Incoming material plate shape quality setting method with continuous annealing stable plate passing as target

Abstract

The invention belongs to the technical field of metallurgical steel rolling, and particularly relates to an incoming material plate shape quality setting method taking continuous annealing stable plate passing as a target, which comprises the following steps of: collecting key equipment characteristic parameters and process parameters of a continuous annealing unit; relevant parameters are defined, and a target function equation of the continuous annealing unit incoming material plate shape is defined; calculating transverse pressure stress locally borne by the strip steel by calculating Poisson stress and thermal stress which influence the width direction of the strip steel; calculating a critical buckling index of the ith section of the strip according to the transverse pressure stress of the strip and the critical instability force of the strip steel; calculating a deviation factor according to the tension difference in the width direction of the strip steel, and setting an initial solution of an optimization parameter and an incoming material plate shape target curve equation; establishing a comprehensive optimization objective function for controlling the continuous annealing incoming material plate shape; a continuous annealing incoming material plate shape comprehensive objective function is judged; and outputting an optimal solution.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical steel rolling technology, and specifically relates to a method for setting the shape and quality of incoming material with the goal of stabilizing the continuous annealing of the plate. Background Technology

[0002] Strip shape, as one of the quality indicators of cold-rolled strip steel, has received increasing attention. Strip shape essentially refers to the transverse distribution of residual stress within the strip. If tensile stress redistributes laterally, localized plastic deformation occurs in the strip. This change in strip shape will not only affect the current unit but also the strip shape at the unit's exit and even the finished strip shape. Furthermore, the strip shape within and at the unit's exit differs. The strip shape within a unit is the result of the superposition of the incoming strip shape from the pickling and rolling mill and the strip shape caused by unevenness in the continuous annealing furnace. The strip shape at the unit's exit is the result of the superposition of both the incoming strip shape from the pickling and rolling mill and the strip shape caused by localized plastic deformation in the continuous annealing furnace. The exit strip shape of the continuous annealing unit is the same as the inlet strip shape of the leveling unit, and its quality directly affects the quality of the finished strip shape.

[0003] Previous research on continuous annealing processes has mainly focused on product performance and strip stability, while also using the cold-rolled exit strip shape as the entry strip shape for continuous annealing flattening, neglecting the impact of the continuous annealing process on the strip shape. This has led to quality problems with the finished strip shape. Therefore, this study develops a method for setting the incoming strip shape quality of continuous annealing with the goal of stabilizing the strip flow of the continuous annealing unit. This method enables control over the incoming strip shape of the continuous annealing unit, thereby better ensuring the strip shape quality of the finished strip. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the technical problem solved by this invention is to provide a method for setting the incoming strip shape quality with the goal of stabilizing the continuous annealing process. Specifically, during the continuous annealing of strip steel, a high-order polynomial function is set as the incoming strip shape at the annealing inlet. Based on the fact that strip steel is prone to deviation and warping due to stress during continuous annealing, a calculation model for the strip deviation factor and warping index during continuous annealing is established. Combining the influence of the incoming strip shape, and with the goal of stabilizing the continuous annealing unit, a comprehensive optimization objective function for the incoming strip shape during the continuous annealing process is established, thus completing the setting of the incoming strip shape quality for continuous annealing.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A method for setting the shape and quality of incoming sheet metal with the goal of stabilizing continuous annealing of the sheet metal includes the following steps:

[0007] (a) Collect key equipment characteristic parameters of the continuous annealing unit, mainly including: furnace roll radius R, mm, and length of the straight section of the furnace roll. mm, furnace roll taper rad, critical taper of furnace roll rad, unit speed V, m / s, friction coefficient between strip and furnace roller ;

[0008] (b) Collect the rolling process parameters, mainly including: the inlet thickness of the strip mm, strip width B, mm, strip Poisson's ratio v, strip critical buckling index , strip critical deviation factor ;

[0009] (c) Define the relevant parameters, mainly including: process segmentation in the width direction of the strip, the total number of segments is 2n+1, i is a certain segment number, i takes the value of 1, 2, 3…2n+1; the strip deviation factor of the ith segment , the strip buckling index of the ith segment , the incoming plate shape comprehensive optimization objective function G(X), the weighting coefficient A, the Poisson's ratio v;

[0010] (d) Define the incoming plate shape objective function equation of the continuous annealing unit, the formula is as follows:

[0011] (1)

[0012] In the formula, each coefficient is the variable to be solved; is the iteration process parameter; j takes the value of 1, 2, 3…m; x is the coordinate value of the center line of each segment of the strip unit, ;

[0013] (e) Calculate the transverse compressive stress suffered by the strip by calculating the Poisson's stress in the width direction of the strip:

[0014] Poisson's stress , the formula is:

[0015] (2)

[0016] In the formula: is the Poisson's stress, MPa; the tension of the strip at x in the i-1 process segment, MPa; the tension of the strip at x in the i process segment, MPa; is the Poisson's ratio; R is the furnace roller radius, mm; L is the furnace roller body length, mm;

[0017] thermal stress , as shown in formula (3):

[0018] (3)​

[0019] wherein: is the thermal stress, MPa; is the stress action range, mm; is the strip linear expansion coefficient; E is the elastic modulus, MPa; is the strip temperature change value, °C;

[0020] sliding friction force and centripetal force , the formula is as follows:

[0021] (4)

[0022] wherein: is the sliding friction force suffered by the transverse movement of the strip instability region, MPa; is the friction coefficient; is the centripetal force suffered by the strip instability region, MPa; is the pass speed, m / s; k is the speed influence coefficient; is the furnace roll taper, rad; is the critical taper angle of the furnace roll, rad; S is the length of the straight section of the furnace roll, mm; b is the width of the strip instability region, mm;

[0023] calculate the transverse compressive stress of the strip in the width direction :

[0024] when , the transverse compressive stress suffered by the local region of the strip is represented as ; when , the local region of the strip shrinks, at this time, the centripetal force generated by the rotation of the furnace roll becomes the driving force, and the transverse compressive stress is represented as ;

[0025] (f) when the strip is in a critical instability state, calculate the critical instability stress of the strip, the formula is as follows:

[0026] (5)

[0027] (g) calculate the critical buckling index of the i-th section of the strip from the transverse compressive stress of the strip and the critical instability force of the strip, the formula is as follows:

[0028] (6)

[0029] (h) calculate the run-off factor through the tension difference in the width direction of the strip, the formula is as follows:

[0030] (7)

[0031] wherein: is the running deviation factor of the ith section; is the tension distribution in the width direction of the strip, MPa; is the strip passing speed, m / s; k is the speed influence coefficient; is the model coefficient; is the strip running deviation, mm; is the friction coefficient between the strip and the furnace roller; is the friction influence coefficient;

[0032] (i) setting the optimization parameter s, letting s=0, setting the optimization step length Δk, the iteration precision , the initial solution of the incoming plate shape target curve equation ;

[0033] (j) letting , ;

[0034] (k) establishing the control continuous annealing incoming plate shape comprehensive optimization target function, the formula is as follows:

[0035] (8)

[0036] In the formula: is the outlet plate shape control function; is the strip stable passing control function; is the continuous annealing incoming plate shape; A, is the weighting coefficient; is the maximum value of the continuous annealing inlet plate shape;

[0037] (l) setting the constraint condition:

[0038] (9)

[0039] (m) judging whether the continuous annealing incoming plate shape comprehensive target function is established, if not, letting , then turning to step (j); otherwise, turning to step (n);

[0040] (n) outputting the optimal solution , substituting into the incoming target curve equation, and obtaining the incoming plate shape target curve meeting the continuous annealing finished product plate shape condition.

[0041] The optimization step length , the iteration precision =0.001.

[0042] Compared with the prior art, the beneficial effects of the present application are:

[0043] This invention sets the incoming strip shape at the continuous annealing inlet as a high-order polynomial function. Based on the fact that strip steel is prone to deviation and warping due to stress during continuous annealing, a calculation model for the strip deviation factor and warping index during continuous annealing is established. Combining the influence of the incoming strip shape, and with the goal of stable strip flow of the continuous annealing unit, a comprehensive optimization objective function for the incoming strip shape during continuous annealing is established. This completes the setting of the incoming strip shape quality for continuous annealing, realizes the control of the incoming strip shape of the continuous annealing unit, and further ensures the strip shape quality of the finished strip steel. Attached Figure Description

[0044] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0045] Figure 1 This is a flowchart for setting the quality of incoming sheet material with the goal of stabilizing the continuous annealing process.

[0046] Figure 2 It is the material plate shape distribution value of the continuous annealing unit in Example 1.

[0047] Figure 3 This is the material plate shape distribution value of the continuous annealing unit in Example 2. Detailed Implementation

[0048] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0049] Example 1:

[0050] like Figure 1 As shown, taking a certain continuous annealing unit as an example, the method for setting the shape and quality of incoming material with the goal of stabilizing the continuous annealing plate described in this invention will be explained in detail.

[0051] Taking HC340LA steel with a specification of 1.2mm×1200mm as an example, the calculation is performed.

[0052] (a) Collect key equipment characteristic parameters of the continuous annealing unit, mainly including: furnace roll radius R=450mm, furnace roll straight section length furnace roller taper =0.003rad, critical taper =0.004rad, unit speed V=6m / s, coefficient of friction between strip and furnace rolls =0.15;

[0053] (b) Collect rolling process parameters, mainly including: strip entry thickness =1.2mm, strip width B=1200mm, strip Poisson's ratio v=0.31, strip critical curvature index = 1.0, strip critical run-out factor = 100;

[0054] (c) define the relevant parameters, mainly including: process segmentation in the width direction of the strip, the total number of segments is 21, i is a certain segment number, i takes the value of 1, 2, 3…21, the strip run-out factor of the i-th segment , the i-th segment strip buckling index , incoming plate shape comprehensive optimization objective function G(X), weighting coefficient A, Poisson's ratio v;

[0055] (d) define the incoming plate shape target function equation of the continuous annealing unit:

[0056]

[0057] In the formula, each coefficient is the variable to be solved; is the iteration process parameter; j takes the value of 1, 2, 3…m; x is the length segmented in the width direction of the strip, ;

[0058] (e) calculate the Poisson stress affecting the transverse compressive stress by formula (2) = {12.18, 11.69, 11.43, 11.39, 11.62, 12.11, 12.87, 13.93, 15.29, 16.97, 17.70, 18.41, 19.10, 19.80, 20.50, 21.22, 21.94, 22.69, 23.47, 24.26, 25.07} MPa; calculate the thermal stress by formula (3) = 60.99 MPa, so that , calculate the sliding friction force and the centripetal force , the calculation results are as follows:

[0059] = {2.18, 2.09, 2.04, 2.04, 2.07, 2.16, 2.29, 2.49, 2.73, 3.03, 3.16, 3.29, 3.41, 3.54, 3.66, 3.79, 3.92, 4.05, 4.19, 4.33, 4.48} MPa;

[0060] = { 17.32, 16.63, 16.25, 16.21, 16.52, 17.21, 18.31, 19.81, 21.75, 24.14, 25.18, 26.19, 27.18, 28.17, 29.16, 30.18, 31.21, 32.28, 33.38, 34.50, 36.65} MPa;

[0061] The lateral pressure on the local strip is calculated as follows:

[0062] = { 19.50, 18.72, 18.29, 18.24, 18.60, 19.37, 20.61, 22.30, 24.49, 27.17, 28.34, 29.48, 30.59, 31.70, 32.82, 33.96, 35.13, 36.33, 37.57, 38.83, 40.13} MPa;

[0063] (f) The critical instability stress of the strip is calculated by formula (5) when the strip is in a critical instability state: = 48.91 MPa;

[0064] (g) The buckling index of the strip is calculated by formula (6): = { 0.35, 0.38, 0.37, 0.37, 0.38, 0.40, 0.42, 0.46, 0.50, 0.56, 0.58, 0.60, 0.63, 0.65, 0.67, 0.69, 0.72, 0.74, 0.77, 0.79, 0.82};

[0065] (h) The runout factor is calculated by formula (7): = { 21.93, 21.05, 20.57, 20.51, 20.91, 21.79, 23.17, 25.08, 27.53, 30.55, 31.86, 33.14, 34.39, 35.64, 36.90, 38.18, 39.50, 40.85, 42.24, 43.66, 45.11};

[0066] (i) The optimization parameter s is set, s = 0, the optimization step size is set , the iteration precision = 0.001, and the initial solution of the target curve equation of the incoming plate shape is ;

[0067] (j) Let , ;

[0068] (k) Establishing the control of the continuous annealing incoming plate shape comprehensive optimization objective function ;

[0069] (l) Setting the critical camber index , the critical run-out factor , given constraints:

[0070]

[0071] (m) Determine whether the continuous annealing incoming plate shape comprehensive objective function is established, if not, let , then go to step (j); otherwise, go to step (n);

[0072] (n) Output the incoming plate shape curve function coefficient . The incoming plate shape distribution diagram of the continuous annealing unit is shown in Figure 2 .

[0073] Example 2:

[0074] Taking the CR260 / 450DP steel with a specification of 1.6mmx1200mm as an example, the calculation is carried out.

[0075] (a) Collecting the key equipment characteristic parameters of the continuous annealing unit, mainly including: furnace roller radius R=450mm, furnace roller flat section length , furnace roller taper =0.003 rad, critical taper =0.004 rad, unit speed V=0.9m / s, friction coefficient between the strip and the furnace roller=0.15;

[0076] (b) Collecting the rolling process parameters, mainly including: the inlet thickness of the strip =1.6mm, the strip width B=1550mm, the Poisson's ratio of the strip v=0.31, the critical camber index of the strip =1.0, the critical run-out factor of the strip =100;

[0077] (c) Defining the related parameters, mainly including: process segmentation in the width direction of the strip, the total number of segments is 21, i is a certain segment number, i takes the value of 1, 2, 3…21, the run-out factor of the i-th segment of the strip , the camber index of the i-th segment of the strip , the incoming plate shape comprehensive optimization objective function G(X), the weighting coefficient A, the Poisson's ratio v;

[0078] (d) Defining the continuous annealing unit incoming plate shape objective function equation:

[0079]

[0080] In the formula, each coefficient is a variable to be solved; is an iteration process parameter; j takes values 1, 2, 3…m; x is the length of a segment divided in the width direction of the strip, ;

[0081] (e) Poisson stress affecting the generation of transverse compressive stress is calculated by formula (2) = {12.18, 11.70, 11.43, 11.40, 11.62, 12.11, 12.87, 13.93, 15.30, 16.97, 17.70, 18.41, 19.11, 19.80, 20.50, 21.22, 21.95, 22.70, 23.47, 24.26, 25.07} MPa, thermal stress = 61.57 MPa, so that sliding friction force is calculated by formula (4) and centripetal force , and the calculation results are as follows:

[0082] = {3.26, 3.13, 3.06, 3.05, 3.11, 3.24, 3.45, 3.73, 4.10, 4.55, 4.74, 4.93, 5.12, 5.30, 5.49, 5.68, 5.88, 6.08, 6.29, 6.50, 6.71} MPa;

[0083] = {17.32, 16.63, 16.25, 16.21, 16.53, 17.22, 18.31, 19.82, 21.75, 24.14, 25.18, 26.19, 27.18, 28.17, 29.16, 30.18, 31.21, 32.28, 33.38, 34.50, 35.65} MPa;

[0084] so as to calculate the transverse compressive stress on the local strip , and the calculation results are as follows:

[0085] = {20.58, 19.76, 19.31, 19.26, 19.64, 20.46, 21.76, 25.55, 25.85, 28.68, 29.92, 31.12, 32.29, 33.47, 34.65, 35.86, 37.09, 38.36, 39.66, 41.00, 42.37} MPa;

[0086] (f) The critical instability stress of the strip is calculated by formula (5) when the strip is in a critical instability state = 86.96 MPa;

[0087] (g) The buckling index is calculated by formula (6): = {0.23, 0.23, 0.22, 0.22, 0.23, 0.24, 0.25, 0.27, 0.30, 0.33, 0.34, 0.36, 0.37, 0.38, 0.40, 0.41, 0.43, 0.44, 0.46, 0.47, 0.48};

[0088] (h) The run-out factor is calculated by formula (7): = {17.61, 16.91, 16.52, 16.48, 16.80, 17.51, 18.62, 20.15, 22.12, 24.54, 25.60, 26.63, 27.63, 28.64, 29.65, 30.68, 31.74, 32.82, 33.94, 35.08, 36.25};

[0089] (i) The optimization parameter s is set, s = 0, the optimization step size , the iteration precision = 0.001, and the initial solution of the target curve equation of the incoming strip shape is set; ;

[0090] (j) Let , ;

[0091] (k) The control continuous annealing incoming strip shape comprehensive optimization target function is established ;

[0092] (l) The critical buckling index , the critical run-out factor , and the given constraint condition are set:

[0093]

[0094] (m) It is determined whether the continuous annealing incoming strip shape comprehensive target function is established or not, if not, let , and then step (j) is entered; otherwise, step (n) is entered;

[0095] (n) The incoming strip shape curve function coefficient is output. The incoming strip shape distribution diagram of the continuous annealing unit is shown in Figure 3 .

[0096] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application. In addition, it should be noted that, in the above-described specific embodiments, various specific technical features can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combination manners. In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed by the present application.

Claims

1. A method for setting the shape quality of incoming material plates aimed at achieving a continuous annealing stable strip, characterized in that, The method comprises the following steps: (a) Collecting the characteristic parameters of the key equipment of the continuous annealing line, mainly including: furnace roller radius R, mm, furnace roller flat section length , mm, furnace roller taper , rad, furnace roller critical taper , rad, line speed V, m / s, friction coefficient between strip and furnace roller ; (b) Collect rolling process parameters, mainly including: strip entry thickness mm, strip width B, mm, strip Poisson's ratio v, strip critical curvature index Critical deviation factor of strip steel ; (c) define relevant parameters, mainly including: process segmentation in the width direction of the strip, the total number of segments is 2n+1, i is a certain segment number, i takes values 1, 2, 3…2n+1; the strip run-out factor of the i-th segment , the strip buckling index of the i-th segment , the incoming plate shape comprehensive optimization objective function G(X), the weighting coefficient A, and the Poisson ratio v; (d) defining a strip shape target function equation of the incoming strip of the continuous annealing unit, and the equation is as follows: （1）； In the formula, each coefficient is a variable to be solved; is an iteration process parameter; j takes values 1, 2, 3…m; x is a coordinate value where the center line of each section of the belt unit is located, ; (e) calculating the transverse compressive stress on the strip at the location by calculating the poisson stress affecting the width direction of the strip , thermal stress :​ Poisson's stress The formula is: （2）； In the formula: Poisson stress, MPa; Tension of the strip at x in the i-1 process section, MPa; Tension of the strip at x in the i process section, MPa; Poisson's ratio; R is the furnace roll radius, mm; L is the furnace roll barrel length, mm; thermal stress as shown in equation (3): （3）； In the formula: is the thermal stress, MPa; is the stress action range, mm; is the strip linear expansion coefficient; E is the elastic modulus, MPa; is the strip temperature change value, °C; sliding friction and centripetal force and centripetal force （4）； In the formula: the sliding friction force suffered by the strip instability region when it moves laterally, MPa; is the friction coefficient; the centripetal force suffered by the strip instability region, MPa; is the strip speed, m / s; k is the speed influence coefficient; is the furnace roll taper, rad; is the critical taper angle of the furnace roll, rad; S is the length of the straight section of the furnace roll, mm; b is the width of the strip instability region, mm; Computing transverse compressive stress in the width direction of a strip : When , the lateral compressive stress on the local area of the strip is represented as ; when , the local area of the strip is represented as shrinkage, at this time, the centripetal force generated by the rotation of the furnace roller becomes the main driving force, and the lateral compressive stress is represented as: ; (f) when the strip is in a critical instability state, calculating a critical instability stress of the strip, and the equation is as follows: （5）； (g) calculating a critical buckling index of the i-th section of the strip according to the transverse compressive stress of the strip and the critical instability stress of the strip, and the equation is as follows: （6）； (h) calculating a running deviation factor according to a tension difference in the width direction of the strip, and the equation is as follows: （7）； In the formula: is the run-out factor of the i-th section; is the strip width direction tension distribution, MPa; is the strip speed, m / s; k is the speed influence coefficient; is the model coefficient; is the strip run-out amount, mm; is the friction coefficient between the strip and the furnace roller; is the friction influence coefficient; (i) setting an optimization parameter s, letting s=0, setting an optimization step length Ak, an iteration precision , initial solution of the incoming plate shape target curve equation ; (j) Let , ; (k) establishing a comprehensive optimization target function of the strip shape of the incoming strip of the continuous annealing unit, and the equation is as follows: （8）； In the formula: is the exit strip shape control function; is the strip steady pass control function; is the continuous annealing incoming strip shape; A, is the weighting factor; is the maximum value of the continuous annealing entry strip shape; (l) given constraint conditions: （9）； (m) judging the comprehensive target function of the continuous annealing incoming material plate shape is not established, let go to step (j); otherwise, go to step (n); (n) outputting the optimal solution , the target curve equation of the incoming material is substituted to obtain the target curve of the incoming material shape that satisfies the shape condition of the continuous annealing finished product.

2. A method of setting the shape quality of incoming material plates targeted at a continuously annealed stable flat-rolled product according to claim 1, characterized in that, the optimization step , iteration accuracy = 0.001.

Images