Segmented cold-rolled strip shape control method

Abstract

This invention discloses a segmented shape control method for cold-rolled strip steel. The method includes: determining whether the cold-rolled strip steel is an ultra-strong, ultra-thick strip steel before the final rolling pass; if it is determined to be ultra-strong, ultra-thick strip steel, then controlling the strip steel's shape during the final rolling pass according to a segmented shape control strategy; if it is determined not to be ultra-strong, ultra-thick strip steel, then controlling the strip steel's shape during the final rolling pass using a pre-set shape control curve; and finally, performing the final rolling pass on the cold-rolled strip steel. In this method, multiple shape control curves are used to control the shape of multiple segments of a whole coil of cold-rolled strip steel separately, thereby achieving more refined shape control of the entire coil from beginning to end. This avoids significant differences in shape control effects between the inner and outer rings of the cold-rolled strip steel coil, making it suitable for the production of thick, high-strength cold-rolled strip steel.

Description

Technical Field

[0001] This invention relates to a cold rolling control technology, and more particularly to a segmented cold-rolled strip shape control method. Background Technology

[0002] When cold-rolled strip steel is rolled in the final pass of the rolling mill, it is usually necessary to control the shape of the cold-rolled strip steel to avoid poor shape of the finished cold-rolled strip steel, such as severe single-sided waves, double-sided waves, middle waves, rib waves, etc.

[0003] Most cold rolling mills currently use "automatic shape control technology". That is, the cold rolling mill has an automatic shape control function. Before rolling the cold-rolled strip, a shape control curve is set and the shape control curve (function) is input into the production control system. The production control system will then control the cold rolling mill to control the shape of the cold-rolled strip according to the shape control curve.

[0004] See Figure 1 Typical plate shape control curves include Figure 1 As shown, the functional form of the plate shape control curve can be expressed as f(x) = ax 2 +bx 6 +c, where a, b, and c are all constants, and the independent variable x( Figure 1 The horizontal axis represents the quantified position of the cold-rolled strip in the width direction, and its calculated function value ( Figure 1 The vertical axis represents the shape control I value, and the shape control curve can be described as the distribution of the shape control I value in the width direction of the cold-rolled strip.

[0005] Currently, when a rolling mill performs the final rolling pass on a whole coil of cold-rolled strip steel, a single shape control curve is used for shape control. This approach is sufficient for most cold-rolled strip steels in terms of shape control performance. However, for high-strength and thick cold-rolled strip steels, such as cold-rolled precision-stamped strip steel for automotive transmissions, the shape control effect is less than satisfactory. Specifically, the main problem lies in the significant difference in shape control between the inner and outer rings of the cold-rolled strip steel coil, often resulting in a situation where "the outer ring of the cold-rolled strip steel coil has a good shape, while the inner ring has a poor shape." The main reason for this is that when the rolled cold-rolled strip steel is coiled by the coiler, initially, due to the smaller coil diameter of the inner ring strip on the coiler, a certain amount of plastic deformation occurs in the thickness direction, leading to poor shape. As the coil diameter of the strip steel on the coiler increases, the large difference in plastic deformation in the thickness direction gradually disappears, and poor shape becomes less likely to occur. Therefore, it is evident that using a traditional single shape control curve for shape control is not entirely suitable for cold-rolled strip steel with high strength and large thickness, such as cold-rolled fine-stamped strip steel for automotive transmissions.

[0006] Chinese patent CN2008100115616 discloses a design method for a target model of cold-rolled strip shape control. Based on the characteristics of cold-rolled strip shape, the structure and working principle of the mill shape control actuator, and the mathematical constraints that the target shape should meet, a mathematical model describing the straightness control of the strip is determined. Different control parameters in the target shape model are determined based on the different process quality requirements of the rolled strip variety and specifications, the requirements of different post-rolling processing steps on strip shape, and the wear of the rolls and changes in thermal crown during rolling, forming different target shape curves for calculation of the mathematical model of cold rolling process control and basic automated real-time shape control. This method cannot solve the problem of poor inner strip shape.

[0007] Furthermore, some concepts involved in this invention are further explained as follows:

[0008] The width-direction position of the cold-rolled strip involved in the strip shape control curve (the independent variable x in the function) is usually quantized using dimensionless values. Specifically, with the centerline of the cold-rolled strip as the zero reference, the width values ​​of the two sides of the cold-rolled strip are -1 and 1, respectively, and the width-direction position of the cold-rolled strip is quantized equally between -1 and 1.

[0009] It should be noted that the strip shape control value I mentioned in this article is a numerical value specifically used to reflect the strip shape. It represents the difference in relative elongation of the strip after rolling, and its calculation formula is as follows: In the formula, ε is the shape control value I, ΔL is the difference between the longest and shortest longitudinal strips after segmenting the rolled strip, and L is the length of the shortest longitudinal strip after segmenting the rolled strip. The unit of measurement for the shape control value I is called I. A larger shape control value I indicates a greater difference between the actual shape value and the target shape value, while a smaller shape control value I indicates that the actual shape value is closer to the target shape value. This shape control value I is common knowledge to those skilled in the art. Summary of the Invention

[0010] The purpose of this invention is to provide a segmented cold-rolled strip shape control method. This method uses multiple shape control curves to implement more refined segmented shape control of a whole coil of cold-rolled strip, solving the problem of large differences in shape control effect between the inner and outer rings of the cold-rolled strip coil.

[0011] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0012] A segmented cold-rolled strip shape control method, the shape control method comprising:

[0013] S1. Before the final rolling pass of the cold-rolled strip, determine whether the cold-rolled strip is an ultra-strong and ultra-thick strip.

[0014] S2. If the cold-rolled strip is determined to be an ultra-strong and ultra-thick strip, the strip shape is controlled according to the segmented strip shape control strategy during the last rolling process.

[0015] S3. If it is determined that the cold-rolled strip is not an ultra-strong and ultra-thick strip, then a pre-set strip shape control curve is used to control the strip shape during the last rolling process.

[0016] S4 is the final rolling pass for cold-rolled strip steel.

[0017] Further, S1 includes:

[0018] S11, compare the yield strength value K of the strip before rolling with the preset yield strength threshold K0, and compare the thickness value H of the strip before rolling with the preset thickness threshold H0.

[0019] S12, if K>K0 and H>H0, then the cold-rolled strip is determined to be an ultra-strong and ultra-thick strip.

[0020] S13. If K≤K0 or H≤H0, then the cold-rolled strip steel is determined not to be ultra-strong and ultra-thick strip steel.

[0021] Furthermore, the yield strength value K of the strip before rolling is determined according to the formula... The calculation yields that, in the formula, K rdenoted as the reference strength of cold-rolled strip, m as the relevant strength offset coefficient of cold-rolled strip, n as the relevant strength coefficient of cold-rolled strip, h as the initial strip thickness, and H as the strip thickness before rolling.

[0022] Furthermore, the segmented plate shape control strategy includes:

[0023] S21, N roll diameter threshold intervals are preset, and corresponding interval plate shape control curves are set for each roll diameter threshold interval;

[0024] S22, During the final rolling process of cold-rolled strip steel, the coil diameter d on the coiler is continuously determined by comparing N coil diameter threshold ranges.

[0025] S23, when determining the strip diameter d on the coiler to be within the diameter threshold range, the cold-rolled strip is controlled according to the shape control curve corresponding to the diameter threshold range.

[0026] Furthermore, the interval plate shape control curve corresponding to the roll diameter threshold interval is obtained by transforming the preset plate shape control curve.

[0027] Furthermore, corresponding compensation coefficients δ and c' are pre-set for each roll diameter threshold interval, and the function expression of the interval plate shape control curve set for the corresponding roll diameter threshold interval is f(x)=(a+δ)x 2 +bx 6 +c', where a and b are constant coefficients in the function of the preset plate shape control curve.

[0028] Furthermore, the cold-rolled strip steel is cold-rolled precision stamping strip steel for automotive transmissions.

[0029] In the shape control method of the present invention, when it is determined that the cold-rolled strip undergoing the final rolling pass is an ultra-strong and ultra-thick strip, instead of using a single shape control curve to control the shape of an entire coil of cold-rolled strip as in the traditional method, multiple shape control curves are used to control the shape of multiple sections of an entire coil of cold-rolled strip. Each shape control curve is specifically set and matched for its corresponding section, and the multiple sections are divided according to the strip coil diameter on the coiler. Thus, each shape control curve is specifically set and matched for a specific strip coil diameter on the coiler, thereby enabling more refined shape control of an entire coil of cold-rolled strip from beginning to end.

[0030] Compared with the prior art, the shape control method of the present invention has the following advantages: In the shape control method of the present invention, multiple shape control curves are used to control the shape of multiple sections of a whole coil of cold-rolled strip steel, thereby achieving more refined shape control of a whole coil of cold-rolled strip steel from beginning to end, avoiding the situation where the shape control effect of the inner and outer rings of the cold-rolled strip steel coil is significantly different, ensuring the implementation effect of shape control of a whole coil of cold-rolled strip steel, and is especially suitable for cold-rolled strip steel with high strength and large thickness. Attached Figure Description

[0031] Figure 1 This is a typical shape control curve diagram for cold-rolled strip steel;

[0032] Figure 2 This is a flowchart of the segmented cold-rolled strip shape control method of the present invention. Detailed Implementation

[0033] First, some concepts involved in this article are explained as follows:

[0034] The "preset shape control curve" mentioned in this article refers to the shape control curve pre-set according to standard processes under normal process systems. Since the processes and product quality systems of different manufacturers vary, the preset shape control curves used will differ from manufacturer to manufacturer. In this embodiment, the functional form of the preset shape control curve is f(x) = ax 2 +bx 6 +c, the domain of the function is [-1.0, 1.0] (i.e., x∈[-1.0, 1.0]). In the function expression of the preset plate shape control curve, x 2 The coefficient 'a' ranges from -70 to 70, and x... 6 The coefficient b ranges from -55 to 55, and the increment constant c ranges from -18 to 18.

[0035] The first pass rolling mentioned in this article is a broad concept. Specifically, for a single-stand reciprocating rolling mill, it is the first pass rolling as it is literally described. For a multi-stand continuous rolling mill, it refers to the rolling of cold-rolled strip by the first stand into which the strip enters.

[0036] The term "final pass rolling" as used in this article is a broad concept. Specifically, for a single-stand reciprocating rolling mill, it refers to the final pass rolling as it is literally described. For a multi-stand continuous rolling mill, it refers to the rolling of cold-rolled strip by the last stand into which the strip enters.

[0037] The term "micro-wave" mentioned in this article usually refers to the wave generated in the middle of the actual rolled strip where the shape control value I is between -5 and 5I.

[0038] The micro-edge waviness mentioned in this article usually refers to the edge waviness generated at the edge of the actual rolled strip with a shape control value between -5 and 5I.

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0040] See Figure 2 This embodiment provides a segmented cold-rolled strip shape control method, which solves the problem of large differences in the shape control effect between the inner and outer rings of cold-rolled strip coils.

[0041] The plate shape control method of this embodiment includes S1 to S4.

[0042] S1. Before the final rolling pass of the cold-rolled strip steel in production, determine whether the cold-rolled strip steel is "ultra-strong and ultra-thick strip steel".

[0043] S2. If the cold-rolled strip is determined to be "ultra-strong and ultra-thick strip", then the strip shape is controlled in the final rolling process according to the "segmented strip shape control strategy".

[0044] S3. If it is determined that the cold-rolled strip is not "ultra-strong and ultra-thick strip", then the "pre-set strip shape control curve" is used to control the strip shape of the cold-rolled strip during the final rolling process.

[0045] S4 is the final rolling pass for cold-rolled strip steel.

[0046] The phrase “S1, before the final rolling pass of the cold-rolled strip steel being produced, determine whether the cold-rolled strip steel is an ultra-strong and ultra-thick strip steel” specifically includes S11 to S13.

[0047] S11, compare the "yield strength value of strip before rolling" K with the preset yield strength threshold K0, and compare the "thickness value of strip before rolling" H with the preset thickness threshold H0.

[0048] The yield strength value K of the strip before rolling is based on the formula. The calculation yields that, in the formula, K r denoted as , where is the reference strength of cold-rolled strip (unit: MPa), m is the relevant strength offset coefficient of cold-rolled strip, n is the relevant strength coefficient of cold-rolled strip, h is the initial strip thickness (unit: mm), and H is the strip thickness before rolling (unit: mm).

[0049] The yield strength value K of the strip before rolling refers to the yield strength of the cold-rolled strip before the final rolling pass. The calculation of this K value is completed automatically by the production control system.

[0050] The pre-rolling strip thickness value H refers to the thickness of the cold-rolled strip before the final rolling pass.

[0051] The initial strip thickness value h refers to the initial thickness of the cold-rolled strip before it enters the rolling mill for the first rolling pass.

[0052] The above K r The coefficients , m, and n are characteristic coefficients representing the initial strength properties of cold-rolled materials before rolling deformation and the increase in deformation resistance of materials after cold rolling with different deformation rates. These coefficients can be determined experimentally after measuring the mechanical properties of the material. The reference strength K of the cold-rolled strip steel described in this invention... r The typical value range is 750–1300 MPa. The typical value range of the relevant strength offset coefficient m for cold-rolled strip steel is 0.05–0.1. The typical value range of the relevant strength coefficient n for cold-rolled strip steel is 0.1–0.4.

[0053] The yield strength threshold K0 is an empirical value, and its range is 600-700 MPa.

[0054] The thickness threshold H0 is an empirical value, which is usually above 2 mm.

[0055] It should be noted that the calculation formula for the yield strength value K of the strip before rolling is common knowledge known to those skilled in the art.

[0056] The thickness H of the strip before rolling can be calculated and measured by the thickness gauge and production control system.

[0057] S12, if "K>K0 and H>H0", then the cold-rolled strip steel is determined to be ultra-strong and ultra-thick strip steel.

[0058] S13. If "K≤K0 or H≤H0", then the cold-rolled strip steel is determined not to be ultra-strong and ultra-thick strip steel.

[0059] In S2, the segmented plate shape control strategy includes S21 to S23.

[0060] S21, for the diameter of cold-rolled strip steel coils, N consecutive "coil diameter threshold intervals" are pre-set, and a corresponding "interval shape control curve" is adaptively set for each coil diameter threshold interval. N is a natural number greater than 1.

[0061] The term "adaptively set" means that during the final rolling process of cold-rolled strip steel, when the strip diameter on the coiler is within a certain diameter threshold range, the interval shape control curve set for that diameter threshold range can adapt to and match the shape control requirements of the cold-rolled strip steel at that moment.

[0062] In this embodiment, the interval plate shape control curve corresponding to each roll diameter threshold interval is obtained by transforming the preset plate shape control curve. The essence of this transformation is to transform the function of the preset plate shape control curve to obtain the function of the interval plate shape control curve, which is to say, the interval plate shape control curve.

[0063] Specifically, corresponding compensation coefficients δ and c' are pre-set for each roll diameter threshold interval, and the function expression of the interval plate shape control curve set for the corresponding roll diameter threshold interval is set as f(x)=(a+δ)x 2 +bx 6 +c', the domain of the function is [-1.0, 1.0] (i.e., x∈[-1.0, 1.0]), where a and b are constant coefficients in the function of the predefined plate shape control curve. In other words, x in the function of the interval plate shape control curve... 2 The coefficients are derived from the "preset plate shape control curve function formula x". 2 The coefficient "a" is added to the pre-set compensation coefficient δ, and the sum of x in the interval plate shape control curve function is given. 6 The coefficients are still determined using a pre-defined plate shape control curve function, where x... 6 The coefficient b, and the incremental constant in the interval slab shape control curve function, use a pre-set compensation coefficient c'. This achieves the goal that "the interval slab shape control curve is obtained by transforming a pre-set slab shape control curve."

[0064] Generally speaking, the values ​​of δ and c' gradually "increase or decrease" as the corresponding roll diameter threshold range increases, so that the shape control curves of each range transition smoothly during the last rolling pass.

[0065] It should be noted that the specific values ​​of δ and c' are determined based on experience. Specifically, when initially adopting the plate shape control method of this embodiment, the values ​​of δ and c' are first set based on experience, and then the values ​​of δ and c' are continuously adjusted according to the effect of the method implementation until the effect of the method implementation meets the target requirements. According to experience, the value range of δ is -80 to 45, and the value range of c' is -18 to 18.

[0066] S22, during the final rolling process of cold-rolled strip steel, the coil diameter d on the coiler is continuously determined by comparing with the pre-set N coil diameter threshold ranges.

[0067] S23, when determining the strip diameter d on the coiler to be within the diameter threshold range, the cold-rolled strip in the rolling process is controlled according to the shape control curve corresponding to the diameter threshold range.

[0068] It should be noted that the strip shape control method of this embodiment is set in the production control system in the form of a program. During the rolling process of cold-rolled strip steel, the strip shape control method of this embodiment is implemented by executing the program through the production control system.

[0069] In this embodiment, the function of all strip shape control curves (including preset strip shape control curves and interval strip shape control curves) has an independent variable x representing the quantitative value of the position of the cold-rolled strip in the width direction, and the calculated function value represents the strip shape control value. This kind of strip shape control curve function is common knowledge known to those skilled in the art.

[0070] In this embodiment, the width position of the cold-rolled strip is quantized using dimensionless values. Specifically, with the central axis of the cold-rolled strip as the zero reference, the width values ​​of the two sides of the cold-rolled strip are -1 and 1, respectively, and the width position of the cold-rolled strip is quantized equally between -1 and 1. This method of using dimensionless values ​​as the quantization value for the width position of the cold-rolled strip is common knowledge known to those skilled in the art.

[0071] The following specific embodiment is provided to further illustrate this:

[0072] A single-stand cold rolling mill (reciprocating type) produces cold-rolled strip steel for automotive transmissions. The raw material is hot-rolled pickled steel. The initial strip thickness h is 4.0 mm. The plan is to roll five passes to reduce the strip thickness to 2.44 mm. The final shape control target is to keep the strip shape within ±15I (shape control value). According to the plan, the initial strip thickness H is 2.517 mm before the fifth pass. Under normal process conditions, the preset shape control curve function is f(x) = 29.25x. 2 -5.25x 6 -9, x∈[-1.0,1.0].

[0073] (Corresponding to S1) Before the final 5th rolling pass of the cold-rolled strip, determine whether the cold-rolled strip is an ultra-strong and ultra-thick strip.

[0074] (Corresponding to S11) Calculate the yield strength value K of the strip before rolling. The required parameters for the calculation are: K r =940, m=0.09, n=0.3, h=4.0, H=2.517, according to the formula Finally, K = 787 MPa was calculated, the preset yield strength threshold K0 = 645 MPa, and the thickness threshold H0 = 2.2 mm.

[0075] (Corresponding to S12) After comparison, K>K0 and H>H0, the cold-rolled strip steel is determined to be ultra-strong and ultra-thick strip steel.

[0076] (Corresponding to S2) If the cold-rolled strip is determined to be an ultra-strong and ultra-thick strip, then the cold-rolled strip will be subjected to shape control according to the segmented shape control strategy during the last 5th rolling process.

[0077] (Corresponding to S21) Four roll diameter threshold intervals are preset, namely the first roll diameter threshold interval (0, 750], the second roll diameter threshold interval (750, 840], the third roll diameter threshold interval (840, 1100], and the fourth roll diameter threshold interval (1100, ∞); a corresponding interval plate shape control curve is set for each roll diameter threshold interval, namely the first interval plate shape control curve, the second interval plate shape control curve, the third interval plate shape control curve, and the fourth interval plate shape control curve.

[0078] For the first volume diameter threshold range, the corresponding compensation coefficients δ1 and c'1 are preset, where δ1 = -42 and c'1 = 5;

[0079] The corresponding compensation coefficients δ2 and c'2 are pre-set for the second volume diameter threshold range, where δ2 = -36 and c'2 = 3;

[0080] For the third volume diameter threshold range, the corresponding compensation coefficients δ3 and c'3 are preset, where δ3 = -15 and c'3 = -4;

[0081] The corresponding compensation coefficients δ4 and c'4 are pre-set for the fourth volume diameter threshold range, where δ4 = 0 and c'4 = -9.

[0082] The function expression for the plate-shaped control curve of the first interval is set as f1(x) = (29.25-42)x 2 -5.25x 6 +5, x∈[-1.0,1.0];

[0083] The function expression for the plate-shaped control curve of the second interval is set as f2(x)=(29.25-36)x 2 -5.25x 6 +3, x∈[-1.0,1.0];

[0084] The function expression for the plate shape control curve of the third interval is set as f3(x) = (29.25-15)x 2 -5.25x 6 -4, x∈[-1.0,1.0];

[0085] The functional expression for the plate-shaped control curve of the fourth interval is set as f4(x) = (29.25 + 0)x 2-5.25x 6 -9, x∈[-1.0,1.0].

[0086] (Corresponding to S22) During the final rolling process of cold-rolled strip steel, the coil diameter d of the strip steel on the coiler is continuously determined by comparing it with the four pre-set coil diameter threshold ranges.

[0087] (corresponding to S23) When the strip diameter d on the coiler is within the first diameter threshold range (0, 750), the first range shape control curve is used to control the shape of the cold-rolled strip during rolling.

[0088] When the strip diameter d on the coiler is within the second strip diameter threshold range (750, 840), the second range strip shape control curve is used to control the strip shape of the cold-rolled strip during rolling.

[0089] When the strip diameter d on the coiler is within the third diameter threshold range (840, 1100), the third range shape control curve is used to control the shape of the cold-rolled strip during rolling.

[0090] When the strip diameter d on the coiler is within the fourth diameter threshold range (1100,∞), the fourth range shape control curve is used to control the shape of the cold-rolled strip during rolling.

[0091] Since the shape control curve of the first interval is a shape control curve with slight medium wavy pattern, while the shape control curve of the fourth interval is a shape control curve with slight edge wavy pattern, the shape control of the cold-rolled strip gradually transitions from slight medium wavy pattern to slight edge wavy pattern during the final fifth rolling process.

[0092] (Corresponding to S4) Based on the above-mentioned segmented strip shape control strategy, the cold-rolled strip is subjected to the final 5th rolling pass. After rolling, the strip shape of both the head and tail portions can reach the level within ±7I, which is within the target range of ±15I, meeting the requirements.

[0093] The shape control method of this embodiment has the following advantages: In this method, when it is determined that the cold-rolled strip undergoing the final rolling pass is an ultra-strong and ultra-thick strip, instead of using a single shape control curve to control the shape of the entire coil of cold-rolled strip as in the traditional method, multiple shape control curves are used to control the shape of multiple sections of the entire coil of cold-rolled strip. Each shape control curve is specifically set and matched for its corresponding section, and these multiple sections are divided according to the diameter of the strip coil on the coiler. In other words, each shape control curve is specifically set and matched for a specific strip coil diameter on the coiler, thereby achieving more refined shape control of the entire coil of cold-rolled strip from beginning to end. This avoids the situation where "the shape control effect of the inner and outer rings of the cold-rolled strip coil is significantly different", ensuring the implementation effect of shape control of the entire coil of cold-rolled strip, and is especially suitable for cold-rolled strip with high strength and large thickness.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A segmented cold-rolled strip shape control method, characterized in that: The plate shape control method includes: S1. Before the final rolling pass of the cold-rolled strip, determine whether the cold-rolled strip is an ultra-strong and ultra-thick strip. S2. If the cold-rolled strip is determined to be an ultra-strong and ultra-thick strip, the strip shape is controlled according to the segmented strip shape control strategy during the final rolling process. S3. If it is determined that the cold-rolled strip is not an ultra-strong and ultra-thick strip, then a pre-set strip shape control curve is used to control the strip shape during the last rolling process. S4 is the final rolling pass for cold-rolled strip steel. The segmented plate shape control strategy includes: S21, N roll diameter threshold intervals are preset, and corresponding interval plate shape control curves are set for each roll diameter threshold interval; S22, during the final rolling process of cold-rolled strip steel, the coil diameter d on the coiler is continuously determined by comparing N coil diameter threshold ranges. S23, when determining the strip diameter d on the coiler to be within the diameter threshold range, the cold-rolled strip is controlled according to the shape control curve corresponding to the diameter threshold range.

2. The segmented cold-rolled strip shape control method according to claim 1, characterized in that: S1 includes: S11, compare the yield strength value K of the strip before rolling with the preset yield strength threshold K0, and compare the thickness value H of the strip before rolling with the preset thickness threshold H0. S12, if K>K0 and H>H0, then the cold-rolled strip steel is determined to be ultra-strong and ultra-thick strip steel; S13. If K≤K0 or H≤H0, then the cold-rolled strip steel is determined not to be ultra-strong and ultra-thick strip steel.

3. The segmented cold-rolled strip shape control method according to claim 2, characterized in that: The yield strength value K of the strip before rolling is based on the formula. The calculation yields that, in the formula, K r denoted as the reference strength of cold-rolled strip, m as the relevant strength offset coefficient of cold-rolled strip, n as the relevant strength coefficient of cold-rolled strip, h as the initial strip thickness, and H as the strip thickness before rolling.

4. The segmented cold-rolled strip shape control method according to claim 1, characterized in that: The plate shape control curve corresponding to the roll diameter threshold range is obtained by transforming the preset plate shape control curve.

5. The segmented cold-rolled strip shape control method according to claim 4, characterized in that: For each roll diameter threshold interval, corresponding compensation coefficients δ and c' are pre-set. The interval plate shape control curve set for the corresponding roll diameter threshold interval is functionally defined as f(x)=(a+δ)x 2 +bx 6 +c', where a and b are constant coefficients in the function of the preset strip shape control curve, x represents the dimensionless quantitative value of the position of the cold-rolled strip in the width direction, x∈[-1.0,1.0], and f(x) represents the strip shape control value.

6. The segmented cold-rolled strip shape control method according to claim 1, characterized in that: The cold-rolled strip steel is cold-rolled precision stamping strip steel for automotive transmissions.

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