阅读说明：本技术 退火炉带钢张力的控制方法 (Method for controlling strip steel tension of annealing furnace ) 是由 李立 刘靖 张兴 兰晓栋 屈英刚 王承刚 于 2021-07-08 设计创作，主要内容包括：本说明书实施例公开了一种退火炉带钢张力的控制方法,在带钢通过退火炉进行退火过程中,获取目标炉辊上带钢的实际温度和所述带钢的热膨胀系数；以及获取所述带钢的基准速度；根据所述实际温度、所述热膨胀系数和所述基准速度,获取所述带钢的实际运行速度；控制所述目标炉辊按所述实际运行速度进行运转。本说明书公开的一种退火炉带钢张力的控制方法,能够有效降低带钢入炉和出炉存在的张力差,达到降低硅钢铁损,提升产品性能目的。(The embodiment of the specification discloses a control method of the strip steel tension of an annealing furnace, which comprises the steps of acquiring the actual temperature of the strip steel on a target furnace roller and the thermal expansion coefficient of the strip steel in the annealing process of the strip steel through the annealing furnace; acquiring the reference speed of the strip steel; acquiring the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed; and controlling the target furnace roller to operate according to the actual operation speed. The control method for the strip steel tension of the annealing furnace disclosed by the specification can effectively reduce the tension difference existing in the strip steel charging and discharging, and achieves the purposes of reducing the iron loss of silicon steel and improving the product performance.)

1. A control method for the strip steel tension of an annealing furnace is characterized by comprising the following steps:

acquiring the actual temperature of the strip steel on a target furnace roller and the thermal expansion coefficient of the strip steel in the annealing process of the strip steel through an annealing furnace; and

acquiring the reference speed of the strip steel;

acquiring the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed;

and controlling the target furnace roller to operate according to the actual operation speed.

2. The method of claim 1, wherein said obtaining the actual temperature of the strip comprises:

acquiring target temperatures of strip steel at outlets of a heating section and a soaking section and a strip steel temperature rise curve;

and acquiring the actual temperature according to the target temperature and the strip steel temperature rising curve.

3. The method of claim 2, wherein said obtaining an actual operating speed of said strip based on said actual temperature, said coefficient of thermal expansion, and said reference speed comprises:

acquiring the thermal expansion amount of the strip steel in unit length according to the actual temperature and the thermal expansion coefficient;

and acquiring the actual running speed according to the thermal expansion amount of the unit length and the reference speed.

4. The method of claim 3, wherein said obtaining the amount of thermal expansion per unit length of said strip based on said actual temperature and said coefficient of thermal expansion comprises:

and acquiring a first product of the actual temperature and the thermal expansion coefficient, and taking the first product as the thermal expansion amount per unit length.

5. The method according to claim 4, wherein said obtaining the actual operating speed based on the amount of thermal expansion per unit length and the reference speed comprises:

acquiring the additional speed of the strip steel according to the thermal expansion amount of the unit length and the reference speed;

and acquiring the actual running speed according to the reference speed and the additional speed.

6. The method of claim 5, wherein said obtaining the additional velocity of the strip based on the amount of thermal expansion per unit length and the reference velocity comprises:

and acquiring a second product of the thermal expansion amount per unit length and the reference speed, and taking the second product as the additional speed.

7. The method of claim 6, wherein said deriving said actual operating speed from said reference speed and said additional speed comprises:

and acquiring the sum of the speeds of the reference speed and the additional speed, and taking the sum of the speeds as the actual running speed.

8. The method of any one of claims 1 to 7, wherein said obtaining a reference speed of said strip comprises:

and acquiring the reference speed through an outlet tension roller in the annealing furnace.

9. The method of any one of claims 1 to 7, wherein said obtaining the actual temperature of the strip comprises:

and measuring the temperature of the strip steel through temperature measuring equipment arranged in the annealing furnace to obtain the actual temperature.

10. The method of any one of claims 1-7, wherein said controlling said target furnace roller to operate at said actual operating speed comprises:

and controlling the target furnace roller to run at the actual running speed by adjusting the rotating speed of an inlet tension roller and an outlet tension roller in the annealing furnace.

Technical Field

The embodiment of the specification relates to the technical field of steel smelting, in particular to a control method for the strip steel tension of an annealing furnace.

Background

The existing cold rolling continuous horizontal annealing furnace mainly comprises a furnace body, a burner, a radiant tube, a resistance band, refractory materials and furnace rollers, and is functionally divided into a heating section, a soaking section and a cooling section. The furnace roller is the core component of the transmission band steel in the furnace and is driven by a variable frequency motor, and the linear speed of the furnace roller is consistent with the speed of the process section. The inlet and the outlet of the annealing furnace are respectively provided with a tension roller and a tensiometer, the tension roller at the inlet of the annealing furnace adjusts the tension of the strip steel in real time, and the tension roller at the outlet is a speed reference roller to keep the strip steel to run at a set speed without participating in the tension adjustment of the strip steel. The tensiometer detects the tension of the strip steel in real time.

In the prior art, the continuous horizontal annealing furnace adopts the direct tension control of the inlet of the annealing furnace in the aspect of the tension control of strip steel in the furnace, and the strip steel tension at the inlet of the annealing furnace can meet the process requirement through the closed-loop control of an inlet tensiometer and an inlet tension roller. However, in the continuous annealing process of the strip steel in the furnace, the strip steel expands with heat and contracts with cold due to the rise and fall of the furnace temperature, the relative rest between the strip steel and the furnace rollers is changed into sliding friction, and the actual tension of the strip steel in the furnace is directly influenced by the friction force which is gathered by a large number of furnace rollers and acts on the strip steel. When the temperature of the strip steel rises and the strip steel extends due to thermal expansion, the actual running speed of the strip steel is increased and is higher than the linear speed of the furnace roller, and the friction force in the opposite direction is generated, so that the tension of the strip steel in the furnace is gradually increased under the condition of not performing any control. The strip steel tension in the annealing furnace, especially the strip steel tension in the recrystallization state of the soaking section, directly determines the performance of the silicon steel product, namely the lower the strip steel tension, the lower the iron loss of the silicon steel, and the better the performance of the product. The common process requirement of the prior art is to set a minimum tension to ensure the normal and stable operation of the strip steel, so that in the actual production process, the strip steel tension in the furnace only adopts a control method of the direct tension of an inlet of an annealing furnace, and the problem of severe tension difference of strip steel entering and leaving the furnace due to the interaction of the thermal expansion and cold contraction of the strip steel and furnace rollers is not considered. The unit tension difference between the charging and discharging of the strip steel is about 3N/mm2 to 5N/mm2, and the total tension difference is about 2kN to 3 kN. Therefore, when the tension in the prior art meets the process, the strip steel is fed into the furnace and discharged from the furnace to have serious tension difference, and the actual tension of the strip steel in the furnace is far higher than the tension of the strip steel at the inlet of the annealing furnace due to the tension difference, so that the problems of iron loss increase, product performance deterioration and the like of silicon steel products are caused.

Disclosure of Invention

The embodiment of the specification provides a method for controlling the tension of strip steel of an annealing furnace, which can effectively reduce the tension difference existing in the process of feeding and discharging the strip steel, reduce the iron loss of silicon steel and obviously improve the product performance.

The embodiment of the specification provides a method for controlling the strip steel tension of an annealing furnace, which comprises the following steps:

acquiring the actual temperature of the strip steel on a target furnace roller and the thermal expansion coefficient of the strip steel in the annealing process of the strip steel through an annealing furnace;

acquiring the reference speed of the strip steel;

acquiring the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed;

and controlling the target furnace roller to operate according to the actual operation speed.

Optionally, the obtaining the actual temperature of the strip steel includes:

acquiring target temperatures of strip steel at outlets of a heating section and a soaking section and a strip steel temperature rise curve;

and acquiring the actual temperature according to the target temperature and the strip steel temperature rising curve.

Optionally, the obtaining the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed includes:

acquiring the thermal expansion amount of the strip steel in unit length according to the actual temperature and the thermal expansion coefficient;

and acquiring the actual running speed according to the thermal expansion amount of the unit length and the reference speed.

Optionally, the obtaining the thermal expansion amount of the strip steel in unit length according to the actual temperature and the thermal expansion coefficient includes:

and acquiring a first product of the actual temperature and the thermal expansion coefficient, and taking the first product as the thermal expansion amount per unit length.

Optionally, the obtaining the actual operating speed according to the thermal expansion amount per unit length and the reference speed includes:

acquiring the additional speed of the strip steel according to the thermal expansion amount of the unit length and the reference speed;

and acquiring the actual running speed according to the reference speed and the additional speed.

Optionally, the obtaining the additional speed of the strip steel according to the thermal expansion amount per unit length and the reference speed includes:

and acquiring a second product of the thermal expansion amount per unit length and the reference speed, and taking the second product as the additional speed.

Optionally, the obtaining the actual operating speed according to the reference speed and the additional speed includes:

and acquiring the sum of the speeds of the reference speed and the additional speed, and taking the sum of the speeds as the actual running speed.

Optionally, the obtaining the reference speed of the strip steel includes:

and acquiring the reference speed through an outlet tension roller in the annealing furnace.

Optionally, the obtaining the actual temperature of the strip steel includes:

and measuring the temperature of the strip steel through temperature measuring equipment arranged in the annealing furnace to obtain the actual temperature.

Optionally, the controlling the target furnace roller to operate at the actual operating speed includes:

and controlling the target furnace roller to run at the actual running speed by adjusting the rotating speed of an inlet tension roller and an outlet tension roller in the annealing furnace.

The beneficial effects of the embodiment of the specification are as follows:

based on the technical scheme, the actual temperature, the thermal expansion coefficient and the reference speed of the strip steel on the target furnace roller are obtained in the annealing process of the strip steel through the annealing furnace; then obtaining the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed; controlling the target furnace roller to operate according to the actual operation speed; therefore, when the actual running speed of the strip steel is determined, the actual running speed of the strip steel is determined according to the actual temperature, the thermal expansion coefficient and the reference speed, the actual running speed of the strip steel considers the factor of the strip steel expansion caused by the actual temperature of the strip steel, and on the basis that the actual running speed considers the factor of the strip steel expansion caused by the actual temperature of the strip steel, the actual running speed can be adjusted according to the expansion length of the strip steel, so that the tension difference existing between the strip steel entering and exiting the furnace can be effectively reduced through the actual running speed, the iron loss of the strip steel can be obviously reduced under the condition of reducing the tension difference, the product performance is improved, and the cost is reduced.

Drawings

FIG. 1 is a schematic structural view of a cold rolling continuous horizontal annealing furnace in an embodiment of the present specification;

FIG. 2 is a schematic structural diagram of a method for controlling the tension of strip steel in an annealing furnace in the embodiment of the present specification;

FIG. 3 is a graph of the strip tension under different tension control methods in the examples of the present specification.

Detailed Description

In order to better understand the technical solutions, the technical solutions of the embodiments of the present specification are described in detail below with reference to the drawings and specific embodiments, and it should be understood that the specific features of the embodiments and embodiments of the present specification are detailed descriptions of the technical solutions of the embodiments of the present specification, and are not limitations of the technical solutions of the present specification, and the technical features of the embodiments and embodiments of the present specification may be combined with each other without conflict.

The annealing furnace mainly comprises a furnace body, a burner, a radiant tube, a resistance band, refractory materials and a furnace roller, wherein the furnace roller is a core part of transmission band steel in the furnace and is driven by a variable frequency motor, and the linear speed of the furnace roller is consistent with the speed of the band steel in a process section. As shown in figure 1, the annealing furnace is functionally divided into a heating section 14, a soaking section 15 and a cooling section 16, an inlet tension roller 10 of the annealing furnace adjusts the tension of the strip steel in real time, an outlet tension roller 11 is a speed reference roller, the strip steel is kept to run at a set speed and does not participate in the adjustment of the tension of the strip steel, and an inlet tension meter 12 and an outlet tension meter 13 detect the tension of the strip steel in real time.

In the prior art, the annealing furnace adopts the direct tension control of the inlet of the annealing furnace in the aspect of the tension control of strip steel in the furnace, and the strip steel tension at the inlet of the annealing furnace can meet the process requirement through the closed-loop control of an inlet tension meter 12 and an inlet tension roller 10. However, in the continuous annealing process of the strip steel in the furnace, the strip steel expands with heat and contracts with cold due to the rise and fall of the furnace temperature, the relative rest between the strip steel and the furnace rollers is changed into sliding friction, and the actual tension of the strip steel in the furnace is directly influenced by the friction force which is gathered by a large number of furnace rollers and acts on the strip steel. When the temperature of the strip steel rises and the strip steel extends due to thermal expansion, the actual running speed of the strip steel is increased and is higher than the linear speed of the furnace roller, and the friction force in the opposite direction is generated, so that the tension of the strip steel in the furnace is gradually increased under the condition of not performing any control. The strip steel tension in the annealing furnace, especially the strip steel tension in the recrystallization state of the soaking section, directly determines the performance of the silicon steel product, namely the lower the strip steel tension, the lower the iron loss of the silicon steel, and the better the performance of the product. The common process requirement of the prior art is to set a minimum tension to ensure the normal and stable operation of the strip steel, so that in the actual production process, the strip steel tension in the furnace only adopts a control method of the direct tension of an inlet of an annealing furnace, and the problem of severe tension difference of strip steel entering and leaving the furnace due to the interaction of the thermal expansion and cold contraction of the strip steel and furnace rollers is not considered. The unit tension difference between the charging and discharging of the strip steel is about 3N/mm2 to 5N/mm2, and the total tension difference is about 2kN to 3 kN. Therefore, when the tension in the prior art meets the process, the strip steel is fed into the furnace and discharged from the furnace to have serious tension difference, and the actual tension of the strip steel in the furnace is far higher than the tension of the strip steel at the inlet of the annealing furnace due to the tension difference, so that the problems of iron loss increase, product performance deterioration and the like of silicon steel products are caused.

In order to solve the problem caused by an excessive tension difference in the prior art, an embodiment of the present specification provides a method for controlling a tension of a strip steel in an annealing furnace, as shown in fig. 2, the method includes:

s201, acquiring the actual temperature of the strip steel on a target furnace roller and the thermal expansion coefficient of the strip steel in the annealing process of the strip steel through an annealing furnace;

s202, acquiring the reference speed of the strip steel;

s203, acquiring the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed;

and S204, controlling the target furnace roller to operate according to the actual running speed of the strip steel.

In step S201, during the annealing process of the strip steel through the annealing furnace, the temperature of the strip steel may be measured by a temperature measuring device provided in the annealing furnace, and the actual temperature of the strip steel may be obtained. The temperature measuring device is a plate thermometer, and can be respectively arranged at the outlets, namely the tail ends, of the heating section 14 and the soaking section 15 so as to obtain the target temperatures of the strip steel at the outlets of the heating section 14 and the soaking section 15 in real time, wherein the target temperatures comprise the strip steel temperature at the tail end of the heating section 14 and the strip steel temperature at the tail end of the soaking section 15. The strip steel temperature of the soaking section is the same, and the strip steel temperature of the heating section 14 and the soaking section 15 is increased and decreased in proportion according to a temperature rising curve. Therefore, when the actual temperature of the strip steel is obtained, the target temperature can be obtained by measuring, the strip steel temperature rising curve is synchronously obtained, and the actual temperature of the strip steel on the target furnace roller is obtained according to the target temperature and the strip steel temperature rising curve.

In step S201, the thermal expansion coefficient of the strip steel is also obtained. In general, the thermal expansion coefficients of the strip steel are different according to the element content of the strip steel. In practical application, the thermal expansion coefficient of the strip steel is measured in a laboratory, and then the stored thermal expansion coefficient is directly read when step S201 is executed.

In the embodiments of the present specification, the thermal expansion coefficient of the strip steel can be represented by α.

Step S202 is next performed in which the reference speed can be acquired by the exit tension roller 11 in the annealing furnace. Since the outlet tension roller 11 is a speed reference roller, the reference speed is acquired by using the actual speed of the outlet tension roller 11 as the reference speed.

Specifically, step S202 may be executed simultaneously with step S201 or before step S201, and this specification is not particularly limited.

After the reference speed, the actual temperature, and the thermal expansion coefficient are acquired, step S203 is executed.

In step S203, the thermal expansion amount per unit length of the strip steel may be obtained according to the actual temperature and the thermal expansion coefficient; and then obtaining the actual running speed of the strip steel according to the thermal expansion amount of the unit length and the reference speed.

Specifically, when the thermal expansion amount per unit length of the strip steel is obtained based on the actual temperature and the thermal expansion coefficient, a first product of the actual temperature and the thermal expansion coefficient may be obtained, and the first product may be used as the thermal expansion amount per unit length. The product of the first product and the set first weight may be used as the thermal expansion amount per unit length, and the present specification is not particularly limited.

Specifically, when the actual running speed is obtained according to the thermal expansion amount per unit length and the reference speed, the additional speed of the strip steel can be obtained according to the thermal expansion amount per unit length and the reference speed; and acquiring the actual running speed according to the reference speed and the additional speed.

Specifically, when the additional speed of the strip steel is obtained according to the thermal expansion amount per unit length and the reference speed, a second product of the thermal expansion amount per unit length and the reference speed may be obtained, and the second product may be used as the additional speed. The product of the second product and the set second weight may also be used as the additional speed, and the description is not particularly limited.

In the embodiment of the present specification, when the actual operating speed is acquired from the reference speed and the additional speed, the sum of the speeds of the reference speed and the additional speed may be acquired and taken as the actual operating speed. The product of the sum of the speeds and the third weight may also be used as the actual operating speed, and the present specification is not particularly limited.

After the actual running speed is acquired, step S204 is executed.

In the step, the rotating speed of the inlet tension roller 10 and the rotating speed of the outlet tension roller 11 in the annealing furnace can be adjusted to control the target furnace roller to operate according to the actual running speed of the strip steel, and the actual running speed of the strip steel is matched with the length of the strip steel when the strip steel expands with heat and contracts with cold, so that the relative rest between the target furnace roller and the strip steel can be ensured, the friction force of the furnace roller to the strip steel is eliminated, and the steel tension of each zone in the furnace is ensured to be consistent. Of course, the operation speed of the outlet tension roll 11 may be directly controlled to be the actual operation speed, and the control target furnace roll may be operated at the actual operation speed of the strip steel.

The control method of the specification is to execute the steps S201-S204 on the strip steel arranged on each furnace roller in the annealing furnace so as to control the running speed of the strip steel on each furnace roller to be the actual running speed.

In this way, the thermal expansion amount Δ L per unit length of the strip at the actual temperature (indicated by T) can be calculated for each furnace roll by using the in-furnace strip thermal expansion model, and if the thermal expansion coefficient of the strip is known to be α, the thermal expansion amount Δ L per unit length of the strip becomes T × α; and acquiring that the reference speed of the strip steel is VS, and the furnace roller additional speed is VF (VS x DeltaL) (VS x T x alpha), so that after the strip steel thermal expansion model is put into the strip steel, the actual running speed V (VS + VF) (VS x (1+ T x alpha)), namely, the actual rotating speed of the furnace roller is determined to be V.

In the practical application process, as shown in fig. 3, a curve 30 is a tension variation trend of the strip steel in the furnace under the prior art, and a curve 31 is a tension variation trend of the strip steel in the furnace under the control method of the present invention, wherein, according to the curve 30, the tension difference of the strip steel in-furnace unit and out-furnace unit is about 3N/mm2 to 5N/mm2, and the total tension difference is about 2kN to 3kN, so that the tension difference of the strip steel in the furnace under the prior art is relatively large, and according to the curve 31, the tension difference of the strip steel in the furnace under the control method of the present invention is very small, so that the iron loss of the strip steel can be significantly reduced, and the product performance can be improved. Meanwhile, the furnace roller nodulation is inhibited, the furnace roller abrasion is reduced, and the service life of the furnace roller and the overhaul period of the unit are prolonged.

The beneficial effects of the embodiment of the specification are as follows:

based on the technical scheme, the actual temperature, the thermal expansion coefficient and the reference speed of the strip steel on the target furnace roller are obtained in the annealing process of the strip steel through the annealing furnace; then obtaining the actual running speed of the strip steel according to the actual temperature, the thermal expansion coefficient and the reference speed; controlling the target furnace roller to operate according to the actual operation speed; therefore, when the actual running speed of the strip steel is determined, the actual running speed of the strip steel is determined according to the actual temperature, the thermal expansion coefficient and the reference speed, the actual running speed of the strip steel considers the factor of the strip steel expansion caused by the actual temperature of the strip steel, and on the basis that the actual running speed considers the factor of the strip steel expansion caused by the actual temperature of the strip steel, the actual running speed can be adjusted according to the expansion length of the strip steel, so that the tension difference existing between the strip steel entering and exiting the furnace can be effectively reduced through the actual running speed, the iron loss of the strip steel can be obviously reduced under the condition of reducing the tension difference, the product performance is improved, and the cost is reduced.

While preferred embodiments of the present specification have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all changes and modifications that fall within the scope of the specification.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present specification without departing from the spirit and scope of the specification. Thus, if such modifications and variations of the present specification fall within the scope of the claims of the present specification and their equivalents, the specification is intended to include such modifications and variations.