figure 3, establish slab it is wide to the online heat tracking computation model in 1/2 position the following steps are included:
Step 1: obtaining and read in slab and initially cast condition and casting process information: including slab size, composition of steel, drawing
Speed, the degree of superheat, length of mould and amount of cooling water, crystallizer temperature difference between the inlet and outlet water, secondary cooling zone divides and the real-time water in each area；
Step 2: it generates tracking cell: in one cycle, generating a new tracking cell in crystallizer meniscus position,
The solidification and heat transfer computation interval of the tracking cell is the solidification and heat transfer of the wide through-thickness on 1/2 position of slab, and to tracking
Unit carries out the initialization of temperature and position, and initialization process is as follows:
Establish the primary condition and boundary condition of online heat-tracking model:
(3-1) primary condition
T0=Ttundish (14)
In formula: T0For node initial temperature, DEG C；TtundishFor pouring temperature, DEG C；
(3-2) boundary condition
The boundary condition at slab center, according to the symmetry of Slab Heat, the distribution of section temperature is distributed with central symmetry,
That is:
The boundary condition of casting billet surface:
In formula: qn、qwIt is by the heat flux of casting billet surface leptoprosopy and wide face, W/m respectively2；X and Y is respectively that cross section is narrow
The overall length on side and broadside, m, k are thermal coefficient, W/Km；
(a) boundary condition of crystallizer
Heat transfer boundary condition setting of the slab in crystallizer are as follows:
In formula: q is the heat flow density of crystallizer, MW/m2, A and B are the undetermined coefficient of crystallizer；Z is slab apart from bent moon
The distance in face, m；
(b) boundary condition of secondary cooling zone
The heat that slab and support roller thermal contact conductance are passed out is handled using the method for increasing convection coefficient, and two is cold
The equivalent heat flow density formula in area is as follows:
Q=hw(Ts-Tw)+σε[(Ts+273.15)4-(Tw+273.15)4] (20)
hw=[1570W0.55(1-0.0075Tw)]/Cm (21)
In formula: hwFor comprehensive convection transfer rate, W/ (m DEG C)；T is the surface temperature of slab, DEG C, TsFor solidus temperature
Degree, DEG C；TwFor cooling water or environment temperature, DEG C；σ is Boltzmann constant 5.67 × 10-8W/(m2·K4)；ε is casting billet surface
Blackness, usually taking 0.8, W is jet density, L/ (m2S), CmFor empirical coefficient, value 4.4；
(c) boundary condition of air cooling zone
Continuous casting enters mainly radiating by way of casting billet surface radiant heat transfer in air cooling zone, and heat flow density formula is such as
Under:
Q=σ ε [(Ts+273.15)4-(Tw+273.15)4] (22)
In formula, σ is Boltzmann constant 5.67 × 10-8W/(m2·K4), ε is the blackness of casting billet surface, usually takes 0.8, Tw
For cooling water or environment temperature；
Step 3: choosing thermal physical property parameter: in a tracking cell, slab being called initially to cast condition and casting process
Information determines slab thickness position, selects the corresponding element segregation degree of the thickness position in the database, and inclined according to element
Analysis degree calls the corresponding thermal physical property parameter in the position in database；
Step 4: tracking cell, which solves, to be calculated: in one cycle, being called above-mentioned thermal physical property parameter, is opened from mold liquid level
Begin all tracking cell Temperature calculating of completion into the entire strand of 1/2 position length wide to slab, specific to calculate
Method is as follows；
It establishes One-dimensional On-line heat tracking computation model and carries out Temperature calculating, solidification biography is carried out for each tracking cell
Heat calculates, governing equation are as follows:
In formula, L is latent heat of solidification coefficient, and value is 2.72 × 105J/kg, ρ are the density of steel, kg/m3；C is the specific heat of steel
Hold, J/ (kg DEG C)；K is the thermal coefficient of steel, W/Km；T is the node temperature of steel, DEG C； fsFor the solid phase fraction of steel；
Step 5: wide by the wide solidified shell growth rhythm at 1/2 position of the slab obtained and above-mentioned slab
, to 1/2 position casting blank solidification shell growth rule relationship, it is wide to 1/4 and 1/8 to obtain slab with wide to 1/8 position, 1/4 position
The solidified shell growth rhythm set；
Step 6: judge tracking cell position: the casting overall length recorded when being generated according to tracking cell subtracts current time
The position that tracking cell reaches within this period is calculated in casting overall length, and position is saved in the attribute of the tracking cell
In, boundary condition is chosen according to above-mentioned tracking cell position, while judging the last one tracking cell position, if finally
The position of one tracking cell is more than casting machine length, that is, thinks that it removes air cooling zone, all properties of this tracking cell are disappeared
It removes, deletes tracking cell, otherwise continue next period calculating.
1 to Fig. 5 the process of the online heat-tracking model based on thermal physical property parameter is carried out specifically with reference to the accompanying drawing
It is bright:
The calculating of physical parameter is completed by the micromodel in Fig. 1 and Fig. 2, the Interface Moving master of micromodel in Fig. 1
If T is calculated using Current Temperatures and interfacelWithTemperature is compared and is determined, TlWithRespectively represent steel
δ/γ phase transition start temperature in liquidus temperature and process of setting, it is every just to need to carry out once by a time step Δ t
The deterministic process of Interface Moving.In δ/l and the interface γ/l, as the T that liquid phase calculateslTemperature is lower than Current Temperatures, will be from liquid phase
δ γ phase is precipitated.Simultaneously at the interface δ/γ, calculated when δ phase nodeTemperature is higher than Current Temperatures, will be precipitated from δ phase
γ phase.The δ phase that model hypothesis is precipitated first in process of setting, though this hypothesis does not meet the error of practical only very little,
When C content is higher,Higher than actual temperature, after first δ phase generates, can change at once in next time step Δ t
For γ phase.Microcosmic SOLIDIFICATION MODEL will not only complete the movement to interface in each time step, it is also necessary to according to nonmetallic folder
The balanced reaction equation of sundries production judges and calculates the precipitation of non-metallic inclusion.Thermal physical property parameter computing module is main
It is to calculate phase composition, then complete that thermal coefficient, specific heat capacity and density are calculated and deposited by phase composition, temperature and solute concentration
Storage is the physical parameters value such as the corresponding solid rate of this composition of steel, thermal coefficient under Current Temperatures.
From figure 3, it can be seen that the physical parameter being calculated has been saved in database.Within each period, generate
One new tracking cell, and the initialization of the attributes such as temperature and position is carried out to new tracking cell.In one cycle, from
All tracking cell that mold liquid level starts in long to entire strand complete a Temperature calculating.Boundary condition is basis
The location of unit calculates to choose the cooling parameter of corresponding position, and physical parameter is to be read from database according to temperature
Take corresponding physical parameter.And the Temperature Distribution of unit and setting condition are saved in the attribute array of tracking cell.It calculates
The position that each unit reaches within this period, and position is saved in the attribute of tracking cell, while to the last one list
Member is judged, if the position of the last one unit removes air cooling zone, all properties of this tracking cell is eliminated, are deleted
Except tracking cell.The result that online heat-tracking model is calculated in process of production passes to dynamic draught Controlling model and moves
State Control Model to Secondary Cooling, the two models have been calculated pressure and two in pairs further according to the data of Temperature Distribution and curdled appearance
The control of cold-zone operates.
Fig. 4 compares the otherness and corresponding solidification of thermal physical property parameter under the conditions of different carbon contents by taking carbon as an example
The otherness of shell growth rule.Such as Fig. 4 (a)-(c) as can be seen that when carbon content changes, the specific heat capacity of slab is led
Hot coefficient, density are all different, therefore the casting blank shell growth rhythm as shown in Fig. 4 (d) is not also identical.In view of in continuous casting process
Concrete condition be divided into 6 different zones from inner arcuate surface to slab center, the element segregation average value according to six regions is true
Its fixed corresponding thermal physical property parameter, and bring into the calculating of online heat-tracking model.
Fig. 5 is that the shell thickness for the different location that heat-tracking model of the present invention and traditional heat-tracking model calculate changes feelings
Condition, the shell thickness that model of the present invention calculates at the position 20.5m in the figure is 116mm, using traditional heat-tracking model in this position
The shell thickness for setting calculating is 129mm, and shoot-pin test result is 119mm, and the error of model of the present invention is 2.5%, and traditional mould
The error of type is 4.4%, it can be seen that this model calculating accuracy is more preferable.
Embodiment described above is merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to this,
Anyone skilled in the art within the technical scope of the present disclosure, the technical solution that can be become apparent to
Simple change or equivalence replacement, all belong to the scope of protection of the present invention.
Claims (3)
1. it is a kind of based on thermal physical property parameter distribution calculate Hot Charging of Continuous Casting Slab tracking and calculating method, which is characterized in that including obtain from
Line number evidence and to establish slab wide to the online heat tracking computation model in 1/2 position；
Obtaining off-line data includes the following contents:
The thermal physical property parameter of off-line calculation steel: the phase point of steel under the conditions of different element segregation degree is calculated using microcosmic SOLIDIFICATION MODEL
Rate calculates the thermal physical property parameter of steel based on the phase fraction, and the thermal physical property parameter includes thermal coefficient, density and specific heat capacity,
And in the database by thermal physical property parameter storage；
It is offline to obtain the wide solidified shell growth rhythm at 1/2 position of slab: using gross segregation detection obtain slab it is wide to
Slab at 1/2 position on through-thickness is segregated the regularity of distribution, and it is wide to " slab at 1/2 position in slab to form element in steel
The solidified shell growth rhythm of thickness position-element segregation degree " simultaneously stores in the database；
It is offline that obtain slab wide to solidified shell growth rhythm relationship at different location: according to two-dimentional macroscopical solidification and heat transfer with it is microcosmic
Solute segregation unity couping computation model acquisition slab is wide to give birth to wide to 1/2 position casting blank solidification green shell to 1/8 position, 1/4 position
Long rule relationship simultaneously stores in the database；
It is wide to the online heat tracking computation model in 1/2 position to establish slab, comprising the following steps:
Obtain and read in slab and initially cast condition and casting process information: including slab size, composition of steel, pulling rate, the degree of superheat,
Length of mould and amount of cooling water, crystallizer temperature difference between the inlet and outlet water, secondary cooling zone divides and the real-time water in each area；
It generates tracking cell: in one cycle, generating a new tracking cell, the tracking cell in crystallizer meniscus position
Solidification and heat transfer computation interval be the wide through-thickness on 1/2 position of slab solidification and heat transfer, and to the tracking cell into
The initialization of trip temperature and position；
Choose thermal physical property parameter: in a tracking cell, call the slab initially cast condition and casting process information it is true
Determine slab thickness position, selects the corresponding element segregation degree of the thickness position in the database, and according to the element segregation
Degree calls the corresponding thermal physical property parameter in the position in database；
Tracking cell, which solves, to be calculated: in one cycle, the thermal physical property parameter is called, it is wide to slab since mold liquid level
All tracking cell into the entire strand of 1/2 position length complete a Temperature calculating；
Non-homogeneous solidification front calculates: by the wide solidified shell growth rhythm at 1/2 position of the slab obtained and
The slab is wide to 1/8 position, 1/4 position and wide to 1/2 position casting blank solidification shell growth rule relationship, obtain slab it is wide to
The solidified shell growth rhythm of 1/4 and 1/8 position；
Judge tracking cell position: the casting overall length recorded when being generated according to tracking cell subtracts the casting overall length meter at current time
Calculation obtains the position that tracking cell reaches within this period, and position is saved in the attribute of the tracking cell, according to institute
It states tracking cell position and chooses boundary condition, while judging the last one tracking cell position, if the last one is tracked
The position of unit is more than casting machine length, that is, thinks that its removes air cooling zone, all properties of this tracking cell are eliminated, delete with
Otherwise track unit continues next period calculating.
2. the Hot Charging of Continuous Casting Slab tracking and calculating method according to claim 1 calculated based on thermal physical property parameter distribution, feature
It is, the gross segregation detection uses in-situ study or drilling cuttings sampling analysis method.
3. the Hot Charging of Continuous Casting Slab tracking and calculating method according to claim 1 calculated based on thermal physical property parameter distribution, feature
It is, establishes One-dimensional On-line heat tracking computation model and carry out the Temperature calculating, tracking cell described in each is carried out
Solidification and heat transfer calculates, governing equation are as follows:
In formula, L is latent heat of solidification coefficient, and value is 2.72 × 105J/kg, ρ are the density of steel；C is the specific heat capacity of steel；K is steel
Thermal coefficient；T is the node temperature of steel；fsFor the solid phase fraction of steel.
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| CN109332627B (en) * | 2018-10-22 | 2021-03-23 | 中冶连铸技术工程有限责任公司 | Method for tracking online thermal state of continuous casting special-shaped blank |
| CN109446748B (en) * | 2018-12-28 | 2023-06-27 | 建龙北满特殊钢有限责任公司 | Method for simulating solidification process of continuous casting round billet |
| CN110851997B (en) * | 2019-12-02 | 2021-10-22 | 北京科技大学 | System and method for measuring and predicting thickness of real initial solidified blank shell in crystallizer |
| CN111998892A (en) * | 2020-07-23 | 2020-11-27 | 麦特勒智能科技(张家港)有限公司 | Mixed steel model system based on flow field and concentration field numerical simulation calculation |
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Application publication date: 20170818 Assignee: MCC SOUTHERN CONTINUOUS CASTING TECHNOLOGY ENGINEERING Co.,Ltd. Assignor: Northeastern University Contract record no.: X2020210000038 Denomination of invention: A calculation method of continuous casting slab heat tracing based on distribution calculation of thermophysical parameters Granted publication date: 20190326 License type: Common License Record date: 20201223 |