Production process of cold-rolled ultra-thin strip steel

Abstract

The invention provides a production process of cold-rolled ultra-thin strip steel, and relates to the field of metal smelting. Comprising the steps that (1) a five-rack continuous rolling mill is designed and built, front four rack rollers of the five-rack continuous rolling mill are cylindrical rollers, and a fifth rack roller is designed to be a cylindrical roller with taper at the two axial ends; 2) setting working parameters of the five-rack continuous mill, wherein the working parameters comprise raw material thickness, production speed, reduction rate distribution between racks, structural parameters of rollers of each rack and emulsion parameters of each rack; wherein the emulsified liquid of the third rack of the five-rack continuous rolling mill is independently controlled to be sprayed, and the spraying pressure of the emulsified liquid is controlled to be gradually reduced in the rolling process of each coil of strip steel; (3) a transition strip steel raw material is selected and subjected to pre-rolling on a five-rack continuous rolling mill to produce transition coil strip steel, and a target coil ultra-thin strip steel is produced according to a preset cold rolling program after pre-rolling is completed; according to the production process, rolling mill vibration during high-speed production of the ultra-thin strip steel can be effectively relieved, the product quality is guaranteed, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of metal smelting technology, specifically to a production process for cold-rolled ultra-thin strip steel. Background Art

[0002] Cold-rolled products are widely used in industries such as home appliances, office supplies, and containers due to their good surface quality, thin dimensions, and good formability. Currently, with increasing cost pressures and technological advancements, product thickness is trending towards even thinner specifications. However, in producing thinner products, the thin strip steel results in low production efficiency. To improve efficiency, the strip running speed is generally increased to over 1000 m / min, which easily leads to mill vibration. Mill vibration causes periodic fluctuations in the finished product thickness, easily resulting in bubble-like defects in subsequent processes, affecting customer use, and in severe cases, causing strip breakage. Currently, to improve product quality and avoid strip breakage accidents, the pickling speed of thin-gauge strip is often reduced to below 700 m / min when mill vibration occurs, severely impacting production efficiency.

[0003] Existing technologies, such as the vibration suppression method for cold continuous rolling mills disclosed in patent CN105522000B, propose to suppress mill vibration by installing vibration monitoring devices on the fourth or fifth stand and independently adjusting the emulsion flow rate based on vibration signals. Patent CN111495980B discloses a method for setting reduction schedules for cold continuous rolling mills with vibration suppression as the goal. This method collects relevant parameters of the mill and strip rolling process parameters, defines vibration judgment indicators for each stand, and sets reduction schedules based on these parameters, including stand bite angle, entry speed, and oil film thickness. It uses the lower threshold of the vibration judgment indicators—where the neutral angle is half the bite angle and the rolling process is in a state of under-lubrication—as a constraint condition to optimize the reduction schedule of the cold continuous rolling mill.

[0004] However, while the above solutions can partially address product quality issues caused by mill vibration during the manufacture of ultra-thin strip steel, the improvement in production efficiency is limited. Therefore, a new production process for cold-rolled ultra-thin strip steel is needed to further address product quality issues caused by excessive strip steel production speed leading to cold rolling mill vibration and improve cold rolling production efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a production process for cold-rolled ultra-thin strip steel. Starting with the thickness of the raw material, the process combines various factors such as the reasonable arrangement of the initial rolling material, production rhythm, optimized reduction ratio distribution, roll design and matching, and emulsion spraying method to ensure uniform load distribution on the rolling mill. This enables high-speed production of thin strip steel while effectively reducing mill vibration.

[0006] To achieve the above objectives, the present invention proposes the following technical solution: a production process for cold-rolled ultra-thin strip steel, applied to a five-stand continuous rolling mill, comprising the following steps:

[0007] 1) Design the structure of the rolls of each stand of the five-stand continuous rolling mill and build the five-stand continuous rolling mill; wherein, the first four stand rolls of the five-stand continuous rolling mill are all cylindrical rolls, and the fifth stand roll is designed as a cylindrical roll with tapered ends in the axial direction.

[0008] 2) According to the size requirements of the ultra-thin strip steel products produced, the working parameters of the five-stand continuous rolling mill are set. The working parameters include: raw material thickness, production speed, inter-stand reduction rate distribution, roll structure parameters of each stand, and emulsion parameters of each stand. Among them, the emulsion spraying of the third stand of the five-stand continuous rolling mill is controlled separately, and the emulsion spraying pressure is gradually reduced during the rolling process of each coil of strip steel after the pre-rolling of the five-stand continuous rolling mill.

[0009] 3) Select transition strip steel raw material and pre-roll it on a five-stand continuous rolling mill to produce transition coil strip steel; wherein, the thickness of the transition strip steel raw material is not less than the maximum value of the raw material thickness selected by the five-stand continuous rolling mill to produce multiple target thickness specifications of ultra-thin strip steel.

[0010] 4) After the transition coil strip is cold rolled, the target coil ultra-thin strip is produced on a five-stand continuous rolling mill according to the preset cold rolling program.

[0011] Furthermore, in step 2), the reduction rate distribution between stands is as follows: the total reduction rate of the five-stand continuous rolling mill does not exceed 90%, and the reduction rate of the third stand of the five-stand continuous rolling mill is 36% to 40%, and the reduction rate of the fifth stand is 28% to 32%.

[0012] Furthermore, the structural parameters of each frame roller in step 2) are as follows:

[0013] The length of any stand roll of the five-stand continuous rolling mill shall not be less than 1200 mm;

[0014] The diameter of the first frame roller is D1≤420mm, and the surface roughness is Ra1≥1.0μm;

[0015] The diameter of the second frame roller is ≤450mm, and the surface roughness Ra2 is ≥1.0μm;

[0016] The diameter of the third frame roller is ≥420mm, and the surface roughness Ra3 is 0.65~0.80μm;

[0017] The diameter of the fourth frame roller is ≥410mm, and the surface roughness Ra4 is 0.50~0.65μm;

[0018] The diameter of the roller in the middle of the fifth frame is ≤410mm, and the roughness Ra5 is 0.45~0.55μm.

[0019] Furthermore, in step 1), the length of the tapered cylindrical structure at any end of the fifth frame roller along its axial direction is 80-120mm, and the difference between the radius of the axial end of the fifth frame roller and the radius of its central cylindrical shape is 0.10-0.15mm.

[0020] Furthermore, the emulsion parameters for each stand in step 2) are as follows: the emulsion concentration C1 for the first four stands of the five-stand continuous rolling mill is ≥1.8%, and the saponification value SV1 is ≥170mgKOH / g; the emulsion concentration C2 for the fifth stand of the five-stand continuous rolling mill is ≥6.0%, and the saponification value SV2 is 180~190mgKOH / g.

[0021] Furthermore, in step 2), the calculation formula used to control the gradual reduction of the emulsion injection pressure during each cold rolling process after the five-stand continuous rolling mill completes the pre-rolling is as follows:

[0022] P = A² + (A₁ - A₂) / (1 + (x / x₀)) a ;

[0023] In the formula: P is the emulsion injection pressure of the third stand; A1, A2 and x0 are all constants, with A1 ranging from 1.035 to 1.040, A2 ranging from 0.50 to 0.55, and x0 ranging from 2.80 to 2.82; a is an exponent, ranging from 2.0 to 2.5; x is the number of coils rolled after pre-rolling in the five-stand continuous rolling mill.

[0024] Furthermore, the correspondence between the raw material thickness selection and the product thickness specification in step 2) of cold rolling ultra-thin strip production is as follows:

[0025] The product thickness specifications are [0.16mm, 0.18mm], and the raw material thickness is 1.6mm;

[0026] The product thickness specification is (0.18mm, 0.19mm), and the raw material thickness is 1.7mm;

[0027] The product thickness specifications are (0.19mm, 0.20mm), and the raw material thickness is 1.8mm.

[0028] Furthermore, in step 3), the thickness of the transition strip steel raw material is not less than 0.2 mm.

[0029] Furthermore, the production speed V1 for rolling transition coil strip steel in the production process is <900m / min, and the production speed V2 for rolling target coil ultra-thin strip steel in the production process is ≥900m / min.

[0030] Furthermore, in step 3), the number of coils of transition strip steel produced is 1.

[0031] As can be seen from the above technical solutions, the technical solutions of the present invention have achieved the following beneficial effects:

[0032] The production process of cold-rolled ultra-thin strip steel disclosed in this invention includes: 1) designing and constructing a five-stand continuous rolling mill, wherein the first four stands of the five-stand continuous rolling mill are all cylindrical rolls, and the fifth stand roll is designed as a cylindrical roll with tapered ends along the axial direction; 2) setting the working parameters of the five-stand continuous rolling mill, including raw material thickness, production speed, inter-stand reduction rate distribution, structural parameters of each stand roll, and emulsion parameters of each stand; wherein, the emulsion spraying of the third stand of the five-stand continuous rolling mill is controlled separately, and the emulsion spraying pressure is gradually reduced during the rolling process of each coil of strip steel after the pre-rolling is completed in the five-stand continuous rolling mill; 3) selecting transition strip steel raw material to pre-roll transition coil strip steel on the five-stand continuous rolling mill, and producing target coil ultra-thin strip steel according to the preset cold rolling program after completion; the production process of this invention can effectively reduce the mill vibration when producing ultra-thin strip steel at high speed, ensure product quality, and reduce production costs.

[0033] This invention addresses the specific aspects of suppressing mill vibration caused by high-speed production of ultra-thin strip steel, including: 1) Starting with raw material thickness, rationally arranging the initial rolling raw materials, and setting raw material thicknesses for strip steel of various thickness specifications to ensure stable strip steel operation between stands during the rolling process; 2) Rolling transition coil strip steel before rolling the target ultra-thin strip steel to increase the temperature of the fifth stand rolls and maintain reasonable roll shape and bending conditions; 3) Optimizing the reduction rate distribution, with the total reduction rate not exceeding 90%, the third stand reduction rate at 36%–40%, and the fifth stand reduction rate at 28%–32%, effectively improving the roll service life; 4) Changing the emulsion spraying method of the third stand, reducing the emulsion flow rate to increase rolling force, prevent slippage, improve rolling process stability, and reduce the probability of mill vibration; 5) Designing the tapered strip of the fifth stand rolls; The combined effects of these processes ensure uniform load distribution during strip steel rolling, improving rolling stability. This invention solves the problems of vibration marks, product quality degradation, and rolling instability caused by mill vibration that are unavoidable when producing ultra-thin strip steel at high speed using conventional production methods. It effectively improves the rolling stability of cold-rolled thin strip steel and avoids problems such as thickness fluctuations and abnormal roll changes caused by mill vibration.

[0034] It should be appreciated that all combinations of the foregoing concepts, as well as additional concepts described in greater detail below, to the extent such concepts are not mutually inconsistent, can be considered to be part of the inventive subject matter of this disclosure.

[0035] The foregoing and other aspects, embodiments, and features of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as features and / or beneficial effects of the exemplary embodiments, will become apparent from the following description or through practice of specific embodiments according to the present invention. Attached Figure Description

[0036] The accompanying drawings are not drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein:

[0037] Figure 1 This is a flowchart of the production process of cold-rolled ultra-thin strip steel according to the present invention;

[0038] Figure 2 This is a front view of the fifth stand roll of the five-stand continuous rolling mill of the present invention;

[0039] Figure 3 This is the fitting curve for the emulsion pressure control of the third frame in this invention. Detailed Implementation

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs.

[0041] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. Terms such as "above," "below," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0042] The existing technologies for addressing the issue of mill vibration caused by high-speed production of ultra-thin strip steel, which leads to reduced product quality, mainly involve prior monitoring to quickly adjust production parameters upon detecting vibration signals, or optimizing specific processes in the cold rolling process to suppress mill vibration. However, these solutions cannot fully resolve the product quality problems caused by mill vibration and do not significantly improve production efficiency. Therefore, this invention aims to propose a production process for cold-rolled ultra-thin strip steel that effectively reduces mill vibration while achieving high-speed cold rolling production of ultra-thin strip steel, without affecting product quality and reducing production costs.

[0043] Combine Figure 1 As shown, the production process for cold-rolled ultra-thin strip steel disclosed in this invention is applied to a five-stand continuous rolling mill and includes the following steps:

[0044] Step S1: Design the structure of the rolls for each stand of the five-stand continuous rolling mill, and construct the five-stand continuous rolling mill; wherein, the first four stands of the five-stand continuous rolling mill all use cylindrical rolls, and the rolls of the fifth stand are designed as... Figure 2 The illustrated cylindrical rolls are tapered at both ends along their axial direction. Specific structural parameters for each stand roll are as follows: First stand roll diameter D1 ≤ 420 mm, surface roughness Ra1 ≥ 1.0 μm; Second stand roll diameter ≤ 450 mm, surface roughness Ra2 ≥ 1.0 μm; Third stand roll diameter ≥ 420 mm, surface roughness Ra3: 0.65~0.80 μm; Fourth stand roll diameter ≥ 410 mm, surface roughness Ra4: 0.50~0.65 μm; Fifth stand roll diameter in the middle section ≤ 410 mm, surface roughness Ra5: 0.45~0.55 μm; Furthermore, the length of any stand roll is not less than 1200 mm. Specifically, the length of the intermediate work roll and support roll in a five-stand continuous rolling mill is set to 1200~1500 mm, and the length of the intermediate roll is set to 1230~1530 mm, with the intermediate roll being 30 mm longer than the work roll or support roll.

[0045] Figure 2 The cylindrical roller shown has tapered ends, and the length of the tapered cylindrical structure at either end along its axial direction is 80-120mm. The difference between the radius of the axial end of the fifth frame roller and the radius of its central cylindrical shape is 0.10-0.15mm. In the following embodiment, the length of the tapered cylindrical structure along its axial direction is designed to be 110mm, and the difference between the radius of the axial end of the fifth frame roller and the radius of its central cylindrical shape is 0.12mm.

[0046] Step S2: According to the size requirements of the ultra-thin strip steel products produced, set the working parameters of the five-stand continuous rolling mill. The working parameters include: raw material thickness, production speed, inter-stand reduction rate distribution, roll structure parameters of each stand, and emulsion parameters of each stand. Among them, the emulsion spraying of the third stand of the five-stand continuous rolling mill is controlled separately, and the emulsion spraying pressure is gradually reduced during the rolling process of each coil of strip steel after the pre-rolling of the five-stand continuous rolling mill.

[0047] The correspondence between the raw material thickness selection and the product thickness specification for cold-rolled ultra-thin strip steel is as follows: for product thickness specifications of [0.16mm, 0.18mm], the raw material thickness is 1.6mm; for product thickness specifications of (0.18mm, 0.19mm], the raw material thickness is 1.7mm; for product thickness specifications of (0.19mm, 0.20mm], the raw material thickness is 1.8mm.

[0048] The reduction rate distribution between stands is as follows: the total reduction rate of the five-stand continuous rolling mill does not exceed 90%, and the reduction rate of the third stand of the five-stand continuous rolling mill is 36% to 40%, and the reduction rate of the fifth stand is 28% to 32%.

[0049] The emulsion parameters for each stand are as follows: for the first four stands of the five-stand continuous rolling mill, the emulsion concentration C1 is ≥ 1.8% and the saponification value SV1 is ≥ 170 mg KOH / g; for the fifth stand of the five-stand continuous rolling mill, the emulsion concentration C2 is ≥ 6.0% and the saponification value SV2 is 180-190 mg KOH / g.

[0050] The calculation formula used to control the gradual reduction of emulsion injection pressure during each cold rolling process after the pre-rolling of the five-stand continuous rolling mill is as follows:

[0051] P = A² + (A₁ - A₂) / (1 + (x / x₀)) a ;

[0052] In the formula: P is the emulsion injection pressure of the third stand; A1, A2 and x0 are all constants, with A1 ranging from 1.035 to 1.040, A2 ranging from 0.50 to 0.55, and x0 ranging from 2.80 to 2.82; a is an exponent, ranging from 2.0 to 2.5; x is the number of coils rolled after pre-rolling in the five-stand continuous rolling mill.

[0053] Step S3: Select transition strip steel raw material and pre-roll it on a five-stand continuous rolling mill to produce transition coil strip steel; wherein, the thickness of the transition strip steel raw material is not less than the maximum value of the raw material thickness selected by the five-stand continuous rolling mill to produce multiple target thickness specifications of ultra-thin strip steel.

[0054] Step S4: After the transition coil strip is cold rolled, the target coil ultra-thin strip is produced on a five-stand continuous rolling mill according to the preset cold rolling program.

[0055] When producing ultra-thin strip steel of the above-mentioned multiple product thickness specifications, the thickness of the transition strip steel raw material shall not be less than 0.2mm, and the production speed of rolling the transition coil strip steel V1 < 900m / min, and the production speed of rolling the target coil ultra-thin strip steel V2 ≥ 900m / min.

[0056] The production process of cold-rolled ultra-thin strip steel disclosed in this invention will be further described in detail below with reference to specific embodiments.

[0057] Example 1: Production of ultra-thin steel strip with a thickness of 0.18mm

[0058] Step S1: Construct a five-stand continuous rolling mill, wherein: the roll diameter D1 of the first stand roll is 419mm, and the surface roughness Ra11.27μm; the roll diameter of the second stand roll is 447mm, and the surface roughness Ra21.03μm; the roll diameter of the third stand roll is 431mm, and the surface roughness Ra3: 0.70μm; the roll diameter of the fourth stand roll is 416mm, and the surface roughness Ra4: 0.52μm; the roll diameter of the middle section of the fifth stand roll is 406mm, and the roll shape is a cylindrical roll with tapered ends along the axial direction, with a surface roughness Ra5: 0.45μm;

[0059] In step S2, the raw material thickness of the cold-rolled strip is 1.6 mm, the product thickness specification is 0.18 mm, and the reduction rate distribution between stands is as follows: the total reduction rate does not exceed 90%, the reduction rate of the third stand of the five-stand continuous rolling mill is 36.0%, the reduction rate of the fifth stand is 29%, and the reduction rate of the remaining stands is automatically allocated by the system.

[0060] The emulsion parameters for each stand are as follows: the emulsion concentration C1 for the first four stands of the five-stand continuous rolling mill is 2.20%, and the saponification value SV1 is 177.47 mgKOH / g; the emulsion concentration C2 for the fifth stand of the five-stand continuous rolling mill is 6.63%, and the saponification value SV2 is 189.59 mgKOH / g.

[0061] The calculation formula used to control the gradual reduction of emulsion injection pressure during each cold rolling process after the pre-rolling of the five-stand continuous rolling mill is as follows:

[0062] P = A² + (A₁ - A₂) / (1 + (x / x₀)) a ;

[0063] In the formula: P is the emulsion injection pressure of the third stand; A1, A2, and x0 are all constants, with A1 taking the value of 1.035, A2 taking the value of 0.50, and x0 taking the value of 2.80; a is an exponent, taking the value of 2.1; x is the number of coils rolled after pre-rolling in the five-stand continuous rolling mill, as shown in Table 1 below; during formal rolling, the emulsion injection pressure of the third stand is shown in Table 1 below. According to the coil number fitting, as the number of coils increases, the emulsion pressure decreases. The fitting curve of the above formula for calculating the emulsion pressure of the third stand is as follows: Figure 3 As shown, the results indicate that the curve fit is good, the rolling force of the subsequent third stand is stable with little variation, the rolling process is stable, and the mill vibration is well controlled.

[0064] Table 1 Emulsion injection pressure of the third frame

[0065] Volumes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 pressure 1 0.88 0.74 0.6 0.59 0.6 0.53 0.53 0.52 0.51 0.51 0.51 0.51 0.51 0.5 0.5

[0066] Step S3: In this embodiment, only one roll of transition strip steel is produced. The thickness of the transition strip steel raw material used in the production is 0.2 mm, and the production speed V1 of rolling the transition strip steel is 850 m / min.

[0067] Step S4: Produce the target coil ultra-thin strip steel on a five-stand continuous rolling mill according to the preset cold rolling program. The production speed V2 of the target coil ultra-thin strip steel is 1100m / min.

[0068] Example 2: Production of ultra-thin steel strip with a thickness of 0.19 mm

[0069] Step S1: Construct a five-stand continuous rolling mill, wherein: the roll diameter D1 of the first stand roll is 414mm, and the roughness Ra1 is 11.30μm; the roll diameter of the second stand roll is 436mm, and the roughness Ra2 is 11.12μm; the roll diameter of the third stand roll is 438mm, and the roughness Ra3 is 0.65μm; the roll diameter of the fourth stand roll is 422mm, and the roughness Ra4 is 0.60μm; the roll diameter of the middle part of the fifth stand roll is 401mm, and the roll shape is a cylindrical roll with tapered ends in the axial direction, with a roughness Ra5 of 0.48μm.

[0070] In step S2, the raw material thickness of the cold-rolled strip is 1.7 mm, the product thickness specification is 0.19 mm, and the reduction rate distribution between stands is as follows: the total reduction rate does not exceed 90%, the reduction rate of the third stand of the five-stand continuous rolling mill is 37.5%, the reduction rate of the fifth stand is 31%, and the reduction rate of the remaining stands is automatically allocated by the system.

[0071] The emulsion parameters for each stand are as follows: the emulsion concentration C1 for the first four stands of the five-stand continuous rolling mill is 2.77%, and the saponification value SV1 is 175.86 mgKOH / g; the emulsion concentration C2 for the fifth stand of the five-stand continuous rolling mill is 6.06%, and the saponification value SV2 is 188.14 mgKOH / g.

[0072] The calculation formula used to control the gradual reduction of emulsion injection pressure during each cold rolling process after the pre-rolling of the five-stand continuous rolling mill is as follows:

[0073] P = A² + (A₁ - A₂) / (1 + (x / x₀)) a ;

[0074] In the formula: P is the emulsion injection pressure of the third stand; A1, A2 and x0 are all constants, with A1 taking the value of 1.040, A2 taking the value of 0.55 and x0 taking the value of 2.82; a is an exponent, taking the value of 2.5; x is the number of rolled coils after pre-rolling in the five-stand continuous rolling mill, and the values ​​are shown in Table 2 below; the emulsion injection pressure of the third stand is shown in Table 2 below.

[0075] Table 2 Emulsion injection pressure of the third frame

[0076] Volumes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 pressure 1.02 0.91 0.77 0.68 0.63 0.60 0.59 0.57 0.57 0.56 0.56 0.56 0.56 0.56 0.55 0.55

[0077] Step S3: In this embodiment, only one roll of transition strip steel is produced. The thickness of the transition strip steel raw material used in the production is 0.2 mm, and the production speed V1 of rolling the transition strip steel is 850 m / min.

[0078] Step S4: Produce the target coil ultra-thin strip steel on a five-stand continuous rolling mill according to the preset cold rolling program. The production speed V2 of the production process for rolling the target coil ultra-thin strip steel is 1200m / min.

[0079] The production process for cold-rolled ultra-thin strip steel disclosed in this invention relies on existing cold-rolling production lines for strip steel. Starting with the thickness of the raw material, it combines various measures such as rationally selecting the initial rolling material thickness and production rhythm based on the target product specifications, optimizing the reduction rate distribution of each stand, roll matching, roll shape of the fifth stand, and emulsion spraying method, to ensure uniform load distribution during the strip steel rolling process. This not only solves the problems of vibration marks and rolling instability caused by mill vibration that are unavoidable in the high-speed production of ultra-thin strip steel using conventional production methods, but also effectively improves the stability of the quality of cold-rolled ultra-thin strip steel, avoiding thickness fluctuations and abnormal roll changes caused by mill vibration.

[0080] While the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Persons skilled in the art will readily appreciate that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A production process for cold-rolled ultra-thin strip steel, characterized in that: Applied to a five-stand continuous rolling mill, the steps include: 1) Designing the structure of each stand roller of a five-stand continuous rolling mill and building the five-stand continuous rolling mill; wherein the first four stand rollers of the five-stand continuous rolling mill are cylindrical rollers, and the fifth stand roller is designed as a cylindrical roller with tapers at both ends of the axial direction; 2) According to the size requirements of the ultra-thin strip steel products to be produced, the working parameters of the five-stand tandem mill are set, and the working parameters include: raw material thickness, production speed, distribution of reduction ratios between stands, structural parameters of rollers of each stand, and parameters of emulsion of each stand; wherein the emulsion of the third stand of the five-stand tandem mill is sprayed separately, and the emulsion spraying pressure is controlled to gradually decrease during the rolling process of each roll of strip steel after the five-stand tandem mill completes pre-rolling; 3) Selecting a transition strip steel raw material for pre-rolling on a five-stand continuous rolling mill to produce transition coil steel; wherein the thickness of the transition strip steel raw material is not less than the maximum value of the thickness of the raw material selected for producing multiple target thickness specifications of ultra-thin strip steel by the five-stand continuous rolling mill; 4) After the transition coil is cold-rolled, the target coil of ultra-thin strip steel is produced on a five-stand continuous rolling mill according to the preset cold rolling program.

2. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: In the step 2), the rolling reduction ratio among the stands is distributed as follows: the total rolling reduction ratio of the five-stand tandem mill does not exceed 90%, and the rolling reduction ratio of the third stand of the five-stand tandem mill is 36% to 40%, and the rolling reduction ratio of the fifth stand is 28% to 32%.

3. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: The structural parameters of each frame roller in step 2) are: The length of any stand roller of the five-stand continuous rolling mill is not less than 1200 mm; The roller diameter of the first stand roller is D1≤420mm, and the roughness is Ra1≥1.0μm; The roller diameter of the second stand roller is ≤450mm, and the roughness Ra2 is ≥1.0μm; The roller diameter of the third stand roller is ≥420mm, and the roughness Ra3 is 0.65~0.80μm; The roller diameter of the fourth stand roller is ≥410mm, and the roughness Ra4 is 0.50~0.65μm; The roller diameter of the middle part of the fifth stand roller is ≤410mm, and the roughness Ra5 is 0.45~0.55μm.

4. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: In the step 1), the length of the tapered cylindrical structure at either axial end of the fifth frame roller is 80-120 mm along its axial direction, and the difference between the radius of the axial end of the fifth frame roller and the radius of the central cylinder is 0.10-0.15 mm.

5. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: The emulsion parameters of each stand in the step 2) are: the emulsion concentration C1 used by the first four stands of the five-stand continuous rolling mill is ≥1.8%, and the saponification value SV1 is ≥170 mgKOH / g; the emulsion concentration C2 used by the fifth stand of the five-stand continuous rolling mill is ≥6.0%, and the saponification value SV2 is 180-190 mgKOH / g.

6. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: In the step 2), the calculation formula used to gradually reduce the emulsion injection pressure during each cold rolling process after the five-stand continuous rolling mill completes the pre-rolling is: <h2 style=";text-align:left;direction:ltr">P = A2 + (A1 - A2) / (1 + (x / x0)<h2 style=";text-align:left;direction:ltr"> a <h2 style=";text-align:left;direction:ltr"> ; Wherein: P is the emulsion injection pressure of the third stand; A1, A2 and x0 are all constants, A1 is 1.035~1.040, A2 is 0.50~0.55, x0 is 2.80~2.82; a is an index, with a value between 2.0-2.5; x is the number of rolled coils after the five-stand continuous rolling mill completes pre-rolling.

7. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: The corresponding relationship between the raw material thickness selection and the product thickness specification of the step 2) cold rolling ultra-thin strip steel is: The product thickness specification is [0.16mm, 0.18mm], and the raw material thickness is 1.6mm; The product thickness specification is (0.18mm, 0.19mm], and the raw material thickness is 1.7mm; The product thickness specification is (0.19mm, 0.20mm], and the raw material thickness is 1.8mm.

8. The production process of cold-rolled ultra-thin steel strip according to claim 7, characterized in that: In the step 3), the thickness of the transition strip steel raw material is not less than 0.2 mm.

9. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: The production speed V1 of the transitional coil steel strip rolled by the production process is less than 900 m / min, and the production speed V2 of the target coil ultra-thin strip steel rolled by the production process is greater than or equal to 900 m / min.

10. The production process of cold-rolled ultra-thin steel strip according to claim 1, characterized in that: The number of coils of transitional strip steel produced in step 3) is 1.

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