JPH02278106A - Measuring apparatus for clad thickness of cladding material - Google Patents

Abstract

PURPOSE:To enable simultaneous measurement of an entire wall thickness and a clad thickness by applying an ultrasonic beam to a cladding material from a probe at a refractive angle in a specified range. CONSTITUTION:In a two-vibrator oblique-angle probe 2, refractive angles of vibrators T and R are set in the range of 35 to 70 deg. and an aperture Y0 between incident points is set in accordance with a thickness to be measured. A transmitter 5 makes an ultrasonic beam enter a cladding material 1 from the vibrator T and a reception amplifier 6 receives an output signal of the vibrator R, while a reception amplifier 7 receives a transmission pulse of the transmitter 5. A minute-echo extracting-computing unit 8 receives outputs (a) and (b) as inputs from the amplifiers 6 and 7 and extracts therefrom a minute echo from a clad surface C and an entire wall thickness computing unit 9 receives the output (a) as an input and determines the entire wall thickness (d) (= t0) of the cladding material 1. Base material thickness computing unit 10 receives an output (c) from the computing unit 8 and determines the thickness (e) (=t1) of a base material, and a clad thickness computing unit 11 computes a difference between the entire wall thickness (d) and the thickness (e) of the base material and determines the thickness (f) (= t2) of a clad. The results of measurement of the entire wall thickness (d) and the thickness (f) of the clad and the results of determination thereof can be displayed in a display unit 13.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method of measuring the cladding thickness of a cladding material made by cladding a base metal with a cladding metal using transverse ultrasonic waves. -1 Regarding fixed equipment.

[Prior art] Clad materials are generally made by cladding a base metal (hereinafter referred to as base metal) of low carbon steel or low alloy steel with a clad metal with excellent corrosion resistance such as stainless steel alloy steel or nickel alloy steel. Seamless and welded steel pipes and steel plates are manufactured using these materials. Generally, the mating part (cladding part) is joined metallically, and the thickness of the cladding metal (hereinafter referred to as cladding thickness) and the base material thickness or total wall thickness (cladding thickness, dotan material thickness, ) is required to guarantee the 1jp1 constant and thickness. In particular, in the case of seamless clad pipes (double pipes), since they are used in corrosive environments such as line pipes and petrochemical refining, it is necessary to set the clad thickness to 7Illll and guarantee the thickness.

By the way, conventional methods for measuring this type of cladding thickness include cutting and polishing both ends of the product and measuring it metallographically (using a metallurgical microscope, etc.), and
No. 205'' or Jitsukasho No. 62-143205, the total wall thickness is determined by ΔP1 using a super wave thickness meter, and the cladding thickness is determined by 31 using an eddy current wall thickness meter (film thickness meter). A method is being used to do so.

[Problems to be Solved by the Invention] However, in the former method, for example, both ends of a seamless clad pipe are cut and polished to metallographically determine the APL, which is non-destructive, resulting in yield loss, a- There was a problem that not only did it take a considerable amount of time, but also that it was impossible to measure the entire length of the entire surface. In addition, in the latter method, since the pipe is an internally clad steel pipe, the total wall thickness can be determined from the outer surface of the pipe using an ultrasonic wall thickness meter, but the cladding thickness can be determined from the inner surface of the pipe using the principle of a film thickness meter. Therefore, not only is there the problem that the cladding metal is limited to non-magnetic materials, but also it is necessary to insert an eddy current sensor into the inner surface of the tube, which requires large-scale equipment and control methods. There were problems such as the wasted time required to pull out the sensor.

In particular, in the case of long materials (long clad pipes), the insertion and tracing mechanism for the eddy current sensor for measuring the inner surface of the pipe becomes large-scale, and at the same time, the measurement position deviates from the ultrasonic wall thickness gauge from the outside. There were problems such as the need for measurement point correction.

The purpose of the present invention is to cover the entire surface (entire circumference) of the cladding material.

To provide a cladding thickness measuring device for a rad material, which enables the ApJ determination of the total wall thickness of the entire length and the cladding thickness from the outer surface at the same time, nondestructively, accurately, efficiently, and inexpensively.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a device for determining the cladding thickness AJ1 of a cladding material made by cladding a cladding metal on a mother and child A by refraction of each vibrator. Corner is 35″
~70＠, a two-element angle probe with a fixed value where the distance between each incident point is arbitrarily set, and a two-element angle probe with a transmitting side transducer to the cladding material. a transmitter that generates a transmitting pulse to cause an ultrasonic beam to be incident on the transducer; , a second reception amplifier that receives the transmission pulse generated from the transmission section, and outputs from the first and second reception amplifiers are input, and calculations are performed based on these to extract minute echoes on the cladding surface. A calculation unit for extracting minute echoes, a total thickness calculation unit which inputs the output from the first receiving amplifier and calculates the total thickness of the cladding material from the beam path to the bottom echo, and a calculation unit for extraction of minute echoes. There is a base material thickness calculation section that inputs the output of The cladding thickness calculator tJ determines the cladding thickness of the cladding material from the difference between the cladding thickness and the cladding thickness.

[Function] Therefore, in the present invention, by adopting the above means, the first. A minute echo on the cladding surface is extracted from the output from each of the second receiving amplifiers by a computing section for extracting a minute echo.

In addition, the total wall thickness of the cladding material is determined by the total thickness calculation section from the beam path from the first receiving amplifier to the bottom echo, and the total thickness of the cladding material is calculated from the beam path from the output from the total thickness calculation section to the cladding surface echo. The material thickness calculation section calculates the thickness of the base material. Furthermore, the cladding thickness of the cladding material is determined by the cladding thickness calculating section from the difference between the determined total wall thickness and the base material thickness. This makes it possible to simultaneously measure the entire surface (entire circumference) of the cladding material, the total thickness of the entire length, and the cladding thickness from the outer surface.

[Example] First, the concept of the present invention will be explained.

FIG. 5 shows the principle of a known wall thickness meter, and there are two types: a one-probe method and a two-probe method, both of which use longitudinal waves. In addition, as a method of measuring the transverse wave sound velocity, a method using a transverse wave vertical probe with a Y-cut vibrator is also known, but due to the physical property that transverse waves do not propagate through the liquid, automatic 71M measurement is possible due to the limitations of the couplant. cannot be used. On the other hand, the sound pressure and reflectance "1□" from the cladding surface is given by the following equation.

r 12 (%) = Pr/Pl = (Z2 Zl) / (Zl +22) Here, ZI■p+ CI Z2-ρ2'C2 (ρ0.
ρ2 is the density and CI+C2 is the speed of sound).

The table below shows the results of calculating the sound pressure and reflectance of transverse waves and longitudinal waves of various cladding materials from acoustic impedance. From the table, it can be seen that the sound pressure and reflectance of transverse waves are higher than those of longitudinal waves for all cladding materials. In addition, the echo level reflected from the cladding surface of an actual cladding material was recognized for transverse waves, but could not be distinguished from noise for longitudinal waves.

Based on the above knowledge, the present invention uses transverse wave ultrasound of the two-oscillator oblique method, increases the echo reflectance of the cladding part, extracts minute echoes using arithmetic methods, and calculates the thickness of the base material of the cladding material. The greatest feature is that the total wall thickness is measured at the same time as n1 is determined, and the cladding thickness is determined from the difference between these.

[Table] Hereinafter, an embodiment of the present invention based on the above concept will be described in detail with reference to the drawings.

FIG. 1 shows the cladding thickness Ap of the cladding material according to the present invention.
FIG. 2 is a block diagram showing an example of the configuration of an I-setting device.

The cladding thickness M1 determination device of this embodiment includes a two-element angle probe 2 disposed on a cladding material (in this embodiment, a cladded steel pipe) 1, a clock oscillator 3, and a timing clock (P
RF) section 4, transmitting section 5, first receiving amplifier 6, second receiving amplifier 'J57, minute echo extraction calculation section 8, zero point adjustment section 9A, gate section 9B, counting section 9C, Total thickness calculation section 9 consisting of sound velocity calculation section 9D and zero point adjustment section 10A
・Base material thickness calculation section 10 consisting of gate section 10B, counting section 10C, and sound velocity calculation section 10D, and cladding thickness calculation section 11
, a setting output section 12 , a display section 13 , and a sweep circuit 14 .

Here, the two-oscillator angle probe 2 has two transducers T and R.
The refraction angle θ is in the range of 35° to 70” (in this example, 38
') is the interval Y between each incident point. is ApJ constant thickness (range)
It has a constant value arbitrarily set by . This incident point interval Y. This determines the focal depth of the ultrasound beam, and its reflected echo level also changes. Further, the clock oscillator 3 oscillates a taro clock for beam path measurement. Furthermore, the timing clock section 4
The transmission timing is selected by inputting the clock from the clock oscillator 3.

On the other hand, the transmitting section 5 generates a transmitting pulse so that the ultrasonic beam is incident on the cladding material 1 from the transmitting side transducer T of the two-transducer oblique probe 2 . Also, the first
The receiving amplifier 6 receives the signal output from the receiving side transducer R of the two-oscillator oblique probe 2 through the cladding material 1.

That is, this first reception amplifier 6 has a two-oscillator oblique angle V
It is a transmission receiver and has an automatic gain control (AGC) circuit 6A that corrects changes in reflected echo level due to the above-mentioned focal depth (fFJ constant depth). FIG. 2 shows the operation, and the thickness of the AGC operating range is the range in which aFJ can be determined (approximately the depth of focus α±30%).

Furthermore, the second reception amplifier 7 receives transmission pulses generated from the transmission section. Further, the minute echo extraction calculation unit 8 inputs the outputs a and b from the first and second reception amplifiers 6 and 7, and performs calculation processing such as subtraction and averaging processing (in this embodiment, , Σ(a-
The subtraction and averaging process PJ (b) is performed to extract minute echoes on the cladding surface.

On the other hand, the total thickness calculation section 9 inputs the clock from the clock oscillation section 3 and the output a- from the first reception amplifier 6, and calculates the total thickness of the cladding material 1 from the beam path to the bottom echo. , during calibration, the speed of sound is determined. The base material thickness calculation unit 10 inputs the output C from the minute echo extraction calculation unit 8, calculates the thickness of the base metal from the beam path to the cladding surface echo, and calculates the speed of sound during calibration. It is. Furthermore, cladding thickness calculation section 1
1 is a total wall thickness and base material thickness calculation unit 1 by a total thickness calculation unit 9;
The cladding thickness of the cladding material 1 is determined from the difference from the base material thickness by 0. Further, the setting output section 12 includes the first. Outputs a, b from the second reception amplifier 6.7, outputs C1 from the minute echo extraction calculation unit 8, outputs from the cladding thickness calculation unit 11 [, outputs d, i from the total thickness calculation unit 9,
Input the output e+J from the base material thickness calculating section 10, set the mode, set for measuring value judgment, and measure the result.

It outputs judgment results and the like, and switches and outputs these based on the sweep signal from the sweep circuit 14.

Furthermore, the display unit 13 may be a CRT (A scope), for example.
It consists of an LED and the like, and displays the output from the setting output section 12.

Next, the operation of the cladding thickness measuring device configured as above will be explained using FIG. 3.

In FIG. 1, the first receiving amplifier 6 receives the signal output from the receiving transducer R of the two-transducer angle probe 2 through the cladding material 1, and the second receiving amplifier 7 receives the signal output from the receiving transducer R of the two-transducer angle probe 2. Transmission pulses generated from the transmitter 5 are received.

The outputs a and b from the first and second receiving amplifiers 6 and 7 are input to the minute echo extraction wave nH8, and based on these, the subtraction and averaging process of Σ(a-b) +111 are performed. The minute echoes of the cladding surface are extracted.

On the other hand, the output a from the first reception amplifier 6 is input to the total thickness calculating section 9, and the total thickness d(-t.) of the cladding material 1 is determined from the beam path to the bottom echo. Sometimes the speed of sound i is required. In addition, the output C from the minute echo extraction calculation unit 8 is input to the base material thickness calculation unit 10, and the thickness e(-t+) of the base material is determined from the beam path from the cladding to the echo. The speed of sound j
is required. Furthermore, the cladding thickness calculation section 11 includes:
The total wall thickness d from the total thickness calculation section 9 and the base material thickness e from the base material thickness calculation section 10 are input, and the cladding thickness f (t2-to-t+) of the cladding material 1 is calculated from both stars. ) is required. The setting output section 12 includes the outputs a and b from the first and second receiving amplifiers 6.7, the output c from the minute echo extraction calculation section 8, the output f from the cladding thickness calculation section 11, the total The outputs d and i from the wall thickness calculation section 9 and the outputs e and j from the base material thickness calculation section 10 are input, and the mode setting,
Settings for Ap+ constant value judgment, 1lFI constant result.

The determination results and the like are output and displayed on the display section 13 based on the sweep signal from the sweep circuit 14. In this way, the total thickness d (=eo) of the cladding material 1 and the cladding thickness f (t2-to-t+) are measured from the outer surface of the cladding material 1.

Using the rad thickness M1 constant device as described above, 7 to 1
Using a thickness reference piece of 4In (1am step),
FIG. 4 shows an example of the relationship between the reference value and the constant thickness of the base 1 for the 4-1 constant range after calibration with +s■ and 14■■.

As shown in the figure, there is a good correlation between the calculated value and the constant value of Δp.

As mentioned above, the cladding thickness Apl fixing lid device of this embodiment utilizes the existing rotating and conveying device such as an ultrasonic flaw detection device as it is to cover the entire surface (all circumferences) of the clad steel pipe, which is the cladding material 1. ), it becomes possible to simultaneously determine Al1 of the entire length and the cladding thickness from the outer surface non-destructively, accurately, efficiently, and inexpensively using one dual-element bevel probe 2.

In addition, when trying to perform ultrasonic waves and wall thickness measurement equipment for conventional steel pipes, it can be applied as is by simply changing the probe and 1lPI meter, and the entire surface (all circumference) of the clad steel pipe, 11-1 of total wall thickness and cladding thickness of full length
This makes it possible to carry out quality determination and quality assurance economically.

[Effects of the Invention] As explained above, according to the present invention, the entire surface (entire circumference) of the cladding material, the entire wall thickness of the entire length, and the cladding thickness can be simultaneously
The cladding thickness of the extremely reliable cladding material, which can be determined non-destructively, accurately, efficiently, and inexpensively from the outer surface, can be provided with an illllllllllll lid device.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the cladding thickness measuring device for cladding material according to the present invention, Fig. 2 is a diagram for explaining the automatic gain control function in the embodiment, and Fig. 3 is the same embodiment. A waveform diagram to explain the effect of
FIG. 4 is a diagram showing an example of the thickness measurement results in the same embodiment, and FIG. 5 is a diagram for explaining the principle of the wall thickness meter. 1... Clad material, 2... Dual element angle probe, 3
... Clock oscillation section, 4 ... Timing clock (
PRF) unit, 5... Transmission unit, 6... First receiving amplifier, 7... Second receiving amplifier, 8... Calculating unit for extracting minute echoes, 9... Total thickness calculation Part, 9A... Zero point adjustment part, 9B... Gate part, 9c... Counting part, 9D.
...Sound velocity calculation section, 10...Base material thickness calculation section, IOA・
...Zero point adjustment section, IOB...Gate section, 1oc...
Counting unit, 10D...Sound velocity calculation unit, 11...Clad thickness calculation unit, 12...Setting output unit, 13...Display unit, 14...Sweep circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] In an apparatus for measuring the cladding thickness of a cladding material made by cladding a base material with a cladding metal, the refraction angle of each vibrator is in the range of 35° to 70°, and the interval between each incident point is a two-oscillator angle probe with a constant value set arbitrarily, and a transmission pulse so that an ultrasonic beam is incident on the cladding material from the transmitting side transducer of the two-oscillator angle probe. a first receiving amplifier that receives a signal output from the receiving side transducer of the dual-element angle probe through the cladding material; and a first receiving amplifier that receives the transmitted pulse generated from the transmitting section. a second receiving amplifier that inputs the outputs from the first and second receiving amplifiers;
A calculation unit for extracting minute echoes extracts minute echoes on the cladding surface by performing calculations based on these, and the output from the first receiving amplifier is input, and the entire thickness of the cladding material is calculated based on the beam path to the bottom echo. a total wall thickness calculation unit that calculates the thickness; a base material thickness calculation unit that inputs the output from the minute echo extraction calculation unit and calculates the thickness of the base material from the beam path to the cladding surface echo; A cladding thickness calculation section that calculates the cladding thickness of the cladding material from the difference between the total wall thickness determined by the wall thickness calculation section and the base material thickness determined by the base material thickness calculation section. Material cladding thickness measuring device.