KR101478465B1 - Mechanized Ultrasonic Testing Method for Curved Pipe Welding Zone - Google Patents

Abstract

The present invention relates to an inspection method for replacing RT used for inspecting a welded portion of a curved pipe joint, and is a method for simultaneously detecting PAST and TOFD and detecting defects that can not be detected according to conditions (thickness and irradiation direction) Is a new concept of ultrasonic inspection of a gypsum piping weld, which enables rapid and quantitative evaluation of the evaluation of the gypsum.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultrasonic testing method for curved pipe welding,

The present invention relates to an ultrasound system capable of quickly and accurately acquiring and storing the results of the health of welds using ultrasonic waves, which is one of nondestructive inspection methods that do not destroy welds applied to high-pressure pipes such as petrochemical plant facilities, shipbuilding marine facilities, And to an inspection method.

(RT) is often used as an inspection method for inspecting the inside of a pipe welded portion. The RT penetrates through a welded portion to form a discontinuous portion (hereinafter, referred to as' defect '), Which can be visually confirmed through a film observer (illuminator with bright illumination), and the size and shape of the defect can be measured. In case of RT, there is a need for an inspection method that can replace RT in industry because of concern about radiation exposure.

On the other hand, TOFD (Time of Flight Diffraction) is an inspection method using an ultrasonic inspection method in which ultrasonic waves generated from a longitudinal wave broadband probe are diffracted at the end of an obstacle to generate a diffraction wave when an obstacle is encountered ], The upper and lower signals of the defect 100 in the weld zone are displayed, respectively, and two signals having a round like B-SCAN signal are displayed on the monitor.

Due to the characteristics of the ultrasonic wave used in the TOFD, the ultrasonic beam 6 propagates along the surface of the weld bead to generate the surface signal LW, and the bottom signal BW reflected back from the weld surface is also generated, And the type of each waveform is analyzed in combination with the A-SCAN signal, and then the type of the defect is determined.

Phased Array Ultrasonic Testing (PAUT) is a phased array ultrasonic test in which a plurality of transducers are mounted on a single PAUT probe 5-P, as shown in FIG. 10, The amplification and delay of the independent signal is controlled by the control unit of the equipment, and individual time delays are input to form a focused ultrasound beam group such that the respective ultrasonic phases generated from the multiple oscillators and the amplification are the same wavefront.

The focused ultrasound beam waveform can generate various refracting angles according to the control device setting of the equipment, and simultaneously form continuous refracting angle groups. The principle is explained in [Figure 13] and [Figure 14].

FIG. 16 is a graph comparing the RT, PAUT, and TOFD test results. The RT shows that the defect is not well detected when the thickness of the applied pipe is thick or inclined at a specific angle.

In FIG. 16, defects 1 and 2 were detected in all three tests including RT, PAUT, and TOFD. However, defects 2 were not detected in RT and detected only in PAUT and TOFD. As can be seen, RT has the disadvantage that it can not detect defects having a specific angle at a specific point.

In addition, since RT represents the transmission intensity of the radiation due to the density difference or the thickness difference of the medium as the contrast (difference in brightness) on the film, if the thickness of the test object becomes thick, small defect or plate exists on the surface of the inspection object, The defects are disadvantageous in that they can not be detected because they are not marked as defects because the density difference of light and dark is not so large on the film.

Ultrasonic inspection device and ultrasonic inspection method (Patent Application No. 10-2007-0119217)

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to solve the above problems, and it is an object of the present invention to provide an inspection method capable of replacing RT used for inspecting the inside of a curved pipe weld, It is an object of the present invention to provide a new concept of a gypsum tube welded portion ultrasonic inspection method which can quickly and quantitatively evaluate an evaluation of defects that can not be detected in accordance with the thickness and irradiation direction.

According to an aspect of the present invention,

In order to perform ultrasound inspection on the welded part of a curved pipe, a PAUT transducer and a TOFD transducer are combined with each other, and ultrasonic inspection is performed to perform two inspection methods of PAUT and TOFD at one time.

(A1) of examining the content requested by the inspection and setting the inspection plan by selecting the probe according to the thickness of the test object and the improved shape condition;

A step (A2) including an equipment calibration step (P) for calibrating ultrasonic equipment in which PAUT and TOFD are simultaneously driven, and a TOFD calibration step (T);

A step (A3) of confirming the surface preparation of the object to be inspected, and confirming the test time from the welding completion time to the time when the inspection is requested;

Setting the inspection direction and the inspection zone (A4);

(A5) installing a Scanner capable of traveling along the circumferential surface of the pipe parallel to the longitudinal direction of the welded portion at a predetermined position;

Attaching the PAUT probe and the TOFD probe to the Scanner and aligning the center line of the pipe weld with a constant distance (A6);

(A7) further correcting the TOFD sound velocity and the wedge delay of the actual test body in order to correct the sound velocity and the wedge delay and the sensitivity in the pipe of the seal member in the case of the TOFD to improve the accuracy;

(A8) delivering the ultrasonic wave to the test body and supplying the contact medium to obtain a uniform signal;

A step (A9) of inspecting a welded portion of the pipe by a combination of a scanner and a probe to obtain data;

Storing the obtained data in the ultrasonic apparatus (A10);

The obtained data is analyzed by TOFD signal and PAUT signal using a dedicated analysis program. The position, size, and type of defects found and defects are identified, and defects at the same position are grouped from the starting point Combining and analyzing the defect (A11);

Determining acceptance and rejection according to the types of defects analyzed and determining whether or not to re-weld the welds (A12);

(A13) issuing a modified welding instruction sheet in which information of defects is recorded when the re-inspection is determined;

Creating a report (A14);

And an ultrasonic inspection method of a gypsum pipe welded portion.

In the present invention,

The equipment calibration step (P)

Set-up procedure for simultaneously executing TOFD and PTUT inspection,

(P1) of forming a channel group for inputting and driving information of a PAUT probe and a TOFD probe to an ultrasonic apparatus capable of simultaneously driving PAUT and TOFD techniques;

(Ultrasonic Beam Configuration, Focusing Linear or Sectorial), selecting the ultrasound type (longitudinal wave or transverse wave), assigning the number of transducers required for the applied transducer as a group, (P2) comprising: setting a probe aperture to be automatically set, and inputting an applied refraction angle and a focus depth;

(P3) calibrating ultrasonic sound velocity using a calibration test piece or a contrast test piece;

(P4) of calibrating the progress distance in the wedge to recognize each transducer (VPA) of the PAUT probe to the same depth for the reflector;

(P5) of calibrating all VPAs to be the same sensitivity for one reflector in the inspector;

(P6) making TCG and DAC corrections to compensate for attenuation of the material, making the gain difference of each VPA for the same reflector;

(P7) of calibrating the encoder to store information on inspection length and defect location at the inspection in the equipment;

Verifying sweep range, VPA sensitivity and TCG (or DAC) with appropriate reference or calibration blocks and verifying the entire inspection system (P8);

A step of re-calibrating the system when a re-calibration reason occurs (P9);

A step (P10) of re-examining the transducer's vibrator after one week of the calibration time and judging whether or not to re-check if an abnormality occurs in the inspection sensitivity;

(P11) confirming all the VPAs of the probe when the probe is re-checked;

A step (P12) of replacing the transducer when the adjacent transducer of all the elements of the transducer is not operated by more than 10% and calibrating again from the step P3;

Storing the calibrated data in a memory of the equipment (P13);

And a control unit.

In the present invention,

The TOFD calibration step (T)

Depending on the thickness of the specimen, the test range is set before the test and the calibration preparation is started.

A step (T1) of selecting and preparing the ultrasonic probe and the wedge selected in step A1;

Determining a refraction angle and a type of inspection (T2);

A step (T3) of calibrating a depth measurement range including the entire thickness of the test piece;

A step (T4) of setting the distance of the probe to the PCS distance so that the surface and the bottom signal according to the sound velocity of the test body can be sufficiently confirmed;

Correcting the TOFD sound velocity and wedge delay of the real test body (T5);

A step (T6) of setting the sensitivity before inspection in the actual test body;

(T7) of confirming and re-grading the set-up at a predetermined error range before inspection or every 4 hours in the test piece versus before inspection;

A step (T8) of correcting again from the step T3 when the cause of recalibration occurs;

A step (T9) of storing the calibration data in the equipment or external memory when the calibration is completed;

And a control unit.

According to another aspect of the present invention,

In inspecting the welded part of the curved pipe, in order to place the PAUT probe only on the straight pipe side and to inspect all the welds in one direction, the inspection is performed by at least one group of linear scan in the group of 64 transducers, Wherein the inspection is performed by scanning linearly in parallel to the welded part by linear scan and sectorial scan inspection, and also performing ultrasonic inspection of the curved pipe welded part.

In the nondestructive inspection of curved pipe welds, the reliability of inspection is ensured by providing inspection results quantitatively more accurate than RT, without causing an inspection time delay due to RT and a risk of safety accidents due to radiation, And the probability of occurrence of a safety accident is reduced. Hereinafter, the effects of the present invention will be described in more detail.

1. Elimination of safety accident caused by radiation exposure

2. Shortening inspection time

(1) Inspection time is shorter than RT

For example, if a double-walled cross-section is taken using a 45-cm diameter iridium isotope with a 25-mm 300A pipe, the thickness of the specimen will be 50 mm because the radiation will pass through the specimen and form an image on the film. Because of this, the inspection time takes about 140 minutes. However, if it is inspected according to the present invention, it takes about 10 minutes, so the inspection time is shortened to 1/14 (the type of film, distance, etc. are the usual times not mentioned).

(2) Inspection time is shorter than conventional ultrasonic inspection

In the conventional ultrasonic inspection, the number of scans should be at least 8 times. However, according to the present invention, the inspection can be completed only by one scanning.

(3) Inspection time and analysis time are shorter than when PAUT and TOFD are separately performed.

In the conventional inspection method, at least two times of PAUT application and one time of TOFD application are required. However, according to the present invention, two types of inspection can be completed by only one scanning.

3. Quantitative evaluation of defects

According to the present invention, only the length of the defect and the kind of the defect are known in the case of RT. However, according to the present invention, the depth of the defect, the width of the defect and the direction of the defect can be known, It is easy.

4. Visibility of defect readings and reproducibility of evaluation results

The present invention is excellent in the reproducibility of the evaluation result since the inspection data is all stored, and the analysis program displays the data in a form that can be easily confirmed by analyzing the data by various techniques.

5. Other effects

(1) Decrease of uncertainty of defect detection as the thickness of specimen increases

Although RT does not show small defects if the thickness of the specimen is thick, it is not influenced by the thickness because it corrects the amplification depending on the thickness according to the present invention.

(2) Reduction of the influence on the directionality of defects

RT does not appear on the film when the defects are inclined in a specific direction, but since the ultrasonic beams of various angles are used for the directionality of the expected defects in the present invention, the influence on the directionality is small.

(3) Conventional ultrasonic inspection improves the problem of not detecting defects due to space limitation

Conventional ultrasonic inspection requires a scanning distance of up to 1 Skip distance, but according to the present invention it is possible to inspect it with a 0.5 Skip distance.

(4) Ability to evaluate defects better than conventional ultrasonic inspection

Existing ultrasonic inspection is only evaluated with A-Scan. However, the present invention can be applied to various types of signal analysis techniques (A-Scan, B-Scan, C-Scan, D-Scan, .

Fig. 1 is a diagram showing the arrangement of probes in a curved pipe inspection.
Fig. 2 is a view showing the outer shape of the curved pipe and the cross section of the welded portion.
3 is a cross-sectional view of a butt double-sided improvement welded portion (BUTT-SV).
4 is a view showing a weld heat affected zone and an improvement surface.
Fig. 5 is a diagram showing the state of occurrence of the separation of the probe contact portion according to the curvature of the curved pipe.
6 is a view showing a TOFD probe arrangement and an ultrasonic beam transmission method.
7 is a view showing the shape of a TOFD probe.
8 is a view showing an ultrasonic beam transmission method of a TOFD probe.
9 is a conceptual diagram showing the principle of inspection of TOFD.
10 is a view showing the shape of a PAUT probe.
11 shows the shape of the wedge of the PAUT probe.
Fig. 12 shows the arrangement of the PAUT probe in the piping weld.
13 is a diagram showing the principle of PAUT linear scan.
14 is a diagram showing the principle of PAUT sectorial scan.
15 is a view showing an ultrasonic beam transmission method of the PAUT inspection.
FIG. 16 is a view comparing RT, PAUT, and TOFD test results. FIG.
FIG. 17 shows the analysis result of defect # 1 in FIG.
FIG. 18 shows the analysis result of defect # 2 in FIG.
FIG. 19 shows the analysis result of defect # 3 in FIG.
20 is a flow chart showing a procedure for inspecting a curved pipe.
Figure 21 is a flow chart illustrating equipment calibration steps including PAUT and TOFD.
Figure 22 is a flow chart illustrating equipment calibration of the TOFD.
23 is a table for explaining the criteria of the TOFD set-up according to the thickness in the butt joint part.
Fig. 24 is an example of installation of a scanner and ultrasonic probe and components equipped with components for inspection of a curved pipe.
25 is a kind of a Scanner applicable to a curved pipe inspection.
26 is a view showing the arrangement of the Scanner and the ultrasonic probe in the curved pipe.
27 is a table showing the arrangement of probes according to the inspection level.
28 is a view showing a representative A-scan of the conventional ultrasonic inspection technique.
29 is a view showing the shape of the contrast test piece.

<Definitions of Related Terms>

Prior to describing the present invention, first, a related term is defined as follows.

1. TOFD Set-Up: This is the act of calibrating the arrangement of the transducers and the arrangement of the center line of the transducers (frequency, oscillator size, refraction angle, waveform etc.) according to the characteristics of the longitudinal broadband transducers.

2. PCS (Probe Center Specification): As shown in Fig. 9, the distance between the TOFD probe transmitter (5-TX) and the TOFD probe receiver (5-RX) )to be.

3. Beam Intersection Point: In the case of TOFD flaw detection in [FIG. 9], the point at which the ultrasonic beam 6 crosses.

4. Indicator: A signal or image in TOFD that is subject to evaluation.

5. TOFD image: It is the indicator with X-Y axis. The signal obtained from A-scan is converted to B-scan. The signal amplification expressed by A-scan is represented by the intensity of grayscale compared to signal amplification in B-scan (TOFD image).

6. Offset-Scan: The broadband probe is separated from the weld center line by a TOFD set-up at a certain distance. For optimum inspection, It is a test.

7. Denominator: Denominator wave or compression wave, which is a wave whose direction of vibration is parallel to the direction of wave propagation.

8. Transverse wave: Also referred to as shear wave, a wave whose direction of vibration is perpendicular to the direction of wave propagation.

9. Pitch: PAUT is the distance between the center of the oscillator and the center, in which a large number of oscillators are arranged in the probe.

10. Encoder: A device that assists in recording data, and is a device that records the position and length of a reading so that it appears quantitatively.

11. Focal Laws: One ultrasonic beam group can be formed in a range of 2 to 32 of a plurality of oscillators in a PAUT probe, and a plurality of groups of ultrasonic beam groups can be formed by combining a plurality of oscillators . Each oscillator oscillates independently, and each oscillation time can be controlled by a computer. At this time, the ultrasound beam can be focused on the region of interest due to the delay of each oscillation time, and the refraction angle can also be adjusted.

12. Linear Scan: A group of ultrasonic beam groups generated from focal laws form a single refraction angle.

13. Sectorial Scan: A group of ultrasonic beams generated from Focal Laws forms a refraction angle range and is scanned. For example, 32 transducers are formed into one beam group, and each of the oscillation times can be varied to detect a refraction angle of 40 degrees to 70 degrees at a time.

14. VPA (Virtual Probe Aperture): A group of ultrasound beams generated from Focal Laws. If 16 transducers form one VPA in 64 transducers, a total of 49 VPAs are generated.

15. Echo height dividing line (DAC): The attenuation compensation line according to the distance of the ultrasonic wave, even if the same defect is located at different depth, it is recognized as the same size.

16. TCG (Time-corrected gain): This is the function to set the same amplitude for the same defect regardless of the distance. This function can increase the accuracy of judgment by obtaining the same amplitude with respect to the change of the time axis in reading.

17. Incident point: It is the point where the ultrasonic beam enters the boundary of the object from the probe.

&Lt; Overview of the present invention &

The present invention is an inspection method in which RT is substituted, and PAUT and TOFD are used at the same time, and the lengths and disadvantages of the respective inspection methods are complemented to each other so that the detection is performed in accordance with the conditions (thickness and irradiation direction) And to evaluate quickly and quantitatively the evaluation of defective defects.

However, in order to replace RT, it is necessary to solve the following problems such as PAUT and TOFD including the conventional ultrasonic inspection.

1. Problems of Conventional Ultrasonic Testing

(1) Conventional ultrasonic inspection has the problem of inspecting the same weld several times in various directions while changing the ultrasonic probe angle by angle.

(2) Conventional ultrasonic inspection is a method in which an ultrasonic probe must be moved in front, back, left, and right to scan.

(3) In the conventional ultrasonic inspection, if defects are generated on the improvement surface of the weld as in [Fig. 4], the defects become directional and both sides must be inspected in order to detect them.

(4) The biggest problem of the conventional ultrasonography is that the test results are not stored and there is no reproducibility of the results.

2. Problems with PAUT

(1) As shown in FIG. 10, PAUT has a large size of the PAUT transducer (5-P) because several PAUT ultrasonic transducers (5-5) are arranged.

(2) Due to the large size of the PAUT probe (5-P), the contact part is separated due to the shape of the curved pipe as shown in Fig.

(3) As shown in Fig. 1, PAUT should be inspected only on the straight pipe side.

3. Problems of TOFD

(1) In case of TOFD, it is difficult to know precisely the horizontal position of the weld defect (only the left and right positions from the center line of the weld) with only one test.

(2) TOFD does not determine whether the defects are summed or not by amplification of ultrasonic signals. In the case of the present invention, the defect is evaluated according to the signal amplification of the defect, and the size of the defect is classified according to the signal amplification which is comparatively evaluated using the standard test piece and the contrast test piece required for the adjacency judgment, .

(3) After confirming the presence of defects using TOFD and checking the defect length, defect depth and type of defects in the welds, re-inspecting the defects only by the existing ultrasonic inspection, It is troublesome to decide whether or not to make correction.

In order to solve the above problems, the present invention solves all the defects with the TOFD inspection method having excellent defect detection capability and amplifies the horizontal position on the welding center line and the ultrasonic signal at one time by inspecting the same inspection region with the PAUT inspection method The test method is presented.

The TOFD and PAUT inspection methods are not separately performed but the ultrasonic transducers are disposed as shown in FIG. 1, and the TOFD and PAUT inspection methods are simultaneously performed. Thus, the inspection is completed by only one scanning operation The system has been configured so that a single integrated inspection method has been implemented by systematizing a series of equipment configuration steps for inspection, equipment set-up step, inspection preparation step, inspection execution step, and result analysis step.

On the other hand, the pipelines to be inspected have many types such as a curved pipe (Elbow), a T-type piping (Tee), and a small diameter piping (Reducer) in addition to a straight line connecting welded part Pipe joint welding occurs. The present invention focuses on the inspection of the gypsum welds.

However, it is difficult to install an ultrasonic probe in the curved pipe welding part to which the inspection method according to the present invention is applied, as shown in FIG. 5 because of the nature of the piping shape. 5 is a view showing a state in which, when an ultrasonic probe, that is, a PAUT probe 5-P to be used in the present invention is disposed on the surface of a curved pipe in a curved pipe welding portion, a void space is generated between the probe and the surface of the pipe, Fig.

In order to solve this problem, the present invention is characterized in that the PAUT probe 5-P is arranged in the straight pipe 2 and tested in one direction and the TOFD probe is connected to the TOFD probe transmitter 5-TX And the TOFD probe receiver 5-RX is disposed in the curved pipe 3 to facilitate detection of defects having a specific angle existing in both directions.

That is, in the present invention, in order to arrange the PAUT probe 5-P only on the straight pipe 2 side and inspect all the welded parts in one direction, the inspection is performed by forming at least one group of linear Linear scan is performed. Linear scan and Sectorial scan test are performed by scanning linearly in parallel with the welded part.

DETAILED DESCRIPTION OF THE INVENTION [

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

The ultrasonic inspection method of the curved pipe welding part according to the present invention can be combined with the Scanner moving parallel to the longitudinal direction of the weld along the outer circumferential surface of the pipe to mount the probe of PAUT and TOFD and simultaneously perform the respective two methods As a method, the main steps of the curved pipe inspection procedure consist of the inspection plan setting step (A1), the calibration step (A2), the inspection progressing steps (A3 to A10), and the analysis steps (A11 to A14). Each step will be described below.

A. Song tube inspection procedure

A1. Set up inspection plans

(1) The test plan shall prove in advance that a test angle appropriate to the weld improvement angle (eg 40 to 60 or 55 to 70) shall be used and each profile shall be used for the selected Wedge.

(2) The inspection plan shall completely include welds and heat affected areas.

(3) The setting of inspection resolution of equipment is applied as follows.

T = thickness of the test specimen

When T = 10 mm, input value 1 mm

When 10 mm <T = 150 mm, input value 2 mm

When 150mm <T, input value 3mm

However, if the resolution of the equipment is set to a high value and the inspection data is not interfered, the resolution is set to the lowest input value.

The input value above is the unit of mm in which the data is stored.

The lower the number, the higher the resolution.

1mm is stored in 1mm unit when scanning and 3mm is stored in 3mm unit. Therefore, as the storage unit is lower, the minimum size of defects that can be separated during data analysis becomes lower and more accurate inspection is performed.

However, if the resolution is too high, the data will be lost in the middle because the data processing speed of the device is limited.

(4) In the case of Sectorial Scan, PAUT uses a wide range of angles, but since it is not scanned back and forth, it can not detect the maximum amplified signal for the defect and it is difficult to quantitatively evaluate the defect.

In the case of linear scanning, since the back-and-forth scanning is performed, defects can be quantitatively evaluated using the maximum amplification signal of defects.

In the present invention, linear defects are evaluated based on linear scanning using both linear scanning and sectorial scanning.

A2. Equipment calibration

(P), and TOFD calibration step (T), which calibrate ultrasonic equipment that simultaneously drives PAUT and TOFD. The equipment calibration step (P) and the TOFD calibration step (T) are described in detail below.

A3. Confirm Inspection Target

Check the target of the inspection to determine whether the following are observed, to prepare for the failure or to cancel the inspection.

(1) Surface preparation confirmation

The surface of the weld shall be free of thick scratches which may interfere with the test.

The scanning surface should be wide enough to cover all of the inspection volume (200 mm on both base materials). The scanning surface should be free of foreign objects (eg rust, accumulation scale, weld spatter, notch, grooves) on the surface in contact with the probe.

(2) Checking the test time

After welding is completed, it should be cooled down to ambient temperature.

Steel with a minimum yield strength of 4200 N / mm ² or more can not be inspected 48 hours before welding.

A4. Inspection direction and inspection zone setting

(1) The inspection is carried out by linearly scanning the probe with 64 transducers parallel to the weld with linear scan and sectorial scan.

(2) At least one group of linear scans shall be performed and shall include all welds and heat affected zones.

(3) Scanning should be done parallel to the welding field.

(4) Inspection is carried out on the straight pipe side on one side of the welded part in case of curved pipe, and on both sides (straight pipe part and curved pipe part) on one side of the welded part in case of TOFD. If a limited inspection is performed, the scope of the inspection shall be recorded.

A5. Installing the Scanner

The Scanner used in the present invention is a device that travels along the circumferential surface of a pipe and moves the ultrasonic probe in parallel to the longitudinal direction of the welded portion, and can be precisely scanned so that an error in position on the center line of the welded portion does not occur. As shown in [Figure 26], a plurality of ultrasonic transducers should be mounted so that the position can be adjusted and the structure can be precisely operated.

The Scanner 10 shown in FIG. 26 is attached to the outer circumferential surface of the straight pipe 2 and rotates along the longitudinal direction of the pipe weld. At this time, the left and right position errors should be within 1 mm with respect to the center of the weld. This is because the minimum unit of data signal acquisition allowed in the present invention is 1 mm. If there is a lot of errors, it is difficult to distinguish defects occurring on the back side of welds during data analysis, and the position error of defects also increases.

The probe holder (11) coupled to the body of the scanner (10) should be able to fix a plurality of ultrasonic probes and be capable of changing positions. In the present invention, the PAUT probe 5-p, the TOFD probe transmitter 5-TX, and the TOFD probe receiver 5-RX are mounted, respectively. 24 and 25 are types of Scanners usable in the present invention.

A6. Sensor placement

(1) A PAUT probe (5-P) and a TOFD probe (5-T) should be mounted on the Scanner (10).

(2) Welded parts and heat affected parts shall be inspected simultaneously with TOFD and PAUT method.

(3) Scanning curve for PAUT (3) is to be applied to the welded part by E-scan (Linear Scan) and S-scan (Sectorial Scans) (See the table of FIG. 27). PAUT follows the equipment calibration step (P) described below. However, in the case of general straight welded joints in piping welds, only PAUT is applied and inspection is carried out on both sides.

(4) The sensitivity and calibration of the instrument should be performed independently of the PAUT and TOFD methods.

A7. TOFD Sensitivity correction with sonic speed and wedge delay

In the case of TOFD, the set-up is stored after the T5 step of the TOFD calibration step (T) to be described later is further performed in order to correct the sound velocity and the wedge delay and sensitivity in the pipe of the seal member. Here, step T5 of the TOFD calibration step (T) is the TOFD sound velocity and wedge delay correction step of correcting the TOFD sound velocity and the wedge delay of the actual test body.

A8. Contact medium supply

The contact medium is supplied for inspection. It is recommended that the contact media be automatically supplied to the specimen so that it can be evenly applied to the surface of the ultrasonic probe. Depending on the application state of the contact medium, the shape of the surface signal may change, causing severe bending on the B-scan, making data analysis difficult. The contact medium is connected to the branch pipe so as to be uniformly supplied to the respective probes by the contact medium supply line 15, as shown in Fig. The automatic supply of contact media and the contact media supply line 15 are not separately described as being easily configurable by anyone skilled in the art. In case of supplying the contact medium, the supply pressure should be adjusted so as not to be too weak or too strong. If the supply pressure is too low, the supply of the contact medium is not performed well, so that the air layer is not formed and the ultrasonic wave is not transmitted. If the supply pressure is too high, bubbles are entered and an abnormal signal is generated in the ultrasonic signal due to the flow impact of the contact medium.

A9. Welding inspection

It is a step to calibrate according to the above step procedure to the welding part inspection step, to start the inspection after preparing the apparatus.

(1) Inspection method

1) The probe shall be scanned parallel to the center of the weld line at the set interval.

2) All information of the indicator should be stored during the inspection, and the existing ultrasonic inspection may be applied to obtain additional information of the indicator or it may be manually scanned.

3) If a split test is performed, an overlap of 100mm should be performed. Also, if you inspect the columnar test one time, make sure the start and end points are sufficiently duplicated.

4) When the contact medium is insufficient, the surface signal and the bottom signal may be reduced. For this purpose, the contact medium pump supplied automatically is used first.

5) Reduce the gain (amplification) within the proper range when the excessive surface signal or noise increases (noise level exceeds 20% of screen height) during inspection.

(2) Scanning speed

1) Scanning should be a speed that can acquire data continuously.

2) The loss of data is allowed up to 5% of the total data. However, it is not allowed if it is lost adjacent.

A10. Data storage

In the data storage step, starting from the start point of the test, the end point of the test is superimposed and examined, then the scanner is stopped and the identification symbol of the test object is inputted and the data is stored in the equipment.

A11. Data Analysis

And analyzing the data on the computer in which the analysis program is installed, using the file storing the inspection results, to identify the presence or absence of defects and the position, dimensions, and types of defects. In the present invention, since PAUT and TOFD are simultaneously performed, it is necessary to analyze each data. The data analysis step A11 is divided into the analysis and analysis step A11-1 of the TOFD image and the analysis step A11-2 of the PAUT.

A11-1. Analysis and analysis of TOFD images

(1) General information

The TOFD signal analysis follows:

1) Evaluate the quality of the TOFD image before signal analysis.

2) Identify and check the related indicator and non-relevant indicator.

3) Classify related indicators.

- Internal reading (linear, point reading)

- Surface touch indicator (surface notch, break, etc.)

4) Determine the position (X and Y position) and size (length and width) of the indicator.

5) Evaluate the indicator value based on acceptance criteria.

(2) Evaluation of quality of TOFD image

Evaluate the quality of the TOFD image first to be able to analyze the indicator. Image quality analysis is performed by the examiner first and checked by the article or NDT Level III. If the quality of the image is bad as shown below, retest.

1) The loss of data is allowed up to 5% of the total data.

2) If the entire signal is moved up and down severely, the depth error is severe.

(3) Distinction of related indicator

1) Once a satisfactory TOFD image is acquired, determine the shape of the indicator.

2) Confirm the form of indicator.

3) In the form of indicator, classify it as related indicator (discontinuous indicator) and non-indicator.

4) Determine the range of the relevant reading (in the TOFD image, it appears as a gray level difference between the gun and the indicator).

5) The point-like point is 10 points per 150mm in length.

4) Related indicator classification

Relevant readings are categorized as surface bursts and internal readings and analyzed as follows.

1) degree of surface wave interference

2) Disturbance level of bottom signal

3) the indication between the surface and the bottom signal

4) Mode conversion signal after the first bottom signal

The defect image of a typical TOFD welding defect is not disclosed because it is known to a person skilled in the art.

(5) Surface disruption discontinuity indicator

Surface discontinuities are classified into the following three types.

1) Test surface discontinuity

2) opposite surface discontinuity

3) Thickness discontinuity

(6) Internal discontinuity indicator

The internal discontinuity indicator is classified into the following three categories.

1) Point-like discontinuity

2) Long, discontinuous discontinuous

3) Long discontinuity to measure height

(7) Unclassified indicator

The indicator values not classified according to (5) and (6) above shall be inspected and analyzed by an additional inspection method.

A11-2. Analysis of PAUT

As an evaluation stage of discontinuity, the method of evaluation of discontinuity follows the rules of each order. If the ordering rule uses the 6 dB drop method, the size of the defect must be measured on a C-scan and the amplification of the signal is color-coded as follows. At this time, in case of signal of 100% or more of TCG line, the defect size is the distance between the center of yellow color on the left and right sides, and in case of 100% ~ 50% signal of TCG line, the defect size is the center of blue color Lt; / RTI &gt;

1) 100% or more of TCG line: red

2) 100% to 50% of the TCG line: Yellow

3) Less than 50% of TCG ships: Blue

A12. Defect check

According to the result of the analysis, if a defect occurs, it is a step of determining whether it is an unacceptable defect or an acceptance defect according to the respective construction-specific regulations. In case of defects that fall outside the allowable range in accordance with the construction regulations, please refer to the A13 step to be described later and send a retest after the completion of the modified welding. Acceptance criteria shall be in accordance with each construction specification.

A13. Corrective welding instructions

This is a modified welding instruction step in which the position and type of defects are recorded and notified so that the welding portion of the test body can be re-checked if the dimension of the defect is out of the allowable range. The modified welds shall be inspected and evaluated in the same manner. The correction inspection is carried out by adding 100 mm at both ends including the correction part.

A14. Create reports

It is the step of preparing the report according to the inspection result. The following information should be recorded in the report and may be changed in accordance with the requirements of the order. After re-inspection after re-inspection according to corrective welding instructions, after completion of inspection, final report is completed.

(1) Subject information

1) Specification number, specimen thickness

2) Material of test body, shape of welded part

3) Test position, welding method, heat treatment

(2) Inspection equipment information

1) Manufacturer, type, equipment identification number

2) Flaw detection method

3) Transducer (type, frequency, bandwidth, size of transducer, refraction angle)

4) Contrast specimen identification number, used contact medium

(3) Test procedure information

1) Test procedure, scope and sensitivity

2) TOFD Set-Up, PAUT Set-Up, Scan Offset,

3) Transducer (type, frequency, bandwidth, size of transducer, refraction angle)

4) Contrast specimen identification number, used contact medium

(4) Test result information

1) TOFD and PAUT images, combined judgment

2) Test data classification table

3) Location and size of related indicators and evaluation results

4) Exam date, inspector and qualifications

P. Equipment calibration

Set-up procedures for TOFD and PAUT checks are described. Select the ultrasonic transducer and wedge selected in step A1 of the inspection planning. Between the ultrasonic probe and the wedge, a contact medium is injected to remove the air layer and tightly bond. In the present invention, two methods, PAUT and TOFD, must be calibrated to simultaneously perform PAUT and TOFD. This step consists of an information input step for each transducer, a measurement range setting step, and a sensitivity calibration step.

P1. Adding and setting ultrasonic groups

On a PC-based PAUT device, use the Wizard to set up one or up to eight ultrasonic groups.

(1) Set the first group using the group menu.

(2) Set / enter the shape, material and thickness of the product to be inspected.

(3) Set the mode to PA and then apply the transducer and wrench.

(4) When setting additional groups, re-enter items (2) to (3) to set the required number of groups.

P2. Set the refraction angle, type of flaw and focal law

After setting ultrasound group, input information about each group as below.

(1) Configure the ultrasound beam configuration, convergence linear scan or sectorial.

(2) Select ultrasonic type (longitudinal wave or transverse wave).

(3) Applying the number of oscillators (total of 64) needed for the probe is set as a group, and if the first oscillator is set, the virtual probe aperture (VPA) is automatically set.

(4) Enter the applicable refraction angle and focus depth.

P3. Ultrasonic sonic correction

Calibrate the sound velocity according to the applied ultrasonic waveform using a calibration test piece or a contrast test piece. The contrast test specimens of each construction in the field of the present invention are not explained individually because the specifications for each construction are all different. However, the contrast test specimen has the same shape and curved surface as the specimen, and it is manufactured by referring to the position size, shape, etc. of the artificial defects per work, and the pipe is sliced so as to be easily moved. As shown in [Figure 29], the piping is cut and the artificial defects are activated to prepare a contrast test piece.

(1) Select "Calibration Mode" from the "Wizard Wizard" menu, and then select Velocity.

(2) Select the radius and choose the depth or thickness according to the type of transducer and the calibration block used.

(3) Enter the size of the first and second radii (depth or thickness) to be measured.

(4) Use A-Scan to adjust the time base and gain value.

(5) Place the probe perpendicular to the ultrasound beam in the artificial hole, and select the reference VPA from the D-scan shown on the screen.

(6) Set the gate of the first maximum echo and get the position.

(7) Set the second echo under the same condition and select the "Apply" menu.

(8) After completing sonic speed correction, calibrate other groups in the same way.

P4. Wedge delay calibration

The distance traveled in the wax is calibrated so that each VPA of different ultrasonic propagation distances within the wax is recognized at the same depth for one reflector in the inspector.

(1) Select "Calibration Mode" from the "Wizard Wizard" menu, and then select Wedge.

(2) Select the radius and choose the depth or thickness according to the type of transducer and the calibration block used.

(3) Enter the distance of the reflector (radial depth or thickness) to be measured.

(4) Use A-Scan to adjust the time base and gain value.

(5) Set the gate range (start and width) and the threshold value to check the depth of the reflector.

(6) Scan all the VPAs in the back and forth direction in response to the reflector.

(7) Select "Calibrate Calibration" menu.

(8) Repeat (6) and (7) until the received signal is within tolerance.

P5. VPA sensitivity calibration

All VPAs are calibrated to the same sensitivity for one reflector in the inspector.

(1) Select the calibration mode from the "Wizard Wizard" menu, and then select Sensitivity.

(2) Select the radius and choose the depth or thickness according to the probe type and the calibration block used.

(3) Use A-Scan to adjust the time base and gain value.

(4) Set the gate range (start and width) and the threshold value to check the depth of the reflector.

(5) Scan all VPAs in the forward and backward directions in response to the reflector.

(6) Select "Calibrate Calibration" menu.

(7) Repeat (5) and (6) until the received signal is within tolerance.

P6. TCG and DAC Calibration

In PAUT, TCG calibration has two purposes, the first of which is to make the difference in the gain of each modified VPA in the same reflector, and the second is to compensate for attenuation of the material. It can be changed from DAC to TCG.

P6-1. TCG calibration

(1) Select "Calibration Mode" from the "Wizard Wizard" menu, and then select TCG.

(2) Adjust the signal in the first object hole below 80% of the full screen height (FSH).

(3) Set the gate range (start and width) and the threshold value to check the depth of the reflector.

(4) Check the direction of all VPAs in response to the reflector and select "Add Point".

(5) Do not adjust the gain value, and repeat the procedure from (3) to (5) by selecting the next point to add another TCG point.

(6) When the TCG curve is completed, select "Accept TCG".

P6-2. DAC calibration

(1) Select "Gate / Alarm" in the "Main" menu and select "Sizing Curve".

(2) Select "DAC" from the "Curve" button and move to "Edit" from the "Mode" button.

(3) Select representative VPA.

(4) Adjust the signal in the first object hole by 80% of full screen height (FSH).

(5) Display the point of (4) and repeat the item (4) and (5) for another DAC point to select the next point.

(6) When the DAC curve is completed, select "TCG" from the "Curve" button.

P7. Encoder calibration

(1) Encoder use is essential for full memory of ultrasonic inspection, and it reflects information about inspection length and defect location.

(2) Select "Calibration mode" from the "Wizard Wizard" menu, and then select "Encoder" from the "Type" menu.

(3) Keep the encoder in the starting position.

(4) Enter "0" in "Origin" and move to the next step.

(5) Enter the number to correct the distance in the "Distance" menu.

(6) Move the start encoder to the end position.

(7) Select "Accept Calibrate" button and select "Accept Accept" button.

P8. System calibration verification

The system calibration verification shall include the entire inspection system. Sweep Scope, VPA Sensitivity and TCG (or DAC) should be verified to the appropriate reference or calibration block.

P9. Reason for recalibration

(1) When replaced by another cable or chain of the same type.

(2) Replace the rechargeable battery.

(3) At least every 4 hours for continuous inspection.

(4) Before and after the start of the test.

(5) When the sensitivity at the time of inspection is judged to be abnormal.

If a problem arises that results in a test result, the system must be recalibrated.

P10. Reason for confirmation of transducer's transducer

Each transducer of the transducer should be inspected once a week according to the procedure of P11. In addition, if it is judged that there is abnormality in the sensitivity of the test, it shall be carried out immediately.

P11. Identifying the transducer's transducer

(1) The probe must be in direct contact without using a wedge.

(2) Each oscillator must be individually responsive to VPA.

(3) Identify all VPAs operating through the pulse echo method.

(4) Elements that are less than 5% after adjusting the total to 80% are considered to be inoperative.

P12. Replacement of the probe

If at least 10% of the total elements are not working, the probe must be replaced. If replacing the transducer with another, proceed with step P3 with the replaced transducer.

P13. Data storage

Store data in memory. Complete calibration and prepare for inspection.

T. TOFD calibration

Describe the TOFD calibration curve. Since the TOFD is set in the seal member instead of the test sensitivity and sound speed and the wedge delay in the seal member, it is necessary to set the group including the probe group in the PAUT calibration in the equipment calibration, and store the group. Calibration to improve accuracy.

The setting of the test range shall be carried out before the test depending on the thickness of the specimen.

(1) Set the range of the offset scan according to the thickness of the test specimen.

(2) Range including heat affected zone: Follow the specifications at least 10mm from both sides of the weld edge.

(3) Determine the above two items and perform Set-Up.

(4) Including heat affected zone setting: At least 10mm from both sides of weld edge or follow specification.

T1. Set-Up of Probes

(1) Prepare ultrasonic transducers and wedges selected in the inspection plan setting stage of A1.

(2) A contact medium is injected between the ultrasonic probe and the wedge to remove the air layer and bond it firmly.

(3) Optimum setting is selected and set in Table 2 of FIG. 23 so that a defect can be detected by the diffraction wave in the defect area.

(4) Two or more set-ups can be applied depending on the thickness of the test specimen. Verification of the set-up shall be confirmed by the test specimen.

(5) The transducer shall be set up to ensure proper range and optimum conditions for the start and detection of the diffraction signal of the region of interest.

(6) One or more Set-Ups (scans) shall be performed depending on the verified function using the specimen thickness and contrast specimen. Table 2 in [Figure 23] can be used as a guide, but the method of contrast test specimens should be performed first.

T2. Determination of refraction angle and type of inspection

The refraction angle and the type of inspection are shown in Table 2 in [Fig. 23].

T3. Calibration of depth measurement range

The depth measurement range shall be at least the range including the total thickness.

(1) When a set-up is performed once, the depth measurement range shall be at least 1 ㎲ for the generation and arrival time of the surface wave, and shall be wide enough so that the surface wave and the bottom signal can be distinguished.

(2) If more than one set-up is required, the depth measurement range shall be overlapped by at least 10% between each set-up file.

(3) The measurement range before the test shall be confirmed.

T4. Depth conversion with sonic time (PCS setting)

(1) The distance of the probe is separated by the PCS distance as shown in Fig. 9 so that the surface and bottom signals according to the sonic velocity of the object can be sufficiently confirmed.

(2) This setting should be checked with similar contrast specimen thickness.

(3) The thickness of the test specimen shall be measured in actual condition. If it can not be confirmed, follow the diagram. Firstly, the thickness is measured in 0.2 mm increments in the A-Scan mode of ultrasonic equipment.

(4) Curvature The specimen shall be measured accurately.

T5. TOFD sound velocity and wedge delay correction

The sound velocity and wedge delay of the TOFD shall be calibrated at the actual member of the site (the object to be inspected), and the thickness requested and the thickness of the actual part shall be checked. For thickness applications, the actual member thickness is to be applied. In the conventional TOFD procedure, all the calibration is performed on the contrast test piece, and only the transition is further compensated in the seal member. However, as a result of testing various methods, it has been found that the error correction method of the present invention reduces the error as much as possible. The verification range of the test specimen is only verified, and the sound speed and wedge delay can be corrected in the seal member to reduce the error as much as possible. The calibration method for the equipment differs from equipment to equipment, so it follows the equipment manual and is not described separately.

T6. Sensitivity setting

According to the present invention, the sensitivity must be set before inspection, and if there is a change in TOFD Set-Up during the inspection, the sensitivity should be set again. The TOFD sensitivity is set in the seal member and follows one of the following.

(1) The surface wave is set within 40% to 80% of the entire screen height.

(2) If the surface wave is inadequate, the sensitivity setting will increase the gain from 18dB to 30dB with the bottom signal at 100% of full screen height.

(3) If the surface or bottom signal is not appropriate, the sensitivity is set so that the noise is between 5% and 10% of the full screen height.

According to the present invention, since the echo amplification of the entire echo is varied according to the surface condition, the TOFD shows that the intensity of the surface signal needs to be maintained at a certain level or more so that the diffraction This is because the signal is not dropped. At this time, the surface signal changes depending on the application condition of the contact medium applied for the inspection, so that it is difficult to analyze the data by making a severe bending on the B-scan.

T7. Confirmation of Set-Up

Verify that the Set-Up (sensitivity and measuring range) is appropriate for the specimen before inspection. A set-up can be checked every 4 hours for continuous testing with a specimen of the appropriate thickness that can be moved. If an error occurs in set-up, follow below.

(1) Sensitivity

a. Do not recalibrate when error = 6dB.

b. If error> 6dB, re-test after re-calibration after the last confirmed test.

(2) Range of measurement

a. If the error is 0.5mm or 2%, whichever is greater, do not recalibrate.

b. If error> 0.5mm or 2%, whichever is greater, re-inspect after re-calibration after final confirmation.

T8. Cause of recalibration

If the cause of recalibration below occurs, repeat from T3.

(1) When replaced by another cable or chain of the same type.

(2) Replace the rechargeable battery.

(3) At least every 4 hours for continuous inspection.

(4) Before and after the start of the test.

(5) When the sensitivity at the time of inspection is judged to be abnormal.

If a problem arises that results in a test result, the system must be recalibrated.

T9. Data storage

Store the calibrated data in the instrument or external memory. The stored calibration file is retrieved when inspecting the same area and checked through the calibration confirmation procedure.

<Effects of the Invention>

In the nondestructive inspection of curved pipe welds, the reliability of inspection is ensured by providing inspection results quantitatively more accurate than RT, without causing an inspection time delay due to RT and a risk of safety accidents due to radiation, And the probability of occurrence of a safety accident is reduced. Hereinafter, the effects of the present invention will be described in more detail.

1. Elimination of safety accident caused by radiation exposure

2. Shortening inspection time

(1) Inspection time is shorter than RT

For example, if a double-walled cross-section is taken using a 45-cm diameter iridium isotope with a 25-mm 300A pipe, the thickness of the specimen will be 50 mm because the radiation will pass through the specimen and form an image on the film. Because of this, the inspection time takes about 140 minutes. However, if it is inspected according to the present invention, it takes about 10 minutes, so the inspection time is shortened to 1/14 (the type of film, distance, etc. are the usual times not mentioned).

(2) Inspection time is shorter than conventional ultrasonic inspection

In the conventional ultrasonic inspection, the number of scans should be at least 8 times. However, according to the present invention, the inspection can be completed only by one scanning.

(3) Inspection time and analysis time are shorter than when PAUT and TOFD are separately performed.

In the conventional inspection method, at least two times of PAUT application and one time of TOFD application are required. However, according to the present invention, two types of inspection can be completed by only one scanning.

3. Quantitative evaluation of defects

According to the present invention, only the length of the defect and the kind of the defect are known in the case of RT. However, according to the present invention, the depth of the defect, the width of the defect and the direction of the defect can be known, It is easy.

4. Visibility of defect readings and reproducibility of evaluation results

The present invention is excellent in the reproducibility of the evaluation result since the inspection data is all stored, and the analysis program displays the data in a form that can be easily confirmed by analyzing the data by various techniques.

5. Other effects

(1) Decrease of uncertainty of defect detection as the thickness of specimen increases

Although RT does not show small defects if the thickness of the specimen is thick, it is not influenced by the thickness because it corrects the amplification depending on the thickness according to the present invention.

(2) Reduction of the influence on the directionality of defects

RT does not appear on the film when the defects are inclined in a specific direction, but since the ultrasonic beams of various angles are used for the directionality of the expected defects in the present invention, the influence on the directionality is small.

(3) Conventional ultrasonic inspection improves the problem of not detecting defects due to space limitation

Conventional ultrasonic inspection requires a scanning distance of up to 1 Skip distance, but according to the present invention it is possible to inspect it with a 0.5 Skip distance.

(4) Ability to evaluate defects better than conventional ultrasonic inspection

Existing ultrasonic inspection is only evaluated with A-Scan. However, the present invention can be applied to various types of signal analysis techniques (A-Scan, B-Scan, C-Scan, D-Scan, .

It will be apparent to those skilled in the art that various modifications, substitutions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are intended to illustrate and not to limit the technical spirit of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments and accompanying drawings. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

1: weld or welding bead 5-4: TOFD ultrasonic vibrator
1-1: Backside Bead 5-5: PAUT Ultrasonic Oscillator
2: Straight piping 5-T: TOFD probe
3: Gauge piping 5-P: PAUT probe
4-1: Heat-affected part and improved surface of straight pipe 5-TX: TOFD probe transmitter
4-2: Heat affected part and improved surface on the curved pipe 5-RX: TOFD probe receiver
5-1: Transducer housing 6: Ultrasonic beam
5-2: Wedge of the probe 10: Scanner
5-3: cable 11: probe holder
15: contact medium supply line 100: defect

Claims (4)

In order to perform ultrasonic inspection on the welded part of the curved pipe, a scanner (10), a PAUT probe (5-P) and a TOFD probe (5-T) are combined and ultrasonic devices are used to perform two inspection techniques PAUT and TOFD A method for ultrasonic inspection of a gypsum pipe welding part,
(A1) of examining the content requested by the inspection and setting the inspection plan by selecting the probe according to the thickness of the test object and the improved shape condition;
A step (A2) including an equipment calibration step (P) for calibrating ultrasonic equipment in which PAUT and TOFD are simultaneously driven, and a TOFD calibration step (T);
A step (A3) of confirming the surface preparation of the object to be inspected, and confirming the test time from the welding completion time to the time when the inspection is requested;
Setting the inspection direction and the inspection zone (A4);
(A5) installing a scanner capable of traveling along the circumferential surface of the pipe parallel to the longitudinal direction of the welded portion at a predetermined position;
A step (A6) of attaching the PAUT probe (5-P) and the TOFD probe (5-T) to the scanner and aligning the center line of the pipe weld with a certain distance;
(A7) further correcting the TOFD sound velocity and the wedge delay of the actual test body in order to correct the sound velocity and the wedge delay and the sensitivity in the pipe of the seal member in the case of the TOFD to improve the accuracy;
(A8) delivering the ultrasonic wave to the test body and supplying the contact medium to obtain a uniform signal;
(A9) of inspecting the welded portion of the pipe by a combination of the scanner (10) and the probe and acquiring data;
Storing the obtained data in the ultrasonic apparatus (A10);
The obtained data is analyzed by TOFD signal and PAUT signal using a dedicated analysis program. The position, size, and type of defects found and defects are identified, and defects at the same position are grouped from the starting point Combining and analyzing the defect (A11);
Determining acceptance and rejection according to the types of defects analyzed and determining whether or not to re-weld the welds (A12);
(A13) issuing a modified welding instruction sheet in which information of defects is recorded when the re-inspection is determined;
Creating a report (A14);
Wherein the grooved pipe weld portion ultrasonic inspection method comprises: The method according to claim 1,
The equipment calibration step (P)
As a set-up procedure for simultaneously executing the TOFD and PTUT tests,
(P1) of forming a channel group for inputting and driving information of the PAUT probe (5-P) and the TOFD probe (5-T) to the ultrasonic equipment capable of simultaneously driving the PAUT and TOFD techniques;
(Ultrasonic Beam Configuration, Focusing Linear or Sectorial), selecting the ultrasound type (longitudinal wave or transverse wave), assigning the number of transducers required for the applied transducer as a group, (P2) comprising: setting a probe aperture to be automatically set, and inputting an applied refraction angle and a focus depth;
(P3) calibrating ultrasonic sound velocity using a calibration test piece or a contrast test piece;
(P4) of calibrating the progress distance in the wedge so as to recognize each of the transducers (VPA) (5-5) of the PAUT probe (5-P) at the same depth with respect to the reflector;
(P5) of calibrating all VPAs to be the same sensitivity for one reflector in the inspector;
(P6) making TCG and DAC corrections to compensate for attenuation of the material, making the gain difference of each VPA for the same reflector;
(P7) of calibrating the encoder to store information on inspection length and defect location at the inspection in the equipment;
Sweep range, VPA sensitivity and TCG (or DAC) with a reference or calibration block and verifying the entire inspection system (P8);
A step of re-calibrating the system when a re-calibration reason occurs (P9);
A step (P10) of re-examining the transducer's vibrator after one week of the calibration time and judging whether or not to re-check if an abnormality occurs in the inspection sensitivity;
(P11) confirming all the VPAs of the probe when the probe is re-checked;
(P12) of replacing the probe and calibrating again from the P3 level when the adjacent transducer of the probe does not operate by more than 10%;
Storing the calibrated data in a memory of the equipment (P13);
Wherein the ultrasonic inspection method comprises the steps of: The method according to claim 1,
The TOFD calibration step (T)
Depending on the thickness of the specimen, the test range is set before the test and the calibration preparation is started.
A step (T1) of selecting and preparing the ultrasonic probe and the wedge selected in step A1;
Determining a refraction angle and a type of inspection (T2);
A step (T3) of calibrating a depth measurement range including the entire thickness of the test piece;
A step (T4) of setting the distance of the probe to the PCS distance so that the surface and the bottom signal according to the sound velocity of the test body can be sufficiently confirmed;
Correcting the TOFD sound velocity and wedge delay of the real test body (T5);
A step (T6) of setting the sensitivity before inspection in the actual test body;
(T7) of confirming and re-grading the set-up in the predetermined error range before inspection or every 4 hours in the test piece versus before inspection;
A step (T8) of correcting again from the step T3 when the cause of recalibration occurs;
A step (T9) of storing the calibration data in the equipment or external memory when the calibration is completed;
Wherein the ultrasonic inspection method comprises the steps of: delete

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