JPH02210258A - Method for measuring material of cold rolled steel sheet and measuring instrument of speed of ultrasonic wave propagated in cold rolled steel plate - Google Patents

Abstract

PURPOSE:To utilize an electromagnetic ultrasonic wave method with eliminates the need for an acoustic coupling medium by making two acoustic speed measuring instruments for SHO plate ultrasonic waves cross each other in the middle of an electromagnetic ultrasonic probe for detection and arranging an electromagnetic ultrasonic probe for a standing wave there. CONSTITUTION:The required press moldability of the cold rolled steel sheet used for the body of an automobile or the outer package of a home electric product is measured. For the purpose, the ratios K1 and K2 of the speeds of a transversal ultrasonic wave which is propagated inside in the thickness direction while vibrating in parallel and at right angles to a rolling direction and the speed of a longitudinal ultrasonic wave which is propagated in the thickness direction and the ratio K3 of the speed of an SHO plate wave ultrasonic wave which is propagated at 45 deg. to the rolling direction and the speed of an SHO plate wave ultrasonic wave which is propagated in parallel or at right angles to the rolling direction are measured. Then the two acoustic speed measuring instrument consisting of electromagnetic ultrasonic probes T1 and T2 for SHO plate wave generation and 1st and 2nd electromagnetic ultrasonic probes R1 and R'1, and R2 and R'2 for SHO plate wave detection are held and crossed at 45 deg. and the electromagnetic ultrasonic probe 50 for the standing wave is arranged at the intersection to measure the ratios K1 - K3 at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for rapidly and non-destructively measuring the material properties of cold-rolled thin steel sheets.

[Conventional technology]

Cold-rolled thin steel sheets are used for car bodies and the exteriors of household electrical appliances, so they require high press formability. Cold-rolled thin steel sheets are polycrystalline, and their press formability is mostly determined by the so-called texture.

Conventionally, press formability has been estimated by the X-ray pole figure method or the Lankford value (r value).

However, the xkIAs dot projection method requires time to cut a test piece from a cold-rolled thin steel plate and irradiate it with X-rays for measurement, and can be said to be a destructive measurement method because the test piece must be cut out.

The method of measuring the Lankford value requires precise measurement of changes in the size of the tensile test piece, which is time-consuming, and it is also a destructive measurement method because the test piece must be cut from a cold-rolled thin steel plate. You can say that.

Because measuring the Lankford value using such a tensile test requires a great deal of time and effort, a simplified method was also proposed (C
, 8, 5tickels and Moulcl, “T
he use of young's modulus
for predicting the plus
ticstrain ratio of low
carbon 5teel 5heets”.

Metallurgical Transaction
n Vol, 1. pp1303-1312 (1970)
). This simple method uses the empirical correlation between the Young's modulus measured by the natural vibration method and the Lankford value, so it is simple, but even with this method, the test piece must be cut from a cold-rolled thin steel sheet and measured. This is also a destructive measurement method.

Therefore, a method of measuring the sound velocity of ultrasonic waves was proposed as a non-destructive method of measuring the natural size of cold-rolled thin steel sheets without the need to cut out the test pieces.

In JP-A No. 57-66355 (“On-line method for determining the texture of a steel plate or material properties dependent on the texture °°”), the sound velocity of S-mode and A-mode plate wave ultrasonic waves was measured and the measured values were A method has been proposed to calculate the Lankford value appropriately.

However, in this method, since the absolute value of the sound velocity is used, the thickness of the thin steel plate must be measured separately, and errors due to errors in the thickness measurement cannot be eliminated. In addition, in this method, water, oil,
Another acoustic coupling medium such as a liquid is required, and therefore problems such as staining the thin steel plate cannot be avoided.

In order to eliminate the error caused by using the absolute value of sound speed, a method using the ratio of sound speeds has also been proposed (Hirao et al. "Non-destructive evaluation of texture of cold-rolled steel sheets by ultrasonic waves", Japan Society of Mechanical Engineers). Excerpt from conference paper lecture, 308A, paper detail, 87-
12118, gave a lecture at the 65th Ordinary General Lecture Meeting on March 30, 1986. and Hikyu rao, et al.
old trasonic monitoring of
exture in cold-rolled 5te
el 5heets”, Journalof Acou
5ociety of America
, Vol. 84(2).

pp667-672 (1988)). There, there are two types of transverse waves: a longitudinal wave that propagates in the thickness direction of the thin steel plate, and S H that propagates within the rolling plane of the thin steel plate and whose polarization direction is also within the rolling plane.
Measure the sound speed of O-mode plate waves, etc., and estimate the Lankford value from the ratio of these sound speeds without performing a tensile test. O,w,
□. , Lao (the meanings of these coefficients will be explained later) and have proposed a method for estimating material properties.

However, like the above-mentioned method, this method also requires an acoustic coupling medium and cannot avoid problems such as staining the thin steel plate. In addition, when measuring the sound velocity of SHO mode plate waves, the probe must be rotated 5 degrees from the rolling direction of the thin steel plate to the direction perpendicular to it, which increases the number of measurements and takes time. This problem arises. Another problem is that procedures such as Fourier analysis of the measured values thus obtained are required.

[Problem to be solved by the invention]

In view of the above problems, the present invention utilizes an electromagnetic ultrasonic method that does not require an acoustic coupling medium, and is completely non-destructive and does not stain the thin steel sheet. The purpose of this invention is to provide a method and device for measuring.

[Means to solve the problem]

The present invention provides a value Kt of the ratio between the velocity of a transverse ultrasonic wave that propagates in the thickness direction while vibrating inside a cold rolled thin steel sheet in a direction parallel to the rolling direction and the velocity of a longitudinal ultrasonic wave that propagates in the thickness direction. , and the ratio of the speed of the transverse ultrasonic wave that propagates in the thickness direction while vibrating inside the cold rolled thin steel sheet in a direction perpendicular to the rolling direction and the speed of the longitudinal ultrasonic wave that propagates in the thickness direction. value K l ,
Also, the speed of the SHO plate wave ultrasonic wave propagating inside the cold rolled thin steel sheet in a direction at 45° to the rolling direction, and the speed of the SHO plate wave ultrasonic wave propagating in a direction parallel to or perpendicular to the rolling direction. 3, as well as the value of the three known elastic modulus of iron single crystal C0□.

"+2 + A method for measuring the material of a cold-rolled thin steel sheet to obtain the pole figure, Young's modulus, and Lankford value of the cold-rolled thin steel sheet from C012 and C044, and also an electromagnetic ultrasonic probe for generating SHO plate waves. and a SHO plate wave ultrasound probe in which a first SHO plate wave detection electromagnetic ultrasound probe and a second SHO plate wave detection electromagnetic ultrasound probe are arranged in a straight line. Two sets of sound velocity measuring devices are crossed at the middle of the 1st and 2nd SHO plate wave detection electromagnetic ultrasonic probes while maintaining an angle of 45°, and one standing wave electromagnetic ultrasonic probe is placed at the intersection. This is an apparatus for measuring the speed of ultrasonic waves propagating in a cold-rolled thin steel sheet, characterized by having a sonic probe arranged therein.

[For production]

First, I will explain the theoretical background. A cold-rolled thin steel sheet is a polycrystalline body consisting of many fine iron single crystals (cubic crystals), but when viewed macroscopically, it can be regarded as a continuum with anisotropy.

A thin steel plate regarded as a continuous body has approximately three mutually orthogonal planes (1. rolling plane (xy plane); 2. plane perpendicular to the rolling plane and parallel to the rolling direction (XZ plane); 3. It is considered to have physical properties that are plane symmetrical with respect to a plane (yz plane) perpendicular to the rolling surface and perpendicular to the rolling direction. However, X is the rolling direction and corresponds to the longitudinal direction of the thin steel sheet. y is a direction perpendicular to this and corresponds to the middle direction of the thin steel plate. Z is a direction perpendicular to both X and y, and corresponds to a direction perpendicular to the surface of the thin steel plate. In such a case, it is already known that the elastic coefficient matrix of the thin steel plate has nine different elastic coefficients, which can be expressed as follows.

It is also known that it can be expressed by series expansion using Z and □.

H(ξ, ψ, φ)= where C1j represents nine different elastic moduli of the thin steel plate.

On the other hand, among the many single crystals that make up a polycrystalline body, the proportion of single crystals that have a certain direction (θ, ψ, φ) relative to the thin steel sheet is determined by the crystal orientation distribution function W(ξ).

ψ, φ) (hereinafter referred to as C0DF) is known to be expressed as (R, J, Roe, “Descriptio
n of crystallite orientati
on in polycrystalline mat
erials”.

Journal of Applied Physics
s, Vol, 36. pp2024-2031 (1965
)), where ξ= cos θ. W(ξ, ψ.

φ) is a generalized Legendre function as follows, where θ, ψ, and φ are Euler angles used to express the relationship between the single crystal and the thin steel plate. Also, ξ=cos θ. Further, W (ξ, ψ, φ) is a function representing the proportion of single crystals having a certain direction (θ, ψ, φ) in the thin steel sheet, and is called a crystal orientation distribution function. W L wr
m is a C0DF coefficient.

Of these... . , -4□. , -44° is known to be related to the elastic properties of polycrystalline materials.

Now, in the case of a cold-rolled thin steel sheet, as mentioned above, there are nine different elastic coefficients Cij, but these are determined by six independent variables, namely the three elastic coefficients of iron single crystal C'll+CO1□+C
012, C044 and three CODF coefficients. . 5-4
□.

, -44° is known to be expressed as follows (C, M, 5ayers + 'UItrason
ic velocities 1nanisotrop
ic polycrystalline aggreg
ates.

Journal of Physics 15, pp2157 2167 (i982)).

however, G =00° C'+z 2C012, C044.

5/2)”” 1°. ] 5/2) '" 1°.] 70) "" -44°] 5/2) '" -4,. ] 5/2)”” W4! . ] 70)”” -44°] Also,. O+ W4□. It is also known that an approximate pole figure can be created by substituting the values of , -44° into the following equation.

4πq(ζ, η)=1+4πP ((3/8.I'2)
(35ζ4-30ζ”+3)L.

+(9/2) (5) ' ” (1-ζ”) [1-
(7/6) (1-ζ”)]ti4□.cos2η+
(3/8) (35ν'' (1-3g) 2H44゜co
s4η) (4) However, P−−4π/
3 (111) Pole figure P=2π (100
) Pole figure P=-π/2 (110) Pole figure η and ξ are angles indicating the relationship between the spherical surface and the thin steel plate for drawing the pole figure.

FIG. 1 shows various modes of ultrasonic waves used in the present invention. Thick arrows indicate the propagation direction of the ultrasound waves, and thin arrows indicate the vibration direction of the ultrasound waves. Although these arrows are drawn on the outside of the thin steel plate, this is for convenience, and it goes without saying that all actual ultrasonic waves propagate within the thin steel plate. ■! , is the sound velocity of a longitudinal wave propagating in the plate thickness direction, ■2X is the sound velocity of a transverse wave deflected in the rolling direction and propagating in the plate thickness direction, ■8
．． represents the sound speed of a transverse wave that is deflected in a direction perpendicular to the rolling direction and propagates in the thickness direction. V5Ho(0') is S which is deflected in the direction perpendicular to the rolling direction and propagates in the rolling direction within the rolling surface.
Sound speed of HO mode plate wave, vsg. (90°) is S deflected in the rolling direction and propagated within the rolling plane in a direction perpendicular to the rolling direction.
The sound speed of the HO mode plate wave, VSHO (45°), represents the sound speed of the SHO mode plate wave propagating within the rolling surface in a direction 45° to the rolling direction. It is already known that each is expressed by the following formula.

9 ■z% = Cxz
(5) ρV, -=C44 (6) ρV,," = css (
7) ρV 11. "=ρVsoo"(0°)=C-6
(8) ρVyX""ρV3MO" (90°) = CI, 6
(9) β ρVs+o''(45')=Cba(1+)2
(10)-C&& ) /c,.

ρ: Density of thin steel plate Among these, Vi, 1o (45°) was recently discovered (R, B, Thompson et al, +
”Re1atfve anisotropyof p
lane waves and guided m
odes in thinorthorhombi
c plates', Llltraonics 25.
pp133-137 (1987)), VsHo(0
″′)=Vsoo(90′), so in reality, only one of them needs to be used.

From now on, for convenience of explanation, VS) 10 (0°) will be used.

The above equations (1) to (10) are known so far. The inventor theoretically studied these equations, discovered a new equation that was unknown until now, and invented a new method using it.

This will be explained next.

First of all, V! If the sound speed ratio of y(!l:V) is 1, then (3
).

The following equation is obtained from equations (5) and (6).

By substituting known values for the three elastic coefficients C0□, Co1□+C012, and C044 of the iron single crystal in equations (11)-(13), equations (11) and (12) yield W4°. and W4!
. This can be solved because it becomes a two-dimensional simultaneous linear equation for . W4° obtained in this way. and W4□
. By substituting .

In the end, each solution is as follows.

Equations (14) and (15) were already known ((:
, M, 5ayersand D,R, 8l1en
+”The 1nfluence of 5tr
ess on the principal pol
arization directions of u
ltrasonicshear waves in t
Extured 5teel plates', Jou
rnalof Physics D 17. pp139
9-1413 (1984)), formula (16) was first discovered by the inventor.

According to equations (14), (15), and (16), the three already known elastic modulus values (C' l
I=237GPa.

C'+2=141GPa, C'na=116GPa
), the sound speed ratio becomes W4° by simply measuring K3. , W4□. .

-44° can all be obtained by calculation. -4°.

. -4□. , W44° are obtained, nine elastic moduli Cf j of the thin steel plate can be obtained by substituting them into equation (3).

Further, it is well known that the Young's modulus E(α) of a thin steel sheet in a rolling plane in a direction forming an angle α with the rolling direction can be expressed by the following equation.

1 /E(cx) =SzzSin' cx +Sth CO3' tx +C5bb'+2S+z) sin"α
cos”cx but 5z=(C2□CIj CzsC
z3)S(I7) Szz-(CIIC33Cl5CI3)SSI2=
(Cl:+Czs ClzC3ff) SS6a=1
/C66 S = 1 / (Cl ICt□Css + 2C+
zczzc+ 3C+ +Czz"-C2□CIj"
By substituting the nine elastic coefficients Ci j of the thin steel plate obtained by the above method into the equation (17), the Young's modulus E(α) can be obtained by calculation.

Next, a method for measuring the sound speed ratio, , , , K3 will be explained. First, a method for measuring Toni 2 will be explained.

The sound speed of an ultrasonic wave propagating in the thickness direction in a thin steel plate with a thickness of about 1 mm or less V 2 m + V fX r
It is already known that the standing wave method (also called "thickness resonance method") using electromagnetic ultrasound is suitable for measuring V zy (S, A, Filimonov, B,
A.

Budenkov, and N.A., Glukhov.
”Ultrasonic contact-Iess
resonance testing method”
, 5oviet journal of Nocles
tructive Te5tir+g, No, 1. pp
102-104 (1971)).

Figure 2 shows an example of an electromagnetic ultrasonic probe for this standing wave method. FIG. 2(a) is a sectional view seen from the front. This electromagnetic ultrasound probe has a rotationally symmetrical structure. Figure 2 (
b) is a view from above and shows the eddy current, electromagnetic force, etc. generated by this electromagnetic ultrasonic probe. Figure 2 (a
) When a high frequency current is passed through the flat circular coil 14 shown in ), an eddy current Iφ is induced in the thin steel plate 16. On the other hand, permanent magnet 1
2, a magnetic field 18 is generated in the thin steel plate 16. The magnetic field 18 has a component Bz perpendicular to the surface of the thin steel plate 16 and a component Bz perpendicular to the surface of the thin steel plate 1
It has a component Br distributed radially and parallel to the surface of 6. The interaction between Iφ and Bz generates an electromagnetic force Fr that is distributed parallel and radially to the surface of the thin steel plate 16. Also I
An electromagnetic force Fz perpendicular to the surface of the thin steel plate 16 is generated due to the interaction between φ and Br. The electromagnetic force Fr can be divided into a component Fx parallel to the rolling direction and a component Fy perpendicular to the rolling direction. Fz generates a longitudinal wave ■2□ that propagates in the thickness direction,
Transverse wave V deflected in the rolling direction by Fx and propagated in the plate thickness direction
. is generated, and a transverse wave V zy is generated which is deflected by Fy in a direction perpendicular to the rolling direction and propagates in the plate thickness direction.

The ultrasonic waves thus generated are detected by the opposite physical process. It is known that standing waves are generated in the thickness direction of a thin steel plate when the frequency of the high-frequency current flowing through the coil satisfies the following equation.

By sweeping the frequency of the high-frequency current flowing through the coil, generating and detecting an ultrasonic wave according to the process described above, and recording the frequency at which the detected ultrasonic wave reaches its maximum, it is expressed by equation (18). frequency can be obtained.

The sound speed, , and can be obtained as follows by using equation (18).

Vzx (ldlm) 1 xtlI
n 1 zzm (19) , (2
According to equation 0), the sound speed ratio is converted to a frequency ratio,
It can be seen that the thickness d of the thin steel plate is erased and does not need to be measured. In order to measure the thickness d of a wide thin steel plate, measurement using X-rays or the like is required, so it is very preferable from a practical point of view that this is not necessary.

Next, a method for measuring the sound speed ratio of 3 will be explained. S
An example of an electromagnetic ultrasonic probe for generating and detecting a plate wave in the HO mode is shown in FIG. 3, and is also well known. That is, when a high frequency pulse current is passed through the rectangular coil 24, an eddy current is induced in the thin steel plate. On the other hand, the periodically arranged permanent magnets 20 generate a periodically distributed magnetic field in the thin steel plate. The interaction of eddy currents and this magnetic field creates a periodically distributed force that generates SHO plate waves. Detection of SHO plate waves is performed by the reverse process of generation. Various devices can be considered for measuring the sound velocity of the SHO plate wave using this, and one example of such a device is shown in FIG.

That is, three probes with the same structure are used. There is one generation probe, which is called TI, and two detection probes, which are called R1 and R2. Tl, R1.

R2 are arranged in this order and housed in a rigid case, and the spacing between them is kept constant. The SHO plate wave generated by T1 propagates and is first detected by R1 and then detected by R2 after some time. If the distance between R1 and R2 is D, the sound speed of the SHO plate wave can be expressed as follows.

■, □ when the traveling direction of the SHO plate waves coincides with the rolling direction. (0°)=D/L, (21)S
When the traveling direction of the HO plate wave is at 45° with the rolling direction, V! IHO (45°) -D/145 (22) However,
tO and t4s are the times required to propagate the distance when the traveling direction of the SHO plate wave forms an angle of 0° and 45° with the rolling direction, respectively.

The sound speed ratio of 3 can be obtained by using equations (21) and (22).

K 3 = Vs,lo (45°)/Vsuo(0°
) = to/tas (23) In other words, the sound speed ratio is converted to the inverse ratio of the propagation time, and it can be seen that the propagation distance is eliminated and does not need to be measured. The fact that this is not necessary is very preferable from a practical point of view.

Now, it has been found that it is possible to measure +, Kz, and * in the sound speed ratio in this way, but if these can be measured simultaneously, the measurement can be made faster, which is practically preferable. An example of a device for this purpose is shown in FIG. In other words, two sets (Tl, I
? 1, R2 and TI', R1', R2
') Prepare and fix them so that they form a 45° angle to each other. Further, a standing wave probe 50 similar to that shown in FIG. 2(a) is fixed at the intersection. In this way, the probe set shown in FIG. 5 allows the sound speed ratio to be measured at the same time as 1 Kz and 'r, which is very preferable in practice.

The sound speed ratio obtained in this way is 1, Kz is 3
and the known elastic modulus of iron single crystal C'z + C'+z,
Nine elastic modulus Ci j・, of thin steel plate by C04a
As already explained, Young's modulus can also be obtained, and an approximate pole figure can also be drawn.

[Example] When actually measured on one thin steel plate, =0
．． 5292. K2 =0.5409. K, =0.
9643 were obtained. These measured values and the known value of the elastic modulus of iron single crystal Co++ = 237 GPa, C''
1t=141GPa, C044=116GPa (
Substituting into 14), (15), and (16), we get
Lo.

=-3,94xlO-3, Lio=-1,36xlO-
3.W44°=-1,83X10-3 was obtained. The ultrasonic pole figure obtained by substituting these values into equation (4) is shown in FIG. 6(a). For comparison, a pole figure obtained by X-ray diffraction is shown in FIG. 6(b).

It can be seen that although the two do not match in detail, they generally match well. That is, it can be seen that the ultrasonic method of the present invention allows polar figures to be drawn non-destructively and quickly, thereby making it possible to estimate the aggregated Mi weave.

Figure 7 shows different 7 types measured by the ultrasonic method of the present invention.
Average value of Young's modulus of two thin steel sheets in the rolling plane (π=
[E (0') + 2 E (45°) 10 E (90
)]/4) and the average value (T=
[r (0°) + 2 r (45°) + r (90°
)]/4). Since it is known that the larger the value of (2), the higher the press formability, it is understood that the press formability can be measured non-destructively by the ultrasonic method of the present invention.

FIG. 8 also shows the anisotropy of Young's modulus within the rolling plane measured by the ultrasonic method of the present invention (ΔE=[E(0°)−2B(45°)+−E(9
0' ) ]/4) and the anisotropy (Δr
= [r (0°) -2r (45°) +r (90'
) ]/4). It is known that the larger the value of Δr, the more likely it is that so-called "ears" will occur during press molding, so it can be seen that the ultrasonic method of the present invention can non-destructively predict the occurrence of "ears". .

According to Fig. 7.8, it can be seen that the average value of the Lankford value within the rolling plane and the anisotropy of the Lankford value within the rolling plane can be estimated nondestructively and quickly by the ultrasonic method of the present invention. .

〔Effect of the invention〕

As mentioned above, the present invention uses an electromagnetic ultrasonic method that does not require an acoustic coupling medium, so it is a completely non-destructive measurement and does not contaminate the thin steel plate (also, it does not measure the absolute value of the sound velocity). Since the sound speed ratio is used, the measurement error is small.Furthermore, it is possible to simply solve three linear algebraic equations (Takede,..., Satoshi, □., W, 4°, and draw a pole figure from these. The Lankford value can be estimated without performing a tensile test.In this way, material properties can be determined non-destructively.
In addition, since it can be measured quickly, quality control and quality assurance of thin steel sheets can be advantageously achieved.

[Brief explanation of the drawing]

Fig. 1 shows the propagation direction and vibration direction of various modes of ultrasonic waves used in the present invention, and Fig. 2 shows longitudinal ultrasonic waves propagating in the thickness direction of a thin steel plate and two types of transverse ultrasonic waves. occurrence·
Figure 3 is a diagram showing an electromagnetic ultrasound probe for standing waves for detection, Figure 3 is a diagram showing an electromagnetic ultrasound probe for generating and detecting plate wave ultrasound in SHO mode, Figure 4 is a diagram showing an electromagnetic ultrasound probe for generating and detecting plate wave ultrasound in SHO mode. Figure 3 shows a method of measuring the sound speed of SHO mode plate wave ultrasound using three electromagnetic ultrasound probes; Figure 5 shows the sound speed ratio Kl, 2. Figure 6 is a diagram showing a comparison between a pole figure obtained by the ultrasonic method of the present invention and an X-ray pole figure, and Figure 7 is a diagram showing a method for simultaneously measuring Figure 8 shows the relationship between the obtained average value of Young's modulus (T) within the rolling plane and the average value of r value (T) within the rolling plane. FIG. 2 is a diagram showing the relationship between the anisotropy (ΔE) of the ratio in the rolling plane and the anisotropy (Δr) of the r value in the rolling plane. (Q) (b) An example of an electromagnetic ultrasonic probe for standing waves Base 2 Seki 18...Magnetic field Ultrasonic waves of various modes used in the present invention ===
=) Ultrasonic propagation direction Ultrasonic vibration direction Z...Direction perpendicular to the steel plate surface Example of electromagnetic ultrasonic probe for SHO plate wave detection Part 3 Figure 24... Oblate rectangular coil SHO plate wave ultrasound An example of a device for measuring the speed of sound in Fig. 4 T An example of a device for simultaneously measuring the sound speed ratio +, 2 r K3 Fig. 5 50...Standing wave probe 25 ) (Q) Myozu Kizu Procedural Amendment (Spontaneous) Yoshi, Commissioner of the Patent Office, S/g, 1999 1) Moon Takeshi 1, Indication of the case 1999 Patent Application No. 29755 2, Name of the invention Method for measuring the material quality of rolled thin steel sheets and a device for measuring the speed of ultrasonic waves propagating in cold rolled thin steel sheets 3, Relationship with the case of the person making the amendment Patent applicant 4 Address of attorney: 105 Toranomon-chome, Minato-ku, Tokyo No. 8, No. 10, No. 5,
Target of amendment (1) "Detailed description of the invention" column of the specification (2) "Brief explanation of the drawings" column 6 of the specification, contents of the amendment (1) In the description, ■ Page 10 Correct the 4th line "Σ" to rΣ j. 1 wealth 0 ■ Page 24, lines 7 to 8, “Yotamaz” is corrected to “j”. ■ Page 26, line 1 [Ci=’J is corrected to ‘CtjJ.’ ■ No. Page 26, line 10' -3,94X10-3 J to F -3,94x 1
Correct as 0-”J. ■ 26th true 10th line' -1,36X10-3 J to r -1,36X10
-'J Correct. ■ Page 26, line 11' -1,83X10-3 r J -1,83X 1
Corrected as O-1J. ■ Correct "cho" in line 6 of page 27 to "T1." Correct "cho" in line 7 of page 27 to "T7." (2) In the specification, ■ Page 29, line 16 r (T”) is amended to “(〒)1.”

Claims (1)

[Claims] 1. Velocity V_z_x of transverse ultrasonic waves propagating in the thickness direction while vibrating in a direction parallel to the rolling direction inside a cold-rolled thin steel plate and velocity of longitudinal ultrasonic waves propagating in the thickness direction The value K_2 of the ratio to V_z_z, the velocity V_z_y of the transverse ultrasonic wave propagating in the thickness direction while vibrating inside the cold rolled thin steel sheet in a direction perpendicular to the rolling direction, and the longitudinal wave propagating in the thickness direction. The ratio K_1 to the ultrasonic velocity V_z_z, and the velocity V_S_H_O (45°) of the SHO plate wave ultrasonic wave propagating inside the cold-rolled thin steel sheet in a direction perpendicular to the rolling direction and parallel to the rolling direction. The value of the ratio K_3 to the velocity V_S_H_O (0°) or V_S_H_O (90°) of the SHO plate wave ultrasonic wave propagating in the direction or perpendicular direction is measured, and the values of K_1, K_2, and K_3 and the known values of the iron single crystal are measured. The three elastic coefficient values C^0_1_1, C^0_1_
2. CODF coefficient W_4_0_0 from C^0_4_4,
A method for measuring the material quality of a cold-rolled thin steel sheet, comprising calculating W_4_2_0 and W_4_4_0 to obtain the pole figure, Young's modulus, or Lankford value of the cold-rolled thin steel sheet. 2. The method for measuring the material quality of a cold rolled thin steel sheet according to claim 1, wherein the values of K_1, K_2 and K_3 are measured using electromagnetic ultrasonic waves. 3. SHO plate wave generation electromagnetic ultrasonic probe and first SHO
Two sets of SHO plate wave ultrasonic sound velocity measuring devices are used, each set including a plate wave detection electromagnetic ultrasonic probe and a second SHO plate wave detection electromagnetic ultrasonic probe arranged in a straight line. The first and second SHO plate wave detection electromagnetic ultrasonic probes were intersected at an angle of 45° between them, and one standing wave electromagnetic ultrasonic probe was placed at the intersection. A device for measuring the speed of ultrasonic waves propagating in a cold-rolled thin steel sheet, characterized in that: