Rolling method of low-nickel austenitic stainless steel cold-rolled thin strip

Abstract

The invention provides a rolling method of a low-nickel austenitic stainless steel cold-rolled thin strip, which comprises the following steps: S1, selecting a low-nickel-iron austenitic stainless steel 2E coil with the nickel content of less than or equal to 1.20% and the manganese content of more than or equal to 10.7% as a raw material, and inspecting the raw material; s2, a twenty-roller reversible cold rolling unit is adopted for multi-pass reversible rolling, the diameter phi of a working roller is 36-48 mm, and a sectional type hydraulic roller bending system is adopted as a supporting roller; s3, by dynamically adjusting the roll gap, the tension and the rolling speed, stepped reduction rate distribution and online strip shape closed-loop regulation and control are implemented, and cooperative control is formed by the stepped reduction rate distribution and the tension gradient increasing mode; s4, in the rolling process, a lubricant containing stainless steel cold rolling oil is adopted for gradient cooling; and S5, two-stage bright annealing treatment is carried out after rolling. The problems that the stainless steel cold-rolled thin strip is insufficient in thickness precision, poor in strip shape control and low in rolling precision are solved.

Description

Technical Field

[0001] The invention relates to the field of stainless steel manufacturing, and in particular to a method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip. Background Art

[0002] Low-nickel austenitic stainless steel is a nickel-saving stainless steel that maintains its austenitic structure by reducing the nickel content (≤1.20%) and increasing elements such as manganese and nitrogen. It offers excellent corrosion resistance, formability, and cost advantages, making it widely used in architectural decoration, home appliances, medical devices, and the food industry. However, traditional cold rolling equipment faces significant technical bottlenecks in the rolling of low-nickel iron austenitic stainless steel. Four- and six-high mills, due to their large work roll diameters (typically Φ120mm or greater), experience significant elastic deformation during rolling, making it difficult to achieve high-precision control of thin strip thicknesses of ≤0.5mm.

[0003] In summary, the prior art has the following problems: the existing rolling process has problems such as insufficient thickness accuracy, poor plate shape control, and low rolling accuracy. Summary of the Invention

[0004] The present invention provides a low-nickel austenitic stainless steel cold-rolled thin strip rolling method to solve the problems of insufficient thickness accuracy, poor plate shape control and low rolling accuracy of the stainless steel cold-rolled thin strip in the existing rolling process.

[0005] To this end, the present invention provides a low-nickel austenitic stainless steel cold-rolled thin strip rolling method, comprising the following steps:

[0006] S1. Select low-nickel iron austenitic stainless steel 2E coil with nickel content ≤ 1.20% and manganese content ≥ 10.7% as raw material and conduct raw material inspection;

[0007] S2, adopts 20-high reversible cold rolling mill for multi-pass reversible rolling, with working roll diameter of Φ36-48mm and support roll adopting segmented hydraulic bending roll system;

[0008] S3. Implementing step-by-step reduction rate distribution and online flatness closed-loop control by dynamically adjusting the roll gap, tension, and rolling speed. The step-by-step reduction rate distribution and the tension gradient increasing mode form a coordinated control;

[0009] S4, during the rolling process, a lubricant containing stainless steel cold rolling oil is used for gradient cooling;

[0010] S5. After rolling, two-stage bright annealing treatment is performed.

[0011] The finished product produced by the above method meets the following requirements: thickness ≤ 0.5mm, tolerance ≤ ± 0.005mm; tensile strength 850-1100MPa, elongation after fracture 15%-55%; surface roughness Ra 0.07-0.25μm; and grain boundary carbide precipitation amount ≤ 0.5%.

[0012] Among them, the raw material inspection includes: thickness deviation ≤±0.02mm, plate convexity range is -0.01~+0.04mm; longitudinal / transverse warping wave height is <10mm, overflow edge single side ≤3mm; yield strength ≤500MPa, tensile strength ≤950MPa, hardness ≤97HRBW; initial grain size is 7.5~9.0 grades.

[0013] The rolling parameter control includes: the first-pass rolling speed is 150-250 m / min, and the speed is automatically reduced by 15%-20% when the measured rolling force exceeds the preset value by 10%;

[0014] Step-by-step reduction rate distribution: first pass 25% to 32%, last pass 7% to 12%, total reduction rate 65% to 80%; bending roll force control range 50 to 200 kN, bending roll response time ≤ 0.5s.

[0015] The tension control adopts the front tension gradient increasing mode: the unit tension gradient is 1.5~2.5N / mm 2 / pass; export unit tension 18~35kg / mm 2 , inlet 14~28kg / mm 2 ; Tension fluctuation rate ≤3%.

[0016] The roller system configuration includes: the crown of the second intermediate non-drive roller is 0.2-0.3 mm; the first intermediate roller is tapered: the taper length is 200-230 mm, the taper is 0.60-0.65 mm; the taper / cone length ratio is 0.0025-0.0035; the taper / crown ratio is 2.0-3.2; and the effective overlap width value is (80±2)% of the strip width.

[0017] The online flatness closed-loop control includes:

[0018] Adopt multi-sensor fusion monitoring: laser scanning plate shape meter (accuracy ±0.3I-unit) + X-ray thickness gauge (accuracy ±0.001mm);

[0019] Multi-parameter coupling control based on fuzzy PID algorithm: rolling force-tension-speed coupling response time ≤ 100ms.

[0020] The gradient cooling satisfies:

[0021] Use stainless steel cold rolling oil, the particle size of which is precisely controlled at 50±5nm and the content is 1.0%±0.1%;

[0022] The spraying interval t (s) and the rolling speed v (m / min) meet the following conditions: t = 60 / v ± 2s;

[0023] The cooling intensity of the edge is 15±3% higher than that of the middle.

[0024] The two-stage bright annealing comprises:

[0025] Front stage: 1050-1100℃×1-2min, hydrogen-nitrogen mixed gas, with hydrogen content of 5%-8%;

[0026] Back stage: 850~900℃×1~1.5min, dew point ≤-60℃;

[0027] Cooling rate: 20-30℃ / s.

[0028] The present invention also provides a low-nickel austenitic stainless steel cold-rolled thin strip, which is rolled using the low-nickel iron austenitic stainless steel cold-rolled thin strip rolling method described above. The cold-rolled thin strip is made of 201J5 stainless steel and has a gradient microstructure: the grain size at the edge is 5% to 8% smaller than that in the middle; the performance anisotropy ratio is ≤1.05; the surface residual stress is -50 to -150 MPa; and the corrosion resistance is: no pitting corrosion after immersion in 5% NaCl solution for 720 hours.

[0029] The raw material composition of the present invention is selected as follows: nickel content 1.1% ± 0.1%, manganese content 10.5% -12% (the contents of other elements are: (chromium (Cr): 13.0% to 16.0%, carbon (C): ≤ 0.15% (for example, 0.10% to 0.15%), silicon (Si): ≤ 0.60%, phosphorus (P): ≤ 0.060%, sulfur (S): ≤ 0.005%, nitrogen (N): ≤ 0.25%, copper (Cu): ≤ 0.8% (for example, 0.3% to 0.6%)), and the rest are iron, trace alloying elements and inevitable impurities.

[0030] Beneficial effects of the present invention:

[0031] 1. The present invention adopts a 20-high reversible cold rolling mill with a segmented hydraulic bending roll system (wherein: the roll system configuration includes: the crown of the second intermediate non-drive roll is 0.2-0.3mm; the first intermediate roll is tapered: the taper length is 200-230mm, the taper is 0.60-0.65mm; the taper / cone length ratio is 0.0025-0.0035; the taper / crown ratio is 2.0-3.2; the effective overlap width is (80±2)% of the strip width), combined with a stepped reduction rate distribution (first pass 25%-32%, last pass 7%-12%, total reduction rate 65%-80%; bending roll force control range 50-200kN, bending roll response time ≤0.5s) and a tension gradient increasing mode (unit tension gradient 1.5-2.5N / mm 2 / pass; export unit tension 18~35kg / mm 2 , inlet 14~28kg / mm 2 ; tension fluctuation rate ≤3%), achieving high-precision rolling with a thickness tolerance of ≤±0.005mm. The application of an online closed-loop flatness control system and a fuzzy PID algorithm enables rolling speeds up to 600m / min, increasing production efficiency by over 40%, while ensuring flatness ≤3I-units. This significantly improves rolling accuracy and production efficiency, providing reliable dimensional accuracy for high-end applications.

[0032] 2. This invention utilizes a two-stage bright annealing process combined with a hydrogen-nitrogen mixed protective atmosphere to achieve a gradient microstructure: grain size at the edges is 5% to 8% smaller than in the center, and carbide precipitation at grain boundaries is ≤0.5%. Gradient cooling of the stainless steel cold rolling oil effectively reduces residual stress. These technical measures ensure that the finished product exhibits both excellent mechanical properties and surface quality. Testing has shown no pitting after immersion in a 5% NaCl solution for 720 hours. This optimizes the microstructure and enhances overall performance, meeting the stringent requirements of high-end applications such as medical devices.

[0033] 3. The present invention significantly reduces production costs while ensuring performance through raw material optimization and process optimization. Specifically, energy consumption per ton of steel is reduced by 15% to 20%, the yield rate is ≥95% (strip breakage rate ≤5%), and the roller life is extended to 8,000 to 10,000 tons / group. The process design takes into account the needs of different application scenarios. It can be used to produce high-precision ultra-thin strips with a thickness of ≤0.3mm (suitable for medical devices and electronic components), and can also be used to produce conventional strips of about 0.5mm through a simplified process (suitable for home appliances and architectural decoration), achieving the best balance between performance and cost, and expanding the application range of low-nickel stainless steel in multiple industrial fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a metallographic photograph of Example 1 of the present invention, magnified 200 times;

[0035] Figure 2 This is a metallographic photograph of Example 2 of the present invention, magnified 200 times;

[0036] Figure 3 This is a metallographic photograph of Example 3 of the present invention, magnified 200 times. DETAILED DESCRIPTION

[0037] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the present invention is now described.

[0038] Example 1: Rolling and performance verification under standard process parameters

[0039] 1. Process details

[0040] Raw material selection:

[0041] The material selection for this example is based on the GB / T3280-2015 "Stainless Steel Cold-Rolled Sheet and Strip" standard and the ultrasonic flaw detection requirements of GB / T2970-2016. The selected materials are 201J5 stainless steel 2E coils with a nickel content of 1.15% ± 0.1% and a manganese content of 11% ± 0.2%.

[0042] The components of Example 1 mainly include: (chromium (Cr): 13.25%, nickel: 1.08%, manganese: 11.51%, carbon (C): 0.149%, silicon (Si): 0.51%, phosphorus (P): 0.05%, sulfur (S): 0.003%, nitrogen (N): 0.192%, copper (Cu): 0.25%), and the rest are iron and unavoidable impurities; in the present invention, the components of each example are shown in Table 1.

[0043] Its initial thickness is strictly controlled at 1.5mm±0.02mm (coiling tension 200±50N / mm 2 ), with a width of 650mm±2mm. Storage conditions must be maintained at 25±5°C and humidity ≤60%RH (in compliance with ISO8573-1:2010) to ensure the stability of the initial quality of the raw materials, laying a high-quality foundation for subsequent rolling processes.

[0044] Rolling system configuration:

[0045] The working rollers are high-precision grinding rollers with a diameter range of Φ36 to 48 mm, with a grinding accuracy of ±0.001 mm and a surface roughness of Ra ≤ 0.05 μm (according to GB / T1800.2-2020 standard);

[0046] The support rolls are equipped with a segmented hydraulic roll bending system, with a pressure sensor accuracy controlled within ±0.1kN, which allows precise adjustment of the roll shape to suit rolling requirements.

[0047] The rolling oil filtration accuracy is ≤5μm (ISO4406-2017 standard), and the temperature is maintained at 40±2℃ to ensure the lubrication and cooling effect of the rolling process.

[0048] Rolling parameters:

[0049] The first-pass rolling speed is set at 180±5m / min, the reduction rate is precisely controlled at 28%±1%, and the unit tension gradient is 2.0±0.1N / mm 2 / pass, the larger reduction rate makes the strip fully deformed, activates the rearrangement of the grains inside the material and optimizes the organizational structure;

[0050] The final pass speed is 320±10m / min, at which point the reduction rate is reduced to 10%±0.5%, and the unit tension gradient is adjusted to 2.3±0.1N / mm 2 / pass, the setting of small reduction rate can effectively control the plate shape and avoid defects such as excessive extension of the edge and waving in the middle;

[0051] The total reduction rate is controlled within the range of 70%±1%, and the bending roll force is maintained at 120±5kN (roll changing cycle 1500±50 tons) to ensure the stability of the rolling process and the uniformity of the strip quality.

[0052] Lubrication and cooling:

[0053] Implementation standard: ISO6743-4 lubricant classification standard

[0054] Stainless steel cold rolling oil is selected, with its particle size precisely controlled at 80±5nm and content of 1.0%±0.1%. The injection interval is dynamically adjusted according to the rolling speed. When the rolling speed is 300±5m / min, the injection interval is set to 0.2±0.01s to achieve precise lubrication;

[0055] The cooling system adopts a gradient cooling mode in which the cooling intensity at the edge is 18%±1% higher than that in the middle, which strengthens heat dissipation at the edge, balances the temperature distribution of the strip, and suppresses problems such as uneven deformation and residual stress concentration caused by temperature differences.

[0056] 2. Annealing process:

[0057] Implementation standard: GB / T13305-2008 "Specification for Heat Treatment of Stainless Steel"; the annealing process is divided into the front section and the back section.

[0058] Pre-annealing: The temperature is precisely set at 1080±5℃, the holding time is strictly controlled at 1.5±0.1min, and high-purity protective gas with H2 purity ≥99.99% and N2 purity ≥99.999% is selected. The pressure in the furnace is maintained within the range of 80±30Pa to ensure that annealing is completed in a non-oxidizing and non-nitriding atmosphere, eliminating work hardening and optimizing the material structure.

[0059] Post-annealing: The temperature is lowered to 880±5°C, the holding time is 1±0.1min, the cooling rate is precisely controlled at 25±1°C / s, and the conductivity of the cooling water is ≤5μS / cm. This ensures the uniformity and stability of the cooling process, further refines the grains, and improves the overall performance of the material.

[0060] 3. Parameter optimization basis

[0061] Stepped reduction rate: A high reduction rate (28%±1%) is used in the first pass to fully stimulate the material's plastic deformation potential, activate dislocation movement and grain crushing, and create conditions for subsequent microstructure refinement; a low reduction rate (10%±0.5%) is used in the final pass to precisely control the strip shape, suppress defects such as edge thinning and center bulge caused by excessive reduction, and achieve high-precision control of strip flatness;

[0062] Tension gradient: Using the pre-tension increasing mode, the tension is dynamically adjusted according to the stress-strain characteristics of the material during the rolling process, and the tension fluctuation rate is strictly controlled within the range of ≤2.5%, effectively reducing the risk of edge cracks and ensuring the integrity and continuity of the strip edge quality;

[0063] Roller configuration: The taper / crown ratio is optimized to 2.5±0.1, and the taper / cone length ratio is 0.003±0.0002. Through precise roll profile design and bending force control, the strip edge thinning is precisely suppressed, keeping it within a very small range of ≤0.003mm, improving the uniformity and consistency of product quality.

[0064] 4. Implementation effect verification

[0065] Finished product performance:

[0066] Implementation standard: GB / T228.1-2021 "Tensile test of metal materials"

[0067] The finished product achieves a precise thickness of 0.48 ± 0.004 mm, a tensile strength of 935 ± 10 MPa, and an elongation at break of 32% ± 1%, demonstrating an excellent balance of strength and ductility. The surface roughness Ra is controlled at 0.09 ± 0.02 μm, and the amount of carbide precipitation at the grain boundaries is only 0.3% ± 0.05%, indicating good surface quality and structural uniformity. The finished product is 650 mm wide.

[0068] Microstructure:

[0069] Implementation standard: ASTM E112-13 "Grain size determination method"

[0070] Metallographic structure Figure 1 As shown, the grain size of the edge is 9.5±0.2 (ASTM standard), the core is 9.0±0.2, and the dislocation density gradient is significant;

[0071] The residual stress is evenly distributed (-100±20MPa), revealing the orderly arrangement of the material's internal structure and the reasonable distribution of stress, providing microstructural support for the material's excellent performance.

[0072] Corrosion resistance:

[0073] Implementation standard: GB / T17899-1999 "Measurement method of pitting potential of stainless steel"

[0074] The finished product showed no pitting corrosion after being immersed in 5% NaCl solution for 720 hours, and the critical pitting temperature (CPT) was ≥38±1℃, which verified the material's excellent corrosion resistance in harsh corrosive environments and expanded its application areas and service life.

[0075] Example 2: High-precision ultra-thin strip rolling (thickness ≤ 0.3 mm)

[0076] 1. Process adjustment

[0077] Raw material optimization: (The main components include: (chromium (Cr): 13.45%, nickel: 1.18%, manganese: 11.85%, carbon (C): 0.142%, silicon (Si): 0.36%, phosphorus (P): 0.045%, sulfur (S): 0.003%, nitrogen (N): 0.201%, copper (Cu): 0.48%), and the rest are iron, trace alloying elements and inevitable impurities. The specific composition of Example 2 is shown in Table 1

[0078] Implementation standard: YB / T5363-2016 "Stainless steel hot-rolled steel plate and strip"

[0079] High-quality raw materials with an initial thickness of 1.2±0.02mm are selected, and a pre-annealing treatment process is innovatively introduced. The annealing temperature is precisely set to 1080±15℃, and the holding time is strictly controlled at 30±2s, which effectively reduces the work hardening rate of the material, provides a good plasticity and toughness foundation for subsequent ultra-thin strip rolling, and reduces the risk of fracture during the rolling process.

[0080] Rolling parameters:

[0081] The first-pass rolling speed was adjusted to 190±5m / min, the reduction rate was 25%±1%, and the unit tension gradient was controlled at 1.8±0.1N / mm2 / passes to meet the special requirements of ultra-thin strip rolling;

[0082] The final pass speed is 280±10m / min, at which time the reduction rate is reduced to 8%±0.5%, the total reduction rate is 68%±1%, and the bending roll force is correspondingly reduced to 80±3kN, effectively reducing the deformation risk of ultra-thin strips during the rolling process and ensuring the dimensional accuracy and surface quality of the strip.

[0083] Lubrication and cooling:

[0084] Implementation standard: ISO4406-2017 "Hydraulic transmission oil solid particle contamination level", optimize the lubrication and cooling system.

[0085] A stainless steel cold rolling oil lubricant with a particle size of 50±5nm and a content of 0.8%±0.1% was selected, and an innovative control strategy was adopted to strictly match the injection frequency with the rolling speed, that is, the injection interval time t=60 / v±1s (v is the rolling speed) to achieve precise lubrication;

[0086] The cooling intensity of the edge is increased by 20%±1% compared with the middle part, which strengthens the heat dissipation of the edge, ensures the temperature uniformity of the strip during the rolling process, and suppresses the problems of uneven deformation and residual stress concentration caused by temperature difference.

[0087] 2. Key innovations

[0088] Shape control: A laser shape meter is introduced for real-time feedback, with measurement accuracy reaching micron level. The roll gap is dynamically adjusted based on the feedback signal, with an adjustment accuracy of up to ±0.0005mm. This enables precise control of the strip shape, effectively suppressing defects such as edge wavyness and central bulge, and improving the strip’s flatness and dimensional accuracy.

[0089] Annealing improvements: Optimize the front-end annealing process and reduce the heating rate to 60±2°C / min. By precisely controlling the heating process, grain coarsening during rapid heating is avoided, ensuring good structural uniformity and mechanical property stability in subsequent processing.

[0090] 3. Effect verification

[0091] Metallographic structure Figure 2 As shown, the grain size at the edge is 10.5±0.2 (ASTM standard), the core is 10.0±0.2, and the dislocation density gradient is significant;

[0092] Finished product performance:

[0093] Implementation standard: GB / T4340.1-2009 "Vickers hardness test for metal materials"

[0094] The finished product has a precise thickness of 0.15±0.003mm, a tensile strength of up to 950±10MPa, an elongation at break of 34%±1%, a surface roughness Ra as low as 0.08±0.02μm, and an anisotropy ratio of ≤1.01±0.01, demonstrating excellent comprehensive performance and meeting the strict requirements of high-end application fields for material strength, plasticity and surface quality.

[0095] Application testing:

[0096] Implementation standard: ISO13485-2016 "Medical Device Quality Management System"

[0097] This material performs excellently in the stamping process of medical devices, with a stamping depth ratio (LDR) ≥ 2.5, fully meeting the forming requirements of complex-shaped parts; after electrolytic polishing, the surface roughness Ra can be further reduced to ≤ 0.05 ± 0.01 μm, successfully meeting the ISO13485 standard requirements, and expanding its application prospects in high-end fields such as medical devices and electronics.

[0098] Example 3: Low-cost and high-efficiency production model

[0099] 1. Process simplification

[0100] ·Raw materials relaxation:

[0101] Implementation standard: GB / T4237-2015 "Stainless steel hot-rolled steel plate and strip"

[0102] Under the premise of ensuring the basic performance of the material, the chemical composition and mechanical property requirements of the raw materials are appropriately relaxed. The lower limit of nickel content is allowed to be reduced to 1.1% ± 0.1%, and the upper limit of manganese content is increased to 10.9% ± 0.2% (the main components include: (chromium (Cr): 13.05%, nickel: 1.02%, manganese: 10.72%, carbon (C): 0.142%, silicon (Si): 0.55%, phosphorus (P): 0.05%, sulfur (S): 0.004%, nitrogen (N): 0.183%, copper (Cu): 0.04%), and the rest are iron, trace alloying elements and unavoidable impurities, see Table 1 for details). The yield strength is relaxed to ≤ 550 ± 10 MPa, broadening the raw material procurement channels and reducing raw material costs, while not affecting the performance of the material in general application scenarios.

[0103] High-quality raw materials with an initial thickness of 1.6±0.02mm are selected, and a pre-annealing treatment process is innovatively introduced. The annealing temperature holding time is strictly controlled at 30+2s, which effectively reduces the work hardening rate of the material and provides a good plasticity and toughness foundation for the subsequent ultra-thin strip rolling with the temperature precisely set at 1080±15℃, reducing the risk of fracture during the rolling process.

[0104] Rolling optimization:

[0105] The first-pass reduction rate is increased to 30%±1%, which greatly increases the deformation amount of a single pass, effectively reduces the total number of rolling passes, shortens the production cycle, and improves production efficiency; the last-pass reduction rate is controlled at 12%±0.5%, and the rolling process parameters are further optimized while ensuring the quality of the plate shape; the tension control is simplified to a fixed front tension of 1.2±0.05 times the rear tension, reducing the complexity of tension adjustment, reducing production costs, and ensuring the stability of the strip during rolling.

[0106] Lubrication replacement:

[0107] Implementation standard: GB / T7631.2-2003 "Lubricant Classification"

[0108] A low-cost composite lubricant is used, with a formula of 0.6%±0.1% composite lubricant and 0.2%±0.05% graphite. On the basis of ensuring the lubrication effect, it significantly reduces the lubrication cost, while improving the adaptability and stability of the lubricant to meet the lubrication needs under different rolling conditions.

[0109] 2. Cost-Benefit Analysis

[0110] Reduced energy consumption: By optimizing and simplifying the rolling process, the total number of rolling passes was successfully reduced to four, resulting in a significant 15% drop in energy consumption per ton of steel. This significantly reduces energy consumption costs during the production process and improves production efficiency and economic benefits.

[0111] Yield rate: Even with simplified processes and reduced costs, the yield rate can still be maintained at a high level of ≥95% (tape breakage rate ≤3%), ensuring the stability of the production process and the qualified rate of products, reducing waste losses and further improving production efficiency.

[0112] 3. Performance balance

[0113] Metallographic structure Figure 3 As shown, the grain size of the edge is 9.0±0.2 (ASTM standard), the core is 8.5±0.2, and the dislocation density gradient is significant;

[0114] Finished product indicators:

[0115] Implementation standard: GB / T10125-2012 "Artificial atmosphere corrosion test salt spray test"

[0116] The thickness of the finished product is 0.53±0.006mm, and the tensile strength reaches 900±10MPa. Although the corrosion resistance is slightly reduced (no pitting after immersion in 5% NaCl solution for 600±10h), it still meets the use requirements in non-extreme environments such as home appliance casings and architectural decoration, showing good cost-effectiveness.

[0117] Applicable Scenarios: Stainless steel strips produced under this low-cost and high-efficiency production model, with its comprehensive performance and cost advantages, are mainly suitable for fields such as home appliance housings and architectural decoration that do not require stringent performance but are more cost-sensitive, providing manufacturers with a more advantageous product choice in the market competition.

[0118] Table 1 Compositions of various examples of the present invention by weight percentage (unit: %)

[0119] Steel Type C Ni Cr Mn Cu Si P S N Mo Co Al Example 1 0.149 1.08 13.25 11.51 0.25 0.51 0.05 0.003 0.192 0.01 0.13 0.005 Example 2 0.142 1.18 13.45 11.85 0.48 0.36 0.045 0.003 0.201 0.013 0.13 0.002 Example 3 0.155 1.02 13.05 10.72 0.04 0.55 0.05 0.004 0.183 0.012 0.14 0.005

[0120] The comprehensive comparison and conclusion of each example are shown in Table 2

[0121] Table 2 Comparison of indicators of various examples of the present invention

[0122]

[0123] in conclusion:

[0124] 1. As a benchmark process that balances performance and cost, Example 1 has excellent overall performance and can meet the needs of most industrial scenarios while maintaining high production efficiency and product quality stability. It is an ideal choice for general-purpose high-end stainless steel strip production.

[0125] 2. Example 2 successfully achieved high-precision rolling of ultra-thin strips through refined adjustments and innovative improvements to a series of process parameters. The product exhibited excellent performance in terms of strength, surface quality, and anisotropy control, fully meeting the stringent requirements of high-end fields such as medical devices and electronics, and was a personalized solution for the needs of the high-end market.

[0126] 3. Example 3 takes process simplification and cost control as the core strategies, and optimizes and adjusts the raw material selection, rolling process, and lubrication system. While ensuring that the basic performance of the product meets the requirements of non-extreme environment applications, it significantly reduces production costs and improves production efficiency, providing a feasible path for low-cost, high-efficiency stainless steel strip production. It is particularly suitable for fields with relatively loose performance requirements such as home appliance housings and architectural decoration, helping companies win market share with cost advantages in market competition.

[0127] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. The various components of the present invention may be combined with each other without conflict, and any equivalent changes and modifications made by a person skilled in the art without departing from the concept and principles of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for cold-rolling thin strip of low-nickel austenitic stainless steel, characterized in that: The low-nickel austenitic stainless steel cold-rolled thin strip rolling method comprises the following steps: S1. Select low-nickel iron austenitic stainless steel 2E coil with nickel content ≤ 1.20% and manganese content ≥ 10.7% as raw material and conduct raw material inspection; S2, adopts 20-high reversible cold rolling mill for multi-pass reversible rolling, with working roll diameter of Φ36-48mm and support roll adopting segmented hydraulic bending roll system; S3. Implementing step-by-step reduction rate distribution and online flatness closed-loop control by dynamically adjusting the roll gap, tension, and rolling speed. The step-by-step reduction rate distribution and the tension gradient increasing mode form a coordinated control; S4, during the rolling process, a lubricant containing stainless steel cold rolling oil is used for gradient cooling; S5. After rolling, two-stage bright annealing treatment is performed.

2. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S3, the rolling speed of the first pass is 150-250 m / min, and the speed is automatically reduced by 15%-20% when the measured rolling force exceeds the preset value by 10%.

3. The method for cold-rolling thin strip of low-nickel austenitic stainless steel according to claim 1, wherein: In step S3, the stepped reduction ratio distribution is specifically as follows: 25% to 32% for the first pass, 7% to 12% for the last pass, and a total reduction ratio of 65% to 80%.

4. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S2, the bending roll force control range is 50 to 200 kN, and the bending roll response time is ≤ 0.5 s.

5. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S3, the tension control adopts the front tension gradient increasing mode: the unit tension gradient is 1.5 to 2.5 N / mm 2 / pass; export unit tension 18~35kg / mm 2 , entrance unit tension 14~28kg / mm 2 ; Tension fluctuation rate ≤3%.

6. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S2, the roller system configuration includes: the crown of the second intermediate non-drive roller is 0.2-0.3 mm; the first intermediate roller is tapered: the taper length is 200-230 mm, the taper is 0.60-0.65 mm; the taper / cone length ratio is 0.0025-0.0035; and the taper / crown ratio is 2.0-3.

2.

7. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S3, the online flatness closed-loop control includes: Adopt multi-sensor fusion monitoring: laser scanning plate shape meter and X-ray thickness gauge fusion monitoring; Multi-parameter coupling control based on fuzzy PID algorithm: rolling force-tension-speed coupling response time ≤ 100ms.

8. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S4, the gradient cooling satisfies: Stainless steel cold rolling oil, wherein the particle size is 50-100nm and the content is 0.5%-1.2%; The relationship between the injection interval t and the rolling speed v satisfies: t = 60 / v ± 2s; the unit of the injection interval t is s, and the unit of the rolling speed v is m / min; The cooling intensity of the edge is 15±3% higher than that of the middle.

9. The method for rolling a low-nickel austenitic stainless steel cold-rolled thin strip according to claim 1, wherein: In step S5, the two-stage bright annealing includes: Front stage: 1050-1100℃×1-2min, hydrogen-nitrogen mixed gas, with hydrogen content of 5%-8%; Back stage: 850~900℃×1~1.5min, dew point ≤-60℃; Cooling rate: 20-30℃ / s.

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