Method for equivalently simulating continuous annealing process of cold-rolled dual-phase steel

Abstract

The invention relates to a method for equivalently simulating a continuous annealing process of cold-rolled dual-phase steel. The method comprises the following steps: S1, determining the length of a steel strip in each furnace area; s2, calculating processing time; s3, making a simulation process curve; s4, performing continuous annealing simulation; s5, hardness testing; s6, mechanical property calculation under the simulation condition; s7, analyzing a mechanical property evolution rule; and S8, determining a continuous annealing process for guiding industrial production. The quenching phase change instrument is used for carrying out differential simulation on heating, heat preservation, slow cooling, rapid cooling, overaging and annealing rates in a laboratory, a continuous annealing process curve simulated by an experimental process scheme is consistent with the temperature change actually experienced by strip steel on a production line, and then equivalent simulation of the continuous annealing process of the cold-rolled dual-phase steel is achieved.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and in particular to a method for equivalently simulating the continuous annealing process of cold-rolled dual-phase steel. Background Technology

[0002] The performance of cold-rolled duplex steel depends on the target microstructure ratio, morphology, and matching mechanical properties. Process parameters such as heating, holding, slow cooling, and over-aging in continuous annealing units directly determine the final performance by influencing the phase transformation and microstructure evolution of the steel sheet. Compared to industrial production line adjustments and tests, laboratory simulations can significantly reduce development risks and costs, accelerate the development cycle, and provide reliable experimental data for new product development and production process optimization in the research and development, process adjustment, and microstructure and property optimization of cold-rolled duplex steel products.

[0003] For example, invention patent application number CN202410768477.8 discloses a method for equivalently simulating the continuous annealing process of ferritic stainless steel sheets. A box furnace is selected for annealing the stainless steel sheets, and the furnace temperature is set to be consistent with the outlet temperature of the continuous annealing furnace in a cold rolling mill. The annealing time in the box furnace is t = r × steel sheet thickness d × continuous annealing furnace length L / TV, where r is a coefficient related to the steel sheet thickness, the furnace length L = preheating section + heating section + soaking section, and TV = steel sheet thickness × continuous annealing line speed. This method can make the laboratory heat treatment regime equivalent to the continuous annealing process in a cold rolling mill, resulting in ferritic stainless steel sheets with consistent microstructure and mechanical properties. In the development of new stainless steel products, application in new production lines, or process optimization and improvement, it can significantly improve experimental efficiency and reduce the cost of on-site experiments in cold rolling mills. However, this invention uses a box furnace for annealing stainless steel sheets. The furnace temperature setting of the box furnace is consistent with the outlet plate temperature of the continuous annealing furnace. The box furnace can only perform thermal simulation of the preheating section + heating section + soaking section, and cannot simulate processes requiring slow cooling, rapid cooling, and over-aging. When the steel plate thickness d < 1.0 mm, the coefficient r is 0.8 to 0.9; when the steel plate thickness 1.0 mm ≤ d < 3.0 mm, the coefficient r is 1 to 1.2; and when the steel plate thickness d ≥ 3.0 mm, the coefficient r is 1.5 to 1.7. The holding time needs to be converted according to the steel plate thickness. In the continuous annealing process, the time of the strip in each furnace zone is determined by the annealing rate. The conversion algorithm is also inconsistent with actual industrial production. Furthermore, the thermal simulation processes that the box furnace can achieve are limited and cannot be applied to the thermal simulation of cold-rolled duplex steel.

[0004] For example, the invention patent with application number CN202011050773.2 discloses a method for determining the effect of different annealing temperatures on cold-rolled duplex steel. This method is used to determine the changes in the internal structure of cold-rolled duplex steel at different annealing temperatures. Specifically, as the annealing temperature increases, the volume fraction of austenite in the steel plate increases significantly. During continuous annealing and cooling, austenite does not undergo ferrite phase transformation at annealing temperatures of 770℃ and 800℃. At an annealing temperature of 830℃, the stability of austenite decreases, and ferrite phase transformation occurs. When the annealing temperature increases from 770℃ to 800℃, the amount of martensite increases, and the island martensite on the grain boundaries changes from a discontinuous distribution to a continuous distribution. When the temperature is increased to 830℃, the size of the blocky ferrite coarsens significantly and the volume fraction increases, while the amount of island martensite decreases. However, this patent only conducted thermal simulations on the insulation temperature of DP590, and the experimental results cannot be applied to industrial production because slow cooling temperature, rapid cooling temperature, over-aging temperature and annealing rate all have a significant impact on the microstructure and properties of duplex steel.

[0005] In conclusion, all existing technologies have certain defects and shortcomings, and there is still room for further improvement and perfection. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a method for equivalently simulating the continuous annealing process of cold-rolled duplex steel. By combining production line configuration and steel grade characteristics, a quenching phase transformation instrument is used in the laboratory to perform differentiated simulations of heating, holding, slow cooling, rapid cooling, over-aging, and annealing rates. The continuous annealing process curve simulated by the experimental process scheme is consistent with the actual temperature changes experienced by the strip steel on the production line, thereby achieving an equivalent simulation of the continuous annealing process of cold-rolled duplex steel. The conclusions obtained can be accurately used to guide industrial production.

[0007] The technical solution adopted in this invention is as follows: The present invention proposes a method for equivalently simulating the continuous annealing process of cold-rolled duplex steel, comprising the following steps: S1. Determine the length of the steel strip in each furnace zone: To simulate the annealing process, determine the length of the steel strip in each furnace zone of the continuous annealing unit, including the heating section, holding section, slow cooling section and over-aging section, based on the specific production line. The unit is m. S2. Calculate the processing time: Based on the simulated annealing rate and the strip length in each furnace zone determined in S1, calculate the processing time of the strip in each furnace zone, in seconds. S3. Develop simulated process curves; S4, Continuous annealing simulation; S5, Hardness test; S6. Calculation of mechanical properties under simulated conditions; S7. Analysis of the evolution law of mechanical properties; S8. Determine the continuous annealing process to guide industrial production: Based on the simulation process and strength results obtained in steps S4 to S7, realize the equivalent simulation of the continuous annealing process of cold-rolled duplex steel.

[0008] Furthermore, step S3 includes: determining the A of the sample using a quenching phase transformation instrument. C1 A C3 With M f Temperature, based on the strength grade of cold-rolled duplex steel and A C1 A C3 Temperature: The heating and holding temperatures are set at 760–850℃; based on the martensite content corresponding to the strength grade of cold-rolled duplex steel, the slow cooling temperature is set at 660–740℃; the rapid cooling temperature is consistent with the over-aging temperature, and lower than M. f The temperature is 10-50℃, and a simulated process curve is formulated based on the processing time calculated in step S2.

[0009] Furthermore, step S4 includes: using a quenching phase change instrument to perform continuous annealing thermal simulation on the sample, welding a thermocouple to the middle of the sample, and then clamping the sample between a quartz tube or ceramic push rod set inside the quenching phase change instrument, and performing continuous annealing simulation according to the simulation process curve established in step S3.

[0010] Furthermore, step S5 includes: cutting the sample after continuous annealing simulation in step S4 along the rolling direction, and then inlaying, grinding and polishing the sample, followed by hardness testing using a Vickers hardness tester.

[0011] Furthermore, step S6 includes: conducting mechanical property and hardness tests on industrially produced 1.2-2.0mm products, calculating the yield strength and tensile strength corresponding to the unit hardness, and calculating the yield strength and tensile strength under simulated conditions based on the Vickers hardness tested in step S5.

[0012] Furthermore, step S7 includes: simulating different heating and holding temperatures, slow cooling temperatures, rapid cooling temperatures, over-aging temperatures, and annealing rates, and obtaining the influence of different annealing process parameters on yield strength and tensile strength based on steps S5 to S6.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention combines the specific production line to determine the length of cold-rolled duplex steel strip in each furnace zone of the continuous annealing unit and applies the processing time calculated based on the annealing rate to the simulation experiment. This allows the continuous annealing process curve simulated in the experiment to be consistent with the temperature changes experienced by the strip steel on the production line, thus achieving equivalent simulation.

[0014] 2. This invention utilizes the mechanical properties and hardness of industrially produced cold-rolled dual-phase steel products to calculate the yield strength and tensile strength corresponding to unit hardness. Applying these properties to small samples after experimental simulation allows for the calculation of mechanical properties under simulated conditions, greatly improving the efficiency of thermal simulation. Compared to multi-functional continuous annealing simulators that use larger samples, the small sample simulation results in more uniform temperature and more accurate simulation results, and eliminates the need to prepare tensile samples for mechanical property testing.

[0015] 3. The present invention adopts the above-mentioned small sample simulation method, which can avoid adjustment tests on industrial production lines, thereby greatly reducing the risk and cost of product development and accelerating the product development cycle. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for equivalently simulating the continuous annealing process of cold-rolled duplex steel proposed in this invention. Figure 2 This is a schematic diagram of the simulated process curve in this invention. Detailed Implementation

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] It should be noted that in the description of this invention, the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not mean that the device or element must have a specific orientation, or be constructed and operated in a specific orientation.

[0019] See appendix Figure 1-2 The present invention proposes a method for equivalently simulating the continuous annealing process of cold-rolled dual-phase steel, comprising the following steps: S1. Determine the length of the steel strip in each furnace zone: To simulate the annealing process, determine the length of the steel strip in each furnace zone of the continuous annealing unit, including the heating section, holding section, slow cooling section and over-aging section, based on the specific production line. The unit is m. S2. Calculate the processing time: Based on the simulated annealing rate and the strip length in each furnace zone determined in S1, calculate the processing time of the strip in each furnace zone, in seconds. S3. Develop simulated process curves: Use a quenching phase transformation instrument to determine the A content of the test steel plate. C1 A C3 With Mf Temperature, specifically the temperatures of the heating and holding sections, determines the initial austenite content during the annealing process of cold-rolled duplex steel. This content is determined by the strength grade and A... C1 A C3 Temperature: The heating and holding temperatures are controlled between 760 and 850℃. The temperature of the slow cooling section determines the martensite content in the finished cold-rolled duplex steel. Based on the martensite content corresponding to the strength grade of the duplex steel, the slow cooling section temperature is controlled between 660 and 740℃. The rapid cooling section temperature is consistent with the over-aging section temperature for stable control in industrial production. Temperatures below M... f The temperature is 10-50℃, and a simulated process curve is formulated based on the processing time calculated in step S2.

[0020] S4. Continuous annealing simulation: The sample is subjected to continuous annealing thermal simulation using a quenching phase change instrument. A thermocouple is welded to the middle of the sample, and then the sample is clamped between the quartz tube or ceramic push rod set inside the quenching phase change instrument. Continuous annealing simulation is performed according to the simulation process curve formulated in step S3.

[0021] S5. Hardness test: The sample after continuous annealing simulation in step S4 is cut along the middle of the rolling direction. The sample is then inlaid, ground and polished, and the hardness is tested using a Vickers hardness tester. S6. Calculation of mechanical properties under simulated conditions: Perform mechanical property and hardness tests on industrially produced 1.2-2.0mm products, calculate the yield strength and tensile strength corresponding to the unit hardness, and calculate the yield strength and tensile strength under simulated conditions based on the Vickers hardness tested in step S5.

[0022] S7. Analysis of the evolution law of mechanical properties: Simulation of different heating and holding temperatures, slow cooling temperatures, rapid cooling temperatures and over-aging temperatures and annealing rates. Based on the steps of S5 to S6, the influence law of different annealing process parameters on yield strength and tensile strength is obtained. S8. Determine the continuous annealing process to guide industrial production: Based on the simulation process and strength results obtained in steps S4 to S7, realize the equivalent simulation of the continuous annealing process of cold-rolled duplex steel.

[0023] This invention utilizes a quenching phase transformation instrument to conduct laboratory small-sample simulations of cold-rolled dual-phase steel. It can accurately reproduce the temperature change curves of the steel plate in each zone of the continuous annealing furnace. By observing the microstructure and testing the hardness of the simulated sample, the mechanical properties under the simulated conditions can be determined, thereby verifying whether the continuous annealing process meets the product development or adjustment goals.

[0024] The method will be further illustrated below with specific examples: Example 1 This embodiment describes a method for equivalently simulating the continuous annealing process of cold-rolled duplex steel DP590 with a thickness of 1.4mm. The specific implementation steps are as follows: S1. Determine the length of the steel strip in each furnace zone: To simulate the annealing process equivalently, based on the actual equipment of the continuous annealing unit, the length of the heating section of the cold-rolled duplex steel strip in the continuous annealing unit is determined to be 550m, the length of the heat preservation section is 240m, the length of the slow cooling section is 123m, the length of the rapid cooling section is 24m, and the length of the over-aging section is 896m.

[0025] S2, Calculation processing time: In industrial production, the average annealing rate of 1.4mm cold-rolled duplex steel DP590 is 120m / min. Based on the length of each furnace zone determined in S1, the processing time of the strip in each furnace zone is 273s, 118s, 62s, 11s and 461s, respectively.

[0026] S3. Develop simulated process curves: The chemical composition of the steel plate sample used for thermal simulation, by mass percentage, is: C: 0.068%, Si: 0.23%, Mn: 1.78%, P: 0.011%, S: 0.008%, Cr: 0.11%, with the balance being Fe and unavoidable impurities.

[0027] A content of the test steel plate was determined using a quenching phase transformation instrument. C1 A C3 With M f Temperature: First, heat the sample to 950℃ at a rate of 0.05℃ / s, hold for 10 min, and then cool to room temperature at a rate of 10℃ / s. The critical points of the test steel plate were determined using the tangent method based on the thermal expansion curve: A C1 =698.85℃, A C3 =834.83℃, M f =312.57℃; the temperatures of the heating and holding sections determine the initial austenite content during the annealing process of cold-rolled duplex steel DP590, based on the strength grade and A... C1 A C3 Temperature: The simulated temperatures for the heating and holding sections are 760, 780, and 800℃, respectively. The temperature of the slow cooling section determines the martensite content in the finished cold-rolled duplex steel DP590. Based on the martensite content corresponding to the strength grade of the duplex steel, the simulated temperatures for the slow cooling section are 660, 680, and 700℃. The temperatures for the rapid cooling section and the over-aging section are consistent for stable control in industrial production; therefore, 260, 280, and 300℃ are selected. A thermal simulation process curve is developed based on the processing time calculated using S2. The thermal simulation process curve is shown below. Figure 2 As shown.

[0028] S4, Continuous Annealing Simulation: A quenching phase change instrument was used to perform continuous annealing thermal simulation on a DP590 cold-hardened steel plate sample with dimensions of 4mm×10mm. The 10mm direction was the rolling direction. The sample was not chamfered and was deburred. The two ends of the 4mm section were clamping ends. The surface parallelism was less than 0.01mm. A thermocouple was welded to the middle of the sample. Then, the sample was clamped between the quartz tube or ceramic push rod set inside the phase change instrument. Continuous annealing simulation was performed according to the simulation process curve set in S3.

[0029] The specific steps are as follows: S4.1 To facilitate comparison of the effects of heating temperature and holding temperature on performance, the intermediate values ​​of slow cooling temperature, rapid cooling section temperature and over-aging section temperature were selected. When the average annealing rate was 120 m / min, the sample was heated to 760, 780 and 800℃ respectively after 273s, held for 118s, slow cooled to 680℃ after 62s, then rapidly cooled to 280℃ for 11s and held for 461s, and finally cooled to room temperature at a cooling rate of 15℃ / s.

[0030] S4.2 To facilitate comparison of the effects of slow cooling temperature on performance, the heating temperature and holding temperature, as well as the rapid cooling section temperature and the over-aging section temperature, were selected as intermediate values. When the average annealing rate was 120 m / min, the sample was heated to 780℃ in 273s, held for 118s, and then slowly cooled to 660, 680 and 700℃ respectively in 62s. After that, it was rapidly cooled to the rapid cooling section temperature and the over-aging section temperature of 280℃ in 11s and held for 461s. Finally, it was cooled to room temperature at a cooling rate of 15℃ / s.

[0031] S4.3 To facilitate comparison of the effects of rapid cooling zone temperature and over-aging zone temperature on performance, the heating temperature, holding temperature, and slow cooling temperature were selected as intermediate values. When the average annealing rate was 120 m / min, the sample was heated to 780℃ in 273s, held for 118s, and then slowly cooled to 680℃ in 62s. After that, it was rapidly cooled to 260, 280, and 300℃ in 11s and held for 461s respectively. Finally, it was cooled to room temperature at a cooling rate of 15℃ / s.

[0032] S4.4 To facilitate comparison of the impact of annealing rate on performance, intermediate values ​​were selected for heating temperature, holding temperature, slow cooling temperature, rapid cooling zone temperature, and over-aging zone temperature. Thermal simulations were performed for annealing rates of 90 and 150 m / min, with corresponding heating times of 364 s and 218 s, holding times of 157 s and 94 s, slow cooling times of 83 s and 50 s, rapid cooling times of 15 s and 9 s, and over-aging times of 615 s and 369 s, respectively. Finally, the temperature was cooled to room temperature at a rate of 15 °C / s.

[0033] S4.5 To facilitate comparison of the effects of slow cooling rate and fast cooling rate on performance, the heating temperature, holding temperature, slow cooling temperature, fast cooling temperature and over-aging temperature were selected as intermediate values. The heating time was 273s, the holding time was 118s, and the over-aging time was 461s. Thermal simulations were performed on the slow cooling rate and fast cooling rate at annealing rates of 90 and 150 m / min, respectively. The corresponding slow cooling rates were 1.2℃ / s and 2.0℃ / s, and the fast cooling rates were 27℃ / s and 44℃ / s, respectively.

[0034] S5, Hardness Test: After the annealing simulation in step S4, the sample is cut along the middle of the rolling direction. The sample is then inlaid, ground, and polished. The hardness is tested using a Wilson Vickers hardness tester with a test force of 5 kgf.

[0035] S6. Calculation of mechanical properties under simulated conditions: Mechanical properties and hardness were tested on 1.4mm products produced in the industry. The yield strength corresponding to the unit hardness was calculated to be 2.06MPa and the tensile strength to be 3.37MPa. The yield strength and tensile strength under the simulated conditions were calculated based on the Vickers hardness tested in S5, as shown in Tables 1 to 5.

[0036] Table 1 Strength at different heating and holding temperatures

[0037] As shown in Table 1, the yield strength and tensile strength under simulated conditions calculated by Vickers hardness show an overall trend of first decreasing and then increasing with the increase of heating temperature and holding temperature. Since the heating temperature and holding temperature determine the initial austenite content in the annealing process of cold-rolled duplex steel DP590, which plays a decisive role in the final performance, the heating temperature and holding temperature should be mainly controlled to optimize the performance level.

[0038] Table 2 Strength at different slow cooling temperatures

[0039] As shown in Table 2, the yield strength and tensile strength under simulated conditions calculated by Vickers hardness show an overall decreasing trend with the increase of slow cooling temperature. The temperature of the slow cooling section determines the martensite content in the finished cold-rolled duplex steel, and the final performance can be fine-tuned according to the user's personalized needs.

[0040] Table 3 Strength at different rapid cooling temperatures and over-aging temperatures

[0041] Table 3 shows that, under the simulated conditions calculated using Vickers hardness, the yield strength and tensile strength generally show a slow decreasing trend with increasing rapid cooling temperature and over-aging temperature. After the two-phase region treatment, the carbon content in the austenite is significantly enriched. f The temperature has been reduced to below 300℃, and the lower over-aging temperature has not had a significant impact on performance.

[0042] Table 4 Strength at different annealing rates

[0043] As shown in Table 4, the yield strength and tensile strength under simulated conditions calculated by Vickers hardness generally show an upward trend with the increase of annealing rate. In order to improve production efficiency, a higher annealing rate should be used in actual production, and the performance level should be optimized by adjusting the slow cooling temperature.

[0044] Table 5 Intensity at different cooling rates

[0045] As shown in Table 5, under the simulated conditions calculated by Vickers hardness, the yield strength and tensile strength generally show an upward trend with the increase of slow cooling and fast cooling rates. Under the condition of a certain annealing rate, the performance level can be controlled by adjusting the slow cooling and fast cooling rates.

[0046] S7. Analysis of the evolution law of mechanical properties: Based on steps S1 to S6, simulations were performed at different annealing temperatures and rates. The strength calculated using different processes indicates that heating temperature and holding temperature are key parameters. Slow cooling temperature, rapid cooling temperature, and over-aging temperature can be adjusted to meet individual user needs. Simultaneously, to ensure production efficiency, production needs to be carried out at a higher annealing rate. Based on actual performance, the slow cooling temperature, rapid cooling temperature, and over-aging temperature are adjusted, and performance is optimized and controlled through the cooling rate.

[0047] S8. Determine the continuous annealing process to guide industrial production: By combining the simulated process and the calculated yield strength and tensile strength under simulated conditions, it can be determined that 1.4mm cold-rolled duplex steel can achieve good strength levels when the heating and holding temperature is 780℃, the slow cooling temperature is 680℃, the rapid cooling temperature is 280℃, and the annealing rate is 120m / min. For users' personalized requirements, the performance can be optimized and adjusted according to the specific impact of the annealing process parameters in Tables 1 to 5.

[0048] In summary, simulation results of different process parameters during the continuous annealing of 1.4mm cold-rolled duplex steel DP590 show that the heating temperature and soaking temperature play a decisive role in product performance. For parameters such as slow cooling temperature, rapid cooling temperature, over-aging temperature, and annealing rate, they can be optimized and adjusted according to the actual needs of product performance.

[0049] The continuous annealing process curve simulated by this invention is consistent with the temperature changes experienced by the strip steel on the production line, thus achieving equivalent simulation. The strength under the simulated conditions can be greatly improved by calculating the hardness, which can greatly improve the efficiency of thermal simulation. The use of small sample simulation can avoid adjustment tests on the industrial production line, reduce the risk and cost of product development, and accelerate the product development cycle. The method steps involved in this application are applicable to cold-rolled duplex steels of other strength grades, and are also applicable to the equivalent simulation of continuous annealing processes for phase transformation steels in industrial production.

[0050] Matters not covered in this invention are common knowledge.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for equivalently simulating the continuous annealing process of cold-rolled duplex steel, characterized in that: The method includes the following steps: S1. Determine the length of the steel strip in each furnace zone: To simulate the annealing process, determine the length of the steel strip in each furnace zone of the continuous annealing unit, including the heating section, holding section, slow cooling section and over-aging section, based on the specific production line. The unit is m. S2. Calculate the processing time: Based on the simulated annealing rate and the strip length in each furnace zone determined in S1, calculate the processing time of the strip in each furnace zone, in seconds. S3. Develop simulated process curves; S4, Continuous annealing simulation; S5, Hardness test; S6. Calculation of mechanical properties under simulated conditions; S7. Analysis of the evolution law of mechanical properties; S8. Determine the continuous annealing process to guide industrial production: Based on the simulation process and strength results obtained in steps S4 to S7, realize the equivalent simulation of the continuous annealing process of cold-rolled duplex steel.

2. The method for equivalently simulating the continuous annealing process of cold-rolled duplex steel according to claim 1, characterized in that: Step S3 includes: determining the A of the sample using a quenching phase transformation instrument. C1 A C3 With M f Temperature, based on the strength grade of cold-rolled duplex steel and A C1 A C3 Temperature: The heating and holding temperatures are set at 760–850℃; based on the martensite content corresponding to the strength grade of cold-rolled duplex steel, the slow cooling temperature is set at 660–740℃; the rapid cooling temperature is consistent with the over-aging temperature, and lower than M. f The temperature is 10-50℃, and a simulated process curve is formulated based on the processing time calculated in step S2.

3. The method for equivalently simulating the continuous annealing process of cold-rolled duplex steel according to claim 2, characterized in that: Step S4 includes: using a quenching phase change instrument to perform continuous annealing thermal simulation on the sample, welding a thermocouple to the middle of the sample, and then clamping the sample between a quartz tube or ceramic push rod set inside the quenching phase change instrument, and performing continuous annealing simulation according to the simulation process curve established in step S3.

4. The method for equivalently simulating the continuous annealing process of cold-rolled duplex steel according to claim 3, characterized in that: Step S5 includes: cutting the sample after continuous annealing simulation in step S4 along the rolling direction, and then inlaying, grinding and polishing the sample, followed by hardness testing using a Vickers hardness tester.

5. The method for equivalently simulating the continuous annealing process of cold-rolled duplex steel according to claim 4, characterized in that: Step S6 includes: conducting mechanical property and hardness tests on industrially produced 1.2-2.0mm products, calculating the yield strength and tensile strength corresponding to the unit hardness, and calculating the yield strength and tensile strength under simulated conditions based on the Vickers hardness tested in step S5.

6. The method for equivalently simulating the continuous annealing process of cold-rolled duplex steel according to claim 5, characterized in that: Step S7 includes: simulating different heating and holding temperatures, slow cooling temperatures, rapid cooling temperatures, over-aging temperatures, and annealing rates, and obtaining the influence of different annealing process parameters on yield strength and tensile strength based on steps S5 to S6.

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