KR19990052679A - Measurement method of Young's modulus, shear rate, texture and average particle size of metal plate using ultrasonic backscattering - Google Patents

Abstract

The present invention relates to a method for measuring online Young's modulus, shear modulus, texture and average grain size using ultrasonic waves of a metal plate, to maintain a constant level by receiving water. The ultrasonic transducer 13 installed in the water tank 17a to be submerged in water receives the pulse wave of the high voltage from the pulse transmitter 11 and scans the ultrasonic wave into the cold rolled coil 16 using water as a contact medium. The ultrasonic transducer 13 receives the ultrasonic wave 13 scattered by the cold rolled coil 16 to the pulse transmitter 11 and amplifies the pulse signal received from the pulse transmitter 11 in the signal amplifier 14 to the calculation unit 15. The calculation unit 15 converts the measured signal into an energy value by an input program, and calculates and outputs the Young's modulus, shear rate, texture, and average particle size of the metal plate 16. The Young's modulus and shear of the metal sheet using ultrasonic backscattering have the effect of measuring the Young's modulus, shear rate, texture and average particle size of the metal sheet on-line by non-destructive It is a measure of rate, aggregate and average particle size.

Description

Method of measuring Young's modulus, shear rate, texture and mean particle size of metal plate using ultrasonic backscattering.

The present invention relates to a method for measuring online Young's modulus, shear modulus, texture and average grain size using ultrasonic waves of a metal plate, and more specifically, to a metal plate and an inclination angle. The critical angle is calculated from the energy of the ultrasonic wave incident and backscattered ultrasonic waves to measure the Young's modulus, shear rate and texture of the sheet on-line, and the energy of the backscattered ultrasonic signal at the Rayleigh critical angle is calculated so that the average particle size of the metallic plate is more accurate. The present invention relates to a method for measuring online Young's modulus, shear rate, texture and average particle size of a metal plate using ultrasonic backscattering which can be measured online.

In general, metal sheets such as stainless steel sheet and carbon steel are subjected to various heat treatments to obtain the average grain size, Young's modulus, shear rate, and texture of the rolled steel sheet. In such heat treatment, a desired metal plate can be made by adjusting the time and temperature of the heat treatment depending on the degree of rolling and the component ratio of the metal plate.

In the conventional method for measuring the average particle size, Young's modulus, shear rate and texture of the metal plate, the specimens are prepared by taking a predetermined length of the front end part or the rear end part of the metal plate, and then the average particle size is observed by an optical microscope and the Young's modulus, It is necessary to check the shear rate and texture, which is required more than a certain time to extract the specimen and to measure the average particle size, and as a result, subsequent work of adjusting the time and temperature of the heat treatment cannot be performed quickly. It is not an optimal method for producing a metal plate of desired quality, thereby causing a problem of loss of product production. In addition, in the online process, the front end and the rear end of the metal plate include many incomplete factors such as temperature, rolling, and components in the manufacturing process. In many cases, the properties of the front and rear metal plates do not guarantee the properties between the metal plate bulbs.

Therefore, the present invention was invented to solve the above-mentioned problems. The ultrasonic backscattering device is installed on the production line of the metal plate to inject the ultrasonic wave at an inclination angle and calculate the critical angle from the energy of the backscattered ultrasonic wave so that the Young's modulus and shear Online Young's Modulus and Shear Rate of Metal Plates Using Ultrasonic Backscattering for On-line Measurement of the Rate and Aggregation and On-line Measurement of the Energy of Backscattered Ultrasonic Signal at Rayleigh Critical Angle Its purpose is to provide a method for measuring aggregate organization and average particle size.

1 is a block diagram schematically showing a device for measuring the average particle size of a steel sheet using ultrasonic backscattering according to the present invention,

Figure 2 is a graph showing the time and amplitude of the ultrasonic signal backscattered in the stainless cold rolled coil,

3 is a graph showing the energy change and the critical angle of the backscattered ultrasound according to the incident angle,

4 is a view showing the reflection and refraction of the ultrasonic wave at the interface of different media as a change in the angle of incidence,

5 is a view for explaining the method of ultrasonic backscattering for the irradiation of the texture of the metal plate,

6 is a graph showing the relationship between the average particle size obtained by measuring the average particle size of the metal plate using ultrasonic backscattering according to the present invention and the average particle size observed by an optical microscope.

<Description of the symbols for the main parts of the drawings>

11 pulse transmitter 12 immersion sensor rod

13: ultrasonic transducer 14: signal amplifier

15: calculator 16: cold rolled coil

17a: small water tank 17b: large water tank

18a, 18b: strip horizontal roller 19: pump

20: annealing furnace 21: pickling equipment

22: line showing the progress of the ultrasonic wave 23: backscattered ultrasonic signal

The present invention for achieving the above object in the method for measuring the average particle size of the stainless steel cold rolled sheet, two rolls (18a) installed in parallel between the annealing furnace 20 and the pickling equipment 21 of the stainless steel cold rolled steel sheet Water tanks (17a), (17b) is installed between the (18b), the stainless cold rolled coil 16 to proceed in the water tank (17a), (17b), cold rolling in the water tank (17a) An ultrasonic transducer 13 is installed on the upper or lower portion of the cold rolled coil 16 at a constant distance and angle from the coil 16 in accordance with λ >> D, the frequency of which is Rayleigh scattering condition. The high voltage pulse is sent to the ultrasonic transducer 13 through the water using the ultrasonic wave 22 generated as the contact medium, and the backscattered ultrasonic wave 22 is received by the ultrasonic transducer 13 to receive the pulse. Sends the signal to the transmitter / receiver 11 and sends a signal from the pulse transmitter / receiver 11 The signal amplifier 14 amplifies and converts an analog signal into a digital signal and sends it to the calculating device 15, which calculates the measured signal. Measure the energy as, and obtain the angle of the critical angle 1 and the critical angle 2 to the minimum value in the graph of the angle of the energy value Overeating The Young's modulus and shear rate of metal sheet are calculated by using, and the energy value is calculated near the Rayleigh critical angle. E = D ⁿ It is obtained by the above, characterized in that the accuracy of the measurement is improved by injecting the ultrasonic wave in the range of ± 1 ° of the Rayleigh critical angle formed by the cold rolled coil 16 and the ultrasonic probe 13.

1 is a schematic view showing an average particle size measuring apparatus of a steel sheet used in the present invention, the operation and use of each configuration is as follows. The water tanks 17a and 17b are installed between the annealing furnace 20 of the stainless cold rolled steel sheet 20 and the pickling facility 21 and installed in parallel to each other. 16) proceeds in the water tank and the ultrasonic transducer 13 is installed at the upper or lower portion of the cold rolled coil at a constant distance and angle with the cold rolled coil 16 in the water tank (17a) to the pulse transmitting and receiving device (11) The high voltage pulse is sent to the ultrasonic transducer 13 through the water using the ultrasonic wave 22 generated as the contact medium, and the backscattered ultrasonic wave 22 is received by the ultrasonic transducer 13 to transmit and receive the pulse. The signal from the pulse transmitter / receiver 14 is amplified by the signal amplifier 14, the analog signal is converted into a digital signal, and sent to the arithmetic unit 15, and the arithmetic unit 15 measures the measured signal. Is the energy value of stainless cold rolled steel It is a device for measuring the average particle size of the coil 16. In the above apparatus, the present invention is not limited to stainless cold rolled coils, but is widely applied to cold rolled steel sheets of carbon steel and various metal sheets, and uses water as an ultrasonic contact medium. In addition to water, glycerin, petroleum, and mechanical oils are used. It is possible to enlarge in a way.

Hereinafter, an ultrasonic scattering theory and a method of applying the theory to the present invention will be described. The scattering of the ultrasonic wave varies depending on the correlation between the use frequency of the ultrasonic probe 13 and the wavelength of the ultrasonic wave determined by the ultrasonic speed in the metal plate. The relationship between the frequency f and the wavelength λ has a relationship as shown in Equation 1 below with the ultrasonic velocity v in a material.

λ = υ / f

The transducer frequency used in the present invention is set as the ultrasonic wavelength is much larger than the average particle size D of the metal plate as shown in Equation 2 so that the scattering in the steel sheet is Rayleigh scattering.

FIG. 2 is an ultrasonic signal 22 that receives a signal detected by sending ultrasonic waves at 30 ° to a stainless cold rolled steel sheet having an average particle size of 9.1 mm at the rear end of the signal amplifier 14. In order to know the relationship between the back scattered ultrasonic signal 22 and the average particle size of the steel sheet, the calculation unit 15 calculates the energy E of the ultrasonic signal as shown in Equation 3 below.

Where V _i is a value obtained by amplifying the ultrasonic signal by the calculator 15 and converting the analog signal to digital, and i is an integer from 1 to N.

3 is an energy value calculated by the calculating unit 15 while changing the incident angle of the ultrasonic probe 13 to the stainless cold rolled coil (16). Examining the ultrasonic signal according to the angle, it can be seen that the first critical angle, the second critical angle and the Rayleigh critical angle exist. Figure 4 shows the principle of reflection and refraction and the generation of the critical angle when the ultrasonic wave is inclined from the liquid to a solid at the liquid / solid interface, the principle of refraction follows Snell's law as shown in equation (4).

Where θ _l is the angle of incidence, θ _i, θ _t is the angle of refraction, υ _i is the velocity of the incident wave in the liquid, and υ _i and υ _l are the velocity of the longitudinal and transverse waves in the solid, respectively. According to Snell's law, the critical angle is when the angle of refraction of the solid is 90 ° and when the angle of longitudinal and transverse wave of the solid is 90 °, the angle of incidence in the liquid is called the first critical angle and the second critical angle, respectively. The first critical angle θ _1c and the second critical angle θ _2c in the liquid have the following relationship with the velocity of the longitudinal and transverse waves of the solid.

Where υ _l and υ _t are the longitudinal and transverse velocities in the solid, respectively, and υ _l is the longitudinal velocities in the liquid to which the transducer belongs. The relationship between the ultrasonic velocity and Young's modulus, Y and Shear modulus, and G in solids is established.

Where ρ is the density of the solid and μ is the Poisson's ratio from the velocity of longitudinal and transverse waves.

Therefore, the Young's modulus and shear rate of the metal plate can be calculated from the first and second critical angles. Figure 3 shows the change of the backscattered ultrasonic energy according to the incident angle by injecting ultrasonic waves in the rolling direction in a stainless steel sheet having an average particle size of 36.5㎛, the energy of the backscattered wave has a minimum value at the first critical angle and the second critical angle It has a maximum at the critical angle. The first and second critical angles of the specimen were measured at 14 ° and 26.5 °, respectively, and the Rayleigh critical angle was measured at 30.88 °. The Young's modulus and shear rate of stainless steel cold rolled sheet are 222 Gpa and 85.8 Gpa, respectively, when the density of the first and second critical angles and the stainless steel sheet is 7.8 g / cm 3 and the longitudinal wave velocity in water is 1490 m / sec. That is, by measuring only the first and second critical angles using ultrasonic backscattering, the Young's modulus and shear rate of the stainless cold rolled coil can be obtained non-destructively. 5 is a view for explaining the method of ultrasonic backscattering for irradiation of the texture of the metal plate. By measuring the ultrasonic backscattering with varying angle Φ with respect to the rolling direction of the metal plate, values for the Young's modulus and shear rate can be obtained. Young's modulus Y (Φ) and shear rate G (Φ) for these angles It represents the texture of. In the above method, ultrasonic backscattering has been described using stainless cold rolled coil as an example, but this technique can be applied to all metal plates without changing the method and apparatus.

Hereinafter, the average particle size measurement of the metal plate using ultrasonic backscattering will be described. The energy of the backscattered ultrasound at the Rayleigh critical angle increases more rapidly than at other incident angles around it, and the energy E of the backscattered ultrasound is proportional to n square of the mean particle size D. Therefore, the energy of the backscattered ultrasound and the average particle size have a relationship as shown in Equation 8 below.

E = D ⁿ

Using Equation 8 to determine the n value by measuring the energy in the test piece having a different average particle size, it is possible to obtain the average particle size of the stainless cold rolled coil from all measured energy values therefrom. 3 also shows that the ultrasonic energy backscattered at an angle (within ± 1 °) around the Rayleigh critical angle (30.88 ° from the interface between the water and stainless cold rolled steel) is 50-400% higher than the energy measured at other incident angles of 10 ° or more. Show that you can get a big signal. This can greatly improve the accuracy of average particle size measurement using ultrasonic backscattering near the Rayleigh critical angle (within ± 1 °).

FIG. 6 compares the magnitude of the average particle size (vertical axis) calculated from an ultrasonic signal measured within ± 1 ° of the Rayleigh critical angle using the apparatus of FIG. 1 and the average particle size (horizontal axis) using an optical microscope. This is well represented. That is, the average particle size of the stainless steel cold rolled sheet can be measured online from the energy of the ultrasonic waves incident by the Rayleigh angle and backscattered. As described above, the on-line measurement technique of the average particle size of stainless steel cold rolled sheet using ultrasonic backscattering is different depending on the liquidity used for the metal sheet and the contact medium. .

As described above, according to the present invention, when ultrasonic backscattering is used, the Young's modulus, shear rate, texture and average particle size of the metal sheet are used as a contact medium of liquid (water, glycerin, petroleum, machinery oil, etc.) in a non-contact or online manner. It can be measured, which reduces the complexity of specimen collection and testing of metal plates.

That is, the Young's modulus and shear rate of the metal plate can be calculated by using Equations 5, 6, and 7 by measuring the energy of backscattered ultrasound with respect to the angle, and obtaining the first and second critical angles from the minimum values of the measured energy. Can be done online without In the aggregate structure, the Young's modulus and the shear rate are applied to the rolling direction of the steel sheet at various angles to obtain the values for the Young's modulus and the shear rate angle.

In the mean particle size measurement using ultrasonic waves, the energy of ultrasonic backscattering is measured around the Rayleigh critical angle (within ± 1 °) and the energy of the signal is 50 ~ 400% larger than the energy measured at other angles of incidence above 10 °. Ultrasonic backscattering can greatly improve the accuracy of average particle size measurements.

Claims (1)

In the method for measuring the average particle size of the stainless steel cold rolled steel sheet, the water tank between the two annealing furnace 20 and the pickling equipment 21 of the stainless steel cold rolled steel sheet and installed in parallel to the water tank (17a) and (17b) are installed, and the stainless cold rolled coil (16) proceeds in the water tank (17a), (17b), the constant distance and angle with the cold rolled coil (16) in the water tank (17a) Pulse transducers are installed on the upper or lower part of the cold rolled coil 16 in accordance with λ »D (λ is the wavelength of the ultrasonic wave, and D is the average particle size of the metal plate). Through the device 11, the high voltage pulse is sent to the ultrasonic transducer 13, and the stainless steel coil 16 is incident on the stainless cold rolled coil 16 through water using the ultrasonic wave 22 generated as a contact medium. 13) to the pulse transmitting and receiving device 11, the pulse transmitting and receiving device 11 Amplifying a call in a signal amplifier 14 and sent to the calculation unit 15 converts the analog signal into a digital signal, the calculation device 15 on the measured signals formula (Ε is the energy of the ultrasonic signal, V _i is the value obtained by converting the analog signal to digital by amplifying the ultrasonic signal by the calculation unit 15, I is an integer from 1 to N) and measures the energy, the angle of the energy value Find the angles of Critical Angle 1 and Critical Angle 2 as the minimum values from the graph for expression Overeating The Young's modulus and shear modulus of the metal plate are calculated using (Y is the Young's modulus, G is the shear rate, ν _l is the velocity of longitudinal wave in solid, ν _t is the velocity of transverse wave in solid, ρ is density of solid, μ is The average particle size (D) of the steel sheet by calculating the energy value near the critical angle of the rail. E = D ⁿ The Young's modulus of the metal plate using ultrasonic backscattering, which improves the measurement accuracy by injecting ultrasonic waves within the range of ± 1 ° of the Rayleigh critical angle formed by the cold rolled coil 16 and the ultrasonic probe 13. , Shear rate, texture and average particle size.