KR19990050913A - Prediction Method and Prediction Method for Width Characteristics of Hot Rolled Steel Sheet - Google Patents

Abstract

According to the present invention, in a continuous hot rolling facility, a width measuring thermometer for measuring the widthwise temperature and transmitting the measured widthwise temperature to a widthwise material deviation prediction calculator is provided on the rear of the finishing mill and the front of the winding machine, respectively. An industrial calculator is installed to collect the data on the process conditions and transmit the collected data to the lateral material deviation prediction calculator. The width material characteristics are calculated from the transmitted width temperature and the data on the process conditions. A widthwise material prediction device for storing and outputting a widthwise material deviation prediction device is installed to predict a material deviation occurring in the width direction and a prediction method using the device. Easily and accurately predict material deviations.

Description

Prediction Method and Prediction Method for Width Characteristics of Hot Rolled Steel Sheet

The present invention relates to a device and a method for predicting the widthwise material characteristics during the production of steel sheet by hot rolling, and more specifically, to measure the widthwise temperature of the steel sheet with a width thermometer installed on the back of the finish rolling mill and the front of the winding machine and The present invention relates to an apparatus and method for easily predicting a deviation of a material by mathematically calculating a material in a width direction by transmitting a material prediction model to an input calculator.

The manufacturing process of the steel sheet by the usual hot rolling is as shown schematically in FIG.

The heated slab is rough rolled in a rough mill and rolled to a predetermined thickness through a finish mill. The finished rolled steel sheet is water-cooled in a run out table and then wound in a coil form in a winder.

In the process of water cooling, the austenite steel undergoes a phase transformation into a ferrite phase, and the mechanical properties of the steel vary depending on the degree of the phase transformation.

Therefore, by controlling the start temperature, end temperature, winding temperature and cooling rate of the water cooling in the water cooling process, it is possible to obtain the steel having the desired mechanical properties by controlling such phase transformation.

For this reason, temperature control in the water cooling zone is managed as an important factor for determining the material of the steel sheet such as the microstructure and mechanical properties of the steel sheet.

However, even in the case of the steel sheet manufactured by strictly controlling the temperature in the water cooling process, the widthwise material deviation occurs in both ends of the width direction compared to the center portion, the strength is high and the elongation is lowered.

Most of the widthwise material deviation occurs because both ends of the widthwise direction are more easily cooled than the widthwise center portion during water cooling.

The width deviation varies depending on the chemical composition, dimensions, and water cooling conditions of the material. The higher the strength of the material, the greater the width deviation.

Due to the widthwise material deviation, plate deformation occurs when cutting and processing steel sheet, non-uniform deformation occurs when forming, and cracking occurs. Therefore, widthwise material deviation should be measured when manufacturing steel sheet. do.

However, in the related art, since the hot rolled product is cut and the tensile test piece is taken from each part in the width direction, the tensile test is performed on the tensile test piece to measure the widthwise material deviation, which is very troublesome and damages the product.

In order to solve the above problems, the present invention uses a continuous hot rolling facility to prepare a steel sheet by using a widthwise thermometer to measure the widthwise temperature of the steel sheet by installing a widthwise thermometer on the rear surface of the finishing mill and the winding machine. It is easy to predict the nonuniformity of the material by mathematically calculating the material in the width direction by sending it to the width direction material deviation prediction calculator in which the material prediction model is input. It is an object of the present invention to provide an apparatus and method which can be known without inspection and tensile test.

1 is a schematic view of a conventional continuous hot rolling mill,

2 is a schematic diagram of a widthwise material characteristic prediction apparatus of the present invention;

3 is a flow chart of a method for calculating the widthwise material properties of the present invention;

Figure 4a is a graph showing the temperature distribution in the width direction on the back of the finish rolling mill and the winder front,

4B is a graph showing the width-wise predicted tensile strength and measured tensile strength at the rear surface of the finish rolling mill and the winder front side;

<Description of Major Symbols in Drawing>

1: finishing mill 2: width direction thermometer (installed on the back of finishing mill)

3: Water cooling device 4: Width thermometer (installed on the front of the winder)

5: Winding machine 6: Hot rolled steel sheet

7: Industrial calculator 8: Width material deviation prediction calculator

In the continuous continuous hot rolling equipment of the present invention, an infra-red type thermometer is installed on the rear of the finishing mill (1) and the front of the winding machine (5), respectively, and an industrial industrial machine for collecting data on the process conditions of hot rolling ( 7) and the width direction material deviation estimator 8 which calculates the width direction material property and saves and outputs the result, and predicts the width direction material property by using the device and the device to predict the width direction material property. It is about how to.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 schematically shows the device of the invention.

In the apparatus for manufacturing a hot rolled steel sheet, an infrared type width direction thermometer (2) (4) for measuring the temperature in the width direction is provided on the rear surface of the finishing mill (1) and the front of the winding machine (5). The measured widthwise temperature is sent to the widthwise material prediction calculator and used to predict the widthwise material properties of the steel sheet.

In addition, an industrial manufacturer (7) is installed to collect data on the process conditions of hot rolling, such as the chemical composition, thickness, width of the steel sheet, the feed rate of the steel sheet. The collected data is sent to the widthwise material prediction calculator and used to predict the widthwise material properties of the steel sheet.

In order to calculate the widthwise material deviation, a widthwise material deviation predicting calculator 8 into which a mathematical model for calculating the widthwise material characteristics is input is installed, and the widthwise material deviation predicting calculator 8 transmits the widthwise temperature and the process. The widthwise material properties are calculated from the data for the condition, and the result is saved and output.

Hereinafter, a method of predicting the widthwise material characteristics using the apparatus of the present invention will be described.

Figure 3 shows the procedure for calculating the widthwise material properties.

When the hot rolled steel sheet 6 rolled to a predetermined thickness through the finishing mill 1 passes and passes under the width thermometer 2 installed on the rear surface of the finishing mill 1, the width thermometer 2 is hot rolled. The widthwise temperature distribution of the steel sheet 6 is measured. The measured widthwise temperature is transmitted to the widthwise material deviation prediction calculator 8.

The hot rolled steel sheet 6 which has passed through the width direction thermometer 2 is water-cooled at the winding temperature preset by the water cooling apparatus 3.

The water-cooled hot rolled steel sheet 6 is transferred to the winder 5 to pass through the widthwise thermometer 4 installed on the front of the winder 5, whereby the widthwise thermometer 4 is hot rolled steel sheet 6 Measure the temperature distribution in (). The measured widthwise temperature is transmitted to the widthwise material deviation prediction calculator 8.

The industrial calculator 7 collects data on process conditions such as chemical composition, thickness, width of the steel sheet, and feed rate of the steel sheet, and the collected data about the process conditions is transmitted to the widthwise material deviation predictor 8.

The width direction material deviation estimator 8 calculates the material properties in the width direction using data on the transmitted width temperature and process conditions, and stores and outputs the data when the calculation is completed.

The material properties in the width direction include calculation of width position and cooling rate, calculation of equilibrium transformation temperature of each phase, transformation start temperature of each phase, average transformation temperature of each phase, fraction and particle calculation of each phase, yield strength, tensile strength, elongation, etc. It is calculated in the order of calculating the tensile properties

4A and 4B show the results of the present invention in the hot rolling process of manufacturing a general carbon steel containing 0.147% carbon and 0.7% manganese in a hot rolled steel sheet having a thickness of 5.9 mm and a width of 1,530 mm.

4A is a graph showing the widthwise temperature distribution measured from the back of the finishing mill 1 and the widthwise temperature distribution measured from the front of the winder 5. FIG.

Figure 4b is a graph showing the width distribution of the measured tensile strength actually measured using the conventional method and the width distribution of the predicted tensile strength calculated by the method of the present invention using the width direction temperature distribution of Figure 4a. .

In the graph of Figure 4b it can be seen that the tensile strength predicted by the method of the present invention is almost in agreement with the actually measured tensile strength.

In the present invention having the above-described configuration, the widthwise material is based on the widthwise temperature of the steel plate measured by the widthwise thermometer installed in the water cooling device and the process conditions collected by the pressure calculator in manufacturing the steel plate using the continuous hot rolling facility. The deviation prediction calculator calculates the material in the width direction mathematically, so it is easy and accurate to predict the deviation of the material without any damage and hassle.

Claims (2)

In a continuous hot rolling facility, a width thermometer which measures the width direction temperature and transmits the measured width direction temperature to the width direction material deviation calculator is installed on the rear surface of the finishing mill and the front surface of the winding machine, respectively. An industrial calculator is installed to collect the data for and transmit the collected data to the lateral material deviation prediction calculator, and calculates the lateral material properties from the transmitted lateral temperature and process conditions, and stores and outputs the result. Width direction material prediction calculator is installed in the width direction material properties prediction device during hot rolled steel sheet manufacturing, characterized in that for predicting the material deviation occurring in the width direction. In the manufacture of steel sheet using continuous hot rolling equipment, the width measuring thermometer installed on the back of the finishing mill and the front of the winding machine measures the widthwise temperature and transmits the measured widthwise temperature to the width direction material prediction calculator. For example, the process by which the industrial operator collects data on the process conditions of hot rolling and transmits the collected data to the width material deviation predictor, and from the data on the width temperature and the process condition to which the width material deviation predictor is transmitted. Calculating the widthwise material properties, and storing and outputting the results to predict the material deviations occurring in the widthwise direction.