CN118883710A - A phased array ultrasonic testing method for steel plates - Google Patents

Abstract

The application provides a phased array ultrasonic detection method for a steel plate, which comprises the following steps: s1: determining the coverage of the sound beam of the detected area, determining the focusing rule and the sensitivity, and inputting relevant parameters into a phased array ultrasonic detector; s2: calibrating the sound beam by using a test block, performing longitudinal vertical scanning and sector scanning, performing angle stepping, and performing process verification; s3: performing conventional ultrasonic straight probe scanning on base materials in trimming ranges on two sides of a detected weld joint, defining a detection area, defining a detection mark and a reference line, and performing transverse defect detection; s4: and importing scanning files generated in the phased array ultrasonic detector into a computer, analyzing the acquired scanning images, analyzing and evaluating data of the detected images, and carrying out defect assessment and quality classification. The application overcomes the construction defect that the weld joint of the bottom plate cannot be subjected to radial detection after repair, and adds a feasible construction process to the nondestructive detection method.

Description

A phased array ultrasonic testing method for steel plates

Technical Field

The invention belongs to the technical field of phased array ultrasonic detection of repaired butt welded joints, and in particular relates to a phased array ultrasonic detection method for steel plates.

Background Art

Common materials for LNG storage tanks include 9Ni steel, 5Ni steel, austenitic stainless steel and aluminum-magnesium alloy steel, etc. 9Ni steel is often used in the manufacture of liquefied natural gas storage tanks due to its excellent low-temperature toughness, high weldability and high strength. The welding quality of 9Ni steel storage tanks is a key factor in the construction of low-temperature storage tanks, which directly determines whether the entire storage tank can operate safely. Therefore, it is particularly important to supervise the quality of the tank welding joints. Non-destructive testing, as one of the important methods for quality control of tank welding joints, runs through the manufacturing, installation and inspection of storage tanks.

Penetrant testing and radiographic testing are commonly used for non-destructive testing of LNG tank butt welds. The penetrant method is used to detect surface defects of welded joints, while the radiographic method is mainly used to detect buried defects of welded joints. However, the sensitivity of penetrant testing is not as good as that of magnetic particle testing, and the defect detection rate will be reduced. In addition, radiographic testing cannot be used after the bottom plate weld is repaired.

Summary of the invention

In view of this, the present invention aims to propose a phased array ultrasonic detection method for steel plates, which uses a phased array ultrasonic detection process to detect the repair welds of butt weld joints on the bottom plate of an LNG storage tank, thereby overcoming the construction disadvantage that radiographic detection cannot be used after the bottom plate welds are repaired, and adding a feasible construction process to the non-destructive testing method.

To achieve the above object, the technical solution of the present invention is achieved as follows:

A steel plate phased array ultrasonic testing method comprises the following steps:

S1: Determine the acoustic beam coverage of the inspected area, determine the focusing law and sensitivity, and input the relevant parameters into the phased array ultrasonic detector;

S2: Use the test block to calibrate the sound beam, perform longitudinal vertical scanning and sector scanning, perform angle stepping, and perform process verification;

S3: Perform conventional ultrasonic straight probe scanning on the parent material within the trimming range on both sides of the inspected weld, clarify the inspection area, clearly define the inspection mark and reference line, and conduct transverse defect detection;

S4: Import the scan files generated by the phased array ultrasonic detector into the computer, analyze the acquired scan images, perform data analysis and evaluation on the detection images, and perform defect assessment and quality grading.

Furthermore, the probe of the phased array ultrasonic testing equipment in step S1 is a dual-crystal longitudinal wave probe, and the nominal frequency of the probe is in the range of 1 MHz to 5 MHz;

The focusing rule in step S1 is based on the delay rule set by the detection thickness, with a fan scanning angle range of 35° to 89° and a focusing depth of 25-30 mm;

In step S1, the sensitivity is determined by using a comparison test block, and a DAC curve is set. At least three points are selected for the DAC curve setting, and the depth (sound path) range of the calibration should at least include the depth (sound path) range to be covered by the test; when the sensitivity is determined, when the test is performed on both sides of the weld, a distance-amplitude curve is made using the horizontal hole in the center of the weld to determine the sensitivity and evaluate it;

When inspecting one side of the weld, the sound beam is passed through the weld metal and a distance-amplitude curve is made using the transverse hole in the fusion zone to determine the sensitivity and evaluation. The scanning sensitivity is determined as follows: the scanning sensitivity should make the echo height of the reflector at the maximum sound path within the detection range reach more than 20%, and the signal-to-noise ratio should be above 2:1.

Furthermore, the surface temperature difference between the comparison test block and the weld to be inspected should not be greater than ±15°C;

The comparison test block is provided with a first defect hole component and a second defect hole component;

The first defect hole assembly includes a plurality of first defect holes, the first defect holes are evenly and equidistantly arranged on the comparison test block, and the first defect hole assembly is perpendicular to the end of the comparison test block;

The second defect hole assembly includes a plurality of second defect holes, the second defect holes are evenly and equidistantly arranged on the comparison test block, and the second defect hole assembly is tiltedly arranged on the comparison test block.

Furthermore, in step S2, the longitudinal vertical scanning and the sector scanning are performed using a scanning device, and the scanning device is provided with a position sensor;

The scanning device includes one of a flat manual scanner, a large tube manual scanner, and a large container manual scanner;

Preferably, the scanning step is 1 mm and the angle step is 1°;

Before using the scanning device, calibrate the position sensor. When the scanning device moves 500mm, compare the displacement displayed by the detection equipment with the actual displacement. The error should be less than 1%.

The scanning speed of the scanning device shall not exceed 50 mm/s.

The process validation in step S2 is as follows: According to Article 4.3.1.4 of the NB/T47013.15-2021 standard, the operating instructions should be subject to process validation as required in 4.3.3 before the first application.

This test is for flat plates of material X7Ni9, butt joints of special welding materials, and repaired parts. For process verification, a representative special comparison test block should be made according to the on-site welding process and welding materials. This comparison test block is used for process verification.

Process validation result requirements:

1) All reference reflectors or defects in the test block should be clearly displayed.

2) The measured reference reflector or defect size deviation value is within the allowable range.

Furthermore, the inspection area in step S3 is the part after inspection and repair. The inspection area should include the width of the weld itself plus 10 mm of the parent material or the actual heat-affected zone on both sides. The moving area of the scanning device on both sides of the weld should be cleaned of welding spatter, iron filings, oil stains and other impurities;

In step S3, the detection mark should be marked on the scanning surface of the workpiece before detection. The marking content at least includes the scanning starting point and the scanning direction. The starting mark is represented by "0" and the scanning direction is represented by an arrow. When the weld length is long and needs to be detected in sections, draw the section mark.

Furthermore, the reference line in step S3 is a predetermined line along the stepping direction during scanning; before detection, a reference line should be set on the scanning surface for longitudinal vertical scanning, and the distance between the reference line and the weld centerline on one side of the detection area should be determined according to the process settings; during scanning, the deviation between the probe position and the set reference line position should be kept within 5%;

In transverse defect detection, the parent material retains the weld excess height, and the edges on both sides of the weld make the angle between the oblique probe and the center line of the weld joint no more than 10°;

Furthermore, the detection images in step S4 include an S-scan image, an A-scan image, a B-scan image, a C-scan image, and a D-scan image; the image display has position information, and the fixed-point detection has angle information;

Before analyzing the data, the collected data should be evaluated to determine its validity. The data should at least meet the following requirements. If the data is invalid, it should be corrected and re-scanned:

a. Data is collected based on the setting of scanning step (except for special cases such as fixed-point detection);

And/or, b. The collected data should be well coupled and the data volume should meet the requirements of the detected length; the detection length is at least 300mm;

And/or, c. The amount of A-scan signal loss in each test data shall not exceed 5% of the total, and the length of continuous loss of adjacent A-scan signals shall not exceed the provisions of NB/T47013.15. The loss of A-scan signal at the defective part shall not affect the assessment of the defect.

Preferably, the continuous loss length of adjacent A-scan signals does not exceed twice the maximum value of the scanning step.

Furthermore, the defect assessment in step S4 includes determining the defect quantitative benchmark, defect depth, defect amplitude, measuring the defect indication length, measuring the defect height itself, and quantifying multiple adjacent defects;

The defect quantitative benchmark is based on the assessment line. For defects whose echo amplitude reaches or exceeds the assessment line, its depth, amplitude, indication length and height are determined; the defect depth is the maximum reflection amplitude of the defect;

For defects that need to be quantified, in order to determine the amplitude of the defect, a sawtooth scan should be added, and the maximum amplitude obtained at this time is taken as the amplitude of the defect.

Furthermore, the method for measuring the height of the defect itself in step S4 comprises the following steps:

A1: Determine the defect height on the S-scan image or D-scan image in combination with the A-scan image;

A2: Select any point on the image and use the -6dB half-wave height method or the end-point diffraction method to measure;

A3: For surface open defects, select any point on the image and use the endpoint diffraction method, -6dB half-wave height method, or other effective methods to determine the position of the upper or lower endpoint of the defect;

A4: The maximum value measured in step A1, step S2 or step A3 is taken as the height of the defect;

The quantitative determination method of multiple adjacent defects comprises the following steps:

The quantitative determination of multiple adjacent defects is that two or more adjacent defects are displayed, and when the spacing in the X-axis direction is less than the length of the smaller defect, the spacing in the Y-axis direction is less than 5mm, and the spacing in the Z-axis direction is less than the height of the smaller defect, they are treated as one defect. The defect depth, defect length and defect height are determined according to the following principles:

B1: Defect depth: The smaller value of two or more defect depths is taken as the single defect depth;

And/or, B2: Defect amplitude: The larger amplitude of two or more defects is taken as the single defect amplitude;

And/or, B3: Defect indication length: the distance between the front and rear end points of two or more defects on the X-axis projection;

And/or, B4: Defect height: If two or more defects have no overlap in their X-axis projections, the larger defect height shall be used as the single defect height; if two or more defects have overlap in their X-axis projections, the sum of the two or more defects heights shall be used as the single defect height.

The quality classification in step S4 is the quality classification of the welded joints, and any hazardous defects such as cracks, lack of fusion at the groove, and lack of penetration are rated as Grade III.

Defects below the assessment line are all rated as Level I.

Quality classification of ultrasonic testing of butt joints

Time for review: a) When the instrument, probe, connecting cable or coupling agent is replaced during the test; b) When the tester has doubts; c) When working continuously for 4 hours or more; d) When the test is completed.

Review content: mainly review sensitivity, position sensor and depth display deviation. For details, see NB/T47013.15-2021 standard

Compared with the prior art, the steel plate phased array ultrasonic testing method described in the present invention has the following advantages:

The present application adopts phased array ultrasonic testing technology to detect the repair welds of the butt weld joints of the inner tank bottom plate (material: X7Ni9) of the LNG storage tank, which overcomes the construction disadvantage that radiographic testing cannot be used after the bottom plate welds are repaired, and adds a feasible construction process to the non-destructive testing method.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

FIG1 is a schematic diagram of an A-type phased array test block according to an embodiment of the present invention;

FIG2 is a schematic diagram of zone I of a type A phased array test block according to an embodiment of the present invention;

FIG3 is a schematic diagram of a B-type phased array test block according to an embodiment of the present invention;

FIG4 is a schematic diagram of a comparison test block according to an embodiment of the present invention;

FIG5 is a schematic diagram of a cross section of a comparison test block according to an embodiment of the present invention;

FIG6 is a schematic diagram of a scanning device according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the longitudinal oblique scanning and the longitudinal parallel scanning according to an embodiment of the present invention (a is a longitudinal oblique scanning diagram, and b is a longitudinal parallel scanning diagram).

DETAILED DESCRIPTION

It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

The invention provides a phased array ultrasonic detection method and quality grading for a flat plate butt joint with a thickness of 28 mm and a material of X7Ni9.

(1) Personnel Qualifications

Personnel engaged in non-destructive testing of pressure equipment should obtain the nationally recognized PAUT qualification in accordance with the requirements of the national assessment of non-destructive testing personnel for special equipment. The qualification levels are divided into Level I (primary) and Level II (intermediate).

Nondestructive testing personnel can only perform testing work corresponding to this level and bear corresponding technical responsibilities. Those who issue reports must have level II qualifications or above, and level I personnel can only perform auxiliary work under the guidance of level II personnel or above. Observers, assessors, report issuers and auditors must have level II qualifications or above.

PAUT testers should be familiar with the PAUT test equipment used.

PAUT inspectors should have practical inspection experience and master certain basic knowledge of pressure equipment structure and manufacturing.

(2) Equipment and Materials

The phased array ultrasonic testing equipment, instruments and materials used should meet the requirements of NB/T47013.15-2021.

Equipment: Use SyncScan 32PT or an instrument of the same type and function;

Probe: Use a dual-crystal longitudinal wave probe, and the nominal frequency of the probe should be in the range of 1MHz to 5MHz. DLA and DMA phased array probes are recommended. This application uses Shanchao's dual-crystal linear array probe 4.0DM16×2S-1.0-3.0.

The number of probe array elements should be selected according to the thickness of the workpiece to be inspected. Generally, the number of array elements for single excitation should not be less than 16 during sector scanning detection, and the number of array elements for single excitation should not be less than 4 during line scanning for longitudinal wave detection.

The phased array probe should be in close contact with the test surface. When the gap between the probe wedge and the contact surface of the workpiece is greater than 0.5 mm, a curved wedge should be used or the wedge should be ground. When grinding, the geometric dimensions of the wedge should be remeasured, and the impact on the sound beam should be considered.

(3) Test block

This embodiment uses a standard test block; a standard test block is a material block with specified chemical composition, surface roughness, heat treatment and geometric shape, which is used to evaluate and calibrate phased array ultrasonic testing equipment, that is, a test block used for instrument probe system performance calibration. The standard test blocks used in this section are nickel-based CSK-IA test blocks, A-type phased array test blocks, and B-type phased array test blocks.

The manufacturing and dimensional accuracy of standard test blocks should meet the requirements of JB/T 8428. The manufacturer should provide product quality certificates and ensure that when each standard test block it manufactures is compared with the same reflector (surface) on the national standard sample or similar standard test block with a value transfer benchmark under the same test conditions, the maximum reflection amplitude difference should be less than or equal to 2dB.

Special comparison test block

The special comparison test block (material X7Ni9) was processed and manufactured on site. Figures 4 and 5 are schematic diagrams of artificial defects of the comparison test block.

(4) Coupling agent

Use an effective medium suitable for the workpiece as the ultrasonic coupling agent. When the ambient temperature is above 0°C, use water. When the ambient temperature is below 0°C, use water plus antifreeze. The coupling agent used in actual testing is the same as the coupling agent used in setting up and calibrating the detection system.

Other requirements:

The surface temperature difference between the reference test block and the weld being inspected should not be greater than ±15°C.

The detection technology level is B.

(5) Process configuration

(5.1) Focus setting

The delay rule is set according to the thickness of the test. The fan scanning angle range is 35°~89° (Shanchao's test solution for coarse-grained materials. This sound beam coverage range is a combination of conventional probes and surface wave probes designed by Shanchao. Because coarse-grained materials generally do not use secondary waves, only primary wave detection is recommended. Using this probe can ensure that the surface defects are covered by the primary wave. This angle is fine-tuned according to the actual situation on site), and the focus depth is 28mm.

(5.2) Sensitivity setting

Select DAC to set the sensitivity: when testing on both sides of the weld, use the horizontal hole in the center of the weld to make a distance-amplitude curve to determine the sensitivity and evaluation; when testing on only one side of the weld, the sound beam should pass through the weld metal and use the horizontal hole in the fusion zone to make a distance-amplitude curve to determine the sensitivity and evaluation. The area from the evaluation line (SL) to the quantitative line (EL) is Zone I; the area from the quantitative line to the scrap line (RL) is Zone II; and the area above the scrap line is Zone III. The sensitivity of the scrap line, quantitative line, and evaluation line is shown in Table 1.

Table 1 Distance-amplitude curve sensitivity

Scanning sensitivity determination: The scanning sensitivity should make the echo height of the reflector at the maximum sound path within the detection range reach more than 20%, and the signal-to-noise ratio should reach 2:1.

(5.3) Selection of scanning method and scanning mode:

The method of longitudinal vertical scanning + sector scanning is adopted.

The scanning device uses a TSE-02 manual scanner for flat panels/large tubes/large containers with a position sensor, as shown in FIG6 .

(5.4) Process validation

According to Article 4.3.1.4 of the NB/T47013.15-2021 standard, the operating instructions should be subject to process validation in accordance with the requirements of 4.3.3 before first use.

This test is for flat plates of material X7Ni9, butt joints of special welding materials, and repaired parts. For process verification, a representative special comparison test block should be made according to the on-site welding process and welding materials. This comparison test block is used for process verification.

Process validation result requirements:

3) All reference reflectors or defects in the test block should be clearly displayed.

4) The measured reference reflector or defect size deviation value is within the allowable range.

Calibration, verification and inspection of equipment and probes:

Calibration or verification: The vertical linearity, horizontal linearity, attenuator accuracy, combined frequency, lateral resolution and longitudinal resolution of fan-scan imaging, as well as the fan-scan angle range and fan-scan angle resolution of the detection instrument and probe combination performance shall be calibrated and recorded at least once a year. The test requirements shall meet the requirements of relevant standards.

Run verification:

1) The vertical linearity and horizontal linearity of the instrument and probe combination performance should be checked and recorded at least once every 6 months. The test requirements should meet the requirements of relevant standards.

2) Perform an operational check on the effectiveness of the array elements at least once a month. Phased array probes are allowed to have failed array elements, but the number of failed array elements shall not exceed 1/4 of the total number of probe elements, and consecutive failure of adjacent array elements is not allowed.

examine:

1) Before each test, check whether the appearance of the instruments and equipment, cable connections, and power-on signal displays are normal.

2) The position sensor should be checked and recorded before each test. The inspection method is to move the scanning device with the position sensor at least 300mm, and compare the displacement displayed by the detection instrument with the actual displacement. The error should be less than 1%.

Review of the testing system:

Review time

The detection system should be reviewed in the following situations:

1) The instrument, probe, connecting cable or coupling agent is replaced during the test;

2) When the tester has doubts;

3) Continuous work for 4 hours or more;

4) When the test is completed.

Review content and requirements:

The main review is for the deviation of sensitivity, position sensor and depth display. The comparison test blocks and other technical conditions used in the review and initial setting should be the same. If the deviation of the parameters of the initial setting is found during the review, it should be implemented according to the provisions of the following table.

Table 2 Deviation and Correction Standards

Test preparation:

Detection area:

The inspection area mainly inspects the repaired parts. The inspection area should include the width of the weld itself plus 10mm of the base material or the actual heat affected zone (whichever is smaller) on both sides.

Test surface preparation:

In principle, the single wave method (direct method) inspection is carried out on one side and two sides of the welded joint. When the inspection can only be carried out on one side or one side of the welded joint due to geometric conditions, the welded joint excess height should be ground flat and the entire inspection area should be inspected as much as possible.

The moving area of the scanning device on both sides of the weld should be cleaned of welding spatter, iron filings, oil stains and other impurities.

Detection mark:

Before testing, the workpiece scanning surface should be marked. The marking content should at least include the scanning starting point and scanning direction. The starting mark is represented by "0" and the scanning direction is represented by an arrow. When the weld is long and needs to be tested in sections, the section marks should be drawn. All marks should have no effect on the scanning.

Reference Lines:

Predetermined route for scanning along the stepping direction:

Before testing, a reference line should be set on the scanning surface for longitudinal vertical scanning. The distance between the reference line and the center line of the weld on one side of the testing area should be determined according to the process settings. During scanning, the deviation between the probe position and the set reference line position should be kept within 5%.

Transverse defect detection:

For welds with excess height, the edges of both sides of the weld can be scanned longitudinally with the inclined probe at an angle of no more than 10° to the center line of the weld joint.

Remove the excess height of the weld and place the probe on the surface of the weld joint for longitudinal parallel scanning in two directions, as shown in Figure 7.

Data analysis and evaluation:

The detection images include S-scan images, A-scan images, B-scan images, C-scan images and D-scan images. The appropriate display mode can be selected according to needs. For complex structures, the defect status should be displayed in the modeling structure.

There is position information in the image display, and angle information should be provided during fixed-point detection.

Before analyzing the data, the collected data should be evaluated to determine its validity. The data should at least meet the following requirements. If the data is invalid, it should be corrected and re-scanned:

1) Data is collected based on the scanning step settings (except for special cases such as fixed-point detection);

2) The collected data should be well coupled and the data volume should meet the requirements of the detected length;

3) The amount of A-scan signal loss in each test data shall not exceed 5% of the total amount, and the length of continuous loss of adjacent A-scan signals shall not exceed twice the maximum scanning step value specified in Table 3 of NB/T47013.15; the loss of A-scan signal at the defective part shall not affect the assessment of the defect.

4) When analyzing data, various displays should be combined with the material, structure and manufacturing characteristics of the inspected object for comprehensive judgment.

Defect assessment:

Defect quantification benchmark: Defect quantification is based on the assessment line. For defects whose echo amplitude reaches or exceeds the assessment line, their depth, amplitude, indication length, height (if necessary), etc. should be determined. If necessary, various focusing methods can be used to improve the quantitative accuracy.

Defect depth:

The position where the maximum reflection amplitude of the defect is obtained is the defect depth.

Defect amplitude:

For defects that need to be quantified, in order to determine the amplitude of the defect, a sawtooth scan should be added, and the maximum amplitude (on different inspection surfaces (sides)) obtained at this time is taken as the amplitude of the defect.

Defect indication length:

Combine the A-scan image with the D-scan image or C-scan image to measure the defect indication length.

When the defect reflection wave has only one high point and is located in Zone II or above Zone II, use the -6dB method to measure its indicated length.

When the peak value of the defect reflection wave fluctuates, has multiple high points, and is all located in Zone II or above Zone II, the indicated length should be measured using the endpoint -6dB method.

When the maximum reflection amplitude of the defect is in zone I, move the probe left and right to reduce the amplitude to the evaluation line, and measure the defect indication length using the evaluation line absolute sensitivity method.

Defect height:

Combine the A-scan image with the S-scan image or D-scan view to measure the defect height.

Select any point on the image and use the -6dB half-wave height method or the end-point diffraction method for measurement. You can also use the equivalent method and other effective methods for measurement. See Appendix K for the transverse wave end-point diffraction method.

For surface open defects, select any point on the image and use the endpoint diffraction method, -6dB half-wave height method, or other effective methods to determine the position of the upper or lower endpoint of the defect.

The maximum value measured at any point is taken as the height of the defect itself.

Sizing of multiple adjacent defects:

Two or more adjacent defects (non-circular) should be treated as one defect when the distance between them in the X-axis direction is less than the length of the smaller defect, the distance between them in the Y-axis direction is less than 5mm, and the distance between them in the Z-axis direction is less than the height of the smaller defect. The defect depth, defect length and defect height are determined according to the following principles:

a) Defect depth: The smaller value of the two defect depths is taken as the single defect depth;

b) Defect amplitude: The larger amplitude of the two defects is taken as the single defect amplitude;

c) Defect indication length: the distance between the front and rear endpoints of two defects on the X-axis projection;

d) Defect height: If the projections of two defects on the X-axis do not overlap, the height of the larger defect shall be taken as the height of the single defect; if the projections of two defects on the X-axis overlap, the sum of the heights of the two defects shall be taken as the height of the single defect (including the spacing).

Quality grading

Any hazardous defects such as cracks, lack of fusion at the groove and incomplete penetration are rated as Level III.

Defects below the assessment line are all rated as Level I.

The quality classification of welded joints shall be carried out in accordance with the provisions of Table 3.

Table 3 Reference austenitic stainless steel butt joint ultrasonic testing quality classification

Test records and reports

According to the actual situation of on-site operation, the relevant information and data of the testing process shall be recorded in detail. In addition to complying with the provisions of NB/T47013.1, the ultrasonic testing record shall also include at least the following contents.

Process specification edition or operating instruction number.

Detection technology level.

Testing equipment and instruments: testing equipment, probes, wedges, coupling agents, scanning devices, test block names and specifications.

Technical requirements for testing: implementation standards, testing technology level, testing timing, testing ratio, qualified level, scanning sensitivity, number of excitation elements, starting position of excitation elements, scanning mode and scanning mode, probe position, focusing depth, angle range, angle step, scanning step, surface preparation before testing and coupling compensation, etc.

The test results should include the following:

1) Schematic diagram of the detection site;

2) Data file name and detection length;

3) Defect records: defect starting position, length, depth, echo amplitude, etc.;

4) Defect assessment level;

5) Defect type and defect height (when using pressure equipment for detection).

Signatures of testers and reviewers.

Table 4 Basic information of the inspected workpiece

Table 5 Testing equipment, probes, test blocks, scanning devices and coupling agents

Table 6 Testing technical requirements

Table 6 Detection settings and parameters

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A phased array ultrasonic detection method for a steel plate is characterized by comprising the following steps of: the method comprises the following steps:

s1: determining the coverage of the sound beam of the detected area, determining the focusing rule and the sensitivity, and inputting relevant parameters into a phased array ultrasonic detector;

s2: calibrating the sound beam by using a test block, performing longitudinal vertical scanning and sector scanning, performing angle stepping, and performing process verification;

s3: performing conventional ultrasonic straight probe scanning on base materials in trimming ranges on two sides of a detected weld joint, defining a detection area, defining a detection mark and a reference line, and performing transverse defect detection;

S4: and importing scanning files generated in the phased array ultrasonic detector into a computer, analyzing the acquired scanning images, analyzing and evaluating data of the detected images, and carrying out defect assessment and quality classification.

2. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps: the probe of the phased array ultrasonic detection equipment in the step S1 is a double-crystal longitudinal wave probe, and the nominal frequency of the probe is in the range of 1 MHz-5 MHz;

The focusing rule in the step S1 is according to the delay rule set by the detection thickness, the fan-scan angle range is 35-89 degrees, and the focusing depth is 25-30mm;

In the step S1, sensitivity determination is carried out by using a reference block, DAC curve setting is carried out, at least three points are selected for DAC curve setting, and the calibrated depth (sound path) range at least comprises the depth (sound path) range to be covered by detection; the sensitivity is determined and evaluated by making a distance-amplitude curve with a transverse hole in the center of the welding seam when the two sides of the welding seam are detected;

when the welding seam single-side detection is carried out, sound beams are made to pass through welding seam metals, a distance-amplitude curve is made by using a fusion area transverse hole to determine sensitivity and evaluation, and scanning sensitivity is determined: the scanning sensitivity should make the reflector echo height at the maximum sound path in the detection range reach more than 20% and the signal-to-noise ratio more than 2:1.

3. The steel plate phased array ultrasonic detection method according to claim 2, wherein the method comprises the following steps:

The surface temperature difference between the reference block and the detected weld joint is not more than +/-15 ℃;

the reference block is provided with a first defect hole assembly and a second defect hole assembly;

The first defect hole assembly comprises a plurality of first defect holes, the first defect holes are uniformly and equidistantly arranged on the reference block, and the first defect hole assembly is perpendicular to the end part of the reference block;

The second defect hole assembly comprises a plurality of second defect holes, the second defect holes are uniformly and equidistantly arranged on the reference block, and the second defect hole assembly is obliquely arranged on the reference block.

4. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps: in the step S2, the longitudinal vertical scanning and the sector scanning are performed by using a scanning device, and the scanning device is provided with a position sensor;

The scanning device comprises one of a flat manual scanner, a large-tube manual scanner and a large-container manual scanner;

When the scanning device is used for calibrating the position sensor before use and the scanning device moves by 500mm, comparing the displacement displayed by the detection equipment with the actual displacement, wherein the error is less than 1%;

the scanning speed of the scanning device is not more than 50mm/s.

5. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps:

The detection area in the step S3 is a part after the repair is detected, the detection area should contain the width of the welding line itself plus the base metal or the actual heat affected zone of 10mm on both sides, and the moving area of the scanning device on both sides of the welding line should remove welding spatter, scrap iron, oil dirt and other impurities;

In the step S3, the detection mark is marked on the scanning surface of the workpiece before detection, the marking content at least comprises a scanning starting point and a scanning direction, the starting mark is represented by 0, the scanning direction is represented by an arrow, and when the length of the welding seam is longer and the sectional detection is needed, the sectional mark is drawn.

6. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps:

in the step S3, the reference line is a preset line walking along the stepping direction during scanning; before detection, setting a reference line on a scanning surface so as to carry out longitudinal vertical scanning, and keeping the deviation between the position of the probe and the position of the set reference line to be no more than 5% during scanning;

the base material keeps the residual height of the welding seam in the transverse defect detection, and the edges of the two sides of the welding seam enable the inclined probe to form an angle of not more than 10 degrees with the central line of the welding joint.

7. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps: the detection images in the step S4 comprise an S-scan image, an A-scan image, a B-scan image, a C-scan image and a D-scan image; the image display has position information and angle information during fixed-point detection;

The collected data is evaluated to determine its validity before analyzing the data, and the data should at least meet the following requirements, if the data is invalid, the data should be scanned again after correction:

a. The data are collected based on the setting of scanning steps, and the scanning steps are not needed in special conditions such as fixed-point detection;

and/or b, the collected data should be well coupled, and the data volume should meet the requirement of the detected length;

And/or c, the loss of the A scanning signals in each detection data cannot exceed 5% of the total quantity, and the continuous loss length of the adjacent A scanning signals does not exceed the specification of NB/T47013.15; the loss of scanning signals of the defect part A cannot influence the assessment of defects;

Preferably, the consecutive loss length of adjacent a-scan signals does not exceed 2 times the maximum value of the scan step.

8. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps: the defect evaluation in the step S4 comprises the steps of determining a defect quantitative reference, defect depth and defect amplitude, measuring the defect indication length, measuring the defect self-height and quantifying a plurality of adjacent defects;

the defect quantitative reference is to use the evaluation line as a reference, and determine the depth, amplitude, indication length and height of the defect that the echo amplitude reaches or exceeds the evaluation line;

the defect depth is the maximum reflection amplitude of the defect;

For defects to be quantified, to determine the amplitude of the defect, a zigzag scan should be added to take the maximum amplitude obtained at this time as the amplitude of the defect.

9. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps: the method for measuring the height of the defect in the step S4 comprises the following steps:

A1: combining the A scanning image to measure the height of the defect on the S scanning image or the D scanning image;

A2: selecting any point on the image, and measuring by adopting a-6 dB half-wave height method or an endpoint diffraction method;

A3: for the surface opening type defect, selecting any point on the image to measure the position of the upper end point or the lower end point of the defect by adopting an end point diffraction method, a-6 dB half-wave height method or other effective methods;

a4: taking the maximum value measured in the step A1, the step S2 or the step A3 as the self-height of the defect;

A method for quantitatively determining a plurality of adjacent defects, comprising the steps of:

Quantification of the plurality of adjacent defects is an indication of two or more adjacent defects having a spacing in the X-axis direction of less than the length of the defect where the spacing is smaller, a spacing in the Y-axis direction of less than 5mm, and a spacing in the Z-axis direction of less than the height of the defect itself where the spacing is smaller, the depth of the defect, the length of the defect, and the height of the defect itself being determined as a defect treatment according to the following principles:

B1: defect depth: taking two or more defect depth smaller values as single defect depth;

and/or B2: defect amplitude: taking the amplitude of two or more defects as a single defect amplitude;

And/or B3: defect indication length: the distance between the front and rear end points of two or more defects on the X-axis projection;

and/or B4: defect itself height: if two or more defects are projected on the X axis without overlapping, taking the self-height of the larger defect as the self-height of the single defect; if two or more defects overlap in the X-axis projection, the sum of the self-heights of the two or more defects is taken as the self-height of a single defect.

10. The steel plate phased array ultrasonic detection method according to claim 1, wherein the method comprises the following steps: the quality classification in the step S4 is the quality classification of the welding joint;

The thickness of the workpieces of the grade I, the grade II and the grade III is 10-80 mm;

the area where the reflection amplitude is positioned is I, the single defect indication length is less than or equal to 40/mm, and the quality grade is I;

the area where the reflection amplitude is located is II, the single defect indication length Lmm is less than or equal to the thickness of the workpiece/3 mm, the minimum can be 10mm, and the quality grade is grade I;

the area where the reflection amplitude is positioned is I, the single defect indication length is less than or equal to 60/mm, and the quality grade is grade II;

The area where the reflection amplitude is located is II, the allowable single defect indication length Lmm is less than or equal to 2 workpiece thickness/3 mm, the minimum is 12mm, the maximum is not more than 40mm, and the quality grade is grade II;

the area where the reflection amplitude is located is II, and the allowable single defect indication length exceeds II level, and the quality grade is judged to be III level;

The area where the reflection amplitude is located is III, the allowed single defect indication length is any defect indication length, and the quality grade is grade III;

the area where the reflection amplitude is located is I, and the allowable single defect indication length exceeds II levels, and the quality grade is judged to be III levels;

The quality grading is carried out on the defect display of hazard of judging that cracks, grooves are not fused and not welded completely, and the defect display is rated as III grade; defects below the evaluation line were rated as grade i.