CN105848808A - Method for continuously casting different grades of steel - Google Patents

Abstract

The present invention relates to a method for continuously casting different grades of steel, comprising the steps of: obtaining dimensionless relative concentrations of following grades of steel with respect to preceding grades of steel respectively in real time at the central portion and the surface portion of a strand continuously being casted; calculating the longitudinal position of the strand having the real-time obtained dimensionless relative concentrations of the central portion and the surface portion; comparing each of the obtained dimensionless relative concentrations of the central portion and the surface portion with a reference concentration to predict a mixing portion in the strand; and trimming the predicted mixing portion. According to embodiments of the present invention, the respective dimensionless concentrations of the central portion and the surface portion of a strand are obtained whenever continuously casting different grades of steel, and the position of the strand having the obtained dimensionless concentrations is calculated to predict the position and the length of a mixing portion, instead of trimming the mixing portion in a predetermined length regardless of working conditions when continuously casting different grades of steel as in the prior art. Accordingly, accuracy of predicting the position and the length of the mixing portion is improved, thereby being capable of preventing profit reduction caused by over-trimming of the mixing portion and preventing a poor quality product due to under-trimming of the mixing portion from being shipped to a client company.

Description

The method casting steel the most of the same race continuously

Technical field

It relates to the method casting dissimilar steel continuously, the method relating more specifically to the following dissimilar steel of casting continuously: In the method, can predict and automatically excise by previously steel and follow-up steel were blended to produce in the method for casting dissimilar steel continuously The mixing portion of stream.

Background technology

The continuous casting operation of dissimilar steel (that is, difference steel) is by using new steel (hereinafter referred to as " follow-up steel ") The continuous casting operation of molten steel, the component of new steel is different from the molten steel of the steel (hereinafter, being referred to as previous steel) of current processing Component.To this end, supply to tundish at the end of the operation of the molten steel previously steel of the follow-up steel being contained in follow-up ladle.At this In the case of Zhong, the molten steel of previous steel and the molten steel of follow-up steel mix in tundish, and the molten steel mixed is by immersion water In mouth injection crystallizer.

Therefore, the some parts of casting stream inevitably defines the mixing portion produced by the mixing of dissimilar steel, And owing to this mixing portion is unsatisfactory for the composition specification of product, mixing portion therefore will be excised and generally as useless gold Belong to recycling.

Generally, in order to excise by the mixing portion that casting produces continuously of dissimilar steel, according to the falcate metal bath surface of stream Mixing portion is cut to predetermined length by position.But, for cutting method, due to the falcate metal bath surface position according to stream Put and mixing portion is cut to predetermined length and does not consider the various variablees of the change of such as steel or the change of casting speed, mixing The cutting position of part is coarse.Therefore, mixing portion may cut too much to make this possibility than actual mixing portion It is the reason that reduces of productivity, or mixing portion may cut few to make the product may be mixed to be mixed with than actual mixing portion Sell under the state of conjunction part.

In order to solve above restriction, make the length data of mixing portion according to type and the combination of previous steel and follow-up steel To make table, and mixing portion cuts to corresponding to previous steel and the type of follow-up steel and combination during the operation of dissimilar steel Resection length.But, even if in superincumbent cutting method, mixing portion also can be made to meet design specification by excessively excision Region may be cut and abandon together with mixing portion, or be likely not to have the most cut and one at all mixing portions A little mixing portions may possibly be mixed in the aspect in product and still suffer from limiting.

Additionally, as another typical method, during casting, the previous steel of stream and the melting concn of follow-up steel are by using Operation data (change, the centre such as ladle weight previously performing operation as disclosed in Korean Patent No. 10-0419886 The change of bag weight and casting speed) calculate.By using the melting concn calculated according to principle of hydrodynamics to determine Mixing portion and excise the two ends of mixing portion.But, for determining that the said method of mixing portion, to melting concn and Mixing portion has carried out prediction and has not accounted for each position in the cross section of stream, i.e. surface and center.Accordingly, because mixing Forecasting reliability or the accuracy of part are low, still suffer from being mixed with at least some of of mixing portion in product and being transported to visitor The situation of family company.

Summary of the invention

Technical problem

A kind of method that present disclose provides continuous casting dissimilar steel, the method can be predicted and automatically excise by even The mixing portion of the stream produced by the mixing of previous steel and follow-up steel in the method for the different steel of continuous casting.

The disclosure additionally provides a kind of continuous casing, and the method can be carried by the position of the mixing portion that calculating is flowed The accuracy of the position of high mixing portion and the prediction of length prevents the mixing portion that casting produces continuously of reason dissimilar steel The product caused is defective.

Technical scheme

According to an exemplary, the method for casting dissimilar steel includes continuously: respectively on the surface of strand and The follow-up steel of internal acquisition in real time is relative to the dimensionless relative concentration of previous steel；Calculate stream having and obtain in real time in a longitudinal direction The surface taken and the position of internal dimensionless relative concentration；By respectively that acquired surface is relative with internal dimensionless Concentration be compared to the mixing portion in pre-flow measurement with reference to concentration；And the mixing portion that excision is predicted.

The position of the acquisition dimensionless relative concentration of stream can be the surface in the short transverse of stream and center.

According to another exemplary embodiment, the method for casting dissimilar steel includes continuously: by using the elder generation in tundish The relative quantity of the previous steel in the relative quantity of front steel and follow-up steel and crystallizer and follow-up steel, respectively from crystallizer solidification and even Multiple positions in the short transverse of the stream of continuous casting obtain the follow-up steel dimensionless relative concentration relative to previous steel in real time； Calculate the stream position with the dimensionless relative concentration of acquisition in real time in a longitudinal direction；By respectively by acquired immeasurable Guiding principle relative concentration be compared to the mixing portion in pre-flow measurement with reference to concentration；And the mixing portion that excision is predicted.

Multiple positions of the acquisition dimensionless relative concentration in the short transverse of stream can include surface and the center of stream.

The method is additionally may included in and obtains in real time in strand follow-up steel relative to the dimensionless relative concentration of previous steel Set with reference to concentration before, wherein set and may include that in the upper concentration of each component by previous steel with reference to concentration Low upper concentration is set as first with reference to concentration；And by the highest least concentration in the least concentration of each component of follow-up steel It is set as second with reference to concentration.

Set first and may include that the densitometer of the component by previous steel is counted as lower limit with reference to concentration and second with reference to concentration Dimensionless concentration and upper limit dimensionless concentration；By immeasurable for the minimum upper limit in the upper limit dimensionless concentration of each component of previous steel Guiding principle concentration is set as first with reference to concentration；The densitometer of the component of follow-up steel is counted as lower limit dimensionless concentration and upper limit dimensionless Concentration；And the highest lower limit dimensionless concentration in the lower limit dimensionless concentration of each component of follow-up steel is set as the second ginseng According to concentration.

The densitometer of each component of previous steel is counted as lower limit dimensionless concentration and upper limit dimensionless concentration may include that When the lower limit dimensionless concentration of previous steel is more than the upper limit dimensionless concentration of previous steel, by the upper limit dimensionless concentration of previous steel Value substitutes the lower limit dimensionless concentration value of previous steel, and substitutes the upper limit of previous steel with the lower limit dimensionless concentration value of previous steel Dimensionless concentration value；And the densitometer of each component of follow-up steel is counted as lower limit dimensionless concentration and upper limit dimensionless concentration Can include when the lower limit dimensionless concentration of follow-up steel is more than the upper limit dimensionless concentration of follow-up steel, with the upper limit of follow-up steel without The lower limit dimensionless concentration value of dimension concentration value alternate subsequent steel, and by the lower limit dimensionless concentration value alternate subsequent of follow-up steel The upper limit dimensionless concentration value of steel.

When at least one the dimensionless relative concentration in the dimensionless relative concentration at acquired surface and center deviates ginseng During according to concentration, stream can be determined that and is in admixture, and the following position on the longitudinal direction flowed may determine that as mixed Close part: in described position, acquired surface is relative with at least one dimensionless in the dimensionless relative concentration at center Deviation of concentration is with reference to concentration.

Stream following position in a longitudinal direction can be determined that the starting point of mixing portion: in described position, institute The dimensionless relative concentration at the center obtained reaches with reference to concentration；And flow following position in a longitudinal direction may determine that into The end point of mixing portion: in described position, the dimensionless relative concentration on acquired surface reaches with reference to concentration.

The method can also include: online receive in tundish the surplus of molten steel, casting speed and previously steel and The data of the concentration of each in follow-up steel and store this data；And continue immeasurable relative to previous steel of steel after the acquisition Follow-up ladle opening signal is detected before guiding principle relative concentration.

The method can also include: obtains surface and the center of stream from the time detecting follow-up ladle opening signal in real time In the dimensionless relative concentration of each, and from the time detecting follow-up ladle opening signal, calculate dimensionless concentration adopt The collection time is to compare in real time with reference time；When dimensionless concentration acquisition time is reference time or is less than reference time Time, the dimensionless relative concentration at acquired center is compared with reference to concentration with first, and by acquired surface Dimensionless relative concentration compares with reference to concentration with second；And when concentration acquisition time is more than reference time, it is right to terminate The surface of stream and in the minds of the collection of dimensionless relative concentration of each.

The method can also include whether the type determining between previous steel and follow-up steel is to preset in dissimilar steel excision table Included type；Type between previous steel and the follow-up steel of experience current operation is to preset in dissimilar steel excision table to be wrapped During the type included, stream is cut to the resection length of the dissimilar steel type of correspondence；And when experience current operation previous steel with When type between follow-up steel is not included in presetting in dissimilar steel excision table, terminate convection current surface and in the minds of each Dimensionless relative concentration collection after, stream is cut to resection length set in advance.

Detect follow-up ladle opening signal and may include that the virtual ladle opening signal of transmission；From sending described virtual ladle The weight detecting described tundish within the millisecond (ms) time as unit in real time is played during opening signal；With with the second (s) for single The predetermined time interval of position, calculates the described weight of the described tundish detected within the millisecond (ms) time as unit Become the average weight of described tundish；And the time utilizing the described average weight of described tundish to increase continuously sets and opens The time of described follow-up ladle.

Work as W_tdT () is the residue weight of steel amount in tundish described in current time and W_td(t-Δ t) is relatively early time institute When stating the weight remaining steel amount in tundish, work as W_td(t)–W_td(t-Δ t) and W_td(t)–W_td(t-2* Δ t) be all higher than or etc. When " 0 ", t-2* Δ t can be confirmed as opening the time of follow-up ladle, from t-2* Δ t obtain stream surface and in the minds of The dimensionless relative concentration of each, and from t-4* Δ t, store the residue steel amount in tundish and casting speed.

The follow-up steel on the surface and center that obtain stream may include that calculating relative to the most firm dimensionless relative concentration Inlet volumetric flow (the Q of the described follow-up steel in described tundish_td-in)；Use the institute of described follow-up steel in described tundish State inlet volumetric flow (Q_td-in) calculate the average dimensionless relative concentration of described molten steel in tundish described in current time (C_td-ave(t+Δt))；The described average dimensionless relative concentration of the described molten steel in tundish described in use current time (C_td-ave(t+ Δ t)) calculates the dimensionless relative concentration (C of the molten steel that current time is discharged from described tundish_td-out(t+Δ t))；The described dimensionless relative concentration (C of the described molten steel that use current time is discharged from described tundish_td-out(t+Δt)) Calculate the average dimensionless relative concentration (C of molten steel described in current time crystallizer_md-aver(t+Δt))；And use current The described average dimensionless relative concentration (C of molten steel described in crystallizer described in the time_md-aver(t+ Δ t)) and current time introduce Dimensionless relative concentration (the C of the molten steel in described crystallizer_md-in(t+ Δ t)) calculates what current time was discharged from described crystallizer Dimensionless relative concentration (the C of described stream_md-out(t+Δt))。

Inlet volumetric flow (the Q of the follow-up steel in tundish_td-in) can calculate according to formula 5.

[formula 5]

$Q_{td-in}=\frac{W_{td}(t+\mathrm{\Δ}t)-W_{td}\left(t\right)}{\mathrm{\Δ}t\×{\mathrm{\ρ}}_L}+Q_{td-out}$

Wherein, W_tdT () is the gross weight of the molten steel in relatively time tundish morning, W_td(t+ Δ t) is current time tundish In the gross weight of molten steel, Q_td-outIt is the volume flow of the molten steel discharged from tundish, and ρ_LIt is the fluid density of molten steel,

Mean concentration (the C of the molten steel in current time tundish_td-ave(t+ Δ t)) can be calculated by formula 6,

[formula 6]

$C_{td-ave}(t+\mathrm{\Δ}t)=\frac{W_{td}\left(t\right)\×C_{td-ave}\left(t\right)+Q_{td-in}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{td-in}\left(t\right)}{W_{td}(t+\mathrm{\Δ}t)}-\frac{Q_{td-out}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{td-out}\left(t\right)}{W_{td}(t+\mathrm{\Δ}t)}$

Wherein, C_td-aveT () is the average dimensionless relative concentration of the molten steel in relatively time tundish morning, Q_td-inT () is relatively Early the time introduces the inlet volumetric flow of the molten steel in tundish, C_td-inT () is entering of the follow-up steel in relatively time tundish morning Mouth concentration (dimensionless relative concentration), Q_td-outT () is the volume flow of the relatively early molten steel that the time discharges from tundish, C_td-out T () is the concentration (dimensionless relative concentration) of the relatively early molten steel that the time discharges from tundish, ρ_LIt is the fluid density of molten steel,

Concentration (the C of the molten steel that current time is discharged from tundish_td-out(t+ Δ t)) can be calculated by formula 7,

[formula 7]

C_td-out(t+ Δ t)=f_td×C_td-ave(t+Δt)+(1-f_td)×C_td-in(t+Δt)

Wherein, f_tdIt is interpolation and the extrapolation factor of tundish, C_td-ave(t+ Δ t) is the molten steel in current time tundish Average dimensionless relative concentration, and C_td-in(it is relative that t+ Δ t) is that current time introduces the dimensionless of the molten steel in tundish Concentration,

Mean concentration (the C of the molten steel in current time crystallizer_md-aver(t+ Δ t)) can be calculated by formula 8,

[formula 8]

$C_{md-ave}(t+\mathrm{\Δ}t)=\frac{W_{md}\left(t\right)\×C_{md-ave}\left(t\right)+Q_{md-in}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{md-in}\left(t\right)}{W_{md}(t+\mathrm{\Δ}t)}-\frac{Q_{md-out}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{md-out}\left(t\right)}{W_{md}(t+\mathrm{\Δ}t)}$

Wherein, W_mdT () is the gross weight of the molten steel in relatively time crystallizer morning, C_md-averT () is relatively time crystallizer morning In the average dimensionless relative concentration of molten steel, Q_md-inT () is the inlet volumetric flow of the molten steel in relatively time crystallizer morning, C_md-inT () is the entrance concentration (dimensionless relative concentration) of the molten steel in relatively time crystallizer morning, W_md(when t+ Δ t) is current Between the gross weight of molten steel in crystallizer, Q_md-outT () is the volume flow of the molten steel discharged from crystallizer, C_md-outT () is relatively The dimensionless relative concentration of the stream that early time discharges from crystallizer, and ρ_LIt is the fluid density of molten steel, and

Concentration (the C of the stream that current time is discharged from crystallizer_md-out(t+ Δ t)) can be calculated by formula 9,

[formula 9]

C_mdx_out(t+ Δ t)=f_md×Cx_d-ave(t+Δt)+(1-f_md)×C_md-in(t+Δt)

Wherein, f_mdIt is interpolation and the extrapolation factor of crystallizer, C_md-aver(t+ Δ t) is the molten steel in current time crystallizer Average dimensionless relative concentration, and C_md-in(it is relative that t+ Δ t) is that current time introduces the dimensionless of the molten steel in crystallizer Concentration.

In calculating the dimensionless relative concentration at center of stream, can be by the interpolation of 4 ± 2 application to formula 7 and extrapolation factor (f_td), and can be by the interpolation of 0.7 ± 0.4 application to formula 9 and extrapolation factor (f_md) to calculate the dimensionless phase at the center of stream To concentration (C_{md-out-center})。

In the calculating of the dimensionless relative concentration on the surface of convection current, can by 2.2 ± 0.6 application to formula 7 interpolation and Extrapolation factor (f_td), and can be by the interpolation of 0.5 ± 0.2 application to formula 9 and extrapolation factor (f_md) to calculate the surface of stream Dimensionless relative concentration (C_{md-out-surface})。

Formula 5,6 and 8 can use the fluid density of molten steel as density (ρ_L) value, and 7000kg/m can be used³Extremely 7400kg/m³Value as the density of molten steel.

The method can also include: sets the position starting to obtain the dimensionless relative concentration on the surface of stream of stream；And Setting the position starting to obtain the dimensionless relative concentration at the center of stream of stream, wherein, stream continues position during ladle after opening Can be set to start obtain the position of the dimensionless relative concentration on the surface of stream, and away from when opening follow-up ladle of stream Position at-4 ± 4m of position can be set to the position starting to obtain the dimensionless relative concentration at the center of stream.

In the calculating of the position of the dimensionless relative concentration on the surface with acquisition in a longitudinal direction of convection current, should Position can be calculated by formula 10, in formula 10, from the volume flow (Q of the molten steel that crystallizer is discharged_md-out) it is divided by the horizontal stroke of stream Sectional area (A_md) and the density of solid (ρ of molten steel_s) product,

[formula 10]

$L(t+\mathrm{\Δ}t)=L\left(t\right)+\frac{Q_{md-out}\×{\mathrm{\ρ}}_L}{A_{md}\×{\mathrm{\ρ}}_S}\×\mathrm{\Δ}t$

Wherein, Q_md-outIt is the volume flow of the molten steel discharged from crystallizer, A_mdIt is the cross-sectional area of stream, ρ_sIt it is molten steel Density of solid, wherein, uses 7600kg/m³To 8000kg/m³Value.

In calculating the position of dimensionless relative concentration at the stream center with acquisition in a longitudinal direction, obtain away from having The dimensionless that position at position-4 ± 4m of the dimensionless relative concentration on the surface taken can be set with center is relative The position of concentration.

The point reality to stream of the first reference concentration is reached from the dimensionless relative concentration at the center of the stream obtained in real time of stream Time the dimensionless relative concentration on surface of stream that obtains reach second and can be predicted to be mixing unit with reference to the region of the point of concentration Point.

The method can also include: the dimensionless relative concentration at the center of the stream obtained in real time of stream is reached the first reference The point of concentration is set as the first excision position；The dimensionless relative concentration on the surface of the stream obtained in real time of stream is reached the second ginseng Point according to concentration is set as the second excision position；And by excising position respectively to flowing in the first excision position and second Mixing portion is excised in row cutting.

The excision of the prediction of the mixing portion of stream and the mixing portion of prediction can perform in the way of online treatment.

Beneficial effect

According to exemplary, obtain stream surface and in the minds of the dimensionless concentration of each, and lead to Cross position and the length using dimensionless concentration to draw mixing portion.It is to say, do not consider Dissimilar steel operating condition and mixing portion is cut to predetermined length, but for dissimilar steel each operation obtain stream surface The dimensionless concentration of each in the minds of in, and the position with acquired dimensionless concentration of stream is set to that prediction is mixed Close position and the length of part.Accordingly, because improve the degree of accuracy of the prediction of the position to mixing portion and length, can in case Only because excessively excising the reduction of the profit margin that mixing portion causes and being possible to prevent cause because mixing portion excision is less to lack Sunken product is transported to client company.

Accompanying drawing explanation

Fig. 1 shows common continuous casting installation for casting；

Fig. 2 shows that the major part of common continuous casting installation for casting is to describe manufacture by the supply of molten steel and process of setting Stream or the process of slab；

Fig. 3 is that order illustrates the method for the dissimilar steel mixing portion of the pre-flow measurement according to an exemplary and makes Cut the flow chart of the method for mixing portion in aforementioned manners；

Fig. 4 and Fig. 5 is to specifically illustrate the mixing unit in the cutting continuous casing according to an exemplary The flow chart of the method divided；

Fig. 6 is the flow process specifically illustrating the process detecting follow-up ladle opening signal according to an exemplary Figure；

Fig. 7 be illustrate according to an exemplary set for pre-flow measurement dissimilar steel mixing portion first With reference to concentration and the flow chart of the method for the second reference concentration；

Fig. 8 is to be shown through previous steel and each component of follow-up steel that the method according to this exemplary obtains The figure of dimensionless concentration；

Fig. 9 be illustrate chromium (Cr) cast continuously by dissimilar steel manufacture stream vertical direction (cross-sectional thickness) and casting The figure of the dimensionless concentration distribution on direction (longitudinal direction)；

Figure 10 is the figure of the concentration changes with time being shown in during the continuous casting operation of dissimilar steel in crystallizer；

Figure 11 is by only considering that the impact of crystallizer does not consider tundish during the continuous casting operation of dissimilar steel Concentration distribution on the longitudinal direction of impact convection current after completing finally to solidify and cross section carries out the result calculated；

Figure 12 shows the side of the dimensionless concentration obtaining stream surface and center according to an exemplary The flow chart of method；

Figure 13 is dimensionless concentration data and the casting at the surface to the stream obtained according to this exemplary and center The curve chart that the measurement result of the real composition on the longitudinal direction of stream compares；

Figure 14 is the data to the mixing portion by predicting according to the Forecasting Methodology of this exemplary and pass through The curve chart that the concentration of the mixing portion measurement collecting prediction compares；

Figure 15 is the length methods analyst 1 by the prediction mixing portion according to this exemplary of mixing portion The chart in year.

Detailed description of the invention

Hereinafter, will be described in detail with reference to the accompanying drawings exemplary.But, the present invention can be with many not similar shapes Formula is implemented and should not be construed as being limited to the particular stated herein.On the contrary, these embodiments are arranged to Make the disclosure by thorough and complete, and the scope of the present invention will be conveyed completely to those skilled in the art.

Hereinafter, crystallizer will solidify, pull out or be expelled to outside crystallizer and by along casting direction extension Formed before excision coagulum body surface be shown as " stream ", and the object table that stream cuts to predetermined length is shown as " slab.

Fig. 1 shows common continuous casting installation for casting.Fig. 2 shows that the major part of common continuous casting installation for casting is with by molten steel Supply and process of setting describe manufacture stream or the technique of slab.

Seeing figures.1.and.2, continuous casting installation for casting includes that ladle 100:110 and 120, described ladle 100:110 and 120 accommodate essence Refining molten steel and may move；Tundish 200, described tundish 200 is configured to accommodate from ladle 100:110 and 120 supply Molten steel；Crystallizer 300, described crystallizer 300 has reservation shape by receiving and solidifying the molten steel generation from tundish 200 Stream S；Nozzle 400, described nozzle 400 is configured by have and is connected to an end of tundish 200 and has installation Molten steel in tundish 200 is injected in crystallizer by least some of of bottom becoming the nozzle inserted in crystallizer 300；Multiple Roller 500, the plurality of roller 500 is configured to transport, along casting direction, the stream S pulled out by crystallizer 300；Multiple fan-shaped section 600, institute State multiple fan-shaped section 600 to be configured to spray cooling water to the stream S transported by multiple rollers 500；And sickle 800, described in cut Cutter 800 will cut to preliminary dimension to manufacture the slab 700 with reservation shape from crystallizer 300 quantity-produced stream S.? Here, gas torch or hydraulic shearing machine can serve as sickle 800.

Tundish 200 has for the outlet by molten steel supply to crystallizer 300, and wherein, outlet can set according to continuous casting It is contoured to correspond in the number of outlet for being arranged to multiple and crystallizer 300 number.Therefore, just there is multiple crystallizer For the continuous casting installation for casting of 300, solidification the stream S from crystallizer 300 pull-out become multiple.

In the continuously casting of dissimilar steel, the molten steel of the different steel with different component is contained in the first ladle 110 and the In two ladles 120, and when arbitrary ladle 110 or 120 completes molten steel to the supply of tundish 200, steel ladle rotary table (does not shows Go out) rotation turnback thus the position of one of ladle 110 or 120 is entered relative to another the position in ladle 110 or 120 Row exchange.Therefore, the molten steel of different steel can alternately supply to tundish.Such as, casting first passes through the first ladle 110 In equipped with molten steel supply carry out to tundish 200, and the molten steel of the second ladle 120 casting at the end of supply to tundish 200 and cast enable to cast continuously dissimilar steel.

In the continuously casting of dissimilar steel, owing to currently just casting and steel at the end of operation (hereinafter, is referred to as " previous steel ") molten steel and the molten steel of steel (hereinafter, being referred to as " follow-up steel ") that introduces below at tundish 200 and crystallizer Mix in 300, create in stream S and be mixed with previous steel and follow-up steel and the mixing portion solidified.

Therefore, in the casting continuously of dissimilar steel, a kind of method that present disclose provides continuous casting dissimilar steel, the method The degree of accuracy of the prediction of mixing portion can be improved and the concentration of S, calculating can be flowed by obtaining in real time via inline system There is the position of the stream S of acquired concentration and the position of position real-time estimate mixing portion that use is calculated and automatically cut Except mixing portion.

Fig. 3 is that order illustrates the method for the dissimilar steel mixing portion of the pre-flow measurement according to an exemplary and makes Cut the flow chart of the method for mixing portion in aforementioned manners.Fig. 4 and Fig. 5 is to specifically illustrate according to an exemplary Cutting continuous casing in the flow chart of method of mixing portion, and Fig. 4 and Fig. 5 include the side that predicts mixing portion The method of the mixing portion of method and cutting drawing 3.

Hereinafter, with reference to Fig. 3 to Fig. 5, will be described the phase that casts continuously in dissimilar steel according to this exemplary Between cut the method for mixing portion of stream.In this case, there are solidification and the multiple streams pulled out from multiple crystallizers Continuous casting installation for casting in, owing to uniform molten steel is supplied by the volume control device such as dam (dam) in tundish or weir (weir) Giving to each stream, the method for cutting mixing portion is equally applicable to each stream.Therefore, by description to single stream application the method Situation.

With reference to Fig. 3, include following mistake according to the method for the dissimilar steel mixing portion of the pre-flow measurement of this exemplary Journey: the process variable of the continuously casting of storage dissimilar steel or process data (S100), detection open ladle equipped with follow-up steel (under Literary composition is referred to as " follow-up ladle) signal (200), set for predicting solidification the xenogenesis steel reinforced concrete of stream from crystallizer pull-out Close the first reference concentration and second reference concentration (S300) of part, at the surface of stream with inside, obtain follow-up steel in real time relative In the dimensionless relative concentration of previous steel and calculate the stream surface with acquisition in real time in a longitudinal direction and internal at The position (S400) of dimensionless relative concentration, carries out reality by the dimensionless relative concentration in acquired stream and first with reference to concentration Time compare, and the dimensionless relative concentration on the surface of acquired stream is compared with reference to concentration in real time with second (S600), dimensionless relative concentration and first according to each in acquired surface and inside are with reference to concentration and the second ginseng The mixing portion (S700) in pre-flow measurement, and the mixing portion that excision is predicted is come according to the comparative result between concentration (S1100)。

Here, surface and the inside of stream can be to flow upper at longitudinal direction (that is, left and right directions) or cross this casting side To vertical direction (or short transverse) on surface and inside, inside can be stream in vertical direction (or short transverse) Center, surface can be any one in the top surface and basal surface flowed.

Additionally, due to follow-up steel is that follow-up steel closes relative to previous steel reinforced concrete relative to the dimensionless relative concentration of previous steel Degree or amount, in other words, dimensionless relative concentration can be previous steel and the degree of follow-up steel reinforced concrete conjunction, i.e. " melting concn ".

Dimensionless concentration is denoted as the typical concentration value of dimensionless ratio or dimensionless number, and wherein dimensionless concentration is The concentration represented by more than 0 or 1 value below.Therefore, follow-up steel also may be used relative to the dimensionless relative concentration of previous steel To be represented by more than 0 or 1 value below.Previously the dimensionless concentration of steel was defined to the dimensionless concentration limit of 0 and follow-up steel It is set to 1.Such as, in the case of dimensionless relative concentration is 1, the feelings that amount is 0% of the follow-up steel in representing in molten steel or flowing Condition, i.e. the situation that follow-up steel does not flows into.On the contrary, in the case of dimensionless relative concentration is 1, represent in molten steel or in stream The amount of follow-up steel is the situation of 100%.Such as, in the case of dimensionless relative concentration is 0.4, represent in molten steel or in stream Previously steel mixed with the ratio of 60% to 40% with follow-up steel.

Compared with the dimensionless relative concentration of each in the center of the stream obtained in real time and surface first is with reference to dense Degree and second is dimensionless concentration value with reference to concentration.

The prediction according to the exemplary shown in Fig. 3 and cut xenogenesis mixing portion method in, according to From follow-up ladle opening time the surface of the stream of calculating and in the minds of the acquisition time of dimensionless relative concentration of each, Can use or can not use the prediction described in Fig. 3 the method cutting xenogenesis mixing portion.

In other words, obtain stream surface and in the minds of the concentration acquisition time of dimensionless relative concentration of each In the case of reference time, perform by the dimensionless concentration of each in the center that will be obtained and surface and the first ginseng The subsequent process of prediction mixing portion is compared with reference to concentration according to concentration and second.On the contrary, at surface and center dense of stream Degree gathers the elapsed time more than in the case of reference time, terminate obtaining surface and in the minds of the process of concentration of each. Mixing portion carries out excising (the mixing unit that type according to previous steel and follow-up steel is preset in described tables of data according to tables of data Point resection length by datumization), or mixing portion be resected to predetermined length (described predetermined length do not consider previous steel and after Continue the type of steel and preset).

Fig. 4 and Fig. 5 is the flow chart including a series of process, and wherein, mixing portion is by the surface according to stream and center In the position of above-mentioned dimensionless relative concentration acquisition time automatic Prediction mixing portion of each and cut, or mixing The mixing portion resection length tables of data that part is preset by using the combination according to dissimilar steel is cut, or mixing unit is cut Cut predetermined length.

With reference to Fig. 4 and Fig. 5, include following process according to the method for the dissimilar steel of casting continuously of this exemplary: Store the process data (S100) of casting continuously based on dissimilar steel, detect follow-up ladle opening signal (S200), to for pre- Survey solidification and be set with reference to concentration with reference to concentration and second from the first of the dissimilar steel mixing portion of the stream of crystallizer pull-out (S300), obtain in real time stream surface and in the minds of the dimensionless relative concentration of each to calculate having of current time stream Acquired surface and in the minds of the position (S400) of dimensionless relative concentration of each, and by the surface of stream and center Dimensionless relative concentration acquisition time and reference time compare (S500).

In the above description, after continuing ladle opening signal (S200) after sensing, perform to be used for predicting solidification and from The first of the dissimilar steel mixing portion of the stream of crystallizer pull-out is set (S300) with reference to concentration and second with reference to concentration.So And, the exemplary of the disclosure is not limited to this, and can change detection follow-up ladle opening signal (S200) and To for predicting solidification and from the first of the dissimilar steel mixing portion of the stream of crystallizer pull-out with reference to concentration and the second reference concentration It is set the order of (S300).

It addition, the dimensionless relative concentration acquisition time on the surface flowed and center is reference time or is less than reference time In the case of (YES), include following process according to the method for the continuously casting dissimilar steel of this exemplary: by acquired The dimensionless relative concentration at center of stream compare in real time and by the surface of acquired stream with reference to concentration with first Dimensionless relative concentration compares (S600) with second in real time with reference to concentration, according to acquired surface and the dimensionless at center Relative concentration and first is predicted with reference to the comparative result between concentration with reference to concentration and second and determines the position of mixing portion of stream Put (S700), and the mixing portion (S1100) that excision is predicted.

Additionally, in the case of the dimensionless relative concentration acquisition time at the surface of stream and center is more than reference time (no), the method includes following process: terminate convection current surface and in the minds of the collection of dimensionless relative concentration of each (S800) whether the type, determining the dissimilar steel (that is, previous steel and follow-up steel) of experience current operation is to preset mixing unit to cut Except type (S900) included in lengths table, when the previous steel of experience current operation and the combination of follow-up steel are that predetermined excision is long During the type that degree table includes (YES) by search with experience the previous steel of this operation and follow-up steel combine corresponding type Mixing portion is cut to corresponding length (S1200), and when the previous steel of experience current operation and the combination of follow-up steel are pre- When determining the type that resection length table do not includes, mixing portion is cut to predetermined length by (no), such as, and greatest length (S1300)。

Hereinafter, the every of the continuous casing according to exemplary will be specifically described with reference to Fig. 6 to Figure 14 Individual process.

Fig. 6 is the flow process specifically illustrating the process detecting follow-up ladle opening signal according to an exemplary Figure.Fig. 7 is to illustrate the first reference setting the dissimilar steel mixing portion for pre-flow measurement according to an exemplary The flow chart of the method for concentration and the second reference concentration.Fig. 8 is that the method being shown through according to this exemplary obtains Previous steel and the chart of dimensionless concentration of each component of follow-up steel.Fig. 9 is to illustrate that chromium (Cr) is continuous by dissimilar steel The figure of the dimensionless concentration distribution in the vertical direction (cross-sectional thickness) of the stream that casting manufactures and casting direction (longitudinal direction).Figure 10 is the figure of the concentration changes with time being shown in during the continuous casting operation of dissimilar steel in crystallizer.Figure 11 is in dissimilar steel even Do not consider by only considering the impact of crystallizer during continuous casting operation that the impact of tundish is right after completing finally to solidify Concentration distribution on the longitudinal direction of stream and cross section carries out the result calculated.Figure 12 shows according to an exemplary embodiment party The flow chart of the method for the dimensionless concentration obtaining stream surface and center of case.Figure 13 is will to obtain according to this exemplary The surface of the stream taken and the dimensionless concentration data at center are carried out with the measurement result of the real composition on the longitudinal direction of casting stream Curve chart relatively.Figure 14 be by the data of the mixing portion by predicting according to the Forecasting Methodology of this exemplary with The curve chart that the concentration measured by collecting the mixing portion predicted compares.

In the storage continuous casting process data of dissimilar steel (S100), store casting condition and the component of such as dissimilar steel Information as the variable data of mixing portion for predicting the stream in dissimilar steel operation.It is to say, store tundish In the surplus of molten steel, casting speed, experience current operation molten steel (hereinafter referred to as " previous steel ") concentration of component, And follow-up supply is to the concentration of component of the molten steel (hereinafter referred to as " follow-up steel ") of tundish.These process datas can be with pin Operation every time to dissimilar steel initializes to be reset and to store.Additionally, in the situation pulling out multiple streams from continuous casting installation for casting Under, store the casting speed of each stream.

In an exemplary embodiment, from follow-up ladle opening time, obtain the dimensionless relative concentration of stream.Cause This, needing to accurately detect storage has the ladle opening signal of follow-up steel.With reference to Fig. 6, detect follow-up ladle opening signal (S200) include following process: send virtual follow-up ladle opening signal (S210), open from sending virtual follow-up ladle Play the weight (S220) detecting tundish within the millisecond (ms) time as unit in real time during signal, with the second (s) as unit Interval, the weight of the tundish detected within the millisecond (ms) time as unit is calculated as the average weight of tundish (S230), the average weight of calculated tundish is determined the most at any time by the data of the average weight of real-time reception tundish Between increase (S240) continuously, and the time that the average weight of tundish increases continuously is set as opening the time of follow-up ladle (S250)。

Generally, in the detection of follow-up ladle opening signal, when follow-up ladle slide gate nozzle with predetermined open than or more When big unlatching is opened than (such as 100%), signal is received and is detected as follow-up ladle opening signal.But, due to rear The outlet of continuous ladle is blocked, even if often occurring slide gate nozzle to open the situation that molten steel is not discharged.Accordingly, because only pass through The operation of sensing slide gate nozzle detects follow-up ladle opening signal, even if it is also such that molten steel is not discharged from ladle, therefore detects Accuracy may be the lowest.

Generally, in order to solve the above-mentioned restriction of the detection follow-up ladle opening signal for predicting mixing portion, tundish Weight use measure according to the sensor of the weight of time detecting tundish, wherein, the weight of tundish is with millisecond (ms) be unit the shortest time interval in measure.Measure in real time within to the millisecond (ms) time as unit When the change of the weight of tundish is analyzed, in the case of the weight of tundish increases continuously, programmable logic system (PLC) Send the signal that follow-up ladle is opened.However, it is possible to because of sensor sensitivity occur in the shortest time interval (i.e. With millisecond (ms) as unit) vibration (hunting) of the weight of tundish that records.Therefore, recurrent situation is: even if When follow-up ladle is the most actually opened, PLC also sends follow-up ladle opening signal.In order to solve such restriction, permit Permitted PLC again to sense after increasing continuously in the weight of tundish when the weight of tundish increases continuously and send follow-up ladle Opening signal.But, owing to again sensing transmission opening signal when the weight of tundish increases continuously, often occur ladle to beat The situation that ON signal postpones and sends inconsistent with practical situation.In order to solve the delay of opening signal, search is in centre The weight of bag increases continuously by the data of 10 minutes before the most sensed and again to perform to set the weight of tundish minimum Time the operation of time.But, this method as servo-actuated (follow-up) method has following restriction: may not be real Time detect follow-up ladle opening signal.Therefore, that follow-up ladle opening signal may be still delay or be not likely to be correct, and And this becomes the reason of the prediction accuracy reducing mixing portion.

Therefore, in order to the most accurately detect the follow-up ladle opening signal during the continuous casting operation of dissimilar steel, PLC according to the operating condition of dissimilar steel (such as, when molten steel casting speed and surplus reduces and casting speed in tundish Degree and residue steel amount be predetermined value or less time) send virtual follow-up ladle opening signal (S210).Hereafter, virtual from sending The weight measuring tundish within the millisecond (ms) time (such as 200ms) as unit is played during follow-up ladle opening signal (S220).Subsequently, with the second (s) predetermined time interval (such as 1 second or 2 seconds) as unit, will with millisecond (ms) as unit Time in the weight of tundish measured be calculated as the average weight (S230) of tundish, and to the tundish calculated Average weight analyze to determine whether the weight of tundish increases continuously (S240) in real time.If it is to say, passed through Equation is described, as " W_td" it is the weight remaining steel amount in tundish, " t " is current time, and when " t-Δ t " is relatively morning Between time, work as W_td(t)–W_td(t-Δ t) and W_tdT (when t-2* Δ t) is all higher than or is equal to " 0 ", t-2* Δ t is defined as beating () Wtd Open the time of follow-up ladle, and therefore, send follow-up ladle opening signal.Surface and the center of stream is calculated from t-2* Δ t In the dimensionless relative concentration of each, and to this end, from t-4* Δ t, store the residue steel amount in tundish and casting speed Degree is it is thus possible to real-time estimate mixing portion.

The dimensionless relative concentration at center and the dimensionless phase on surface with the stream of the mixing portion for predicting dissimilar steel Compare concentration first is dimensionless concentration value with reference to concentration and second with reference to concentration.Describe according to one next, with reference to Fig. 7 The calculating first of individual exemplary is with reference to concentration and the method for the second reference concentration.

With reference to Fig. 7, set first of the dissimilar steel mixing portion for pre-flow measurement according to an exemplary Comprise the steps: to receive all groups of each in previous steel and follow-up steel with reference to concentration and second with reference to the method for concentration The concentration data (S310a and S310b) divided, the lower limit dimensionless concentration and the upper limit dimensionless that calculate each component of previous steel are dense Degree (S320a), the lower limit dimensionless concentration of each component of calculated for subsequent steel and upper limit dimensionless concentration (S320b), will previously Minimum upper limit dimensionless concentration in the upper limit dimensionless concentration value of each component of steel is set as first with reference to concentration (S330a), and by the highest lower limit dimensionless concentration value in the lower limit dimensionless concentration value of each component of follow-up steel set It it is the second reference concentration (S330b).

It is to say, previously the lower limit dimensionless concentration of each component of steel is calculated by formula 1, and each of previous steel The upper limit dimensionless concentration of component is calculated by formula 2.Additionally, the lower limit dimensionless concentration of each component of follow-up steel is by formula 3 Calculate, and the upper limit dimensionless concentration of each component of follow-up steel is calculated by formula 4.

[formula 1]

[formula 2]

[formula 3]

[formula 4]

In formula 1 to 4, in the dimensionless concentration computing interval to each concentration of component, the previously lower limit dimensionless of steel In the case of concentration is more than the upper limit dimensionless concentration of previous steel, substitute previous steel with the upper limit dimensionless concentration value of previous steel Lower limit dimensionless concentration value, and the upper limit dimensionless concentration value of previous steel is substituted with the lower limit dimensionless concentration value of previous steel. Additionally, in the case of the lower limit dimensionless concentration of follow-up steel is more than the upper limit dimensionless concentration of follow-up steel, in an identical manner, With the lower limit dimensionless concentration value of the upper limit dimensionless concentration value alternate subsequent steel of follow-up steel, and the lower limit with follow-up steel is immeasurable The upper limit dimensionless concentration value of guiding principle concentration value alternate subsequent steel.When the concentration of component of previous steel is higher than the concentration of component of follow-up steel Time, application is such as upper type.

Such as, previously the C that carbon (C) concentration is 0.4wt% (0.38wt% to 0.42wt%) and follow-up steel of steel contains In the case of amount is for 0.2wt% (0.18wt% to 0.22wt%), the C dimensionless concentration of previous steel is when performing dimensionless transformation Become 0 (0.1 to-0.1).It is to say, owing to the upper limit dimensionless concentration of previous steel becomes-0.1 and the lower limit of previous steel Dimensionless concentration becomes 0.1, and these values are mutually replaced.

Typically, there are the design specification concentration for each component of type according to steel to be manufactured.It is to say, only Meet the condition of steel to be manufactured when the concentration of each component is included in design specification concentration range, and design specification is dense Degree scope includes between the minimum higher limit for each component and the highest lower limit and minimum higher limit and the highest lower limit Value.Therefore, in the casting continuously of dissimilar steel, exist for the design specification concentration range of each component of previous steel, and And exist for the design specification concentration range of each component of follow-up steel.

Additionally, previously the concentration of each component of steel represents each of the molten steel that first casts in current dissimilar steel operates The concentration of component, and be the concentration determined to the refinery practice before tundish by molten steel supply, wherein, previous steel each The concentration of individual component is included in the concentration value in the design specification concentration range of previous steel.Similarly, each group of follow-up steel The concentration divided represents the concentration of each component of the molten steel of follow-up supply, and is also supplied before tundish by molten steel The concentration that refinery practice determines, wherein, the concentration of each component of follow-up steel is included in the design specification concentration model of follow-up steel Enclose interior concentration value.

In formula 1 to 4, the lower limit dimensionless concentration of previous steel and the lower limit of upper limit dimensionless concentration and follow-up steel are immeasurable Guiding principle concentration and upper limit dimensionless concentration are by using the above-mentioned design specification least concentration of previous steel, the design specification of previous steel Upper concentration, the design specification least concentration of follow-up steel, the design specification upper concentration of follow-up steel, the concentration of previous steel and The concentration of follow-up steel calculates.The previously minimum upper limit dimensionless concentration value in the upper limit dimensionless concentration value of each component of steel It is set as that first is dense with reference to the highest lower limit dimensionless in concentration, and the lower limit dimensionless concentration value of each component of follow-up steel Angle value is set as second with reference to concentration.Additionally, in subsequent process, first with reference to the nothing that concentration is center with the stream calculated The value that dimension relative concentration compares in real time, and second be relative with the dimensionless on the surface of the stream calculated with reference to concentration The value that concentration compares in real time.

Fig. 8 shows each group of the previous steel by calculating and follow-up steel according to the method for this exemplary The chart of the dimensionless concentration divided.Such as, C, manganese (Mn) and Cr are included in each in previous steel and follow-up steel, and When the lower limit dimensionless concentration of C, Mn and Cr component and upper limit dimensionless concentration are calculated by above-mentioned equation 1-4, result such as Fig. 8 Shown in.With reference to Fig. 8, among the upper limit dimensionless concentration of C, Mn and Cr, the upper limit dimensionless concentration of the Cr upper limit than C or Mn Dimensionless concentration is low.Therefore, the upper limit dimensionless concentration of Cr is set to first with reference to concentration.Immeasurable at the lower limit of C, Mn and Cr Among guiding principle concentration, the lower limit dimensionless concentration of the Cr lower limit dimensionless concentration than C or Mn is high.Therefore, the lower limit dimensionless of Cr is dense Degree is set to second with reference to concentration.Therefore, according to the described example of Fig. 8, as predicting that the dimensionless of mixing portion is dense The first of the minimum higher limit of degree is 0.07 with reference to concentration, and second as the highest lower limit is 0.95 with reference to concentration.Change Yan Zhi, the dimensionless concentration of mixing portion in the range of 0.07 with up to less than 0.95, and from the center of the stream calculated in real time The point that dimensionless relative concentration is 0.07 be mixing unit to the regional prediction of the point that dimensionless relative concentration is 0.95 on surface Point.

Previously it is set to the first minimum with reference to concentration among the upper limit dimensionless concentration value of each component of steel The comparison of upper limit dimensionless concentration value and the dimensionless relative concentration at the center calculated in real time and in each component of follow-up steel Lower limit dimensionless concentration value among be set to second with reference to concentration the highest lower limit dimensionless concentration value with calculate in real time The reason of comparison of dimensionless relative concentration on surface as follows.

During the casting continuously of dissimilar steel, one end of the mixing portion of the stream being closed by previous steel and follow-up steel reinforced concrete and being solidified Concentration meet the design specification concentration of previous steel, and the other end of mixing portion meets the design specification concentration of follow-up steel.Mixed Close the region previously steel between one end and the other end of part and each in follow-up steel design specification concentration range it Outward.

With reference to Fig. 9, it is to be understood that concentration is along the vertical direction (cross-sectional thickness direction) of slab and casting direction (longitudinal direction) changes.Position i.e. surface and the dimensionless relative concentration at center in the vertical direction of stream have different trend Pattern.Specifically, occur after the time that being mixed between previous steel and follow-up steel opens follow-up ladle in the surface of stream. But, relative to center, occur in stream before being mixed in the time opening follow-up ladle.Reason is due to Concentraton gradient Occur to be mixed by tundish and crystallizer and the diffusion of decomposite molten steel center non-solidified steel water layer in stream.Namely Saying, the center being blended in stream between previous steel and follow-up steel is more morning than what the surface at stream started.

Therefore, in the disclosure, each of previously steel is reached when the dimensionless relative concentration at the center of the stream obtained in real time Minimum upper limit dimensionless concentration value (that is, first with reference to concentration) among the upper limit dimensionless concentration value of individual component or deviate minimum During upper limit dimensionless concentration value (that is, first with reference to concentration), it is defined as the state that mixing starts, and in this case, stream Position on longitudinal direction is confirmed as the first excision position.It addition, the dimensionless on the surface of the stream that ought calculate in real time is the denseest Degree reaches the highest lower limit dimensionless concentration value (that is, second among the lower limit dimensionless concentration value of each component of follow-up steel With reference to concentration) or when deviateing the highest lower limit dimensionless concentration value (that is, second with reference to concentration), it is defined as the state that mixing terminates, And in this case, the position of stream is confirmed as the second excision position.In other words, the center on the longitudinal direction of stream is immeasurable Guiding principle relative concentration is the position of the minimum upper limit dimensionless concentration among the upper limit dimensionless concentration of each component of previously steel For the original position of mixing portion, the dimensionless relative concentration on the surface on the longitudinal direction of stream is each component at follow-up steel The final position that position is mixing portion of the highest lower limit dimensionless concentration among lower limit dimensionless concentration.Therefore, in these public affairs In opening, previously the minimum upper limit dimensionless concentration among the upper limit dimensionless concentration of each component of steel is named as the first reference Concentration and first compares with reference to the dimensionless relative concentration of concentration with the center of acquisition.Each component at follow-up steel The highest lower limit dimensionless concentration among lower limit dimensionless concentration be named as second with reference to concentration and second with reference to concentration with The dimensionless relative concentration on the surface obtained compares to be predicted as the mixing portion that dissimilar steel is mixed.It is to say, stream Longitudinal direction on the dimensionless relative concentration at the center obtained in real time reach first and be confirmed as the with reference to the position of concentration The dimensionless relative concentration on the surface on one excision position, and the longitudinal direction flowed reaches the position of the second reference concentration by really It is set to the second excision position to excise mixing portion.

In typical case, in the prediction of mixing portion, mixing portion is predicted, and does not individually consider each section of stream Position, face, i.e. surface and center.It is to say, in typical case, the concentration of a stream position on the longitudinal direction assuming stream The surface at the place of putting and the concentration at center be identical in the case of obtain.Accordingly, because the accuracy of the position of mixing portion or mixed The premeasure closing part is low, and therefore mixing portion is mixed in the product and is transported to the phenomenon of client company and frequently occurs.

Therefore, in the disclosure, it is appreciated that the table of a position on the longitudinal direction of stream as above Face concentration and centre concentration are different, and the surface flowed and in the minds of the dimensionless relative concentration of each respectively different Obtain to predict mixing portion during planting the casting continuously of steel.

In the typical casting operation continuously of dissimilar steel, when supplying follow-up steel to tundish, previous steel and follow-up steel Tundish mixes, and in this case, a part for mixing steel is quilt during mixing the process of previous steel and follow-up steel Discharge and remainder remixes while continuous recirculation in tundish continuously.Additionally, tundish mixes and mixes again The molten steel closed is discharged in crystallizer by submersed nozzle, and wherein, the molten steel discharged by submersed nozzle has turbulent flow. Therefore, be incorporated into from tundish in crystallizer mixing molten steel due to the molten steel in crystallizer turbulent flow and in upper area Produce recirculation flow, and therefore, mixing phenomena and remix phenomenon and happen over and over again the most in a crystallizer and in crystallizer Concentration real-time change (sees Figure 10).The mixing portion closed with reference to Figure 11, previous steel and follow-up steel reinforced concrete is present in from crystallizer In the stream solidified and pull out, and the thickness of slab when the mixing only considering the mixing of crystallizer and do not account in tundish In the case of 0.4m, the length of mixing portion is about 4m.

By the above description of Figure 10 and Figure 11, it is to be appreciated that being blended in crystallizer and tundish of dissimilar steel Carry out, and the mixing portion that previously steel and follow-up steel reinforced concrete had closed obtains by mixing in a crystallizer to come in stream.

In typical case, owing to mixing portion is by only considering that mixing in tundish does not accounts in crystallizer Mixing is predicted, therefore the accuracy of the position of mixing portion or the premeasure of mixing portion are low, and therefore, mixing portion At least some of mixing in the product and is transported to the phenomenon of client company and frequently occurs.

Therefore, in the disclosure, owing to mixing portion is by considering the mixing of dissimilar steel in crystallizer and tundish Predicted and excision, therefore, the degree of accuracy of the excision of mixing portion can improve.

During the continuously casting of dissimilar steel, the surface in stream and in the minds of the meter of dimensionless relative concentration of each The calculating (S400) of the position on the longitudinal direction of the stream calculated and have corresponding dimensionless relative concentration includes following process: from inspection Survey time of follow-up ladle opening signal get up to obtain in real time stream surface and in the minds of the dimensionless relative concentration of each , and calculate the position (S420) with calculated surface concentration and centre concentration of stream (S410).

In order to calculate surface concentration and the centre concentration of stream from the time detecting follow-up ladle opening signal in real time (S410), carry out in the case of calculating the mixing in considering the crystallizer as described in the disclosure, and therefore, be used for The formula (hereinafter referred to " formula 9 ") calculating the surface of stream and the concentration at center includes the concentration of the steel discharged from crystallizer.? In following formula, " t+ △ t " represents that current time and " t " represent the relatively early time.

Hereinafter, by surface concentration and the center obtaining stream from the time detecting follow-up ladle opening signal in real time The process of concentration is described.In an exemplary embodiment, the surface concentration of stream and the acquisition of centre concentration are by root Calculate concentration according to following formula to carry out.Therefore, in other words, " surface concentration of stream and the acquisition of centre concentration " can be by " the surface of stream Concentration and the calculating of centre concentration " represent.

In terms of physics, the change of the molten steel amount being incorporated in tundish can by the change of the weight of tundish divided by time Between change (△ t) and the fluid density of molten steel represent.In an exemplary embodiment, follow-up steel in tundish Inlet volumetric flow (Q_td-in) first pass through utilization and be incorporated into the above-mentioned physical concept of the change of molten steel amount in tundish and calculate (S411)。

In this case, the inlet volumetric flow (Q of the follow-up steel in tundish_td-in) can be calculated by following formula 5.

[formula 5]

$Q_{td-in}=\frac{W_{td}(t+\mathrm{\Δ}t)-W_{td}\left(t\right)}{\mathrm{\Δ}t\×{\mathrm{\ρ}}_L}+Q_{td-out}$

Wherein, W_tdT () is the gross weight of the molten steel in the tundish of relatively early time, W_td(t+ Δ t) is in current time Between the gross weight of molten steel in bag, Q_td-outThe volume flow of the molten steel for discharging from tundish, and ρ_lIt is the liquid of molten steel Density.

The relatively early gross weight (W of the molten steel in the tundish of time_td(t)) and the tundish of current time in molten steel total Weight W_td(t+ Δ t) is measured in real time by the sensor being arranged on the outer bottom of tundish, and will discharge from tundish The volume flow (Q of molten steel_td-out) be calculated as the cross sectional dimensions of crystallizer and surveyed by the sensor on the side being arranged on stream The summation of the product of the casting speed of amount.Further, since molten steel is liquid, therefore use the fluid density 7000kg/m of molten steel³ To 7400kg/m³Rather than use the density of solid 7600kg/m of molten steel³To 8000kg/m³.Specifically, such as, use about 7200kg/m³The fluid density of molten steel rather than use about 7800kg/m³The density of solid of molten steel.

Hereafter, the average dimensionless relative concentration (C of the molten steel in tundish_td-ave(t+ Δ t)) utilizes the centre calculated Inlet volumetric flow (the Q of the follow-up steel in bag_td-in) calculate (S412).The stream of the molten steel produced in tundish can be categorized into one Secondary stream and Secondary Flow, it includes dead band (dead zone), and therefore, the concentration of molten steel can be according to molten steel in tundish Position and local is different.But, in the disclosure, carry out pre-for the concentration that the up, down, right and left position according to stream is produced The purpose surveyed, it is assumed that the average dimensionless relative concentration of the molten steel in tundish is represented by particular value, and do not account for local The situation of stream, and the average dimensionless relative concentration of molten steel that particular value is defined as in tundish.In this case, middle The average dimensionless relative concentration (C of the molten steel in bag_td-ave(t+ Δ t)) can be calculated by equation 6 below.

[formula 6]

$C_{td-ave}(t+\mathrm{\Δ}t)=\frac{W_{td}\left(t\right)\×C_{td-ave}\left(t\right)+Q_{td-in}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{td-in}\left(t\right)}{W_{td}(t+\mathrm{\Δ}t)}-\frac{Q_{td-out}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{td-out}\left(t\right)}{W_{td}(t+\mathrm{\Δ}t)}$

Wherein, C_td-ave(t+ Δ t) is the average dimensionless relative concentration of the molten steel in the tundish of current time, W_td(t) For the gross weight of the molten steel in the tundish of relatively early time, C_td-aveT () is the average nothing of the molten steel in the tundish of relatively early time Dimension relative concentration, Q_td-inT () is the inlet volumetric flow of the relatively early molten steel being incorporated in tundish of time, C_td-in(t) be The relatively early entrance concentration (dimensionless relative concentration) of the follow-up steel in the tundish of time, Q_td-outT () is that relatively early the time is therefrom Between the volume flow of molten steel discharged in bag, C_td-outT () is that the Molten steel concentration discharged from tundish of relatively early time is (immeasurable Guiding principle relative concentration), and ρ_LFluid density for molten steel.

Here, the inlet volumetric flow of the follow-up steel that the value calculated by formula 5 as above is used as in tundish (Q_td-in), the relatively early gross weight (W of the molten steel in the tundish of time_td(t)) and the tundish of current time in molten steel total Weight (W_td(t+ Δ t)) is respectively the sensor by being arranged in tundish (i.e., at predetermined intervals) in real time and measures Value, the volume flow (Q of molten steel discharged from tundish of current time_td-out) cross section of crystallizer can be calculated as Size with by the summation of the product of the casting speed of the sensor measurement on the side being arranged on stream, ρ_LLiquid for molten steel is close Degree, wherein uses 7000kg/m³To 7400kg/m³E.g., from about 7200kg/m³Value.

When the follow-up steel supply that will be contained in ladle is to tundish, at the follow-up steel that relatively early the time is incorporated in tundish Concentration (C_td-in) it is always " 1 ", this is because this process is before follow-up steel is supplied to tundish and is mixed.It addition, The relatively early average dimensionless relative concentration (C of the molten steel in the tundish of time_td-ave(t)) initial value and from tundish arrange Dimensionless relative concentration (the C of the molten steel gone out_td-out(t)) initial value be set as " 0 ".

The average dimensionless relative concentration (C of the molten steel in the tundish of current time_td-ave(t+ Δ t)) is set by utilization It is set to above-mentioned initial value to calculate.

It follows that the average dimensionless of the molten steel value calculated by formula 6 being used as in the tundish of current time is relative Concentration (C_td-ave(t+ Δ t)), and current time will be used as by the value staying in the current time that formula 7 described below calculates The dimensionless relative concentration (C of molten steel discharged from tundish_td-out(t+Δt))。

Average dimensionless relative concentration (C when the molten steel in the tundish calculating current time_td-aveTime (t+ Δ t)), when Dimensionless relative concentration (the C of the molten steel discharged from tundish of front time_td-out(t+ Δ t)) utilizes average dimensionless relative Concentration (C_td-ave(t+ Δ t)) calculates (S413).In this case, in the disclosure, molten steel immeasurable discharged from tundish Guiding principle relative concentration (C_td-out(t+ Δ t)) is calculated by equation 7 below.

[formula 7]

C_td-out(t+ Δ t)=f_td×C_td-ave(t+Δt)+(1-f_td)×C_td-in(t+Δt)

Wherein, C_td-out(t+ Δ t) is the dimensionless relative concentration of molten steel discharged from tundish of current time, C_td-ave(t+ Δ t) is the average dimensionless relative concentration of the molten steel in the tundish of current time, C_td-in(t+ Δ t) is current The dimensionless relative concentration of the molten steel being incorporated in tundish of time.Molten steel in the tundish of current time the most immeasurable Guiding principle relative concentration (C_td-out(t+ Δ t)) is calculated and used as discussed above by formula 6, and current time be incorporated into tundish In the dimensionless relative concentration (C of follow-up steel_td-in) it is 1.f_tdFor interpolation and extrapolation factor, wherein, use respectively different interior Slotting and extrapolation factor calculates the dimensionless relative concentration at the center of stream and the dimensionless relative concentration on the surface of stream.Namely Say, for calculating interpolation and the extrapolation factor (f of the concentration at the center of stream_td-center) it is 4 ± 2, and for calculating the surface of stream The interpolation of concentration and extrapolation factor (f_td-surface) it is 2.2 ± 0.6.

Subsequently, the average dimensionless relative concentration (C of the molten steel in the crystallizer of current time_md-aver(t+ Δ t)) utilizes Dimensionless relative concentration (the C of the molten steel discharged from tundish of current time_td-out(t+ Δ t)) calculates and by this Formula 8 in Gong Kai calculates.

[formula 8]

$C_{md-ave}(t+\mathrm{\Δ}t)=\frac{W_{md}\left(t\right)\×C_{md-ave}\left(t\right)+Q_{md-in}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{md-in}\left(t\right)}{W_{md}(t+\mathrm{\Δ}t)}-\frac{Q_{md-out}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{md-out}\left(t\right)}{W_{md}(t+\mathrm{\Δ}t)}$

Wherein, W_mdT () is the gross weight of the molten steel in the crystallizer of relatively early time, C_md-averT () is the knot of relatively early time The average dimensionless relative concentration of the molten steel in brilliant device, Q_md-inT () is the inlet volumetric of the molten steel in the crystallizer of relatively early time Flow, C_md-inT () is the entrance concentration (dimensionless relative concentration) of the molten steel in the crystallizer of relatively early time, W_md(t+ Δ t) is The gross weight of the molten steel in the crystallizer of current time, Q_md-outT () is the volume flow of the molten steel discharged from crystallizer, C_md-outT () is the dimensionless relative concentration of the relatively early steel (that is, stream) discharged from crystallizer of time, and ρ_LFor molten steel Fluid density, its Midst density is 7000kg/m³To 7400kg/m³, such as, about 7200kg/m³。

In the text, the gross weight (W of the molten steel in the crystallizer of current time_mdThe crystallizer of (t+ Δ t)) and relatively early time In the gross weight (W of molten steel_md(t)) the available length of crystallizer, the density of cross-sectional area and motlten metal calculates.Also That is, gross weight can be by the formula " gross weight (W of the molten steel in crystallizer_mdThe top of the total length of)=(crystallizer-crystallizer Length to falcate metal bath surface) fluid density of interior cross-sectional area × molten steel of × crystallizer " calculate.Here, crystallization The interior cross-sectional area of device is identical with the cross-sectional area of stream.It addition, the flow of the stream (or steel) discharged from crystallizer can be calculated Become the interior cross-sectional area of crystallizer and by the summation of the product of the casting speed of the sensor measurement on the side being arranged on stream.Relatively The early dimensionless relative concentration (C of the follow-up steel being incorporated in crystallizer of time_md-in(t)) always with the relatively early time from centre Dimensionless relative concentration (the C of the follow-up steel discharged in bag_td-out(t)) identical.It addition, the molten steel in the crystallizer of relatively time morning Average dimensionless relative concentration (C_md-aver(t)) initial value and the dimensionless relative concentration of molten steel discharged from crystallizer (C_md-out(t)) initial value be set as 0.

The average dimensionless relative concentration (C of the molten steel in the crystallizer of current time_md-aver(t)) utilize the initial of setting Value calculates.

It follows that use the value calculated by formula 8 relative as the average dimensionless of the molten steel in the crystallizer of current time Concentration (C_md-aver(t+ Δ t)), and use by staying in the value of the current time that the formula 9 being hereinafter described calculates as current time The dimensionless relative concentration (C of molten steel discharged from crystallizer_md-out(t+Δt))。

Hereinafter, the dimensionless relative concentration of the steel (that is, stream) discharged from crystallizer of current time is calculated (C_md-out(t+Δt))(S415).In the disclosure, the dimensionless phase of the steel (that is, stream) discharged from crystallizer of current time To concentration (C_md-out(t+ Δ t)) is calculated by equation 9 below.

[formula 9]

C_md-out(t+ Δ t)=f_md×C_md-ave(t+Δt)+(1-f_md)×C_md-in(t+Δt)

Wherein, C_md-out(t+ Δ t) is that the dimensionless of the steel (that is, stream) of discharge from crystallizer of current time is the denseest Degree, C_md-ave(t+ Δ t) is the average dimensionless relative concentration of the molten steel in the crystallizer of current time, and C_md-in(t+Δt) Dimensionless relative concentration for the molten steel being incorporated in crystallizer of current time.Here, the row from crystallizer of current time Dimensionless relative concentration (the C of the steel gone out_md-out(t+ Δ t)) is solidifying from crystallizer and discharging or pull out of current time The dimensionless relative concentration of stream and for the value that calculated by formula 9.It addition, use the value calculated by above-mentioned formula 8 as current time Crystallizer in average dimensionless relative concentration C of molten steel_md-ave(t+ Δ t), f_mdFor interpolation and extrapolation factor, wherein, for The calculating of the dimensionless relative concentration on the dimensionless relative concentration at center of stream and the surface of stream, use respectively different interpolations and Extrapolation factor.It is to say, be used for interpolation and the extrapolation factor (f of the dimensionless relative concentration calculating at center_{md_center}) it is 0.7 ± 0.4, the interpolation of the dimensionless relative concentration calculating for the surface of stream and extrapolation factor (f_{md_surface}) it is 0.5 ± 0.2.This Outward, the dimensionless relative concentration (C of the molten steel being incorporated in crystallizer of current time_md-in(t+ Δ t)) be current time from Dimensionless relative concentration (the C of the steel discharged in tundish_td-out(t+ Δ t)), wherein uses the value calculated by above-mentioned formula 7.Due to The molten steel discharged from crystallizer mainly includes liquid molten steel, therefore uses fluid density value 7000kg/m of molten steel³Extremely 7400kg/m³, e.g., from about 7200kg/m³。

Obtain in real time during by said method operation dissimilar steel stream surface and in the minds of the dimensionless of each Relative concentration, then calculate the surface with in real time acquisition on the longitudinal direction (or casting direction) of stream and in the minds of every The position (S420) of the dimensionless relative concentration of one.

For this purpose, stream, on longitudinal direction (or casting direction), is first carried out the dimensionless phase on the surface of convection current The step that the position that the dimensionless relative concentration at the center that concentration starts position and the stream being acquired starts to be acquired is set Suddenly.As it has been described above, reason for this is that, during the casting continuously of dissimilar steel, the mixing unit between previous steel and follow-up steel Occur in after dividing the time continuing ladle after opening on the surface of stream, but the mixing of the center of stream occurs to continue after opening Before the time of ladle.It is to say, reason is, occur due to Concentraton gradient to be mixed by tundish and crystallizer and The diffusion of decomposite molten steel center not solidified molten steel layer in stream.Therefore, being blended between previous steel and follow-up steel The center of stream occurs Zao than the surface at stream, and, in general, the mixing at center usually occurs in the follow-up ladle of detection and beats The position that position is-4 ± 4m away from stream during time of ON signal.

It is necessary to set concentration starts the position that the concentration of the position being acquired, especially center starts to be acquired.

Therefore, in the disclosure, the position of the stream during time continuing ladle opening signal after sensing is set to stream The dimensionless relative concentration on surface starts measured position.Additionally, distance to be continued after sensing the time of ladle opening signal Time the position of-4 ± 4m of position of stream be set as the position that starts to obtain the dimensionless relative concentration at the center of stream.

When set the surface of stream starting to obtain and in the minds of the position of dimensionless relative concentration of each time, right What the having of the position of dimensionless relative concentration at the center of the stream with calculated current time of stream and stream was calculated works as The position of the dimensionless relative concentration on the surface of the stream of front time carries out calculating (S420).

First, the position with calculated surface dimensionless relative concentration of stream can be by length value calculated as below Obtain: the volume flow (Q that the crystallizer in stream is discharged_md-out) with the product of the fluid density of molten steel divided by the cross-sectional area of stream (A_md) and the density of solid (ρ of molten steel_s) product.When this is represented by formula (hereinafter referred to as " formula 10 "), formula is such as Under.

[formula 10]

$L(t+\mathrm{\Δ}t)=L\left(t\right)+\frac{Q_{md-out}\×{\mathrm{\ρ}}_L}{A_{md}\×{\mathrm{\ρ}}_S}\×\mathrm{\Δ}t$

Here, the density of solid (7600kg/m of molten steel is used³To 8000kg/m³) be to consider as the reason of density value Due to the solidification of liquid molten steel and contraction in a longitudinal direction.

The value calculated by formula 10 is length value, and the position of mobile up to based on stream falcate metal bath surface is calculated The position that position is the stream with corresponding surface concentration of point of length value.It addition, there is calculated centre concentration The position of stream is the position of position-4 ± 4m with surface concentration of the stream that distance obtains simultaneously.

Therefore, in the disclosure, the dimensionless relative concentration on the surface of stream and the immeasurable of center is obtained by said method Guiding principle relative concentration, and calculate have on the longitudinal direction of stream acquired surface with in the minds of the dimensionless of each relative The position of concentration.It addition, the calculating time be from the surface calculating stream with in the minds of the dimensionless of calculating of each relative dense The time of degree rises and starts metering, and the time that calculates compares (S500) in real time with reference time.

In continuous casting operation, from crystallizer, the stream of pull-out is cut along with the casting time elapses i.e. to arrange along casting direction The direction of cutter is transmitted.Therefore, the mixing portion produced in stream is progressively closer to sickle along with operating time passage, and The prediction to mixing portion must be completed before under mixing portion is arranged on sickle.In other words, in actual mixing unit Dividing before being arranged under sickle, the dimensionless relative concentration at the center calculated must reach first with reference to concentration and institute The dimensionless relative concentration on the surface calculated must reach second with reference to concentration.Therefore, in an exemplary embodiment, exist Consider and set in the case of the casting speed of dissimilar steel with reference to draw-out-time, wherein, reference time from start gauging surface and The dimensionless relative concentration of each in the minds of in plays metering and not over sickle and arrives cutting for mixing portion The time in the precalculated position before device.In this case, precalculated position can be according to the position of sickle and operation equipment or operation Condition and change, and can estimate during typical dissimilar steel operates with casting speed arrive needed for above-mentioned precalculated position time Between.Reference time can obtain by utilizing casting speed and change according to operation equipment described above and operating condition.

Obtain stream surface and in the minds of each dimensionless relative concentration while real time measure acquisition time And (S500) is compared in real time with reference time.Wherein, if acquisition time (YES) in reference time, then acquired The dimensionless relative concentration at center compare with reference to concentration with first and the dimensionless relative concentration on acquired surface and Second compares (S600) with reference to concentration.

In this case, on the longitudinal direction of stream, the dimensionless relative concentration at center reaches the position quilt of the first reference concentration It is set as starting point, and the dimensionless relative concentration of the longitudinal direction upper surface flowed reaches second and set with reference to the position of concentration It is set to terminating point so that be predicted to be the position (S700) of mixing portion from the position of the starting point of mixing portion to terminating point. It is to say, when the dimensionless relative concentration at center reaches the first reference concentration, the collection of the dimensionless relative concentration at center Repeated or terminated, and the center dimensionless relative concentration flowed is reached first and is set to mixing portion with reference to the position of concentration Original position, i.e. first excision position.It addition, when the dimensionless relative concentration on surface reaches the second reference concentration, surface The collection of dimensionless relative concentration repeated or terminated, and the dimensionless relative concentration on the surface flowed reaches second with reference to dense The position of degree is set to the final position of mixing portion, the i.e. second excision position.Hereafter, sickle is by excising position first The place of putting and the second excision position cutting stream excise the mixing portion (S1100) of prediction from stream.

On the contrary, it is not reaching to first with reference to concentration or the dimensionless relative concentration on surface when the dimensionless relative concentration at center Be not reaching to second with reference to concentration time, repeat stream surface and in the minds of the acquisition of dimensionless relative concentration of each And the calculating (S420) of position of corresponding dimensionless relative concentration (S410).It addition, such as, the dimensionless at center is the denseest Degree reach first with reference to concentration but the dimensionless relative concentration on surface be not reaching to second reference concentration in the case of, the nothing at center The collection of dimension relative concentration is repeated or is terminated, and again carries out the acquisition of the dimensionless relative concentration on surface and position The process calculated.On the contrary, the dimensionless relative concentration on surface reaches the second reference concentration but the dimensionless relative concentration at center In the case of being not reaching to the first reference concentration, the collection of the dimensionless relative concentration on surface is repeated or is terminated, and again Carry out the acquisition of the dimensionless relative concentration at center and the process of the calculating of position.

As the example of another situation, obtain stream surface and in the minds of dimensionless relative concentration same of each Time real time measure acquisition time and compare (S500) with reference time in real time.Wherein, if acquisition time exceedes reference Time (no), then terminate stream surface and in the minds of the collection (S800) of dimensionless relative concentration of each.It addition, determine Whether the previous steel of experience current operation and the combination of follow-up steel are class included in the resection length table presetting mixing portion Type (S900).

Such as, included in the resection length table being combined as default mixing portion of the dissimilar steel of experience current operation In the case of type, flow cut to resection length (S1200) listed in mixing portion resection length table.In this situation Under, stream can be cut corresponding resection length in position based on the falcate metal bath surface flowed.But, at experience current operation Dissimilar steel the type being combined as not included in the resection length table of default mixing portion in the case of, flow based on stream curved The position of month shape metal bath surface is cut the resection length (S1300) of maximum.

With reference to Figure 13 and Figure 14, it will be understood that, the method for exemplary the position of the mixing portion calculated Or excision position is consistent with each other with the position of the mixing portion detected by the component directly measuring stream or excision position.It addition, As shown in Figure 14, reach with reference to the dimensionless relative concentration on concentration and surface when the dimensionless relative concentration at center reaches first During to the second reference concentration, the collection of the dimensionless relative concentration on surface and the calculating of position will terminate automatically.It is described above In, it has been described that predict mixing portion by the dimensionless concentration obtaining the surface in the short transverse of stream and center Method.But, the collection position of dimensionless concentration is not limited to center and surface, and mixing portion can be by the short transverse of stream Multiple positions or stream have differing heights position obtain dimensionless concentration predict.

Hereinafter, by referring to figs. 1 through Fig. 7 and Figure 12 continuing on casting xenogenesis continuously according to exemplary The method of steel.In this case, the steel first experiencing casting operation is named as previous steel, the steel quilt that casting operation then begins to Named follow-up steel.The explanation overlapping with described above will be omitted and maybe will be briefly described.

First, reduce at the end of the operation of casting speed previously steel, and when the surplus of the previous steel in tundish For time below scheduled volume, programmable logic system (PLC) sends virtual follow-up ladle opening signal (S200).Hereafter, middle The weight of bag started with the millisecond (ms) time (example as unit from the time sent in virtual follow-up ladle opening signal Such as, 200ms) in measure (S220) in real time.Subsequently, with the second (s) the predetermined time interval (such as, 1s or 2s) as unit, The weight of the tundish of detection within the millisecond (ms) time as unit is calculated as the average weight (S230) of tundish, and And the average weight of the tundish calculated is analyzed to determine whether the average weight of tundish increases continuously in real time (S240).It is to say, at W_td(t)-W_td(t-Δ t) and W_td(t)-W_td(when t-2* Δ t) is all higher than equal to " 0 ", t-2* Δ t It is confirmed as opening the time of follow-up ladle, and therefore, detects follow-up ladle opening signal (S200).

After sending virtual follow-up ladle opening signal (S210), the data for the mixing portion of pre-flow measurement are stored In the controller of continuous casting installation for casting (S100).It is to say, receive and store the surplus of the molten steel in tundish, casting speed Spend, experience the concentration of the component (hereinafter, being referred to as " previous steel ") of the molten steel of current operation and supply with backward tundish The concentration of component (hereinafter, being referred to as " follow-up steel ") of molten steel.In this case, store in tundish from t-4* Δ t Residue steel amount and casting speed enable to real-time estimate mixing portion.It addition, just produce multiple stream continuous casting installation for casting and Speech, determines that whether this equipment operate for each stream and whether the casting speed of each stream is stored.

It follows that the first reference concentration of the dissimilar steel mixing portion for predicting the stream solidifying from crystallizer and pulling out Set with the concentration data of each component of the second previous steel stored by utilization with reference to concentration and each component of follow-up steel (S300).Specifically, the minimum upper limit dimensionless concentration value among the upper limit dimensionless concentration value of each component of previous steel is set It is set to first with reference to concentration.It addition, the highest lower limit dimensionless among the lower limit dimensionless concentration value of each component of follow-up steel is dense Angle value is set to second with reference to concentration.Calculate each concentration of component dimensionless concentration during, previously the lower limit of steel without In the case of dimension concentration is more than the upper limit dimensionless concentration of previous steel, substitute previous steel by the upper limit dimensionless concentration of previous steel Lower limit dimensionless concentration and substitute the upper limit dimensionless concentration of previous steel by the lower limit dimensionless concentration of previous steel.Additionally, In the case of the lower limit dimensionless concentration of follow-up steel is more than the upper limit dimensionless concentration of follow-up steel, in an identical manner with follow-up The lower limit dimensionless concentration of the upper limit dimensionless concentration alternate subsequent steel of steel and substituting by the lower limit dimensionless concentration of follow-up steel The upper limit dimensionless concentration of follow-up steel.When previously the concentration of component of steel is more than the concentration of component of follow-up steel, application is such as upper type.

First with reference to concentration and second with reference to the reference value that concentration is for predicting mixing portion, wherein, first with reference to dense Degree and second changes according to previous steel and the type of follow-up steel and combination with reference to concentration.

When to for predict that the first of mixing portion is set with reference to concentration with reference to concentration and second time, the surface of stream with The dimensionless relative concentration of each in the minds of in (i.e. carries out reality t-2* Δ t) from the time detecting follow-up ladle opening signal Time calculate, and for calculating time of dimensionless relative concentration from time (the t-2* Δ t) detecting follow-up ladle opening signal Rise and carry out measuring (S410).It addition, be set as starting to measure by the position at the time sending follow-up ladle opening signal of stream The position of the dimensionless relative concentration on the surface of stream.Additionally, distance is opened the position-4 of the stream at the time of follow-up ladle ± The position of 4m is set as the position starting to obtain the dimensionless relative concentration at the center of stream.

As it has been described above, the method obtaining surface and center dimensionless relative concentration includes following process: first, utilize formula 5 Inlet volumetric flow (the Q of the follow-up steel in calculating tundish_td-in)(S411)；By the follow-up steel in the tundish that will be calculated Inlet volumetric flow (Q_td-in) to be applied to formula 6 the denseest to the average dimensionless of the molten steel in the tundish calculating current time Degree (C_ave(t+Δt))(S412)；The average dimensionless relative concentration (C of the current time by being calculated_ave) it is applied to formula 7 Calculate the dimensionless relative concentration (C of the molten steel discharged from tundish of current time_td-out(t+Δt))(S413)；Pass through Dimensionless relative concentration (C by the molten steel discharged from tundish of the current time that calculated_td-out(t+ Δ t)) is applied to Formula 8 calculates the average dimensionless relative concentration (C of the molten steel in the crystallizer of current time_md-aver(t+Δt))(S414)；With And the dimensionless relative concentration (C of the molten steel of discharge from tundish of the current time by being calculated_td-out(t+Δt)) Average dimensionless relative concentration (C with the molten steel in the crystallizer of the current time calculated_md-aver(t+ Δ t)) is applied to formula Dimensionless relative concentration (the C of 9 streams discharged from crystallizer calculating current time_md-out(t+Δt))(S415).At this In the case of, due to the dimensionless relative concentration (C of the molten steel being incorporated in crystallizer of the current time in formula 8_md-in(t+Δt)) Dimensionless relative concentration (C for the molten steel discharged from tundish of current time_td-out(t+ Δ t)), is therefore counted by formula 7 Dimensionless relative concentration (the C of the molten steel discharged from tundish of the current time calculated_td-out(t+ Δ t)) is applied in formula 8 The dimensionless relative concentration (C of the molten steel being incorporated in crystallizer_md-in(t+Δt))。

In the said method calculating concentration, the surface dimensionless relative concentration of stream can be by the calculating by being used for surface The dimensionless that interpolation is applied to the molten steel discharged from tundish for calculating current time with the value of extrapolation factor is relative dense Degree (C_td-outThe formula 7 of (t+ Δ t)) and for calculating the dimensionless relative concentration of the steel discharged from crystallizer of current time (C_md-outInterpolation and the extrapolation factor (f) of each in the formula 9 of (t+ Δ t)) and calculate.It is to say, the nothing on the surface of stream Dimension relative concentration can obtain in the case where there: is the molten steel discharged from tundish for calculating by 2.2 ± 0.6 application Dimensionless relative concentration (C_td-outThe interpolation of the formula 7 of (t+ Δ t)) and extrapolation factor (f), and by 0.5 ± 0.2 application for being used for Calculate the dimensionless relative concentration (C of the molten steel discharged from crystallizer_md-outThe interpolation of the formula 9 of (t+ Δ t)) and extrapolation factor (f).Similarly, the dimensionless relative concentration at the center of stream can obtain in the case where there: by 4 ± 2 application for working as calculating Dimensionless relative concentration (the C of the molten steel discharged from tundish of front time_td-outThe interpolation of the formula 7 of (t+ Δ t)) and extrapolation because of Son (f), and 0.7 ± 0.4 application is the denseest for the dimensionless of the steel discharged from crystallizer for calculating current time Degree (C_md-outThe interpolation of the formula 9 of (t+ Δ t)) and extrapolation factor (f).

When obtain in real time stream surface and in the minds of the dimensionless relative concentration of each time, on the longitudinal direction of convection current The position of the dimensionless relative concentration on the surface having calculated center dimensionless relative concentration and calculated calculates (S420).The position with calculated surface dimensionless relative concentration of stream can be by being carried out as follows meter as described in formula 10 Calculate: make the crystallizer displaced volume flow (Q in stream_md-out) and motlten metal fluid density product divided by stream cross section Long-pending (A_md) and the density of solid (ρ of molten steel_s) product.Here, the density of solid 7600kg/m of molten steel is used³To 8000kg/m³, E.g., from about 7800kg/m³As density value.Additionally, the position with acquired center dimensionless relative concentration of stream is distance What the same time was dirty has the position of position-4 ± 4m of calculated surface dimensionless relative concentration.

By said method obtain stream surface and in the minds of the dimensionless relative concentration of each, and in convection current Have on longitudinal direction acquired surface and in the minds of the position of dimensionless relative concentration of each carry out calculating same Time, the time calculating concentration is compared (S500) in real time with reference time.If the time calculated is in reference time (YES), then the surface of the stream calculated and in the minds of each dimensionless relative concentration respectively with first with reference to concentration and the Two compare (S600) with reference to concentration.

When the dimensionless relative concentration at the center obtained in real time, to reach first relative with reference to the dimensionless on concentration and surface When concentration reaches the second reference concentration, the calculating of termination concentration and prediction and setting mixing portion (S700).It is to say, work as When the dimensionless relative concentration at the center obtained in real time reaches the first reference concentration, terminate, on the longitudinal direction of convection current, there is center The calculating of position of dimensionless relative concentration, and the dimensionless relative concentration at the center of stream is reached first with reference to concentration Position is set as original position.It addition, when the dimensionless relative concentration on the surface obtained in real time reaches the second reference concentration, eventually Only there is on the longitudinal direction of convection current the calculating of the position of the dimensionless relative concentration on surface, and the dimensionless on the surface by stream Relative concentration reaches second and is set as final position with reference to the position of concentration.Here, by the dimensionless at the center of the acquisition from stream The dimensionless relative concentration on the surface that relative concentration reaches the first acquisition extremely flowed with reference to the position of concentration value reaches the second reference The regional prediction of the position of concentration value is mixing portion.Hereafter, due to sickle at original position and final position automatic Ground cutting stream, therefore the mixing portion of dissimilar steel is excised (S1100) from stream.

Do not have with reference to the dimensionless relative concentration on concentration or surface when the dimensionless relative concentration at center is not reaching to first When reaching the second reference concentration, repeat the surface of stream and the acquisition (S410) of the dimensionless relative concentration at center and corresponding nothing The calculating (S420) of the position of dimension relative concentration.

If exceeding reference time (no) for obtaining the time of concentration and calculating position, then terminate surface and the center of stream The collection of concentration and the calculating (S800) of position.Additionally, whether determine the combination of the experience previous steel of current operation and follow-up steel For type (S900) included in the resection length table of default mixing portion.Such as, in the dissimilar steel of experience current operation In the case of being combined as presetting combination included in mixing portion resection length table, stream is cut mixing portion resection length Resection length (S1200) listed in table.In this case, stream can be cut based on the falcate metal bath surface position of stream Corresponding resection length.But, experience current operation dissimilar steel be combined as be not included on presetting the cutting of mixing portion In the case of the type in lengths table, flow position based on falcate metal bath surface and be cut predetermined resection length, such as, Greatest length (S1300).After stream is cut predetermined length, the slab before mixing portion and the plate after mixing portion Base is set to exotic materials and component and is verified by component analysis device.

Figure 15 is by carrying out the length of mixing portion point according to the method for exemplary prediction mixing portion Analysis reaches the chart of 1 year.

With reference to Figure 15, it is to be appreciated that the length of mixing portion according to the concentration of real-time operation method and steel from 0m to 23m changes.It is to say, in the disclosure, owing to length and the position of mixing portion are entered by each operation for dissimilar steel Row calculates, and does not consider as in correlation technique that stream is excised in advance by the operating condition of each operation of dissimilar steel Measured length, has therefore carried out prediction and has been then sliced out, and therefore, its accuracy has been improved mixing portion.Specifically, in real time Obtain stream surface and in the minds of the dimensionless relative concentration of each, and by utilizing dimensionless relative concentration to derive The length of mixing portion and position.Therefore, in the disclosure, can avoid being caused profit to drop owing to mixing portion too much excises Low and can avoid owing to excision is less and cause faulty goods to be transported to client company.

Industrial applicibility

The method of the dissimilar steel of casting continuously according to the disclosure is measurable to be manufactured by previous steel and the mixing of follow-up steel The mixing portion of stream, and can automatically excise mixing portion.Accordingly, because the standard of the prediction of the position of mixing portion and length Exactness is enhanced, and the profit caused due to the too much excision of mixing portion therefore can be avoided to decline and can avoid due to mixing The less excision of part and the faulty goods that causes is transported to client company.Therefore, have to improve and cast continuously in dissimilar steel Operation manufactures the effect of the productivity ratio of high-quality slab.

Claims (25)

1. a method for continuous casting dissimilar steel, described method includes:

Obtain the dimensionless relative concentration relative to previous steel of the follow-up steel in the surface of strand and inside the most in real time；

Calculating described stream, to have the described surface of in real time acquisition in a longitudinal direction relative dense with the described dimensionless of described inside The position of degree；

By respectively the dimensionless relative concentration on acquired described surface and described inside being compared to with reference to concentration Predict the mixing portion in described stream；And

The mixing portion that excision is predicted.

Method the most according to claim 1, the position that the described dimensionless relative concentration of wherein said stream is acquired be Surface in the short transverse of described stream and center.

3. a method for continuous casting dissimilar steel, described method includes:

By using the previous steel in tundish relative with follow-up steel with the previous steel in the relative quantity of follow-up steel and crystallizer Amount, the described follow-up steel of the most real-time multiple positions obtained in the short transverse of the stream solidified from crystallizer and cast continuously Dimensionless relative concentration relative to described previous steel；

Calculate described stream and there is the position of the described dimensionless relative concentration of acquisition in real time in a longitudinal direction；

By by acquired dimensionless relative concentration and being compared to predict the mixing unit in described stream with reference to concentration respectively Point；And

The mixing portion that excision is predicted.

Method the most according to claim 3, wherein the denseest in the described stream described dimensionless in described short transverse The plurality of position that degree is acquired includes surface and the center of described stream.

5., according to the method described in claim 1 or 3, it is additionally included in the real-time described follow-up steel obtained in described strand relative Before the described dimensionless relative concentration of described previous steel, set described with reference to concentration,

The wherein said setting with reference to concentration includes:

Minimum upper concentration in the upper concentration of each component of described previous steel is set as first with reference to concentration；

The highest least concentration in the least concentration of each component of described follow-up steel is set as second with reference to concentration.

Method the most according to claim 5, wherein said first with reference to concentration and the setting bag of described second reference concentration Include:

The densitometer of the described component of described previous steel is counted as lower limit dimensionless concentration and upper limit dimensionless concentration；

Minimum upper limit dimensionless concentration in the described upper limit dimensionless concentration of each component described in described previous steel is set For described first with reference to concentration；

The densitometer of the described component of described follow-up steel is counted as lower limit dimensionless concentration and upper limit dimensionless concentration；And

The highest lower limit dimensionless concentration in the described lower limit dimensionless concentration of each component described in described follow-up steel is set For described second with reference to concentration.

Method the most according to claim 6, is wherein counted as described by the densitometer of each component described in described previous steel Lower limit dimensionless concentration and described upper limit dimensionless concentration include when the described lower limit dimensionless concentration of described previous steel is more than institute When stating the described upper limit dimensionless concentration of previous steel, substitute described previous steel with the upper limit dimensionless concentration value of described previous steel Lower limit dimensionless concentration value, and with the described lower limit dimensionless concentration value of described previous steel substitute described previous steel described on Limit dimensionless concentration value；And

The densitometer of each component described in described follow-up steel is counted as described lower limit dimensionless concentration and described upper limit dimensionless Concentration includes when the described lower limit dimensionless concentration of described follow-up steel is more than the described upper limit dimensionless concentration of described follow-up steel, The lower limit dimensionless concentration value of described follow-up steel is substituted with the upper limit dimensionless concentration value of described follow-up steel, and with described follow-up The described lower limit dimensionless concentration of steel substitutes the described upper limit dimensionless concentration of described follow-up steel.

8. according to the method described in claim 2 or 4, wherein relative with the dimensionless at described center when acquired described surface When at least one dimensionless relative concentration in concentration deviates described reference concentration, described stream is determined to be in admixture, And

Described stream following position in the longitudinal direction is confirmed as described mixing portion: in described position, acquired Described surface and described center dimensionless relative concentration at least one dimensionless relative concentration deviation described with reference to dense Degree.

Method the most according to claim 8, wherein said stream following position in the longitudinal direction is confirmed as institute Stating the starting point of mixing portion: in described position, the dimensionless relative concentration at acquired described center reaches described reference Concentration, and

Described stream following position in the longitudinal direction is confirmed as the end point of described mixing portion: in described position In, the dimensionless relative concentration on acquired described surface reaches described with reference to concentration.

10., according to the method described in claim 2 or 4, also include:

Receive online in the concentration of each, casting speed and the described tundish in described previous steel and described follow-up steel The data of surplus of molten steel and store described data；And

Before the described follow-up steel of acquisition is relative to the described dimensionless relative concentration of described previous steel, detect follow-up ladle open Signal.

11. methods according to claim 10, also include:

Obtain in real time from the time detecting described follow-up ladle opening signal described stream described surface and described in the minds of The dimensionless relative concentration of each, and from the time detecting described follow-up ladle opening signal, metering dimensionless concentration is adopted The collection time is to compare in real time with reference time；

When described dimensionless concentration acquisition time be described reference time or less than described reference time time, described in acquired The dimensionless relative concentration at center compares with reference to concentration with described first, and the dimensionless by acquired described surface Relative concentration compares with reference to concentration with second；And

When described concentration acquisition time is more than described reference time, terminate to the described surface of described stream and described in the minds of The collection of the described dimensionless relative concentration of each.

12. methods according to claim 11, also include:

Determine whether the type between described previous steel and described follow-up steel is to preset type included in dissimilar steel excision table；

Described type between described previous steel and the described follow-up steel of experience current operation is the excision of described default dissimilar steel During included in table type, described stream is cut into the resection length of the dissimilar steel type of correspondence；And

Described type between described previous steel and the described follow-up steel experiencing described current operation is not included in described presetting Time in dissimilar steel excision table, terminate to the described surface of described stream with described in the minds of the described dimensionless of each relative After the collection of concentration, described stream is cut into resection length set in advance.

13. methods according to claim 10, wherein said detection follow-up ladle opening signal includes:

Send virtual ladle opening signal；

Within with the millisecond (ms) time as unit, described centre is detected in real time described virtual ladle opening signal from sending The weight of bag；

With with the second (s) predetermined time interval as unit, by detect within the millisecond (ms) time as unit described in Between the described weight of bag be calculated as the average weight of described tundish；And

The time utilizing the described average weight of described tundish to increase continuously sets the time opening described follow-up ladle.

14. methods according to claim 13, wherein work as W_tdT () is the residue steel amount in tundish described in current time Weight and W_td(when t-Δ t) is the weight remaining steel amount in tundish described in relatively time morning,

Work as W_td(t)–W_td(t-Δ t) and W_td(t)–W_td(when t-2* Δ t) is all higher than or is equal to " 0 ", t-2* Δ t is confirmed as beating Open the time of described follow-up ladle,

Obtain from t-2* Δ t described stream described surface and described in the minds of the described dimensionless relative concentration of each, And

The described residue steel amount in described tundish and described casting speed is stored from t-4* Δ t.

15. according to the method described in claim 2 or 4, wherein obtains the described surface of described stream and the described of described center Follow-up steel includes relative to the described dimensionless relative concentration of described previous steel:

Calculate the inlet volumetric flow (Q of described follow-up steel in described tundish_td-in)；

Use the described inlet volumetric flow (Q of described follow-up steel in described tundish_td-in) calculate in the middle of described in current time The average dimensionless relative concentration (C of the described molten steel in bag_td-ave(t+Δt))；

The described average dimensionless relative concentration (C of the described molten steel in tundish described in use current time_td-ave(t+Δt)) Calculate the dimensionless relative concentration (C of the molten steel that current time is discharged from described tundish_td-out(t+Δt))；

The described dimensionless relative concentration (C of the described molten steel that use current time is discharged from described tundish_td-out(t+Δt)) Calculate the average dimensionless relative concentration (C of molten steel described in current time crystallizer_md-ave(t+Δt))；

Use the described average dimensionless relative concentration (C of molten steel described in crystallizer described in current time_md-ave(t+ Δ t)) and Current time is incorporated into the dimensionless relative concentration (C of the molten steel in described crystallizer_md-in(t+ Δ t)) calculates current time from institute State the dimensionless relative concentration (C of the described stream that crystallizer is discharged_md-out(t+Δt))。

16. methods according to claim 15, the inlet volumetric flow of follow-up steel described in wherein said tundish (Q_td-in) calculated by formula 5,

[formula 5]

$Q_{td-in}=\frac{W_{td}(t+\mathrm{\Δ}t)-W_{td}\left(t\right)}{\mathrm{\Δ}t\×{\mathrm{\ρ}}_L}+Q_{td-out}$

Wherein W_tdT () is the gross weight of molten steel, W described in tundish described in relatively time morning_td(t+ Δ t) be described in current time in Between the gross weight of molten steel described in bag, Q_td-outIt is the volume flow of the described molten steel discharged from described tundish, ρ_LIt it is described steel The fluid density of water,

Mean concentration (the C of molten steel described in tundish described in current time_td-ave(t+ Δ t)) is calculated by formula 6,

[formula 6]

$C_{td-ave}(t+\mathrm{\Δ}t)=\frac{W_{td}\left(t\right)\×C_{td-ave}\left(t\right)+Q_{td-in}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{td-in}\left(t\right)}{W_{td}(t+\mathrm{\Δ}t)}-\frac{Q_{td-out}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{td-out}\left(t\right)}{W_{td}(t+\mathrm{\Δ}t)}$

Wherein C_td-aveT () is the average dimensionless relative concentration of molten steel, Q described in tundish described in relatively time morning_td-inT () is Relatively early the time introduces the inlet volumetric flow of the described molten steel in described tundish, C_td-inT () is tundish described in relatively time morning Described in the entrance concentration (dimensionless relative concentration) of follow-up steel, Q_td-outT () is the institute that relatively early the time discharges from described tundish State the volume flow of molten steel, C_td-outT () is concentration (the dimensionless phase of the relatively early described molten steel that the time discharges from described tundish To concentration), ρ_LIt is the fluid density of described molten steel,

Concentration (the C of the described molten steel that current time is discharged from described tundish_td-out(t+ Δ t)) is calculated by formula 7,

[formula 7]

C_td-out(t+ Δ t)=f_td×C_td-ave(t+Δt)+(1-f_td)×C_td-in(t+Δt)

Wherein f_tdIt is interpolation and the extrapolation factor of described tundish, C_td-ave(t+ Δ t) is described in current time described in tundish The average dimensionless relative concentration of molten steel, C_td-in(t+ Δ t) is that current time introduces the immeasurable of the described molten steel of described tundish Guiding principle relative concentration,

Mean concentration (the C of molten steel described in crystallizer described in current time_md-aver(t+ Δ t)) is calculated by formula 8,

[formula 8]

$C_{md-ave}(t+\mathrm{\Δ}t)=\frac{W_{md}\left(t\right)\×C_{md-ave}\left(t\right)+Q_{md-in}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{md-in}\left(t\right)}{W_{md}(t+\mathrm{\Δ}t)}-\frac{Q_{md-out}\left(t\right)\×\mathrm{\Δ}t\×{\mathrm{\ρ}}_L\×C_{md-out}\left(t\right)}{W_{md}(t+\mathrm{\Δ}t)}$

Wherein W_mdT () is the gross weight of molten steel, C described in crystallizer described in relatively time morning_md-averT () is to tie described in relatively time morning The average dimensionless relative concentration of molten steel, Q described in brilliant device_md-inT () is entering of molten steel described in crystallizer described in relatively time morning Mouth volume flow, C_md-inT () is the entrance concentration (dimensionless relative concentration) of molten steel described in crystallizer described in relatively time morning, W_md(t+ Δ t) is the gross weight of molten steel described in crystallizer, Q described in current time_md-outT () is discharged from described crystallizer The volume flow of described molten steel, C_md-outT () is that the dimensionless of the relatively early described stream that the time discharges from described crystallizer is the denseest Degree, ρ_LIt is the fluid density of described molten steel, and

Concentration (the C of the described stream that current time is discharged from described crystallizer_md-out(t+ Δ t)) is calculated by formula 9,

[formula 9]

C_md-out(t+ Δ t)=f_md×C_md-ave(t+Δt)+(1-f_md)×C_md-in(t+Δt)

Wherein f_mdIt is interpolation and the extrapolation factor of described crystallizer, C_md-aver(t+ Δ t) is institute in crystallizer described in current time State the average dimensionless relative concentration of molten steel, C_md-in(t+ Δ t) is the described molten steel that current time introduces in described crystallizer Dimensionless relative concentration.

17. methods according to claim 16, wherein in the described dimensionless relative concentration at the described center to described stream Calculating in,

By described interpolation and the extrapolation factor (f of 4 ± 2 application to formula 7_td), and

By described interpolation and the extrapolation factor (f of 0.7 ± 0.4 application to formula 9_md) to calculate the described nothing at the described center of described stream Dimension concentration (C_{md-out-center})。

18. methods according to claim 16, wherein in the described dimensionless relative concentration on the described surface to described stream Calculating in,

By interpolation and the extrapolation factor (f of 2.2 ± 0.6 application to formula 7_td), and

By interpolation and the extrapolation factor (f of 0.5 ± 0.2 application to formula 9_md) to calculate the described dimensionless on the described surface of described stream Relative concentration (C_{md-out-surface})。

19. methods according to claim 16, wherein use close as in formula 5,6 and 8 of the fluid density of described molten steel Degree (ρ_L) value, and

Use 7000kg/m³To 7400kg/m³Value as the described density of described molten steel.

20. methods according to claim 10, also include:

Set the position of the described dimensionless relative concentration on the described surface starting to obtain described stream of described stream；And

Set the position of the described dimensionless relative concentration at the described center starting to obtain described stream of described stream；

The wherein said stream position when opening described follow-up ladle is set to start to obtain the institute on the described surface of described stream State the position of dimensionless relative concentration, and

It is described that position at described position-4 ± 4m when opening described follow-up ladle of described stream is set to start acquisition The position of the described dimensionless relative concentration at the described center of stream.

21. methods according to claim 20, wherein acquired to described stream having in the longitudinal direction In the calculating of the position of the dimensionless relative concentration on described surface,

Described position is calculated, in formula 10, from the volume flow (Q of the described molten steel that described crystallizer is discharged by formula 10_md-out) It is divided by following value: by the cross-sectional area (A of described stream_md) divided by the density of solid (ρ of described molten steel_s) value of gained,

[formula 10]

$L(t+\mathrm{\Δ}t)=L\left(t\right)+\frac{Q_{md-out}\×{\mathrm{\ρ}}_L}{A_{md}\×{\mathrm{\ρ}}_S}\×\mathrm{\Δ}t$

Wherein Q_md-outIt is the volume flow of the described molten steel discharged from described crystallizer, A_mdIt is the cross-sectional area of described stream, ρ_sIt is The density of solid of described molten steel, wherein uses 7600kg/m³To 8000kg/m³Value.

22. methods according to claim 21, wherein acquired to described stream having in the longitudinal direction In the calculating of the described position of the dimensionless relative concentration at described center,

Position at described position-4 ± 4m of dimensionless relative concentration with acquired described surface is set to tool There is the position of the described dimensionless relative concentration at described center.

23. methods according to claim 22, wherein from the nothing at the described center of the described stream obtained in real time of described stream Dimension relative concentration reaches the some nothing to the described surface of the described stream obtained in real time of described stream of described first reference concentration Dimension relative concentration reaches described second and is predicted to be described mixing portion with reference to the region of the point of concentration.

24. methods according to claim 22, also include:

The dimensionless relative concentration at the described center of the described stream obtained in real time of described stream is reached described first with reference to concentration Position be set as the first excision position；

The described dimensionless relative concentration on the described surface of the described stream obtained in real time of described stream is reached described second reference The position of concentration is set as the second excision position；And

By described stream being carried out cutting excise described in described first excision position and described second excision position respectively Mixing portion.

25. according to the method described in claim 1 or 3, the prediction of the described mixing portion of wherein said stream and mixing of being predicted The excision of conjunction part performs in the way of online treatment.