Hot continuous rolling control method for enhancing fine grain strengthening effect

Abstract

The invention relates to a hot continuous rolling control method for enhancing a fine grain strengthening effect, and belongs to the technical field of steel rolling control methods. According to the technical scheme, the method comprises the following steps: collecting data, and calculating austenite non-recrystallization temperature and rough rolling inlet temperature of a plate blank and outlet temperature data of a rolled piece passing through two rough rolling mills; and by judging the relation between the austenite non-recrystallization temperature Tnr and the rough rolling inlet temperature and the outlet temperature of the rolled piece passing through the two rough rolling mills, the rolling reduction in the finish rolling stage and the rough rolling stage is adjusted till the austenite non-recrystallization temperature is larger than or equal to the rough rolling inlet temperature, and the plate blank is allowed to enter the rough rolling mills to be rolled. The method has the beneficial effects that the rolling reduction at the non-recrystallization temperature of austenite is increased through temperature-deformation cooperative control and dynamic rolling reduction distribution, the problems that grain refinement is insufficient and performance fluctuation is large in a traditional process are solved, and an efficient hot rolling process scheme is provided for high-end products such as high-strength steel and automobile plates.

Description

TECHNICAL FIELD

[0001] The application relates to a hot continuous rolling control method for enhancing fine-grain strengthening, and belongs to the technical field of rolling control methods. BACKGROUND

[0002] In the modern steel industry, hot continuous rolling technology is one of the key processes for producing high-quality steel. The performance of steel is largely dependent on its microstructure, and a suitable rolling process can control the recrystallization process of austenite, realize fine-grain strengthening, and significantly improve the comprehensive performance of steel such as strength and toughness, which has important application value in steel production. However, the traditional hot continuous rolling control method can realize the rolling production of steel to some extent, but it has obvious shortcomings in fine-grain strengthening. On the one hand, the adjustment of rolling thickness in the traditional method is often based on experience or fixed process parameters, and lacks the ability to flexibly adjust according to the actual temperature. This makes it difficult to fully utilize the rolling deformation to promote the crushing and recrystallization of austenite grains during the rolling process, and it is difficult to achieve effective grain refinement. On the other hand, due to the difference in chemical composition of different steel grades, the austenite unrecrystallization temperature is also different, especially for materials containing niobium (Nb), vanadium (V), titanium (Ti) and other micro-alloy elements. If effective rolling operation cannot be carried out in the appropriate temperature range, the austenite grains cannot be fully refined, thereby affecting the fine-grain strengthening effect. In addition, with the increasing demand for steel quality and performance in the market, the steel produced by the traditional hot continuous rolling control method gradually shows its limitations in meeting the needs of high-end application fields. For example, in the fields of automobile manufacturing, aerospace and other fields, higher requirements are put forward for the strength and toughness of steel. The performance of steel produced by the traditional method in these aspects is difficult to meet the ideal standard, and it is often solved by adding expensive alloy elements, causing unnecessary waste of resources. SUMMARY

[0003] The purpose of the present application is to provide a hot continuous rolling control method for enhancing fine-grain strengthening, which increases the reduction amount at the austenite unrecrystallization temperature through temperature-deformation coordination control and dynamic reduction distribution, solves the problems of insufficient grain refinement and large performance fluctuation in the traditional process, provides an efficient hot rolling process scheme for high-strength steel, automobile sheet and other high-end products, and effectively solves the above-mentioned problems existing in the background technology.

[0004] The technical scheme of the present application is as follows: a hot continuous rolling control method for enhancing fine-grain strengthening, comprising the following steps: S1, after the heated slab passes through the high-temperature meter detection point after the furnace descaling outlet, collecting the slab online data; S2, calculating the austenite unrecrystallization temperature Tnr of the slab, the rough rolling inlet temperature RET, and the outlet temperature data R1DT and R2DT of the rolled piece passing through two times of rough rolling mill; S3, determining whether the austenite unrecrystallization temperature Tnr satisfies Tnr≥RET, determining yes, executing S4 step; otherwise executing S5 step; S4, rough rolling mill according to original setting rolling, directly to S10 step; S5, determining whether the austenite unrecrystallization temperature Tnr satisfies Tnr≤R2DT, determining yes, executing S6 step; otherwise executing S7 step; S6, increasing the intermediate blank setting thickness by 5% to increase the finishing rolling stage reduction, directly to S10 step; S7, determining whether the austenite unrecrystallization temperature Tnr satisfies R1DT≥Tnr>R2DT; determining yes, executing S8 step; otherwise executing S9 step; S8, increasing the setting thickness of the slab after R1 rolling mill by 10% to increase the R2 rolling mill reduction, directly to S10 step; S9, reducing the setting thickness of the slab after R1 rolling mill by 10% to increase the R1 rolling mill reduction; S10, the slab is allowed to enter the rough rolling mill rolling.

[0005] In the step S1, the slab online data includes slab width, the highest temperature TRF of the slab detected by the pyrometer, the setting thickness R1H of the slab after R1 rolling mill, the intermediate blank setting thickness R2H of the slab after R2 rolling mill, the setting rolling pass R1F and R2F of the slab through rough rolling R1 and rough rolling R2, and the chemical composition of the slab.

[0006] In the step S2, Tnr, RET, R1DT and R2DT are calculated according to the following formula (1)~(4): Tnr = 890- 11Mn + 464C + 6445Nb - 644Nb^(1 / 2) + 732V - 230V^(1 / 2) +890Ti+363Al-357Si (1) RET = -45.46 + 0.00276 H + 0.98744 TRF (2) R1DT = 337.9 - 0.01574 H + 0.8266 TRF - 24.93 R1F - 1.0006 R1H (3) R2DT=263.6- 0.01157 H+ 0.7553 TRF+ 0.7054 R1H- 31.032 R2F - 1.4326R2H (4) In formulas (1)-(4), Tnr is the austenite non-recrystallization temperature of the slab, RET is the rough rolling inlet temperature, R1DT is the rough rolling R1 outlet temperature, R2DT is the rough rolling R2 outlet temperature, TRF is the highest temperature value detected by the high-temperature gauge at the descaling outlet after the slab passes through the furnace, Tnr, RET, R1DT, R2DT and TRF are in units of ℃; C, Mn, Nb, V, Ti, Al and Si are the alloy contents of carbon, manganese, niobium, vanadium, titanium, aluminum and silicon elements in the slab, in units of %; H is the slab width, R1H is the set thickness of the slab after being rolled by the R1 rolling mill, R2H is the set thickness of the intermediate slab after being rolled by the R2 rolling mill, H, R1H and R2H are in units of mm; R1F is the rolling pass of rough rolling R1, R2F is the rolling pass of rough rolling R2, R1F and R2F are in units of passes.

[0007] The beneficial effects of the present application are: through temperature-deformation synergistic control and dynamic reduction distribution, the reduction at the austenite non-recrystallization temperature is increased, the problems of insufficient grain refinement and large performance fluctuation in the traditional process are solved, and an efficient hot rolling process scheme is provided for high-end products such as high-strength steel and automobile sheet. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a method flowchart of the present application. DETAILED DESCRIPTION

[0009] In order to make the purpose, technical scheme and advantages of the embodiment of the application clearer, the technical scheme in the embodiment of the application will be clearly and completely described below in combination with the drawings in the embodiment. Obviously, the described embodiment is only a part of the embodiments of the application, not all the embodiments of the application. Based on the embodiment in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0010] A hot continuous rolling control method for enhancing fine-grain strengthening effect, comprising the following steps: S1, after the heated slab passes through the descaling outlet high-temperature gauge detection point after the furnace, collecting the slab online data; S2, calculating the austenite non-recrystallization temperature Tnr of the slab, the rough rolling inlet temperature RET, and the outlet temperature data R1DT and R2DT of the rolled piece passing through two passes of rough rolling mills; S3, judging whether the austenite non-recrystallization temperature Tnr satisfies Tnr≥RET, if yes, executing S4 step; otherwise, executing S5 step; S4, the rough rolling mill is rolled according to the original setting, and directly goes to S10 step; S5, judge whether the austenite unrecrystallization temperature Tnr satisfies Tnr≤R2DT, judge yes, execute S6 step; otherwise execute S7 step; S6, increase the intermediate blank set thickness by 5% to increase the finishing rolling stage reduction, directly go to S10 step; S7, judge whether the austenite unrecrystallization temperature Tnr satisfies R1DT≥Tnr>R2DT; judge yes, execute S8 step; otherwise execute S9 step; S8, increase the set thickness of the slab after rolling through R1 rolling mill by 10% to increase the R2 rolling mill reduction; S9, reduce the set thickness of the slab after rolling through R1 rolling mill by 10% to increase the R1 rolling mill reduction; S10, the slab is allowed to enter the rough rolling mill rolling.

[0011] In the step S1, the slab online data includes slab width, the highest temperature TRF of the slab detected by the pyrometer, the set thickness R1H of the slab after rolling through R1 rolling mill, the intermediate blank set thickness R2H of the slab after rolling through R2 rolling mill, the set rolling pass R1F and R2F of the slab through rough rolling R1 and rough rolling R2, and the chemical composition of the slab.

[0012] In the step S2, Tnr, RET, R1DT and R2DT are calculated according to the following formula (1)-(4): Tnr = 890- 11Mn + 464C + 6445Nb - 644Nb^(1 / 2) + 732V - 230V^(1 / 2) +890Ti+363Al-357Si (1) RET = -45.46 + 0.00276 H + 0.98744 TRF (2) R1DT = 337.9 - 0.01574 H + 0.8266 TRF - 24.93 R1F - 1.0006 R1H (3) R2DT=263.6- 0.01157 H+ 0.7553 TRF+ 0.7054 R1H- 31.032 R2F - 1.4326R2H (4) In the formula (1)-(4), Tnr is the austenite non-recrystallization temperature of the slab, RET is the rough rolling inlet temperature, R1DT is the rough rolling R1 outlet temperature, R2DT is the rough rolling R2 outlet temperature, TRF is the highest temperature value detected by the high-temperature gauge at the descaling outlet after the furnace, Tnr, RET, R1DT, R2DT and TRF are in units of ℃; C, Mn, Nb, V, Ti, Al and Si are the alloy contents of carbon, manganese, niobium, vanadium, titanium, aluminum and silicon elements of the slab, in units of %; H is the slab width, R1H is the set thickness of the slab after being rolled by the R1 rolling mill, R2H is the set thickness of the intermediate slab after being rolled by the R2 rolling mill, H, R1H and R2H are in units of mm; R1F is the rolling pass of rough rolling R1, R2F is the rolling pass of rough rolling R2, R1F and R2F are in units of pass.

[0013] In practical application, the present application comprises the following steps: S1, after the heated slab passes through the high-temperature gauge detection point at the descaling outlet after the furnace, collect the data of the slab width, the highest temperature TRF detected by the high-temperature gauge, the set thickness R1H of the slab after being rolled by the R1 rolling mill, the set thickness R2H of the intermediate slab after being rolled by the R2 rolling mill, the set rolling passes R1F and R2F of the slab after being rolled by the rough rolling R1 and R2, and the chemical composition of the slab.

[0014] S2, calculate the austenite non-recrystallization temperature Tnr, the rough rolling inlet temperature RET, the outlet temperature data R1DT and R2DT of the rolled piece passing through the two-arch rough rolling mill according to the following formula (1)-(4); Tnr = 890- 11Mn + 464C + 6445Nb - 644Nb^(1 / 2) + 732V - 230V^(1 / 2) +890Ti+363Al-357Si (1) RET = -45.46 + 0.00276 H + 0.98744 TRF (2) R1DT = 337.9 - 0.01574 H + 0.8266 TRF - 24.93 R1F - 1.0006 R1H (3) R2DT=263.6- 0.01157 H+ 0.7553 TRF+ 0.7054 R1H- 31.032 R2F - 1.4326R2H (4) In the formulas (1)-(4), Tnr is the austenite non-recrystallization temperature of the slab, RET is the rough rolling inlet temperature, R1DT is the rough rolling R1 outlet temperature, R2DT is the rough rolling R2 outlet temperature, TRF is the highest temperature value detected by the high-temperature gauge at the slab descaling outlet after the furnace, Tnr, RET, R1DT, R2DT, and TRF are in units of ℃; C, Mn, Nb, V, Ti, Al, and Si are the alloy contents of carbon, manganese, niobium, vanadium, titanium, aluminum, and silicon elements in the slab, in units of %; H is the slab width, R1H is the set thickness of the slab after being rolled by the R1 rolling mill, and R2H is the set thickness of the intermediate slab after being rolled by the R2 rolling mill, H, R1H, and R2H are in units of mm; R1F is the rolling pass of rough rolling R1, and R2F is the rolling pass of rough rolling R2, R1F and R2F are in units of passes.

[0015] S3, determining whether the austenite non-recrystallization temperature Tnr satisfies Tnr≥RET, and if yes, performing S4; otherwise, performing S5; S4, the rough rolling mill rolls according to the original setting, and directly goes to S10; S5, determining whether the austenite non-recrystallization temperature Tnr satisfies Tnr≤R2DT, and if yes, performing S6; otherwise, performing S7; S6, increasing the set thickness of the intermediate slab by 5% (increasing the reduction amount in the finishing rolling stage), and directly going to S10; S7, determining whether the austenite non-recrystallization temperature Tnr satisfies R1DT≥Tnr>R2DT, and if yes, performing S8; otherwise, performing S9; S8, increasing the set thickness of the slab after being rolled by the R1 rolling mill by 10% (increasing the R2 reduction amount), and directly going to S10; S9, decreasing the set thickness of the slab after being rolled by the R1 rolling mill by 10% (increasing the R1 reduction amount); S10, the slab is allowed to enter the rough rolling mill for rolling; Examples 1-5 are produced according to the above-described embodiments, and are shown in Table 1 and Table 2.

[0016] Table 1 Chemical composition of the slab in the examples

[0017] Table 2 Online data of the slab in the examples and the actual rough rolling process

[0018] The above examples are only used to illustrate but not to limit the technical solutions of the present application. Although the present application is described in detail with reference to the above examples, those skilled in the art should understand that the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or partial replacement should be covered in the scope of claims of the present application.

Claims

1. A method of controlling hot continuous rolling for enhancing fine grain strengthening, characterized by The method comprises the following steps: S1, collecting the online data of the slab after the high-temperature meter detection point after the slab passes through the furnace and the descaling outlet; S2, calculating the austenite non-recrystallization temperature Tnr, the rough rolling inlet temperature RET, and the outlet temperature data R1DT and R2DT of the rolled piece passing through the two rough rolling mills; S3, judging whether the austenite non-recrystallization temperature Tnr satisfies Tnr≥RET, and if yes, executing S4; otherwise, executing S5; S4, the rough rolling mill is rolled according to the original setting, and directly proceeding to S10; S5, judging whether the austenite non-recrystallization temperature Tnr satisfies Tnr≤R2DT, and if yes, executing S6; otherwise, executing S7; S6, increasing the intermediate blank setting thickness by 5% to increase the reduction amount in the finishing rolling stage, and directly proceeding to S10; S7, judging whether the austenite non-recrystallization temperature Tnr satisfies R1DT≥Tnr>R2DT, and if yes, executing S8; otherwise, executing S9; S8, increasing the setting thickness of the slab after being rolled by the R1 mill by 10% to increase the reduction amount of the R2 mill, and directly proceeding to S10; S9, decreasing the setting thickness of the slab after being rolled by the R1 mill by 10% to increase the reduction amount of the R1 mill; S10, allowing the slab to enter the rough rolling mill for rolling.

2. The method of claim 1, wherein the method is characterized by: In the step S1, the online data of the slab comprises the slab width, the highest temperature TRF of the slab detected by the high-temperature meter, the setting thickness R1H of the slab after being rolled by the R1 mill, the intermediate blank setting thickness R2H of the slab after being rolled by the R2 mill, the setting rolling passes R1F and R2F of the slab passing through the rough rolling R1 and the rough rolling R2, and the chemical composition of the slab.

3. The method of claim 1, wherein the method is characterized by: In the step S2, Tnr, RET, R1DT and R2DT are calculated according to the following formulas (1)-(4): Tnr = 890- 11Mn + 464C + 6445Nb - 644Nb^(1 / 2) + 732V - 230V^(1 / 2) + 890Ti+363Al-357Si (1) RET = -45.46 + 0.00276 H + 0.98744 TRF (2) R1DT = 337.9 - 0.01574 H + 0.8266 TRF - 24.93 R1F - 1.0006 R1H (3) R2DT=263.6- 0.01157 H+ 0.7553 TRF+ 0.7054 R1H- 31.032 R2F - 1.4326 R2H(4) In the formulas (1)-(4), Tnr is the austenite non-recrystallization temperature of the slab, RET is the rough rolling inlet temperature, R1DT is the rough rolling R1 outlet temperature, R2DT is the rough rolling R2 outlet temperature, TRF is the highest temperature value detected by the high-temperature gauge at the slab descaling outlet after the furnace, Tnr, RET, R1DT, R2DT and TRF are in units of ℃; C, Mn, Nb, V, Ti, Al and Si are the alloy contents of carbon, manganese, niobium, vanadium, titanium, aluminum and silicon elements in the slab, in units of %; H is the slab width, R1H is the set thickness of the slab after being rolled by the R1 rolling mill, R2H is the set thickness of the intermediate slab after being rolled by the R2 rolling mill, H, R1H and R2H are in units of mm; R1F is the rolling pass of rough rolling R1, R2F is the rolling pass of rough rolling R2, R1F and R2F are in units of passes.

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