CN1431060A - Method for predicting evolvement and performances of structure of strip steels in hot rolled proces - Google Patents

Abstract

A method for predicting the structure variation and properties of band steel in hot rolling procedure features that its system is composed of the preprocessing module for reading the technological parameters needed by hot rolling from database, the heating module, rolling module, cooling phase-change module and mechanical performance module for simulating the hot rolling procedure and predicting the final structure performance, and the post-precessing module for displaying the final result.

Description

A kind of course of hot rolling band structure of steel develops the method with performance prediction

Technical field

The present invention relates to the belt steel rolling technology, specifically a kind of course of hot rolling band structure of steel develops the method with performance prediction.

Background technology

In the prior art, need after tested (tensile strength, yield strength and percentage elongation) just can put on market behind the belt steel rolling, production cycle is longer, it is bigger to take the space, delivery room, and for the belt steel product that has a large capacity and a wide range, it is rolled with the speed of a rolling volume of a few minutes, so the test volume after producing is very big, not only waste of manpower, but also waste material resources, and, more or less can influence measuring accuracy again in test because of human factor is arranged.If can reach inspection-free degree by the performance of computer simulation means prediction product, this is challenging beyond doubt.In order to reach this purpose, just should understand change procedure, and the observation and the test that in big the production tissue are changed are impossible in each parameter of rolling cooling procedure.Along with development of computer, can dynamically simulate course of hot rolling band structure of steel and changes of properties process by simulation means, thereby can predict the final performance of product, but the present domestic report that yet there are no of this technology.

Summary of the invention

The purpose of this invention is to provide a kind of method that can predict the differentiation of course of hot rolling band structure of steel with the performance prediction of the final performance of product.

For achieving the above object, technical scheme of the present invention is: be made up of pre-processing module, heating module, rolling module, cooling phase-change module, mechanical property module and six modules of post processing, the function of pre-processing module is to read the required technological parameter of course of hot rolling from database, for follow-up flow process provides primary condition; Described heating module, rolling module, cooling phase-change module and mechanical property module are to finish each metallurgical physical quantity of course of hot rolling is simulated dynamically, dope the final structure property of band steel; The function of described post-processing module is to finish the demonstration output of course of hot rolling analog result; Specific as follows:

Described pre-processing module idiographic flow is: at first read processing parameter from database, comprise: the parameter that steel grade and chemical composition, steel billet specification and product specification, production technology are set (comprising roller radius, roughing road number of times, the type of cooling and heating furnace tapping temperature, roughing outlet temperature, finishing temperature, the temperature of curling), before affirmation, import segments, confirm that the back shows the input parameter summarized results, whether reexamine input parameter correct, errors excepted then can return and read processing parameter again, as import and errorlessly then change heating module over to by section;

The function of described heating module is to utilize empirical equation to calculate the size of grain growth after the complete austenitizing, and idiographic flow is: earlier from the selected parameter of pre-processing module, determine final furnace temp in conjunction with on-the-spot heating curves; Utilize concrete empirical equation then $D^n=k_1\exp \left(\frac{-Q_{\mathrm{app}}}{\mathrm{RT}}\right)t+{D_0}^n$ Initial grain size in conjunction with the steel billet of determining by test calculates austenite grain size, with its primary condition as rolling module;

Described rolling module comprises roughing and two steps of finish rolling, crystallization again takes place in the operation of rolling, make grain refinement, current pass result of calculation is as the primary condition (roughing first passage is got the initial crystallite dimension of austenite grain size conduct that heating module calculates) of a time calculating down, the roughing road number of times of setting according to the scene is rolled, the result of calculation of last passage of roughing is as the primary condition of finish rolling first passage, and the finish rolling process is identical with the roughing process, and every time idiographic flow is as follows:

At first calculate temperature, strain stress and the overstrain of this passage, the crystallite dimension that passage is calculated in the utilization calculates critical strain ε _c, and compare with strain stress that current pass calculates, if ε＞ε _cDynamic recrystallization then takes place, if ε＜=ε _cStatic state crystallization more then takes place; When dynamic recrystallization takes place, utilize Dynamic Recrystallization Model $x_v=1-\exp (-0.693{\left(\frac{t}{t_{0.5}}\right)}^{1.5})$ Provide crystalline fraction X again _v, and judge whether X _v＞0.95, if＞0.95, complete dynamic recrystallization then takes place, also will judge that passage time t is greater than 1 second or smaller or equal to 1 second, selects the computing formula of crystallite dimension in view of the above this moment; When Xv＜=0.95, complete dynamic recrystallization does not then take place, again according to the model that perfect recrystallization does not take place ${d_0}_{i+1}={d_{\mathrm{rex}}}_i{x}^{4/3}+{d_0}_i{(1-x_i)}^2$ Directly calculate austenite grain size; When static state taking place again during crystallization, utilizing static state crystal model again $x_v=1-\exp (-0.693\left(\frac{t}{t_{0.5}}\right))$ Calculate crystalline fraction Xv again, and whether judge Xv＞0.95, if＞0.95, the crystallization again of complete static state then takes place, also will judge that passage time t is greater than 1 second or smaller or equal to 1 second, selects the computing formula of crystallite dimension in view of the above this moment; If the crystallization again of complete static state does not then take place in Xv＜=0.95, then according to the model that perfect recrystallization does not take place ${d_0}_{i+1}={d_{\mathrm{rex}}}_i{x}^{4/3}+{d_0}_i{(1-x_i)}^2$ Directly calculate austenite grain size;

Autstenitic grain size that described cooling phase-change module provides with rolling module and overstrain are as primary condition, calculate ferrite mark, pearlite mark and bainite mark respectively, its idiographic flow is as follows: at first calculate balance each other temperature Ae3 and starting temperature of transformation, calculate Avrami equation X=1-exp (kt again ⁿ) in parameter k, next calculate phase transformation mark and austenite concentration of carbon under each temperature, utilize the Scheil rule to calculate maximal phase variation number at last, judge end mark again: austenite concentration of carbon Cau is greater than Fe-C phasor concentration C _Acm, the result returns the calculating of phase transformation mark and austenite concentration of carbon when being negative; The result is that phase transformation finishes when affirming, utilizes revised empirical model to calculate ferrite mark, pearlite mark and bainite mark and ferrite grain size again;

The ferrite mark that described mechanical property module provides with the cooling phase-change module, pearlite mark, bainite mark and ferrite grain size are as primary condition, (empirical model in data or the document can not calculate the mechanical property of band steel exactly to utilize revised empirical model, must revise according to the actual conditions of production line) calculate yield strength, tensile strength and the percentage elongation of final band steel, again data are delivered to post-processing module;

The function of described post processing is to show output result of calculation, multiple modes such as employing form, curve, animation are exported the result of heating, roughing, finish rolling, cooling, five parts of mechanical property, also comprise an intelligence report (comprising plain text report and Excel report).

The present invention has following advantage:

1. can predict the final performance of product.The present invention has the function of segmentation multiple spot prediction, by simulation means, energy is simulation course of hot rolling band structure of steel and changes of properties process dynamically, thereby the final performance of prediction product, with can only test the steel billet head in the prior art, the afterbody tissue is compared with performance, the present invention can test the structure property of each position of steel billet, and result of calculation more accurately, reliably; Intelligence report provided by the present invention helps the staff to improve the process conditions of production to result's analysis, enhances product performance; In addition, the data of the present invention output are a large amount of, full and accurate, the data of having living space, road secondary data, time data, and output form is various form, curve, animation, is analysis process system or to carry out theoretical research all helpful concerning the user.

2. easy to operate, save time, laborsaving.Adopting the inventive method to make the field personnel is exploitation new steel grade or the work of carrying out alloy designs all becomes easier; Have a large amount of processing parameters in the database provided by the invention, easy to use, simple to operation; Further, friendly interface of the present invention, input, output all are consistent easy operating with production process.

3. be convenient to safeguard, develop.Interface portion of the present invention adopts Visual Basic to write, and core calculations partly adopts Visual C++ to write, and has realized separating of calculating and result's output, is convenient to debugging, upgrading, maintenance and the transplanting of program.

Description of drawings

Fig. 1 is an entire block diagram of the present invention.

Fig. 2 is a pre-processing module flow chart among Fig. 1.

Fig. 3 is a heating module flow chart among Fig. 1.

Fig. 4 is a rolling module flow chart among Fig. 1.

Fig. 5 is a cooling phase-change module flow chart among Fig. 1.

Fig. 6 is mechanical property module post processing result among Fig. 1.

The specific embodiment

Below in conjunction with accompanying drawing the present invention is described in further detail.

Embodiment 1

As shown in Figure 1, the present invention is research object with the straight carbon steel, set up the Physical Metallurgy model of system, its technical scheme is: be made up of pre-processing module, heating module, rolling module, cooling phase-change module, mechanical property module and six modules of post processing, the function of pre-processing module is to read the required technological parameter of course of hot rolling from database, for follow-up flow process provides primary condition; Described heating module, rolling module, cooling phase-change module and mechanical property module are to finish each metallurgical physical quantity of course of hot rolling is simulated dynamically, dope the final structure property of band steel; The function of described post-processing module is to finish the demonstration output of course of hot rolling analog result; Specific as follows:

As shown in Figure 2, described pre-processing module idiographic flow is: at first read processing parameter from database, as: steel grade is Q235B, chemical composition (C=0.143, Mn=0.44, Si=0.171, P=0.015, S=0.017), the steel billet specification is that 230mm * 9000mm and product specification are 9.75mm, the parameter that production technology is set (comprises shaping roll radius 1163.5mm, planishing roll radius 793.5mm, roughing road number of times is 7, the type of cooling is 1230 ℃ of front end cooling and heating furnace tapping temperatures, 1120 ℃ of roughing outlet temperatures, 850 ℃ of finishing temperatures, 600 ℃ of the temperature of curling), input segments 15 before affirmation, confirm that the back shows the input parameter summarized results, whether reexamine input parameter correct, errors excepted then can return and read processing parameter, as import and errorlessly then change heating module over to by section;

As shown in Figure 3, the function of described heating module is to utilize empirical equation to calculate the size of grain growth after the complete austenitizing, idiographic flow is: earlier from the selected parameter of pre-processing module, determine that in conjunction with on-the-spot heating curves final furnace temp is 1230 ℃; Utilize the initial grain size of concrete empirical equation then, calculate austenite grain size, its primary condition as rolling module in conjunction with the steel billet of determining by test;

The Physical Metallurgy process of described heating module is: the Q235B slab will be heated to more than 1200 ℃ usually before rolling and be incubated more than 3 hours, when being heated to eutectoid temperature (about 727 ℃), material generation austenite changes, this process is known as austenitization, and this process has material impact to the formulation of heating cycle.Generally with this process separated into two parts, the one, pearlitic dissolving, the one, ferritic phase transformation, the first step takes place when being higher than eutectoid temperature, cementite dissolving in the ferrite, because the cemetite lamellae interfloor distance is shorter, this process is carried out comparatively fast; Second process can take place in 727～856 ℃ of temperature ranges, and is subjected to the restriction of eutectoid reaction line, and this process generation carbon spreads to pro-eutectoid ferrite from the austenite of rich carbon, is the phase transition process of diffused.After austenitization finished, material was in about high-temperature region more than 900 ℃, austenite generation grain growth.Under the isothermal condition, the empirical equation of describing grain growth is $D^n=k_1\exp \left(\frac{-Q_{\mathrm{app}}}{\mathrm{RT}}\right)t+{D_0}^n$

D wherein ₀The initial crystallite dimension of being determined by experiment when not heating during for time t=0, n is the grain growth index, k ₁Be constant, Q _AppBe the activation energy of grain growth, originally execute example, determine the grain growth process Q of straight carbon steel by Gleeble 1500 thermal simulation experiments _App=190kJ/mol, k ₁=4.3 * 10 ⁹, n=2.6, D ₀=50um, t=7200s, then D=303um.

As shown in Figure 4, described rolling module comprises roughing and two steps of finish rolling, crystallization again takes place in the operation of rolling, make grain refinement, current pass result of calculation is as the primary condition (roughing first passage is got the initial crystallite dimension of austenite grain size conduct that heating module calculates) of a time calculating down, the roughing road number of times of setting according to the scene is rolled, the result of calculation of last passage of roughing is as the primary condition of finish rolling first passage, the finish rolling process is identical with the roughing process, and every time idiographic flow is as follows:

At first calculate temperature (comprising the temperature difference that air cooling causes, the temperature difference that water-cooled causes, the temperature difference that frictional heat causes, the temperature difference that distortion heat causes, the temperature difference that contact heat causes) strain stress and the overstrain of this passage, the crystallite dimension of passage calculating calculates critical strain in utilizations ${\mathrm{\ϵ}}_c=5.6\×{10}^{-4}\·D_0^{0.3}\·Z^{0.17}$ , wherein $Z=\stackrel{\·}{\mathrm{\ϵ}}\·\exp (300000./8.31T)$ , and compare with strain stress that current pass calculates, if ε＞ε _cDynamic recrystallization then takes place, if ε＜=ε _cStatic state crystallization more then takes place; When dynamic recrystallization takes place, utilize Dynamic Recrystallization Model $x_v=1-\exp (-0.693{\left(\frac{t}{t_{0.5}}\right)}^{1.5})$ Provide crystalline fraction X again _v, and judge whether X _v＞0.95, if＞0.95, complete dynamic recrystallization then takes place, also will judge that passage time t is greater than 1 second or smaller or equal to 1 second, selects the computing formula of crystallite dimension in view of the above this moment; When Xv＜=0.95, complete dynamic recrystallization does not then take place, again according to the model that perfect recrystallization does not take place ${d_0}_{i+1}={d_{\mathrm{rex}}}_i{x}^{4/3}+{d_0}_i{(1-x_i)}^2$ Directly calculate austenite grain size;

Crystal grain again when complete dynamic recrystallization and passage time t＞1 second take place is of a size of: $d^7={d_{\mathrm{MRX}}}^7+8.2\×{10}^{25}(t_{\mathrm{ip}}-2.65t_{0.5})\exp \left(\frac{-400000}{8.31T}\right)$ , the crystal grain again when passage time t＜=1 second is of a size of $d^2={d_{\mathrm{MRX}}}^2+1.2\×{10}^7(t_{\mathrm{ip}}-2.65t_{0.5})\exp \left(\frac{-113000}{8.31T}\right)$ , d wherein _MRX=2.6 * 10 ⁴Z ^-0.23For dynamic recrystallization finish after crystallite dimension (μ m);

When static state taking place again during crystallization, utilizing static state crystal model again $x_v=1-\exp (-0.693\left(\frac{t}{t_{0.5}}\right))$ Calculate crystalline fraction Xv again, and whether judge Xv＞0.95, if＞0.95, the crystallization again of complete static state then takes place, also will judge that passage time t is greater than 1 second or smaller or equal to 1 second, selects the computing formula of crystallite dimension in view of the above this moment; If the crystallization again of complete static state does not then take place in Xv＜=0.95, then according to the model that perfect recrystallization does not take place ${d_0}_{i+1}={d_{\mathrm{rex}}}_i{x}^{4/3}+{d_0}_i{(1-x_i)}^2$ Directly calculate austenite grain size; When take place complete static state again the crystal grain again when crystallization and passage time t＞1 second be of a size of: $d^7={d_{\mathrm{SRX}}}^7+1.5\×{10}^{27}(t_{\mathrm{ip}}-4.32t_{0.5})\exp \left(\frac{-400000}{8.31T}\right)$ , the crystal grain again when passage time t＜=1 second is of a size of $d^2={d_{\mathrm{SRX}}}^2+4.0\×{10}^7(t_{\mathrm{ip}}-4.32t_{0.5})\exp \left(\frac{-113000}{8.31T}\right)$ , wherein $d_{\mathrm{SRX}}=343{\mathrm{\ϵ}}^{-0.5}{d_0}^{0.4}\exp \left(\frac{-45000}{8.31T}\right)$ Be static state crystallite dimension (μ m) after crystallization is finished again;

The analog result of present embodiment roughing the 7th passage crystallite dimension is: 75.17um, and the analog result of crystalline fraction is again: 100%, the analog result of finish rolling the 7th passage crystallite dimension is: 13.85um, the analog result of crystalline fraction is again: 19.47%;

As shown in Figure 5, autstenitic grain size that described cooling phase-change module provides with rolling module and overstrain are as primary condition, calculate ferrite mark, pearlite mark and bainite mark respectively, its idiographic flow is as follows: at first calculate balance each other temperature Ae3 and starting temperature of transformation, calculate Avrami equation X=1-exp (kt again ⁿ) in parameter k, next calculate phase transformation mark and austenite concentration of carbon under each temperature, utilize the Scheil rule to calculate maximal phase variation number at last, judge end mark again: austenite concentration of carbon Cau is greater than Fe-C phasor concentration C Acm, and the result returns the calculating of phase transformation mark and austenite concentration of carbon when being negative; The result is that phase transformation finishes when affirming, obtains ferrite mark, pearlite mark and bainite mark, utilizes revised empirical model to calculate ferrite grain size again;

Its formula X=1-exp (kt ⁿ) in, X is the phase transformation mark, t is the time, and k and n are phase transition parameter, and steel grade is in the straight carbon steel cooling procedure of Q235B, austenite resolves into ferrite and pearlite, austenitic phase transition process adopts the position saturated model, and the n value is a constant, and the k value then is the function of temperature, in order correctly to describe the relation of temperature and k, need the form of careful selection k=f (T).Present embodiment adopts the Gauss function representation of revising: $k=P\left(1\right)\·\exp {[-\frac{T-P\left(2\right)}{P\left(3\right)}]}^{P\left(4\right)}$

Wherein, P (1), P (2), P (3), P (4) are phase transition parameter, and be relevant with austenitic crystallite dimension and chemical composition, sees table 1 for details:

The relation of table 1 phase transition parameter and chemical composition (wt%) and austenite grain size (μ m)

Starting temperature of transformation: the beginning temperature that each changes mutually can be determined by calculation of thermodynamics or test, when temperature drops to equilibrium temperature Ae3, ferrite transformation begins, Ae3 is calculated under equilibrium condition by thermodynamic parameter, it is the phase transition process of being controlled by the bulk diffusion of carbon that austenite is transformed into ferrite, along with the carrying out of ferritic transformation, the concentration of carbon constantly increases in the austenite, and concentration of carbon can be calculated by following formula in the austenite: $C_{\mathrm{\γ}}=\frac{C_0-X_{\mathrm{\α}}\·C_{\mathrm{\α}}}{1-X_{\mathrm{\α}}}$ , X wherein _αBe the ferritic mark that changes, C ₀Be initial carbon concentration.For the Q235B steel, Ae3, Ae1 adopt following formula to calculate: Ae3=904.8-374.2C+195.4C ²Ae1=727.The ferrite mark is subjected to the restriction of equilibrium condition: transformation mark maximum under the uniform temperature is obtained according to lever law.Balance ferrite mark: $X_{\mathrm{\α}}^e=\frac{0.8-C\%}{0.8-0.02}$ , balance pearlite mark: $X_P^e=\frac{C\%-0.02}{0.8-0.02}$ 。Definite method of the beginning temperature of pearlitic transformation is: on equilbrium phase diagram, when concentration of carbon in the austenite reaches extrapolation Acm line, think that perlitic transformation begins.The influence that overstrain changes austenite: define effective autstenitic grain size $d_{\mathrm{\γ}}^{\mathrm{eff}}=\frac{d_{\mathrm{\γ}}}{1+0.5\mathrm{\ϵ}}$ , in the formula, ε is an overstrain, ε=ε ' (1-x), ε ' is the strain in the recrystallization process, x is the austenite recrystallization umber.So, when considering the influencing of residual stress, with the d in the table 1 _γWith

Replace.

Ferritic crystallite dimension d _{α 0}=(β ₀+ β ₁Ceq)+(β ₂+ β ₃Ceq) q ^-0.5+ β ₄(1-exp (β ₅d _y) wherein, d _γ: austenitic crystallite dimension (μ m), q: cooldown rate (℃/s), Ceq:C+Mn/6..Each coefficient value of following formula is as shown in table 2 below:

Each parameter in the table 2 ferrite grain size computation model

Ceq＜0.35 Ceq＞0.35

β ₀＝-0.4 β ₀＝22.6

β ₁＝6.37 β ₁＝-57.0

β ₂＝24.2 β ₂＝3

β ₃＝-59 β ₃＝0

β ₄＝22.0 β ₄＝22.0

β ₅＝-0.015 β ₅＝-0.015

If consider the influence of overstrain, then ferritic crystallite dimension is: $d_{\mathrm{\α}}=d_{\mathrm{\α}0}(1-0.45\sqrt{{\mathrm{\ϵ}}_{\mathrm{\γ}}})$

The ferrite mark that described mechanical property module provides with the cooling phase-change module, pearlite mark, bainite mark and ferrite grain size are as primary condition, (empirical model in data or the document can not calculate the mechanical property of band steel exactly to utilize revised empirical model, must revise according to the actual conditions of production line) calculate yield strength, tensile strength and the percentage elongation of final band steel, again data are delivered to post-processing module;

Yield strength, tensile strength and percentage elongation are three basic indexs weighing the straight carbon steel mechanical property: the calculation of Tensile Strength model is: $T_b=200.0+60.0\·V_f+118.0\·(V_P+V_b)+19.9\·\mathrm{pow}(d_f/1000.0-0.5)=449\mathrm{Mpa}$ The yield strength computation model is: $\mathrm{TS}=97.0+64.9\·V_f+15.1\·(V_P+V_b)+17.25\·\mathrm{pow}(d_f/1000.0-0.5)=306\mathrm{Mpa}$ Percentage elongation calculates model: $\mathrm{\δ}=11.0+3.0\·V_f+1.53\·(V_P+V_b)-0.03\·V_b+1.8\·\mathrm{pow}(d_f/1000.0-0.5)=29.7\%;$ Wherein, V _f=80.3%w is the ferrite mark, V _P=13.0% is the pearlite mark, V _b=6.7% is the bainite mark, d _f=12.5um is a ferrite grain size.

The function of described post processing is to show output result of calculation, multiple modes such as employing form, curve, animation are exported the result of heating, roughing, finish rolling, cooling, five parts of mechanical property, also comprise an intelligence report (comprising plain text report and Excel report), the particular content of each module output is as follows:

1) heating module output comprises that the simulation animation of grain size-temperature-time curve and grain growth shows;

2) rolling module (roughing module and finish rolling module) output content is: a) list data, the temperature difference that comprises the temperature, crystallite dimension of each passage of each section, causes at crystalline fraction, strain, strain rate, critical strain, overstrain and air cooling, the temperature difference that water-cooled causes, the temperature difference that frictional heat causes, the temperature difference that contact heat causes, the temperature difference that distortion heat causes and time of crystallization 50% again, reach the production technology data, comprise the roll-force and the rolling time of each passage; B) road secondary data comprises the temperature, crystallite dimension of each position section, the curve that changes with passage of crystalline fraction again; C) time data, the crystallite dimension of each position section, the time dependent curve of crystalline fraction again; D) spatial data is at the temperature of each passage diverse location section, crystallite dimension, the change curve of crystalline fraction again;

3) cooling phase-change module output content is: a) cooling curve; B) the temperature variant curve of phase transformation mark and the animation of each section; C) batch ferrite grain size curve afterwards;

4) mechanical property module output content has two aspects: a) curve of tensile strength, yield strength, percentage elongation; B) reasonableness check of performance indications, the present invention adopts the form of target practice to reflect that very intuitively the performance of rolling back steel plate drops within that scope, referring to Fig. 6;

5) output content of intelligence report has two aspects, a) input parameter, the i.e. processing parameter of importing at pre-processing module; B) performance evaluation, the 15th section is the result of " afterbody ", comprise: yield strength, tensile strength, percentage elongation, thick/crystallite dimension of each passage of finish rolling, crystalline fraction, and ferrite grain size again, ferrite mark, pearlite mark, bainite mark; After this whether qualified and reason that causes the process system of this performance of Zhi Neng the index that analyzes performance, and system time and signature.The intelligence report is on all four by textual form and two kinds of form outputs of Excel form in terms of content.

Present embodiment input, output result all with prior art in input, the output (manual measurement) of Anshan iron and steel plant 1780 hot rolling lines the result is consistent, proved that the present invention can predict the final performance of product, save time, laborsaving, accurate, efficient.

Claims (3)

1. a course of hot rolling band structure of steel develops the method with performance prediction, it is characterized in that: form by pre-processing module, heating module, rolling module, cooling phase-change module, mechanical property module and six modules of post processing, the function of pre-processing module is to read the required technological parameter of course of hot rolling from database, for follow-up flow process provides primary condition; Described heating module, rolling module, cooling phase-change module and mechanical property module are to finish each metallurgical physical quantity of course of hot rolling is simulated dynamically, dope the final structure property of band steel; The function of described post-processing module is to finish the demonstration output of course of hot rolling analog result;

Described pre-processing module idiographic flow is: at first read processing parameter from database, comprise: the parameter that steel grade and chemical composition, steel billet specification and product specification, production technology are set, before affirmation, import segments, confirm that the back shows the input parameter summarized results, whether reexamine input parameter correct, errors excepted then can return and read processing parameter again, as import and errorlessly then change heating module over to by section;

The function of described heating module is to utilize empirical equation to calculate the size of grain growth after the complete austenitizing, and idiographic flow is: earlier from the selected parameter of pre-processing module, determine final furnace temp in conjunction with on-the-spot heating curves; Utilize the initial grain size of concrete empirical equation then, calculate austenite grain size, with its primary condition as rolling module in conjunction with steel billet;

Described rolling module comprises roughing and two steps of finish rolling, crystallization again takes place in the operation of rolling, make grain refinement, the conduct of current pass result of calculation is the primary condition of a time calculating down, wherein: roughing first passage is got the initial crystallite dimension of austenite grain size conduct that heating module calculates, the roughing road number of times of setting according to the scene is rolled, the result of calculation of last passage of roughing is as the primary condition of finish rolling first passage, the finish rolling process is identical with the roughing process, and every time idiographic flow is as follows:

At first calculate temperature, strain stress and the overstrain of this passage, the crystallite dimension that passage is calculated in the utilization calculates critical strain ε _c, and compare with strain stress that current pass calculates, if ε＞ε _cDynamic recrystallization then takes place, if ε＜=ε _cStatic state crystallization more then takes place;

Autstenitic grain size that described cooling phase-change module provides with rolling module and overstrain are as primary condition, calculate ferrite mark, pearlite mark and bainite mark respectively, its idiographic flow is as follows: at first calculate balance each other temperature Ae3 and starting temperature of transformation, calculate the parameter k in the Avrami equation again, next calculate phase transformation mark and austenite concentration of carbon under each temperature, utilize the Scheil rule to calculate maximal phase variation number at last, judge end mark again: austenite concentration of carbon Cau is greater than Fe-C phasor concentration C _Acm, the result returns the calculating of phase transformation mark and austenite concentration of carbon when being negative; The result is that phase transformation finishes when affirming, utilizes revised empirical model to calculate ferrite mark, pearlite mark and bainite mark and ferrite grain size again;

The ferrite mark that described mechanical property module provides with the cooling phase-change module, pearlite mark, bainite mark and ferrite grain size are as primary condition, utilize revised empirical model to calculate yield strength, tensile strength and the percentage elongation of final band steel, again data are delivered to post-processing module;

The function of described post processing is to show output result of calculation, and multiple modes such as employing form, curve, animation are exported the result of heating, roughing, finish rolling, cooling, five parts of mechanical property.

2. according to the method for the described course of hot rolling band of claim 1 structure of steel differentiation, it is characterized in that: when dynamic recrystallization takes place, utilize Dynamic Recrystallization Model to provide crystalline fraction X again with performance prediction _v, and judge whether X _v＞0.95, if＞0.95, complete dynamic recrystallization then takes place, also will judge that passage time t is greater than 1 second or smaller or equal to 1 second, selects the computing formula of crystallite dimension in view of the above this moment; When Xv＜=0.95, complete dynamic recrystallization does not then take place, directly calculate austenite grain size according to the model that perfect recrystallization does not take place again.

3. according to the method for the described course of hot rolling band of claim 1 structure of steel differentiation with performance prediction, it is characterized in that: when static state taking place again during crystallization, utilize static state again crystal model calculate crystalline fraction Xv again, and whether judge Xv＞0.95, if＞0.95, the crystallization again of complete static state then takes place, and also will judge that passage time t is greater than 1 second or smaller or equal to 1 second, selects the computing formula of crystallite dimension in view of the above this moment; If the crystallization again of complete static state does not then take place in Xv＜=0.95, directly calculate austenite grain size according to the model that perfect recrystallization does not take place then.

Images