阅读说明：本技术 一种以控制板形为目标的连退机组水雾冷却段喷淋工艺横向调整方法 (Horizontal adjusting method for spray process of water mist cooling section of continuous annealing unit by taking control plate shape as target ) 是由 杜国强 胡广魁 王骏飞 王彦辉 于 2021-08-11 设计创作，主要内容包括：本发明公开了一种以控制板形为目标的连退机组水雾冷却段喷淋工艺横向调整方法,包括以下步骤：收集设备特征参数和产品参数；收集出口的板形曲线及带钢入口的温度；根据当前出口板形,计算沿带钢宽度方向板形超差区域；根据板形超差区域内各段的板形超差量,计算水雾冷却喷淋工艺横向调整量。本发明以连退出口带钢板形优化为目标,研究了快速冷却装置喷头开放位置、数量、流量及压力等工艺参数与板带在快冷段的冷却效果,以及与板形变化的内在关系,实现了对喷头开放位置、数量、流量及压力等参数的定量控制,避免了采用经验表格法无法准确确定冷却位置与冷却程度的弊端。经实际生产使用验证,提高了产品板形质量,给企业带来经济效益。(The invention discloses a horizontal adjusting method of a spray process of a water mist cooling section of a continuous annealing unit by taking a control plate shape as a target, which comprises the following steps: collecting device characteristic parameters and product parameters; collecting a plate-shaped curve of an outlet and the temperature of a strip steel inlet; calculating the plate shape out-of-tolerance area along the width direction of the strip steel according to the current outlet plate shape; and calculating the transverse adjustment amount of the water mist cooling spraying process according to the plate shape tolerance amount of each section in the plate shape tolerance area. The invention aims at optimizing the shape of the strip steel plate at the continuous exit, researches the process parameters of the rapid cooling device such as the opening position, the quantity, the flow rate, the pressure and the like of the spray head, the cooling effect of the strip steel plate at the rapid cooling section and the internal relation of the strip steel plate and the shape change, realizes the quantitative control of the parameters of the opening position, the quantity, the flow rate, the pressure and the like of the spray head, and avoids the defect that the cooling position and the cooling degree cannot be accurately determined by adopting an empirical table method. The practical production and use verifies that the quality of the plate shape of the product is improved and economic benefits are brought to enterprises.)

1. A method for transversely adjusting a spraying process of a water mist cooling section of a continuous annealing unit by taking a control plate shape as a target is characterized by comprising the following steps of: the method comprises the following steps:

(a) collecting basic equipment characteristic parameters of a three-cold-rolling continuous annealing unit, comprising the following steps: minimum flow F of nozzle₀Flow characteristic coefficient K, band steel running speed V, effective nozzle spraying area S and longitudinal nozzle number n_yLongitudinal length L of cooling, water temperature T_wat；

(b) Collecting typical gauge of annealing processProduct parameters of the grade steel, including: strip steel width B, strip steel elastic modulus E, strip steel Poisson ratio v, and strip steel specific heat capacity C_tLinear expansion coefficient of strip steelStatic heat exchange coefficient a of strip steel and cooling water_wat ^*Target shape curve f_rk(x) X is the distribution of the strip steel along the transverse coordinate;

(c) obtaining a plate shape curve f of the outlet of the rapid cooling section according to the data acquisition system of the plate shape instrument at the outlet of the rapid cooling section_ck(x) And obtaining the temperature T (x) of the inlet of the rapid cooling section through a rapid cooling section inlet thermodetector data acquisition system;

(d) calculating and determining a plate shape out-of-tolerance area along the width direction of the strip steel according to the current outlet plate shape condition of the rapid cooling section; the method comprises the following steps:

(d1) by adopting a segmentation dispersion method, the strip is divided into 20 sections along the width direction of the strip, i represents the ith section, and each section has the length ofInitial i ═ 1;

(d2) calculating the average plate shape difference value of the ith section

(d3) Determination of Δ f_iIf the value is more than 0, recording the corresponding value i into an array X, and turning to the step (d4), otherwise, directly turning to the step (d 4);

(d4) judging whether i is greater than or equal to 20, if so, switching to the step (d5), otherwise, switching to the step (d2) if i is equal to i + 1;

(d5) output array X and corresponding position of the spray head

(e) Calculating the transverse adjustment amount of the water mist cooling spraying process according to the plate shape over-differential amount of each section in the plate shape over-differential area; the method comprises the following steps:

(e1) setting the step length delta h when i is equal to 1;

(e2) making the optimization step number m equal to 1;

(e3) calculating the dynamic convective heat transfer coefficient a of the strip steel and the cooling water_wat：

In the formula, F_iThe flow value of the nozzle at the ith section position in the width direction of the strip steel is obtained; p_iThe flow rate F of the ith section in the width direction of the strip steel at a nozzle_iThe value of the injection pressure under action;

(e4) calculating the cooling temperature of the i-th section

(e5) Calculating the actual residual stress of the i-th sectionAverage deformation of i-th section of actual plate shape

(e6) Judgment of beta_iIf' (x) < 2I is true, if yes, record F at that time_i,P_iRecording the values in an array F and an array P respectively, and turning to the step (e 7); if not, making m equal to m +1, and proceeding to step (e 3);

(e7) judging whether i is greater than or equal to 20, if so, switching to a step (e8), otherwise, switching to a step (e2) if i is equal to i + 1;

(e8) output F ═ F_i},P＝{P_iA value;

(f) and finishing the transverse adjustment of the water mist cooling and spraying process of the continuous annealing unit.

2. The method of claim 1, wherein: all the steps are executed by computer control.

Technical Field

The invention relates to the field of metallurgy, in particular to a transverse adjusting method of a spray process of a water mist cooling section of a continuous annealing unit by taking a control plate shape as a target.

Background

The technology is from field production practice, and particularly relates to a transverse adjusting method of a spray process of a water mist cooling section of a continuous annealing unit by taking a control plate shape as a target. The search keyword of the present invention includes: water mist cooling (Water mist cooling), Continuous annealing unit (Continuous annealing unit), and shape optimization (shape optimization). The search using the keywords can find the metallurgy field, and the patent of the similar technology is not searched.

With the rapid development of the automobile industry in the directions of energy conservation, light weight and environmental protection in recent years, the application proportion of the ultrahigh-strength steel (the strength grade is more than 80 kg) in automobiles is increased year by year. The continuous annealing is used as an important process for producing the ultrahigh-strength steel, plays an important role in the quality of finished products, and particularly in a rapid cooling section of an annealing furnace, the cooling effect directly influences the transverse distribution condition of residual stress in the strip steel under the action of tension so as to influence the shape quality of the finished products. At present, the most advanced cooling method is a strong water mist cooling system, as shown in fig. 1 and fig. 2, which can meet the technical requirement of the cooling rate of the ultra-high strength steel with the thickness cooling rate greater than 500 mm ℃/s (different strip thicknesses and different cooling rates). From the continuous annealing equipment configuration of advanced foreign enterprises (such as new-day iron, pump item and the like), only pump item adopts an annealing unit cooled by aerosol (specific parameters and technologies are unknown), but due to the technical secrecy condition, no literature related to temperature and plate shape control after cooling by aerosol is retrieved. The company stein (stainer) in france is equipped with corresponding powerful water mist cooling equipment in the Zhanjiang steel for the first time, and corresponding temperature and plate shape control technologies are not developed yet. And other domestic and foreign enterprises have not found the unit adopting the powerful water mist cooling technology similar to that adopted by the triple cold rolling continuous annealing unit. In China, the water quenching process adopted by the Bao steel pilot test C122 unit has poor plate shape control condition, although the subsequent technical improvement of the unit is realized, one set of plate shape instrument is arranged in a furnace, the plate shape instrument can only meet the plate shape display function, the corresponding plate shape automatic control function is not arranged, and the automatic closed-loop control of the plate shape cannot be realized. Therefore, how to achieve the purpose of controlling the strip steel plate shape by effectively adjusting key process parameters such as the opening position, the number, the pressure, the flow and the like of the spray heads of the cooling device at the rapid cooling section of the continuous annealing unit becomes a technical problem which needs to be solved urgently on site.

Based on the method, on the basis of a large amount of field test tracking and theoretical research, the invention considers the equipment and process characteristics in the water mist cooling process of the three-cold rolling continuous annealing unit, and particularly provides a transverse adjusting method of the spraying process of the water mist cooling section of the continuous annealing unit by taking the control plate shape as the target. With the optimization of the shape of the steel plate at the continuous exit port as a target, the open positions, the number, the pressure and the flow of the spray heads of the rapid cooling device are researched to improve the quality of the shape of the product plate and bring economic benefits to enterprises.

Disclosure of Invention

The invention aims to provide a horizontal adjusting method of a spray process of a water mist cooling section of a continuous annealing unit by taking plate shape control as a target.

In order to achieve the purpose, the invention adopts the technical scheme that: a method for transversely adjusting a spray process of a water mist cooling section of a continuous annealing unit by taking a control plate shape as a target comprises the following steps:

(a) collecting basic equipment characteristic parameters of a three-cold-rolling continuous annealing unit, comprising the following steps: minimum flow F of nozzle₀Flow characteristic coefficient K, band steel running speed V, effective nozzle spraying area S and longitudinal nozzle number n_yLongitudinal length L of cooling, water temperature T_wat；

(b) Collecting product parameters of steel grades with typical specifications of an annealing process, comprising: strip steel width B, strip steel elastic modulus E, strip steel Poisson ratio v, and strip steel specific heat capacity C_tLinear expansion coefficient of strip steelStatic heat exchange coefficient a of strip steel and cooling water_wat ^*Target shape curve f_rk(x) X is the distribution of the strip steel along the transverse coordinate;

(c) obtaining a plate shape curve f of the outlet of the rapid cooling section according to the data acquisition system of the plate shape instrument at the outlet of the rapid cooling section_ck(x) And obtaining the temperature T (x) of the inlet of the rapid cooling section through a rapid cooling section inlet thermodetector data acquisition system;

(d) calculating and determining a plate shape out-of-tolerance area along the width direction of the strip steel according to the current outlet plate shape condition of the rapid cooling section; the method comprises the following steps:

(d1) by adopting a segmentation dispersion method, the strip is divided into 20 sections along the width direction of the strip, i represents the ith section, and each section has the length ofInitial i ═ 1;

(d2) calculating the average plate shape difference value of the ith section

(d3) Determination of Δ f_iIf the value is more than 0, recording the corresponding value i into an array X, and turning to the step (d4), otherwise, directly turning to the step (d 4);

(d4) judging whether i is greater than or equal to 20, if so, switching to the step (d5), otherwise, switching to the step (d2) if i is equal to i + 1;

(d5) output array X and corresponding position of the spray head

(e) Calculating the transverse adjustment amount of the water mist cooling spraying process according to the plate shape over-differential amount of each section in the plate shape over-differential area; the method comprises the following steps:

(e1) setting the step length delta h when i is equal to 1;

(e2) making the optimization step number m equal to 1;

(e3) calculating the dynamic convective heat transfer coefficient a of the strip steel and the cooling water_wat：

In the formula, F_iThe flow value of the nozzle at the ith section position in the width direction of the strip steel is obtained; p_iThe flow rate F of the ith section in the width direction of the strip steel at a nozzle_iThe value of the injection pressure under action;

(e4) calculating the cooling temperature of the i-th section

(e5) Calculating the actual residual stress of the i-th sectionAverage deformation of i-th section of actual plate shape

(e6) Judgment of beta_iIf' (x) < 2I is true, if yes, record F at that time_i,P_iRecording the values in an array F and an array P respectively, and turning to the step (e 7); if not, making m equal to m +1, and proceeding to step (e 3);

(e7) judging whether i is greater than or equal to 20, if so, switching to a step (e8), otherwise, switching to a step (e2) if i is equal to i + 1;

(e8) output F ═ F_i},P＝{P_iA value;

(f) and finishing the transverse adjustment of the water mist cooling and spraying process of the continuous annealing unit.

Further, all the steps are performed by computer control.

The invention has the beneficial effects that: compared with the prior art, the invention aims at optimizing the shape of the continuous exit strip steel plate, researches the process parameters of the rapid cooling device such as the opening position, the quantity, the flow rate, the pressure and the like of the spray head, the cooling effect of the strip at the rapid cooling section and the internal relation of the change of the shape, realizes the quantitative control of the parameters of the opening position, the quantity, the flow rate, the pressure and the like of the spray head, and avoids the defect that the cooling position and the cooling degree cannot be accurately determined by adopting an empirical table method. The practical production and use verifies that the quality of the plate shape of the product is improved, the scheme of the invention is feasible, economic benefits are brought to enterprises, the method can be further popularized to other similar units, and the popularization and application prospect is wide.

Drawings

FIG. 1 is a schematic view of a continuous annealing rapid cooling stage;

FIG. 2 is a schematic front view of a continuous annealing rapid cooling stage;

FIG. 3 is a step diagram of the horizontal adjustment method of the spray process of the water mist cooling section of the continuous annealing unit.

Detailed Description

To illustrate the application process of the related art of the present invention, taking a water mist cooling system of a certain continuous annealing unit as an example, a calculation process for lateral adjustment of a spraying process of a water mist cooling section is described in detail as follows, as shown in fig. 3, and includes the following steps executed by a computer:

(a) collecting basic equipment characteristic parameters of a three-cold-rolling continuous annealing unit, comprising the following steps: minimum flow F of nozzle₀0L/min, 80 flow characteristic coefficient, 150m/min running speed of steel strip, 0.0132m effective area of nozzle²Number of longitudinal nozzles n_y40, cooling longitudinal length L11727 mm, water temperature T_wat＝20℃；

(b) Collecting product parameters of steel grades with typical specifications of an annealing process, comprising: strip steel width B1080 mm, strip steel elastic modulus E206X 10⁹Pa, Poisson ratio v of strip steel and specific heat capacity C of strip steel_t460J/(kg DEG C.), the linear expansion coefficient of the strip steelTemperature characteristic coefficient alpha of strip steel_ktStatic heat exchange coefficient a of strip steel and cooling water_wat ^*＝3000W/(m²C.) target plate shape curve f_rk(x)＝0.37×(4.0853×10^-10x⁴-0.000233668x²+16.7),x∈[-540,540]X is the distribution of the strip steel along the transverse coordinate;

(c) obtaining a plate shape curve f of the outlet of the rapid cooling section according to the data acquisition system of the plate shape instrument at the outlet of the rapid cooling section_ck(x)＝1.512×10^-10x⁴+1.24×10^-7x³-0.000086x²+6.18,x∈[-540,540]And obtaining a temperature curve T (x) 680+0.00001453x of the inlet of the rapid cooling section by a rapid cooling section inlet thermodetector data acquisition system²-0.000213x；

(d) Calculating and determining a plate shape out-of-tolerance area along the width direction of the strip steel according to the current outlet plate shape condition of the rapid cooling section;

(d1) by adopting a segmentation dispersion method, the strip is divided into 20 sections along the width direction of the strip, i represents the ith section, and each section has the length ofInitial i ═ 1;

(d2) calculating the average plate shape difference value of the ith section

(d3) Determination of Δ f₁If the result is more than 0, if not, the step is carried out (d 4);

(d4) judging whether i is greater than or equal to 20, if not, making i equal to i +1, and turning to the step (d2) to circulate;

(d5) output array X {1, 2, 3, 4, 5, 6, 15, 16, 17, 18, 19, 20}, number of digits in array n_xI.e. the number of nozzles, n_xOutputting the position corresponding to the spray head as 12:

(e) calculating the transverse adjustment amount of the water mist cooling spraying process according to the plate shape over-differential amount of each section in the plate shape over-differential area;

(e1) setting the step length delta h to be 0.1L/min when i is equal to 1;

(e2) making the optimization step number m equal to 1;

(e3) calculating the dynamic convective heat transfer coefficient a of the strip steel and the cooling water at the moment_wat＝5000W/(m²·℃)；

(e4) Calculating the cooling temperature delta T of the 1 st section₁'(x)＝323℃；

(e5) Calculating the actual residual stress delta sigma of the 1 st segment₁'(x)＝64MPa, 1 st section actual plate shape average deformation beta₁'(x)＝3.6I；

(e6) Judgment of beta₁If' (x) < 2I is true, if not, let m be m +1, proceed to step (e3) until the inequality is true, and record F at that time₁,P₁Recording the values in an array F and an array P respectively, and turning to the step (e 7);

(e7) judging whether i is greater than or equal to 20, if not, making i equal to 1+1, and turning to the step (e2) to circulate;

(e8) output F ═ 150,132,110,93,80,76,0,0,0,0,0,0,0,140,132,160,200, 260} L/min,

P＝{0.352,0.272,0.19,0.135,0.1,0.08,0,0,0,0,0,0,0,0.272,0.306,0.4,0.625，0.625,1.056}MPa

(f) and finishing the transverse adjustment of the water mist cooling and spraying process of the continuous annealing unit.

The set values of the process parameters such as the shower head cooling open position, the amount, the flow rate, and the pressure were thus obtained as shown in table 1.

Table 1 technological parameter setting table for water mist cooling system of quick cooling section of continuous annealing unit

The above description is only for the purpose of illustrating the technical solutions of the present invention, and those skilled in the art can make simple modifications or equivalent substitutions on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.