TWI680186B - Calculation method of annealed coil temperature - Google Patents

Abstract

A method for calculating the temperature of annealed steel coil includes a data input step, a preliminary judgment step, a furnace temperature sensing step, a cold spot judgment step, a uniform temperature judgment step, an equivalent judgment step, and a result output step. . Using the temperature inside the annealing furnace to calculate the temperature of the coil can overcome the problem of too long heating average temperature to reduce energy consumption and increase production.

Description

Calculation method of annealing coil temperature

The invention relates to a calculation method, in particular to a calculation method for annealed steel coil temperature.

In cold-rolled steel coils, after coiling the steel strip one by one into a steel coil, in order to further improve the quality of the steel coil and eliminate the residual stress of the steel coil during the coiling process, the steel coil is sent to a box for return The furnace is annealed. Due to the large volume of steel coils, and most of them are stacked in the box annealing furnace, the temperature of the surface of the coil (hot spots) does not reflect the actual temperature of the interior of the coil (cold spots). Temperature measurement to ensure consistent annealing quality inside and outside the coil.

In addition, the annealing process using the box sealing annealing furnace is one of the cold rolled steel coil annealing methods. Due to the relationship between process characteristics, the temperature distribution of each point inside the steel coil (cold spot) during annealing is not uniform. The change of cold spot temperature is the main key to determine the quality of steel coil after annealing.

In addition, the calculation formulas of the heating average temperature time in the past annealing treatment adopt the fixed heating time method to perform the annealing treatment, and the material temperature is not calculated by considering the performance of the annealing furnace and the effect of the temperature uniformity of the coil, which leads to the lengthening of the annealing time and the temperature uniformity. Poor phenomena cause waste of energy.

Therefore, it is necessary to provide an improved method for calculating the temperature of annealed steel coils in order to solve the problems existing in the conventional techniques.

The main purpose of the present invention is to provide a method for calculating the temperature of annealed steel coils. The temperature of the steel coils can be calculated by taking the measured current value of the temperature in the box-sealed annealing furnace. The measured current value of the internal temperature can be used to infer the temperature of the steel coil to overcome the problem of too long heating average temperature to reduce energy consumption and increase production.

In order to achieve the above object, the present invention provides a method for calculating the temperature of annealed steel coil, including a data input step, a preliminary judgment step, a furnace temperature sensing step, a cold spot judgment step, a uniform temperature judgment step, An equivalent judgment step and a result output step; in the data input step, a plurality of data is input into a processor, wherein the data includes at least one coil size, at least one annealing cycle, and at least one thermal conductivity coefficient; In this preliminary judgment step, the processor uses an initial time step in conjunction with the data to determine whether the calculation has a convergence, if not, re-enter another time step, and if so, proceed to the next step; in the furnace In the temperature sensing step, the temperature in a furnace of at least one annealing furnace is sensed at intervals by at least one sensor, and the temperature of a coil of a steel coil is calculated based on the temperature in the furnace; in the cold spot judgment step, In the process, the processor selects a heat conduction boundary condition based on the steel coil size and the thermal conductivity coefficient to calculate an internal cold spot temperature of the steel coil, and then judges Whether the cold spot temperature meets the coldest temperature of a machine. If not, extend the annealing cycle to compensate and return to the data input step. If yes, proceed to the next step. In the average temperature judgment step, through the processor Extract a maximum value and a minimum value of a plurality of steel coil temperatures, and determine whether the difference between the maximum value and the minimum value is less than a predetermined temperature; if not, extend the annealing cycle to compensate and return to the data input step, If yes, proceed to the next step; in the equivalence judgment step, in a predetermined time section of an annealing time, the processor integrates a change in cold spot temperature to obtain a cold spot temperature thermal history equivalent And determine whether the cold-spot temperature thermal history equivalent corresponds to the minimum threshold of a thermal equivalent area; if not, extend the annealing cycle to compensate and return to the data input step; if yes, proceed to the next step; in the result output step In the process, a temperature curve formed by the cold spot temperature and the annealing time is output through the processor.

In an embodiment of the present invention, in the data input step, the data further includes at least a thermal resistance adjustment coefficient, and the thermal resistance adjustment coefficient corresponds to a steel coil thickness.

In an embodiment of the present invention, in the cold spot judgment step, a finite difference method is used to calculate a cold spot temperature inside an steel coil based on the steel coil size and the heat conduction boundary condition.

In one embodiment of the present invention, in the furnace temperature sensing step, the interval time is 1, 3, or 5 minutes.

In an embodiment of the present invention, in the step of determining the average temperature, the predetermined temperature is 20 degrees Celsius or less.

In one embodiment of the present invention, the cold spot temperature thermal history equivalent is calculated as: G = T (C + log t); where T is a cold spot temperature, t is a time, and C is a constant.

As mentioned above, the method for calculating the coil temperature of the annealing treatment of the present invention is to calculate the coil temperature of the steel coil by taking the measured current value of the furnace temperature of the box-sealing annealing furnace on the line. The performance is good or bad, the steel coil temperature (material temperature) can be inferred according to the measured present value of the corresponding furnace temperature to overcome the problem of too long heating average temperature to reduce energy consumption and increase production.

S201‧‧‧Data entry steps

S202‧‧‧ preliminary judgment steps

S203‧‧‧furnace temperature sensing steps

S204‧‧‧Cold spot judgment steps

S205‧‧‧Judging steps for average temperature

S206‧‧‧Equivalent Judgment Step

S207‧‧‧Result output step

T1‧‧‧ scheduled time zone

FIG. 1 is a flowchart of a preferred embodiment of a method for calculating the temperature of annealed steel coils according to the present invention.

Figures 2 and 3 are schematic diagrams of the thermal equivalent area of a preferred embodiment of the method for calculating the temperature of annealed steel coils according to the present invention.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments of the present invention and the accompanying drawings in detail, as follows. Furthermore, the directional terms mentioned in the present invention include, for example, top, bottom, top, bottom, front, back, left, right, inside, outside, side, periphery, center, horizontal, horizontal, vertical, vertical, axial, Radial, uppermost or lowermost, etc., are only the directions in which the reference objects are generally placed. Therefore, the directional terms used are for explaining and understanding the present invention, but not for limiting the present invention.

Please refer to FIG. 1, which is a preferred embodiment of a method for calculating the temperature of annealed steel coils according to the present invention, which is mainly a furnace for a box annealing furnace (not shown) through one or more sensors. The internal temperature is sensed, and then a processor (not shown) is used to capture the measured value of the furnace temperature and perform simulation operations to obtain the annealing coil temperature, wherein the annealing coil temperature is calculated It includes a data input step S201, a preliminary judgment step S202, a furnace temperature sensing step S203, a cold spot judgment step S204, a uniform temperature judgment step S205, an equivalent judgment step S206, and a result output step S207. The present invention will explain the operation principle of each step in detail below.

Continuing to refer to FIG. 1, in the data input step S201, a plurality of data are input into the processor, wherein the data includes at least one coil size, at least one annealing cycle, and at least one thermal conductivity coefficient, wherein The coil size is the coil to be placed in the box annealing furnace For a steel coil size, the annealing cycle is an annealing cycle of the box-sealing annealing furnace, and the thermal conductivity coefficient is a thermal conduction coefficient of the box-sealing annealing furnace. In this embodiment, the data further includes at least one thermal resistance adjustment coefficient, and the thermal resistance adjustment coefficient is a steel coil thickness corresponding to the steel coil of the box-sealing annealing furnace.

Continuing to refer to FIG. 1, in the preliminary judgment step S202, the processor uses an initial time step to cooperate with the data to determine whether the calculation has a convergence. If not, re-enter another time step. If yes, Then, the furnace temperature sensing step S203 is performed. For example, if a calculation is used to determine whether the calculation cannot be completed, if the calculation cannot be completed, the time scale is reduced. When the calculation can be completed, the time layout is used as the simulation calculation.

Continuing to refer to FIG. 1, in the furnace temperature sensing step S203, a sensor disposed in the box-sealing annealing furnace is used to sense the temperature in a furnace of the box-sealing annealing furnace at intervals, and according to the The temperature in the furnace calculates a coil temperature of a steel coil. In this embodiment, the processor calculates a plurality of coil temperatures according to the sensed multiple furnace temperatures, and understands the coil temperatures through the plurality of coil temperatures. The change of the coil temperature of the coil, wherein the interval time of the sensor of the box sealing annealing furnace is 1, 3 or 5 minutes, preferably 1 minute.

Continuing to refer to FIG. 1, in the cold spot judgment step S204, the processor calculates the steel coil by selecting a heat conduction boundary condition according to the furnace temperature of the box annealing furnace, the steel coil size, and the thermal conductivity coefficient. An internal cold spot temperature, and then determine whether the cold spot temperature meets the coldest temperature of the machine. If not, extend the annealing cycle to compensate and return to the data input step S201. If yes, perform the uniform temperature. Decision step S205. In this embodiment, the processor uses the finite difference method to calculate the cold spot temperature inside the steel coil based on the steel coil size and the heat conduction boundary conditions. It should be noted that the cold spot temperature is measured after the experimental annealing average temperature time The cold spot temperature is 631 ° C. This cold spot temperature is a temperature that can be passed organically. Therefore, the cold spot temperature calculated in different furnaces in the future must meet the minimum threshold of 631 ° C. If it is not reached, extend the annealing time to achieve demand.

Continuing to refer to FIG. 1, in the uniform temperature determining step S205, a maximum value and a minimum value of a plurality of steel coil temperatures are captured by the processor, and it is determined whether a difference between the maximum value and the minimum value is less than A predetermined temperature; if not, the annealing cycle is extended for compensation and the data input step S201 is returned, and if it is, the equivalent judgment step S206 is performed. In this embodiment, the predetermined temperature is 20 degrees Celsius or less, and preferably, the predetermined temperature is 20 degrees.

Continuing to refer to FIG. 1 and cooperating with FIG. 2, in the equivalent judgment step S206, in a predetermined time section T1 of an annealing time, a change in a cold spot temperature is integrated through the processor to obtain A cold spot temperature thermal history equivalent, and determine whether the cold spot temperature thermal history equivalent meets the minimum threshold of a thermal equivalent area. If not, extend the annealing cycle to compensate and return to the data input step S201. If yes, perform this The result is output to step S207. In this embodiment, the formula for calculating the thermal history equivalent of the cold spot temperature is: G = T (C + log t); where T is a cold spot temperature, t is a time, and C is a constant. It should be noted that because experiments were performed before the simulation, the cold hot spot temperature was measured, and after the experimental annealing soaking time was completed, the experimental measured cold spot thermal history equivalent area was used as the standard value. If the threshold is not reached, the annealing time is extended. As shown in Figure 3, the integrated area of the cold spot calculated by the simulation must conform to the area of the slant line in the figure below (the threshold value of the experimental cold spot temperature measurement after integration over time). If the threshold area value is not reached, the annealing time needs to be increased to Meet your needs.

Continuing to refer to FIG. 1, finally, in the result output step S207, a temperature curve formed by the cold spot temperature and the annealing time is output through the processor. To be able to The temperature curve of the steel coil is calculated by measuring the present value of the temperature in the box-sealing annealing furnace, which not only overcomes the shortcomings of too long heating average temperature, but also reduces energy consumption and increases production.

With the above design, first enter the coil size, annealing cycle and thermal conductivity into the processor, and then use the processor to judge whether the calculation using the initial time step has a convergence, and then use the sensor to interval Time to sense the temperature in the box annealing furnace to understand the change in the coil temperature of the coil, and then use the processor to calculate the cold spot temperature inside the coil and determine whether the cold point temperature is in line with the machine. The coldest point temperature, and whether the difference between the maximum and minimum values of the multiple coil temperatures is less than the predetermined temperature, and then the processor determines whether the thermal history equivalent of the cold point temperature meets the minimum threshold of the thermal equivalent area, and finally The temperature curve formed by the cold spot temperature with the annealing time is output.

As mentioned above, the method for calculating the temperature of the annealed steel coil of the present invention can calculate the cold spot temperature of the coil according to the coil size and the heat transfer boundary conditions of the coil through the finite difference method. The above calculation process is to be formulated. After a suitable time step, start to calculate the coldest point temperature that meets the machine as the standard condition for program control. It is worth mentioning that in order to grasp the accuracy of the calculation, the thermal resistance adjustment coefficient value of the steel coil's thermal conductivity needs to be classified according to the thickness of the steel coil. For example, the thickness of the steel coil is thicker, and the radial coil of the steel coil and the The density between the pieces is better, so the radial heat conduction capacity is good. Conversely, the thickness of the steel coil is thinner, and the density between the pieces is poor, so the radial heat conduction capacity is poor. Therefore, the method for calculating the temperature of the annealed steel coil in the present invention establishes a thermal resistance adjustment coefficient to meet the calculation accuracy, and the error generated by the calculation can be controlled within 5%. In addition, the method for calculating the temperature of annealed steel coils of the present invention is to calculate the coil temperature of the steel coil by taking the measured current value of the temperature in the box-sealing annealing furnace on the line, so the performance of different annealing furnaces is good Bad, according to The corresponding measured present value of the furnace temperature is used to infer the coil temperature (material temperature) to overcome the problem of too long heating average temperature to reduce energy consumption and increase production.

Although the present invention has been disclosed in a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. The scope of protection shall be determined by the scope of the attached patent application.

Claims (5)

A method for calculating the temperature of annealed steel coil includes: a data input step, inputting a plurality of data into a processor, wherein the data includes at least one coil size, at least one annealing cycle and at least one thermal conductivity coefficient; A preliminary judgment step. The processor uses an initial time step in conjunction with the data to determine whether the calculation has a convergence. If not, re-enter another time step, and if so, proceed to the next step. The measuring step uses an interval of at least one sensor to sense a furnace temperature of at least one annealing furnace, and calculates a coil temperature of a steel coil based on the furnace temperature. A cold spot judgment step passes the processing The device selects a heat conduction boundary condition to calculate a cold spot temperature inside an steel coil according to the size of the steel coil and the thermal conductivity coefficient, and then determines whether the cold spot temperature meets the coldest temperature of the machine. If not, extend The annealing cycle is compensated and returned to the data input step. If so, the next step is performed, where a minimum threshold value of the cold spot temperature is 631 ° C; Step, the processor retrieves a maximum value and a minimum value of the multiple coil temperatures, and determines whether the difference between the maximum value and the minimum value is less than a predetermined temperature; if not, the annealing cycle is extended to compensate And return to the data input step, if yes, proceed to the next step; an equivalent judgment step, in a predetermined time section of an annealing time, integrate the change of a cold spot temperature through the processor to obtain a cold Spot temperature thermal history equivalent, and determine whether the cold spot temperature thermal history equivalent meets the minimum threshold of a thermal equivalent area; if not, extend the annealing cycle to compensate and return to the data input step; if yes, proceed to the next step; And a result output step, a temperature curve formed by the cold spot temperature and the annealing time is output through the processor. According to the method for calculating the temperature of the annealed steel coil described in item 1 of the scope of patent application, in the data input step, the data further includes at least one thermal resistance adjustment coefficient, and the thermal resistance adjustment coefficient is corresponding to a steel Roll thickness. According to the method for calculating the temperature of the annealed steel coil described in item 1 of the scope of the patent application, in the furnace temperature sensing step, the interval is 1, 3, or 5 minutes. The method for calculating the temperature of the annealed coil as described in item 1 of the scope of the patent application, wherein in the cold spot judgment step, the finite coil method is used to calculate the coil based on the coil size and the heat conduction boundary conditions. This cold spot temperature inside. The method for calculating the temperature of the annealed steel coil described in item 1 of the scope of the patent application, wherein in the step of determining the average temperature, the predetermined temperature is 20 degrees Celsius or less.