A method of evaluating the solidification shrinkage behavior of a parison

Abstract

The present application relates to a kind of methods for evaluating the solidification shrinkage behavior of blank shell, belong to continuous casting method technical field.The technical scheme of the present application is: the temperature value of thermocouple array installed on crystallizer copper plate is measured, thermocouple data is processed, and temperature distribution is obtained according to the actual temperature distribution characteristics of crystallizer copper plate;The extreme point of the temperature change rate of each row is calculated, these extreme points are identified and curve is drawn;The solidification shrinkage behavior is judged by the shape and position of the curve.The beneficial effects of the present application are: the uneven phenomenon of blank shell solidification shrinkage caused by the influence of protected slag inflow, slag strip or air gap and other factors can be expressed, especially the blank shell shrinkage condition near the narrow side, so as to help to assist in judging the cooling shrinkage behavior and temperature distribution of blank shell in crystallizer, and the transparency and controllability of continuous casting production process are improved.

Description

Technical Field

[0001] This invention relates to a method for evaluating the solidification shrinkage behavior of billet shells, belonging to the technical field of continuous casting methods. Background Technology

[0002] The crystallizer is the "heart" of the continuous casting machine's production process. Influenced by factors such as the inflow of protective slag, slag bars, or air gaps, uneven solidification shrinkage of the billet shell can occur. Furthermore, online width adjustment (hereinafter referred to as online width adjustment) during the casting process is a relatively complex unsteady-state process within the crystallizer. During this process, the width of the wide-faced billet shell changes, and the solidification shrinkage process of the billet shell also changes due to the width change. This can potentially lead to adhesion and production accidents, requiring strengthened monitoring and understanding of the process status during this stage. Summary of the Invention

[0003] The purpose of this invention is to provide a method for evaluating the solidification shrinkage behavior of billet shells. By processing the temperature data measured by thermocouples, the extreme points of temperature changes are further marked on the plotted temperature cloud map. This method can express the uneven solidification shrinkage of billet shells caused by factors such as the inflow of protective slag, slag strips, or air gaps, especially the shrinkage of billet shells near the narrow side. This helps to assist in judging the cooling shrinkage behavior and temperature distribution of billet shells in the crystallizer, improves the transparency and controllability of the continuous casting production process, and effectively solves the above-mentioned problems existing in the background art.

[0004] The technical solution of the present invention is: a method for evaluating the solidification shrinkage behavior of a billet shell, comprising the following steps:

[0005] (1) Measure the temperature of the thermocouple array installed on the copper plate of the crystallizer, process the thermocouple data, and select an appropriate interpolation method to obtain the temperature distribution based on the actual temperature distribution characteristics of the copper plate of the crystallizer; (2) Calculate the extreme points of the temperature change rate of each row, mark these extreme points and draw the curve; (3) Determine the solidification shrinkage behavior by the shape and position of the curve.

[0006] In step (1), the temperature value of the thermocouple installed on the copper plate of the crystallizer is measured, and interpolation and calculation are performed according to its position coordinates to obtain temperature distribution data.

[0007] In step (2), the temperature gradient change of each row of thermocouples is calculated and its extreme point is obtained. The extreme points are obtained by dividing the vertical center line of the copper plate and distributing them on the left and right sides respectively. Curves are then drawn based on the extreme points on both sides.

[0008] In step (3), the solidification shrinkage behavior of the current billet shell is analyzed based on the position and shape of the curve drawn in step (2), and compared with the curve under normal conditions to determine whether it is abnormal.

[0009] The beneficial effects of this invention are: by processing the temperature data measured by thermocouples, the extreme points of temperature change are further marked on the drawn temperature cloud map, which can express the uneven solidification shrinkage of the billet shell caused by factors such as the inflow of protective slag, slag strips or air gaps, especially the shrinkage of the billet shell near the narrow side, thereby helping to judge the cooling shrinkage behavior and temperature distribution of the billet shell in the crystallizer, and improving the transparency and controllability of the continuous casting production process. Attached Figure Description

[0010] Figure 1 This is a diagram showing the effect of the temperature gradient extreme line under stable operating conditions presented by the present invention.

[0011] Figure 2 This is a display effect diagram of the online width adjustment process of the crystallizer in the embodiment;

[0012] Figure 3 This is a display effect diagram after the online width adjustment of the crystallizer is completed in the embodiment. Detailed Implementation

[0013] To make the purpose, technical solutions, and advantages of the invention's embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only a small part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0014] A method for evaluating the solidification shrinkage behavior of a billet shell includes the following steps:

[0015] (1) Measure the temperature of the thermocouple array installed on the copper plate of the crystallizer, process the thermocouple data, and select an appropriate interpolation method to obtain the temperature distribution based on the actual temperature distribution characteristics of the copper plate of the crystallizer; (2) Calculate the extreme points of the temperature change rate of each row, mark these extreme points and draw the curve; (3) Determine the solidification shrinkage behavior by the shape and position of the curve.

[0016] In step (1), the temperature value of the thermocouple installed on the copper plate of the crystallizer is measured, and interpolation and calculation are performed according to its position coordinates to obtain temperature distribution data.

[0017] In step (2), the temperature gradient change of each row of thermocouples is calculated and its extreme point is obtained. The extreme points are obtained by dividing the vertical center line of the copper plate and distributing them on the left and right sides respectively. Curves are then drawn based on the extreme points on both sides.

[0018] In step (3), the solidification shrinkage behavior of the current billet shell is analyzed based on the position and shape of the curve drawn in step (2), and compared with the curve under normal conditions to determine whether it is abnormal.

[0019] In practical applications, in step (1), the temperature value of the thermocouple installed on the copper plate of the crystallizer is measured, and interpolation and calculation are performed based on its position coordinates to obtain temperature distribution data.

[0020] Let the number of thermocouple rows be m and the number of thermocouple columns be n. If the number of interpolation points between the temperature points of each thermocouple in each row is s and the number of interpolation points between the temperature points of each thermocouple in each column is t, then the total number of rows and columns after interpolation is m + (m-1) × s and n + (n-1) × t, respectively.

[0021] Considering the characteristics of temperature data distribution, bicubic interpolation is used to calculate the interpolated temperature distribution data. Although bicubic interpolation is more complex than other interpolation algorithms, the number of thermocouples installed on the copper plate of the crystallizer is limited, generally three to six rows and a dozen columns. In actual production, the temperature change rate is limited, and calculations with a period of 1 to 2 seconds are usually sufficient to meet the process control requirements.

[0022] In step (2), the temperature gradient change of each row of thermocouples after interpolation is calculated and its extreme points are obtained. The extreme points are obtained by dividing the longitudinal center line of the copper plate and distributing them on the left and right sides respectively, and curves are further drawn based on the extreme points on both sides.

[0023] In step (3), the solidification shrinkage behavior of the billet shell in the crystallizer can be analyzed based on the two curves drawn, and can be used as a monitoring indicator. Specifically, under normal casting conditions, the curve is close to a slightly tapered straight line, which also conforms to the actual tapered setting in the crystallizer. During production, the solidification shrinkage behavior of the billet shell is judged to be normal by real-time calculation and comparison with the shape of the curve under normal conditions. Example

[0024] Taking one wide face of the crystallizer as an example, let X be the horizontal direction and Y be the vertical direction. There are 4 interpolation points in the X direction and 5 interpolation points in the Y direction. First, the temperature at the interpolation points is calculated using a bicubic interpolation algorithm. A temperature cloud map is then drawn using a conventional planar display. Next, according to the method of this invention, the extreme point curves of the temperature gradient on both sides are drawn. That is, the extreme points of the temperature values ​​in each row after interpolation are calculated and their positions are marked along the center line of the copper plate. Then, these points are connected to form a spline curve.

[0025] The thermographic images of the crystallizer thermocouple temperature and the extreme value curve of the temperature gradient under normal and stable operating conditions are shown as follows: Figure 1As you can see, the curves on both sides are relatively straight and symmetrically distributed, with a small inverted taper from top to bottom, which is consistent with the taper setting of the narrow side of the copper plate on both sides in the actual situation.

[0026] Online width adjustment (hereinafter referred to as online width adjustment) during the casting process in a continuous casting machine is a relatively complex unsteady-state process within the crystallizer. During this process, the width of the wide-faced billet shell changes, and simultaneously, due to this change in width, the solidification shrinkage process of the billet shell changes, resulting in significant variations in heat flux and thermocouple temperature. Strengthening monitoring and understanding of this stage is beneficial for the stable implementation and further optimization of the process. For example... Figure 2 The thermocouple temperature thermal image and temperature gradient extreme value curve of the crystallizer of the present invention timely reflect the non-uniformity of temperature distribution and its change process in this process.

[0027] After the online width adjustment process is completed, the narrow side of the crystallizer reaches a new position, re-establishing a new heat transfer equilibrium. The thermogram of the crystallizer and the extreme value curve of the temperature gradient show a relatively stable new state, such as... Figure 3 .

[0028] The above are merely embodiments of the present invention, but are not limitations thereof. Any modifications, substitutions, etc., made in accordance with the principles and rules of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for evaluating the solidification shrinkage behavior of a billet shell, characterized in that... The process includes the following steps: (1) Measure the temperature of the thermocouple array installed on the copper plate of the crystallizer and obtain the temperature distribution by bicubic interpolation; (2) Calculate the temperature change rate of each row, divide the copper plate surface into left and right sides and obtain the extreme points respectively, mark these extreme points and draw the curve; (3) Determine the solidification shrinkage behavior by the shape and position of the curve.

2. The method for evaluating the solidification shrinkage behavior of a billet shell according to claim 1, characterized in that: In step (3), the solidification shrinkage behavior of the current billet shell is analyzed based on the position and shape of the curve drawn in step (2), and compared with the curve under normal conditions to determine whether it is abnormal.

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