A method for increasing speed and production of cold-rolled low-alloy high-strength steel

Abstract

The present invention provides a method for increasing the production rate and output of cold-rolled low-alloy high-strength steel, specifically: determining the starting strip speed V0 before speed increase, the starting soaking temperature T0 before speed increase, the niobium and titanium mass fractions of the cold-rolled low-alloy high-strength steel, the cold rolling reduction rate P, and the target strip speed V1 after speed increase in the continuous annealing process; calculating the target soaking temperature T1 after speed increase through the following formula: T1 = T0 + 0.25×(V1 - V0)X1X2 + M; X1—the influence coefficient of the starting soaking temperature, X2—the influence coefficient of the chemical composition, M—the temperature compensation of the cold rolling reduction rate; Under the condition that the strip raw material process remains unchanged, the present invention can quickly realize the matching design of the strip speed and the soaking temperature of the cold-rolled low-alloy high-strength steel by establishing a calculation model of strip speed - soaking temperature, thereby quickly realizing the increase of the production rate and output of the cold-rolled low-alloy high-strength steel.

Description

Technical Field

[0001] The present invention belongs to the field of alloy production, and particularly relates to a method for increasing the production speed and output of cold-rolled low-alloy high-strength steel. Background Art

[0002] For a long time, steel has been the basic material for the automotive industry. Automotive sheets are the largest consumption variety among automotive steels, accounting for about 70%. Compared with ordinary steel sheets, automotive sheets have a long production process, high process requirements, and good product profits. In order to adapt to the change of steel consumption structure, major steel enterprises have vigorously developed automotive sheets. Currently, automotive sheet manufacturers mainly include ArcelorMittal, ThyssenKrupp, Nippon Steel & Sumitomo Metal, POSCO, SSAB from abroad and Baowu Steel Group, Ansteel Group, Shougang Group, HBIS Group, Hunan Valin Steel Co., Ltd. from domestic.

[0003] With the rapid development of the automotive industry, the market demand for automotive sheets is increasing day by day. Under the existing equipment conditions, increasing production speed and output and reducing costs and increasing efficiency are two important issues. Cold-rolled low-alloy high-strength steel usually adopts a micro-alloying composition design, with high process sensitivity and large performance fluctuations. After retrieval, there are few solutions for increasing the production speed and output of cold-rolled low-alloy high-strength steel in the existing technical solutions. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for increasing the production speed and output of cold-rolled low-alloy high-strength steel. By using the method of the present invention, the matching design of the strip speed and soaking temperature of cold-rolled low-alloy high-strength steel can be quickly realized, so as to achieve the purpose of increasing production and efficiency.

[0005] The specific technical solution of the present invention is as follows:

[0006] A method for increasing the production speed and output of cold-rolled low-alloy high-strength steel, specifically:

[0007] Determine the starting strip speed V before speed increase in the continuous annealing process 0 , the starting soaking temperature T before speed increase 0 , the niobium-titanium mass fraction of cold-rolled low-alloy high-strength steel, the cold rolling reduction rate P and the target strip speed V after speed increase 1 ; calculate the target soaking temperature T after speed increase in the continuous annealing process through the following formula 1 ;

[0008] T 1 = T 0 + 0.25×(V 1 - V 0 )X 1 X 2 + M;

[0009] Wherein,

[0010] T 1 — The target soaking temperature after speed increase, °C;

[0011] T 0 — The initial soaking temperature before speed increase, °C;

[0012] V 1 — The target strip speed after speed increase, m / min;

[0013] V 0 — The initial strip speed before speed increase, m / min;

[0014] X 1 — The influence coefficient of the initial soaking temperature; when 740°C ≤ T 0 < 780°C, X 1 = 1.5; when 780°C ≤

[0015] T 0 < 820°C, X 1 = 1.0; when 820°C ≤ T 0 ≤ 840°C, X 1 = 0.5;

[0016] X 2 — The influence coefficient of chemical composition; when the mass fractions of Nb and Ti in cold-rolled low-alloy high-strength steel satisfy 0.02% ≤ Nb + 0.5×Ti ≤ 0.05%, X 2 = 1.0; when the mass fractions of Nb and Ti satisfy 0.05% < Nb + 0.5×Ti ≤ 0.08%, X 2 = 1.5;

[0017] M — The temperature compensation of cold rolling reduction rate, °C; when the cold rolling reduction rate P satisfies 40% ≤ P ≤ 70%, M = 0; when the cold rolling reduction rate P satisfies 70% < P ≤ 85%, M = 160×(P - 0.7).

[0018] The initial strip speed V before speed increase 0 is 60 - 200 m / min; the initial soaking temperature T before speed increase 0 is 740°C - 840°C; the cold rolling reduction rate P is 40 - 85%;

[0019] The target strip speed after speed increase satisfies: V 0 < V 1 ≤ 300 m / min, and the calculated target soaking temperature T of the strip 1 ≤ 850°C;

[0020] The thickness of the cold-rolled low-alloy high-strength steel is 0.3 - 2.5 mm;

[0021] The composition of the cold-rolled low-alloy high-strength steel satisfies: 0.02% ≤ Nb + Ti ≤ 0.08%;

[0022] The composition of the cold-rolled low-alloy high-strength steel satisfies: 0.02% ≤ Al ≤ 0.08%, Si ≤ 0.5%.

[0023] The method for increasing production speed of the cold-rolled low-alloy high-strength steel includes uncoiling, welding, cleaning, and continuous annealing; in the continuous annealing process, after the speed increase, the heating temperature and soaking temperature are adjusted synchronously, and the difference between the target heating temperature and the target soaking temperature does not exceed 10°C;

[0024] Furthermore, in the continuous annealing process, the process after soaking remains unchanged and is carried out according to the original annealing process.

[0025] Furthermore, the strip raw material is prepared according to the industrial process of smelting → continuous casting → hot rolling → pickling cold rolling, and the process of the strip raw material remains unchanged before and after the speed increase.

[0026] The main structure of the cold-rolled low-alloy high-strength steel is ferrite + pearlite + second-phase precipitates;

[0027] The cold-rolled low-alloy high-strength steel is a bare board or a coated board.

[0028] The properties of steel materials depend on the structure, and the structure depends on the composition and process. The cold-rolled low-alloy high-strength steel adopts a microalloying composition design, which can play a good role in precipitation strengthening and grain refinement strengthening. However, solute drag and precipitate pinning will delay and inhibit the recrystallization of ferrite. Therefore, there is often a large intersection between the ferrite recrystallization temperature range and the ferrite + austenite two-phase region. Under the influence of the mutual competition between ferrite recrystallization and austenite transformation, the ferrite recrystallization process is further slowed down. The strip speed, soaking temperature, chemical composition, and cold rolling reduction rate all have an impact on the ferrite recrystallization process. Therefore, the calculation model of the target soaking temperature after the speed increase designed in the present invention has an influence coefficient X of the starting soaking temperature 1 and an influence coefficient X of the chemical composition 2 and a temperature compensation M of the cold rolling reduction rate. The difference is that only when the cold rolling reduction rate is greater than 70%, the influence on the product performance will be fully manifested. Therefore, when calculating in the present invention, when the cold rolling reduction rate P satisfies 40% ≤ P ≤ 70%, M = 0; when the cold rolling reduction rate P satisfies 70% < P ≤ 85%, M = 160×(P - 0.7).

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: The method of the present invention uses a conventional continuous annealing furnace. Under the condition that the strip raw material process remains unchanged, by establishing a calculation model of strip speed-average heating temperature, the matching design of the strip speed and average heating temperature of cold-rolled low-alloy high-strength steel strip can be quickly realized, so as to quickly realize the speed increase and production increase of cold-rolled low-alloy high-strength steel. The average heating temperature calculation model is simple and efficient, the product performance difference before and after speed increase is small, and the produced products meet the performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the metallographic structure of Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] A method for increasing the speed and production of cold-rolled low-alloy high-strength steel provided by the present invention includes the following technological processes: The strip raw material is prepared according to the process of smelting → continuous casting → hot rolling → pickling and cold rolling, and the process of the strip raw material remains unchanged before and after the speed increase; in the continuous annealing process, determine the starting strip speed V 0 before the speed increase in the continuous annealing process, the starting average heating temperature T 0 , the niobium and titanium mass fractions of the cold-rolled low-alloy high-strength steel, the cold rolling reduction rate P, and the target strip speed V 1 after the speed increase; calculate the target average heating temperature T 1 in the continuous annealing process through the following formula;

[0032] The starting strip speed V 0 before the speed increase is 60 - 200 m / min; the starting average heating temperature T 0 before the speed increase is 740°C - 840°C; the cold rolling reduction rate P is 40 - 85%;

[0033] T 1 = T 0 + 0.25×(V 1 - V 0 )X 1 X 2 + M;

[0034] Wherein,

[0035] T 1 —The target average heating temperature after the speed increase, °C;

[0036] T 0 —The starting average heating temperature before the speed increase, °C;

[0037] V 1 —The target strip speed after the speed increase, m / min;

[0038] V 0 —The starting strip speed before the speed increase, m / min;

[0039] X 1 — Influence coefficient of the starting soaking temperature; when 740°C ≤ T 0 < When T < 780°C, X 1 = 1.5; when 780°C ≤

[0040] T 0 < When T < 820°C, X 1 = 1.0; when 820°C ≤ T 0 ≤ 840°C, X1 = 0.5;

[0041] X 2 — Influence coefficient of chemical composition; when the mass fractions of Nb and Ti in the cold-rolled low-alloy high-strength steel satisfy 0.02% ≤ Nb + 0.5×Ti ≤ 0.05%, X 2 = 1.0; when the mass fractions of Nb and Ti satisfy 0.05% < Nb + 0.5×Ti ≤ 0.08%, X 2 = 1.5;

[0042] M — Temperature compensation of cold rolling reduction rate, °C; when the cold rolling reduction rate P satisfies 40% ≤ P ≤ 70%, M = 0; when the cold rolling reduction rate P satisfies 70% < P ≤ 85%, M = 160×(P - 0.7).

[0043] The target strip speed after speed increase satisfies: V 0 < V 1 ≤ 300 m / min, and the calculated target soaking temperature T of the strip 1 ≤ 850°C;

[0044] The thickness of the cold-rolled low-alloy high-strength steel is 0.3 - 2.5 mm;

[0045] The composition of the cold-rolled low-alloy high-strength steel satisfies: 0.02% ≤ Nb + Ti ≤ 0.08%;

[0046] The composition of the cold-rolled low-alloy high-strength steel satisfies: 0.02% ≤ Al ≤ 0.08%, Si ≤ 0.5%.

[0047] The method for increasing production by speed increase of the cold-rolled low-alloy high-strength steel includes uncoiling, welding, cleaning and continuous annealing; in the continuous annealing process, the heating temperature and soaking temperature are adjusted synchronously after speed increase, and the difference between the target heating temperature and the target soaking temperature does not exceed 10°C;

[0048] The method for increasing production by speed increase of the cold-rolled low-alloy high-strength steel is generally carried out according to the following steps:

[0049] 1) Parameter collection, including strip speed, soaking temperature, Nb and Ti mass fractions, cold rolling reduction rate under the existing process conditions;

[0050] 2) Parameter assignment, for T 0 , V 0 , X 1 , X 2 , P, M are assigned values; T 0 —The starting soaking temperature before speed increase, °C; V 0 —The starting strip speed before speed increase, m / min; X 1 —The influence coefficient of the starting soaking temperature; when 740°C ≤ T 0 < 780°C, X 1 = 1.5; when 780°C ≤ T 0 < 820°C, X 1 = 1.0; when 820°C ≤ T 0 ≤ 840°C, X 1 = 0.5; X 2 —The influence coefficient of chemical composition; when the mass fractions of Nb and Ti in cold-rolled low-alloy high-strength steel satisfy 0.02% ≤ Nb + 0.5×Ti ≤ 0.05%, X 2 = 1.0; when the mass fractions of Nb and Ti satisfy 0.05% < Nb + 0.5×Ti ≤ 0.08%, X 2 = 1.5; M—the temperature compensation of cold rolling reduction rate, °C; when the cold rolling reduction rate P satisfies 40% ≤ P ≤ 70%, M = 0; when the cold rolling reduction rate P satisfies 70% < P ≤ 85%, M = 160×(P - 0.7).

[0051] 3) Parameter calculation, design the target strip speed V 1 after speed increase, and calculate the target soaking temperature T 1 after speed increase;

[0052] 4) Parameter execution, the target strip speed after speed increase is controlled according to V 1 , and the target heating temperature and soaking temperature after speed increase are controlled according to T 1 , and other annealing process parameters remain unchanged. By using the method of the present invention, the speed increase and production increase of cold-rolled low-alloy high-strength steel can be quickly realized, and the product performance difference before and after speed increase is small, and the product performance meets the requirements.

[0053] Several preferred embodiments of the present invention are as follows:

[0054] Example 1

[0055] A method for speed increase and production increase of cold-rolled low-alloy high-strength steel, the component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 1-1.

[0056] Table 1-1 Component of Nb, Ti, Al, and Si in Cold-Rolled Low-Alloy High-Strength Steel of Example 1

[0057]

[0058] The production process flow of Example 1 is as follows: The strip steel raw material goes through smelting → continuous casting → hot rolling → pickling and cold rolling → uncoiling → welding → cleaning → continuous annealing;

[0059] The method for increasing the speed and output of cold-rolled low-alloy high-strength steel in this example is generally carried out according to the following steps:

[0060] 1) Parameter collection, including strip steel speed, soaking temperature, niobium and titanium mass fractions, and cold rolling reduction rate under the existing process conditions;

[0061] 2) Parameter assignment, assigning values to T 0 、V 0 、X 1 、X 2 、P, and M; specifically as shown in Table 1-2;

[0062] 3) Parameter calculation, designing the target strip steel speed V 1 = 200 m / min after speed increase, and calculating the target soaking temperature T 1 ;

[0063] 4) Parameter execution, controlling the target strip steel speed after speed increase according to V 1 , controlling the target heating temperature and soaking temperature after speed increase according to T 1 , and keeping other annealing process parameters unchanged. By using the method of the present invention, the speed increase and output increase of cold-rolled low-alloy high-strength steel can be quickly achieved, and the product performance difference before and after speed increase is small, and the product performance meets the requirements. The target process after speed increase in Example 1 and the mechanical properties of the produced products are shown in Table 1-3.

[0064] Table 1-2 Initial process and model parameters of Example 1

[0065] Number <![CDATA[T 0 / ℃]]> <![CDATA[V 0 / (m / min)]]> <![CDATA[X 1 > <![CDATA[X 2 > M / ℃ P / ％ Example 1 800 150 1.0 1.0 0 65.7

[0066] Table 1-3 Target process after speed increase in Example 1 and mechanical properties of the produced products

[0067] Number Thickness / mm <![CDATA[V 1 / (m / min)]]> <![CDATA[T 1 / ℃]]> Yield strength / MPa Tensile strength / MPa Elongation after fracture / % Example 1 1.2 200 812.5 383 485 28.0

[0068] Comparative Example 1

[0069] A production method of cold-rolled low-alloy high-strength steel is produced according to the process and parameters before speed increase. The component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 1-1. The components of the cold-rolled low-alloy high-strength steel in Comparative Example 1 are the same as those in Example 1. The process parameters and performance of the production method in Comparative Example 1 are shown in Table 4.

[0070] Table 4 Production process parameters and product performance of Comparative Example 1 - Comparative Example 5

[0071] Number Thickness / mm <![CDATA[V 0 / (m / min)]]> <![CDATA[T 0 / ℃]]> Yield strength / MPa Tensile strength / MPa Elongation after fracture / % Comparative Example 1 1.2 150 800 382 483 28.0 Comparative Example 2 0.4 150 800 400 492 27.5 Comparative Example 3 1.5 100 770 379 486 28.5 Comparative Example 4 2.0 80 825 467 585 20.0 Comparative Example 5 1.5 100 770 401 517 26.5

[0072] Example 2

[0073] A method for increasing the production rate of cold-rolled low-alloy high-strength steel, the component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 2-1.

[0074] Table 2-1 Component of Nb, Ti, Al, and Si in Cold-Rolled Low-Alloy High-Strength Steel in Example 2

[0075]

[0076] The method for increasing the production rate of cold-rolled low-alloy high-strength steel in this example is generally carried out according to the following steps:

[0077] 1) Parameter collection, including strip speed, soaking temperature, niobium-titanium mass fraction, and cold rolling reduction rate under existing process conditions;

[0078] 2) Parameter assignment, assign values to T 0 , V 0 , X 1 , X 2 , P, and M; specifically shown in Table 2-2;

[0079] 3) Parameter calculation, design the target strip speed V 1 = 200 m / min after speed increase, and calculate the target soaking temperature T 1 ;

[0080] 4) Parameter execution, control the target strip speed after speed increase according to V 1 , and control the target heating temperature and soaking temperature after speed increase according to T 1 , and other annealing process parameters remain unchanged. By using the method of the present invention, the production rate of cold-rolled low-alloy high-strength steel can be quickly increased, and the product performance difference before and after speed increase is small, and the product performance meets the requirements. The target process after speed increase in Example 2 and the mechanical properties of the produced products are shown in Table 2-3.

[0081] Table 2-2 Initial Process and Model Parameters in Example 2

[0082] Number <![CDATA[T 0 / ℃]]> <![CDATA[V 0 / (m / min)]]> <![CDATA[X 1 > <![CDATA[X 2 > M / ℃ P / ％ Example 2 800 150 1.0 1.0 16 80.0

[0083] Table 2-3 Target Process after Speed Increase in Example 2 and Mechanical Properties of Produced Products

[0084] Number Thickness / mm <![CDATA[V 1 / (m / min)]]> <![CDATA[T 1 / ℃]]> Yield strength / MPa Tensile strength / MPa Elongation after fracture / % Example 2 0.4 200 828.5 391 486 28.0

[0085] Comparative Example 2

[0086] A production method of cold-rolled low-alloy high-strength steel, which is produced according to the process and parameters before speed increase. The component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 2-1. The composition of the cold-rolled low-alloy high-strength steel in Comparative Example 2 is the same as that in Example 2. The process parameters and performance of the production method in Comparative Example 2 are shown in Table 4.

[0087] Example 3

[0088] A method for increasing production by speed increase of cold-rolled low-alloy high-strength steel, wherein the component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 3-1.

[0089] Table 3-1 Composition of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel of Example 3

[0090]

[0091] The method for increasing production by speed increase of the cold-rolled low-alloy high-strength steel in this example is generally carried out according to the following steps:

[0092] 1) Parameter collection, including strip speed, soaking temperature, niobium-titanium mass fraction, and cold rolling reduction rate under existing process conditions;

[0093] 2) Parameter assignment, assigning values to T 0 、V 0 、X 1 、X 2 、P, and M; specifically shown in Table 3-2;

[0094] 3) Parameter calculation, designing the target strip speed V 1 = 180 m / min after speed increase, and calculating the target soaking temperature T 1 after speed increase;

[0095] 4) Parameter execution, controlling the target strip speed after speed increase according to V 1 and controlling the target soaking temperature after speed increase according to T 1 , and keeping other annealing process parameters unchanged. By using the method of the present invention, the production increase by speed increase of cold-rolled low-alloy high-strength steel can be quickly realized, and the product performance difference before and after speed increase is small, and the product performance meets the requirements. The target process after speed increase and the mechanical properties of the products produced in Example 3 are shown in Table 3-3.

[0096] Table 3-2 Starting process and model parameters of Example 3

[0097] Number <![CDATA[T 0 / ℃]]> <![CDATA[V 0 / (m / min)]]> <![CDATA[X 1 > <![CDATA[X 2 > M / ℃ P / ％ Example 3 770 100 1.5 1.0 0 62.5

[0098] Table 3-3 Target process after speed increase and mechanical properties of the products produced in Example 3

[0099] Number Thickness / mm <![CDATA[V 1 / (m / min)]]> <![CDATA[T 1 / ℃]]> Yield strength / MPa Tensile strength / MPa Elongation after fracture / % Example 3 1.5 180 800.0 375 478 28.5

[0100] Comparative Example 3

[0101] A production method of cold-rolled low-alloy high-strength steel, the component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 3-1. The components of the cold-rolled low-alloy high-strength steel in Comparative Example 3 are the same as those in Example 3. The process parameters and properties of the production method in Comparative Example 3 are shown in Table 4.

[0102] Example 4

[0103] A method for increasing the speed and production of cold-rolled low-alloy high-strength steel, the component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 4-1.

[0104] Table 4-1 Components of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel of Example 4

[0105]

[0106] The method for increasing the speed and production of the cold-rolled low-alloy high-strength steel in this example is generally carried out according to the following steps:

[0107] 1) Parameter collection, including strip speed, soaking temperature, niobium-titanium mass fraction, and cold rolling reduction rate under existing process conditions;

[0108] 2) Parameter assignment, assign values to T 0 , V 0 , X 1 , X 2 , P, and M; specifically shown in Table 4-2;

[0109] 3) Parameter calculation, design the target strip speed V 1 = 120 m / min, calculate the target soaking temperature T 1 ;

[0110] 4) Parameter execution, control the target strip speed after speed increase according to V 1 , control the target heating temperature and soaking temperature after speed increase according to T 1 , and keep other annealing process parameters unchanged. By using the method of the present invention, the speed and production of cold-rolled low-alloy high-strength steel can be quickly increased, and the product performance difference before and after speed increase is small, and the product performance meets the requirements. The target process and mechanical properties of the product produced after the speed increase in Example 4 are shown in Table 4-3.

[0111] Table 4-2 Starting process and model parameters of Example 4

[0112] Number <![CDATA[T 0 / ℃]]> <![CDATA[V 0 / (m / min)]]> <![CDATA[X 1 > <![CDATA[X 2 > M / ℃ P / ％ Example 4 825 80 0.5 1.5 0 55.5

[0113] Table 3-3 Target Process after the Speed Increase in Example 4 and Mechanical Properties of the Produced Products

[0114]

[0115]

[0116] Comparative Example 5

[0117] A production method of cold-rolled low-alloy high-strength steel, the component contents of Nb, Ti, Al, and Si in the cold-rolled low-alloy high-strength steel are shown in Table 3-1, and the components of Comparative Example 5 are the same as those of Example 3. The difference is that Comparative Example 5 only simply increases the speed, and the strip speed after the speed increase is the same as that of Example 3, but other annealing process parameters including the soaking temperature remain unchanged according to the original process.

[0118] Comparative Examples 1-4 have the same components as Examples 1-4 of the present application respectively, but Comparative Examples 1-4 are produced according to the process before the speed increase, and their mechanical properties are shown in Table 4. From the comparison data of Examples 1-4 and Comparative Examples 1-4, it can be obtained that the annealing soaking temperature method designed and matched after the speed increase by using the formula of the present invention can quickly realize the speed increase and production increase of cold-rolled low-alloy high-strength steel, and the product performance difference before and after the speed increase is small, and the product performance meets the requirements. Comparative Example 5 has the same components as Example 3, and the results show that simply increasing the speed without matching and adjusting the soaking temperature will result in problems of increased strength and decreased plasticity, which will not only affect the product use, but even lead to too high strength, resulting in downgrading and rejudgment, increasing the losses of the enterprise.

[0119] The measurement method of the mechanical properties of each product of the present invention adopts the national standard GB / T 228.1-2021, the specimen type is P6, and the specimen direction is transverse.

[0120] More specifically, although the exemplary embodiments of the present invention have been described herein, the present invention is not limited to these embodiments, but includes any and all embodiments that can be recognized by those skilled in the art through modification, omission, for example, combination between various embodiments, adaptive changes, and / or substitutions according to the foregoing detailed description. The limitations in the claims can be widely interpreted according to the language used in the claims and are not limited to the examples described in the foregoing detailed description or during the implementation of this application, and these examples should be considered non-exclusive. Any steps listed in any method or process claim can be executed in any order and are not limited to the order set forth in the claim. Therefore, the scope of the present invention should be determined only by the appended claims and their legal equivalents, rather than by the description and examples given above.

Claims

1. A method for increasing the speed and production of cold-rolled low-alloy high-strength steel, characterized in that: The specific method for speed increase and production increase is as follows: Determine the starting strip speed V0 before speed increase, the starting soaking temperature T0 before speed increase, the niobium-titanium mass fraction of the cold-rolled low-alloy high-strength steel, the cold-rolled reduction ratio P, and the target strip speed V1 after speed increase in the continuous annealing process; Calculate the target soaking temperature T1 after speed increase in the continuous annealing process through the following formula; T1 = T0 + 0.25×(V1 - V0)X1X2 + M; Wherein, T1—the target soaking temperature after speed increase, °C; T0—the starting soaking temperature before speed increase, °C; V1—the target strip speed after speed increase, m / min; V0—the starting strip speed before speed increase, m / min; X1—the influence coefficient of the starting soaking temperature; when 740°C ≤ T0 < 780°C, X1 = 1.5; when 780°C ≤ T0 < 820°C, X1 = 1.0; when 820°C ≤ T0 ≤ 840°C, X1 = 0.5; X2—the influence coefficient of chemical composition; when the mass fractions of Nb and Ti in the cold-rolled low-alloy high-strength steel satisfy 0.02% ≤ Nb + 0.5×Ti ≤ 0.05%, X2 = 1.0; when the mass fractions of Nb and Ti satisfy 0.05% < Nb + 0.5×Ti ≤ 0.08%, X2 = 1.5; M—the temperature compensation of the cold-rolled reduction ratio, °C; when the cold-rolled reduction ratio P satisfies 40% ≤ P ≤ 70%, M = 0; when the cold-rolled reduction ratio P satisfies 70% < P ≤ 85%, M = 160×(P - 0.7).

2. The method for increasing speed and production according to claim 1, characterized in that: The composition of the cold-rolled low-alloy high-strength steel satisfies: 0.02% ≤ Nb + Ti ≤ 0.08%.

3. The method for increasing speed and production according to claim 1 or 2, characterized in that: The composition of the cold-rolled low-alloy high-strength steel satisfies: 0.02% ≤ Al ≤ 0.08%.

4. The method for increasing speed and production according to claim 1 or 2, characterized in that: The composition of the cold-rolled low-alloy high-strength steel satisfies: Si ≤ 0.5%.

5. The method for increasing speed and production according to claim 1 or 2, characterized in that: The thickness of the cold-rolled low-alloy high-strength steel is 0.3 - 2.5 mm.

6. The method for increasing speed and production according to claim 1 or 2, characterized in that: The starting strip speed V0 before speed increase is 60 - 200 m / min.

7. The method for increasing speed and production according to claim 1 or 2, characterized in that: The starting soaking temperature T0 before speed increase is 740°C - 840°C.

8. The method for increasing speed and production according to claim 1 or 2, characterized in that: The cold-rolled reduction ratio P is 40 - 85%.

9. The method for increasing speed and production according to claim 1 or 2, characterized in that: The target strip speed after speed increase satisfies: V0 < V1 ≤ 300 m / min, and the calculated target soaking temperature T1 of the strip ≤ 850°C.

10. The method for increasing speed and production according to claim 1 or 2, characterized in that: The cold-rolled low-alloy high-strength steel is a bare board or a coated board.

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