Method for formulating reduction annealing process of high-strength dual-phase steel alloy
Through the reduction of the annealing process, the proportional temperature of the new component is calculated and the annealing temperature and range is determined, the problem of excessive alloy materials of existing high-strength duplex steel products is solved, and the rapid and accurate annealing process is achieved, which reduces the use and R&D cycle of transition materials, meets customer usage requirements and reduces costs.
Patent Information
- Application Number
- CN202411880327.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-04-08
AI Technical Summary
Excessive addition of existing high-strength duplex steel products has resulted in abundant performance but cannot meet the actual use requirements of customers. The R&D cycle is long, the thermal simulation experiment costs are high and inaccurate. The use of transitional materials in industrial production has led to an increase in costs.
Through the reduced annealing process, the proportional temperature of the new components in the same proportion of austenite is calculated, the annealing temperature and range are determined, industrial trial production and performance trend drawing are carried out, and the annealing process for the reduced product is quickly and accurately formulated to reduce the use of transition materials.
It has achieved rapid and accurate formulation of the annealing process for reduced quantization products, reduced the use of transitional materials in industrial production, reduced R&D cycle and experimental costs, met customer usage requirements, and reduced overall costs.
Smart Images
Figure CN119776649A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for formulating a reduction annealing process for a high-strength dual-phase steel alloy, and belongs to the technical field of material process formulating methods. Background Art
[0002] As market competition becomes increasingly fierce, cost reduction and efficiency improvement have become important directions for steel companies. In order to ensure product performance, steel products often have more alloy components added, especially cold-rolled high-strength dual-phase steel products. The main problems with current high-strength dual-phase steel products are as follows: 1) Too much alloy material is added to the product, the performance is greatly improved, and there is huge room for cost reduction.
[0003] 2) The basic performance of the product is qualified, but due to excessive addition of alloy, the product's hole expansion rate, bake hardening value, etc. do not meet the customer's actual usage requirements.
[0004] 3) Competition on the steel plate user side is becoming increasingly fierce, and the requirements for raw steel plates are gradually increasing, requiring steel suppliers to respond to demand quickly and the product development cycle must be short.
[0005] 4) The new product development process requires a large number of thermal simulation experiments. At the same time, the experiments can only simulate trends qualitatively, and actual production still requires trial production. The experiments are costly, time-consuming, and inaccurate, and cannot meet the fast-paced requirements of the user end, often resulting in customer loss.
[0006] 5) During the industrial production process, due to the differences in process temperatures of different products, a large amount of transition materials are required. Transition materials can only be treated as tertiary products or even waste, which often increases the overall cost of steel plates. Summary of the invention
[0007] The purpose of the present invention is to provide a method for formulating a reduction annealing process for a high-strength dual-phase steel alloy. By calculating the austenite proportion temperature of the new component in the same proportion after reduction, industrial trial production and performance trend drawing are carried out, and the annealing process of the reduced product can be quickly, accurately and effectively formulated. While developing new products through reduction, the use of transition materials in industrial production can be effectively reduced, thereby achieving overall cost reduction and efficiency improvement, and effectively solving the above-mentioned problems existing in the background technology.
[0008] The technical solution of the present invention is: a method for formulating a reduction annealing process for a high-strength dual-phase steel alloy, comprising the following steps: (1) calculating the ferrite-austenite ratio of the existing components; (2) calculating the temperature of the austenite ratio of the new components with the same proportion after reduction; (3) determining the trial annealing temperature and range; (4) industrial trial production; and (5) performance rating and performance trend drawing.
[0009] In the step (1), simulation software is used to calculate the ratio of ferrite to austenite of the pre-reduced existing components, and the actual annealing temperature of the existing components is set.
[0010] In the step (2), the composition of the reduced design is calculated using simulation software to calculate the temperature of ferrite and austenite in the same proportion as the existing composition.
[0011] In the step (3), based on the actual annealing temperature of the existing components, the temperature difference of +10°C is simulated and measured in the same proportion as the starting point of the annealing temperature, the annealing temperature range is ≤30°C, and the upper limit temperature is 830°C.
[0012] In the step (4), the annealing temperature is controlled manually or automatically, and the temperature is controlled to be continuously raised to the target temperature. The leveling mill adopts a constant rolling force or constant elongation mode. The exported steel coil is divided into three coils, and one sample is taken at each coil division, for a total of four samples.
[0013] The trial production leveling mill process for the new component product refers to the rolling force C and elongation D of the original component and adopts a constant rolling force mode, with a rolling force of C±1000KN and an elongation of D±0.1%.
[0014] In the step (5), the performance values of the four samples are measured, with the length range of the steel strip as the horizontal axis and the temperature and performance value as the vertical axis. The temperature and elongation at different positions of the steel strip are plotted in a table, and the performance values of the four samples are marked at the sampling positions.
[0015] The beneficial effects of the present invention are as follows: by calculating the austenite proportion temperature of the new component in the same proportion after reduction, industrial trial production and performance trend drawing can be carried out, so that the annealing process of the reduced product can be quickly, accurately and effectively formulated. While developing new products through reduction, the use of transition materials in industrial production can be effectively reduced, thereby achieving overall cost reduction and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is a schematic diagram of the steel strip sampling and coiling, the steel strip temperature trend and the steel strip direction of the present invention; Figure 2 Schematic diagram of the relationship between the rolling force, elongation and process temperature of a steel strip in an embodiment of the present invention; Figure 3 This is a diagram showing the annealing process and product performance rules of an embodiment of the present invention; Figure 4 It is the yield strength performance data distribution diagram of the present invention; Figure 5 This is a distribution diagram of the tensile strength performance data of the present invention; Figure 6 It is a physical diagram of the parts of the present invention; In the figure: sampling position one 1, sampling position two 2, sampling position three 3, sampling position four 4, coiling position 5, steel strip temperature trend line 6, steel strip out-of-furnace direction 7. DETAILED DESCRIPTION
[0017] In order to make the purpose, technical solutions and advantages of the invention implementation cases clearer, the technical solutions in the implementation cases of the present invention will be clearly and completely described below in conjunction with the drawings in the implementation cases. Obviously, the implementation cases described are only a small part of the implementation cases of the present invention, rather than all the implementation cases. Based on the implementation cases in the present invention, all other implementation cases obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0018] A method for formulating a reduction annealing process for a high-strength dual-phase steel alloy comprises the following steps: (1) calculating the ratio of ferrite to austenite in the existing composition; (2) calculating the temperature of austenite in the same ratio of the new composition after reduction; (3) determining the trial annealing temperature and range; (4) industrial trial production; and (5) performance rating and performance trend drawing.
[0019] In the step (1), simulation software is used to calculate the ratio of ferrite to austenite of the pre-reduced existing components, and the actual annealing temperature of the existing components is set.
[0020] In the step (2), the composition of the reduced design is calculated using simulation software to calculate the temperature of ferrite and austenite in the same proportion as the existing composition.
[0021] In the step (3), based on the actual annealing temperature of the existing components, the temperature difference of +10°C is simulated and measured in the same proportion as the starting point of the annealing temperature, the annealing temperature range is ≤30°C, and the upper limit temperature is 830°C.
[0022] In the step (4), the annealing temperature is controlled manually or automatically, and the temperature is controlled to be continuously raised to the target temperature. The leveling mill adopts a constant rolling force or constant elongation mode. The exported steel coil is divided into three coils, and one sample is taken at each coil division, for a total of four samples.
[0023] The trial production leveling mill process for the new component product refers to the rolling force C and elongation D of the original component and adopts a constant rolling force mode, with a rolling force of C±1000KN and an elongation of D±0.1%.
[0024] In the step (5), the performance values of four samples are measured, with the length range of the steel strip as the horizontal axis and the temperature and elongation at different positions of the steel strip as the vertical axis. The temperature and elongation of the steel strip at different positions are plotted in a table, and the performance values of the four samples are marked at the sampling positions.
[0025] In practical application, the specific steps are as follows: (1) Calculation of austenite ratio of existing composition and process. The existing composition product must have performance margin in the corresponding process. At the same time, in order to meet the actual production annealing temperature a of the new composition industry not exceeding 830℃, the corresponding annealing temperature of the existing composition is 790℃ or below. The simulation software is used to calculate the ferrite austenite ratio of the pre-reduced existing composition.
[0026] (2) The temperature of austenite in the same proportion as the new composition after reduction is calculated. The composition of the reduced design is calculated using simulation software, and the temperature of ferrite and austenite in the same proportion as the existing composition is calculated and set to b℃.
[0027] (3) Determination of trial annealing temperature and range. The trial annealing temperature of the new composition is b+10℃. The trial steel coil serves as the transition zone of the normal production product. The transition temperature range is 20-30℃, and the highest transition temperature is 830℃. The temperature is controlled to rise continuously and steadily from b+10℃ to b+30~40℃ or to the target temperature of 830℃. The continuous and steady temperature rise in the transition temperature range is convenient for subsequent observation and comparison of the changing trend of rolling force or elongation. At the same time, the temperature of each small coil of the coil can be controlled within ±5℃ to ensure the uniformity of product performance. On the other hand, it can effectively reduce the increase in total cost caused by transition materials.
[0028] (4) Industrial trial production: According to the annealing temperature requirements in step (3), industrial trial production is carried out. During the trial production, the annealing temperature is continuously raised to the target temperature through manual or automatic interlocking control to ensure that the temperature of the entire large coil rises continuously from the beginning to the end. The entire large coil is divided into three coils, and the annealing temperature range of each small coil is within 5°C. One piece of sample is taken at each coil division, for a total of four pieces. When the strip passes through the leveling mill, the new composition product trial leveling mill process refers to the original composition rolling force C and elongation D and adopts a constant rolling force mode, with a rolling force of C±1000KN and an elongation of D±0.1%.
[0029] (5) Performance rating and performance trend drawing: Determine the performance values of four samples, including elongation, yield strength and tensile strength. With the length range of the steel strip as the horizontal axis and the temperature and performance as the vertical axis, observe the change law of rolling force (elongation) under constant elongation (rolling force), plot the temperature and elongation at different positions of the steel strip in the table, and mark the performance of the four samples at the sampling position. Because the strip is in a continuous heating process, the strip temperature and the strip position are positively correlated. Then draw the relationship curve between temperature and elongation (rolling force), and then use the strip temperature as the horizontal axis and the elongation as the vertical axis, invert the vertical axis to draw the plot, the elongation (rolling force) trend is the performance trend, and the performance of the four samples defines the performance range of the product at different soaking temperatures. Finally, determine the process temperature that meets the conditions and the optimization direction of the subsequent process temperature for optimizing the performance of incoming material fluctuations. Example
[0030] The present invention will be further described below by way of embodiments with reference to the accompanying drawings.
[0031] The existing HC420 / 780DP product with continuous annealing temperature of 760℃ has yield strength of 482Mpa, tensile strength of 830Mpa, and BH2 of 21Mpa. The customer requested that the BH2 value of the product be greater than 30Mpa, and the existing product performance has surplus. In order to meet customer requirements and reduce product costs, the product is reduced in quantity. The components before and after the reduction are shown in Table 1.
[0032] Table 1 Comparison of ingredient adjustments
[0033] 1) The ferrite-austenite ratio of the existing composition is calculated using simulation software. The ratio of austenite to ferrite at 760°C is 1:3.
[0034] 2) Using simulation software to calculate the new composition of austenite and ferrite ratio of 1:3, the corresponding temperature is 775℃. The starting temperature of the industrial trial production is determined to be 785℃, and the temperature is raised to 815℃.
[0035] 3) The test coil on the production line has a steel coil specification of 1.2*1200mm. The interlocking control temperature is set to continuously rise from 785℃ to 815℃. The flattening mill adopts a constant rolling force mode with a fixed rolling force of 2500KN. The entire large coil is divided into 3 coils. Samples are taken at each division, for a total of 4 pieces. After production is completed, the rolling force and elongation values are derived, and the curve is exported using origin.
[0036] The actual length of the steel coil is 1300mm, and the approximate length of each small coil on the production line is 430m. The actual control of the absorptive temperature is smoothly increased from 787℃ to 813℃, the rolling force is stable at 2500±40KN, and the elongation shows a parabolic trend. The performance tests of each sampling position are as follows: Table 2 Sampling location performance data
[0037] The relationship between rolling force, elongation and temperature is derived and plotted, and the sampling position and performance value are marked at the elongation, such as Figure 2 .
[0038] 4) Since the temperature of the entire coil corresponds to the position of the steel coil and shows a smooth upward trend, that is, the temperature is positively correlated with the steel strip, the relationship between temperature, elongation and rolling force can be directly plotted. Since the rolling is basically constant, the elongation is inversely proportional to the strip strength, and the corresponding relationship between temperature and elongation can be plotted, that is, the relationship between temperature and strip performance. At the same time, the product performance at the corresponding sampling position can be calibrated, and the corresponding relationship diagram between annealing process temperature and performance can be presented.
[0039] The specific operation steps of this process are as follows: import the elongation and temperature data into origin, flip the vertical axis, and the curve presented is the trend chart of annealing process and performance. Calibrate the sampling position performance in the trend chart, which is the accurate annealing process and product performance law, such as Figure 3 .
[0040] 5) This experiment can conclude that when the absorptive temperature is between 785-815℃, as the absorptive temperature increases, the strength of the new component 780DP increases first and then decreases, reaching an extreme value at around 800~805℃. When the absorptive temperature is between 795-810℃, it can meet the product's factory performance: Rp0.2≥420Mpa, Rm≥780Mpa, A80≥15%, BH2≥30Mpa requirements, and the process window range is large. Because the temperature fluctuation of each small roll is controlled within the range of ±5℃, the performance fluctuation is within the allowable range. The first small roll is judged as a qualified product of HC340 / 590DP, the second small roll is judged as a qualified product of HC420 / 780DP, and the third small roll is judged as a qualified product of HC420 / 780DP after being re-rolled and cut for 50m. The product value is realized to the greatest extent. The product is shipped to customers and the customers have good results.
[0041] At present, more than 600 tons of products have been produced by this method. The actual process of the product is between 795-805℃. The actual control performance is relatively stable and meets the factory standard requirements of HC420 / 780DP. For details on the specific performance distribution, see Figure 4 and Figure 5 .
[0042] The present invention can accurately, quickly and efficiently formulate the cold rolling annealing process of new products after weight reduction, thereby solving the problem of long development cycle of new products and resulting in loss of customers; it can reduce the usage of transition materials in the actual production process, and can convert the transition materials into qualified products for sale, thereby solving the problems of high thermal simulation cost, long cycle and inaccurate results.
Claims
1. A method for formulating a reduction annealing process for a high-strength dual-phase steel alloy, characterized in that The method includes the following steps: (1) calculation of the ferrite-austenite ratio of the existing composition; (2) calculation of the austenite ratio temperature of the new composition with the same ratio after reduction; (3) determination of the trial annealing temperature and range; (4) industrial trial production; and (5) performance rating and performance trend drawing.
2. The method for formulating a reduction annealing process for a high-strength dual-phase steel alloy according to claim 1, characterized in that: In the step (1), simulation software is used to calculate the ratio of ferrite to austenite of the pre-reduced existing components, and the actual annealing temperature of the existing components is set.
3. The method for formulating a reduction annealing process for a high-strength dual-phase steel alloy according to claim 1, characterized in that: In the step (2), the composition of the reduced design is calculated using simulation software to calculate the temperature of ferrite and austenite in the same proportion as the existing composition.
4. The method for formulating a reduction annealing process for a high-strength dual-phase steel alloy according to claim 1, characterized in that: In the step (3), based on the actual annealing temperature of the existing components, the temperature difference of +10°C is simulated and measured in the same proportion as the starting point of the annealing temperature, the annealing temperature range is ≤30°C, and the upper limit temperature is 830°C.
5. The method for formulating a reduction annealing process for a high-strength dual-phase steel alloy according to claim 1, characterized in that: In the step (4), the annealing temperature is controlled manually or automatically, and the temperature is controlled to be continuously raised to the target temperature. The leveling mill adopts a constant rolling force or constant elongation mode. The exported steel coil is divided into three coils, and one sample is taken at each coil division, for a total of four samples.
6. The method for formulating a reduction annealing process for a high-strength dual-phase steel alloy according to claim 5, characterized in that: The trial production leveling mill process for the new component product refers to the rolling force C and elongation D of the original component and adopts a constant rolling force mode, with a rolling force of C±1000KN and an elongation of D±0.1%.
7. The method for formulating a reduction annealing process for a high-strength dual-phase steel alloy according to claim 5, characterized in that: In the step (5), the performance values of the four samples are measured, with the length range of the steel strip as the horizontal axis and the temperature and performance value as the vertical axis. The temperature and elongation at different positions of the steel strip are plotted in a table, and the performance values of the four samples are marked at the sampling positions.