Ultrasonic flaw detectors. Pipeline flaw detection Increasing the volume and quality of pipe flaw detection services

Ministry of Energy Engineering

Technical management

Ministry of Energy and Electrification of the USSR
Main technical department

INSTRUCTIONS

ON Flaw detection of bends in pearlite steel pipelines

RD 34.17.418
(And 23 SD-80)

Date of introduction 1982-01-01

COMPLETED BY "Soyuztechenergo", Vinnitsaenergo, Kievenergo, TsRMZ Mosenergo, Donbasenergo, TsNIITmash, VTI Compiled by: engineers A.P. Kizhvatov (Soyuztechenergo), B.V. Barkhatov (Vinnitsaenergo), I.A. Zaplotinsky (Kievenergo), V.I. Barmin (TsRMZ), V.A. Mentsov (Energomontazhproekt), I.P. Lyamo (CHP-23), candidates of technical sciences. Sciences V.G. Shcherbinsky, V.E. Bely (TsNIITmash), V.S. Grebennik (VTI), N.V. Bugai (Donbasenergo), engineer. L.I. Savina (Soyuztechenergo) APPROVED by Deputy Head of the Technical Directorate of the Ministry of Power Engineering A.K. Krylov July 31, 1981, Deputy Head of the Main Technical Directorate of the Ministry of Energy and Electrification of the USSR D.Ya. Shamarakov on August 5, 1981. Changes and additions were made, Amendment approved by the Technical Directorate of the Ministry of Energy Engineering and the Main Scientific and Technical Directorate of Energy and Electrification of the Ministry of Energy and Electrification of the USSR, 1987.

1. INTRODUCTION 2. GENERAL PROVISIONS 3. VISUAL INSPECTION AND OVALITY MEASUREMENT 4. MAGNETIC POWDER FECTOSCOPY (MPD) 5. ULTRASONIC THICKNESS METRY 6. ULTRASONIC FECTOSCOPY 7. REGISTRATION OF TECHNICAL REPORT DOCUMENTATION ON THE RESULTS OF DEFECTOSCOPY 8. SAFETY MEASURES Appendix 1 METHODOLOGICAL INSTRUCTIONS FOR ULTRASOUND BENDS ON PRESENCE OF TRANSVERSE CRACKS Appendix 2 METHODOLOGICAL INSTRUCTIONS FOR ULTRASONIC CONTROL OF BENDS BY SURFACE WAVES Appendix 3 Appendix 4 THICKNESS METHOD USING UDM-1M and UDM-3 INSTRUMENTS Appendix 5 METHOD FOR CHECKING THE SUITABILITY OF FINDERS FOR CONTROL GIBOV Appendix 6 IMPROVEMENT OF THE PIEZO PLATE ATTACHMENT UNIT Appendix 7 TECHNIQUES FOR CONTROL OF BENDS WITH USING AN ACOUSTIC UNIT Appendix 8 METHOD FOR ADJUSTING THE SCANNING SPEED OF DEVICES TYPE UDM AND DUK Appendix 9 METHODOLOGICAL INSTRUCTIONS FOR SENSE BENDS WITH A RATIO OF WALL THICKNESS TO OUTER DIAMETER MORE THAN 0.17

1. INTRODUCTION

1.1. The instructions were developed taking into account the accumulated experience in flaw detection of bends of unheated boiler tubes and pipelines during their manufacture, installation and operation. 1.2. With the release of this Instruction, the effect of the “Instructions for flaw detection quality control of metal bends of various standard sizes of unheated boiler pipes and steam pipelines for fresh steam and hot reheating of thermal power plants” (M.: STSNTI ORGRES, 1974) is canceled. 1.3. This Instruction was compiled on the basis of experimental and production control of a large number of bends of various standard sizes of unheated boiler pipes and steam pipelines in operation at power plants of the USSR Ministry of Energy, as well as new pipe bends manufactured by boiler plants, installation and repair enterprises. 1.4. The instructions were developed taking into account the requirements of the Rules of the State Mining and Technical Supervision of the USSR, TU-14-3-460-75 "Seamless steel pipes for steam boilers and pipelines. Technical conditions", OST 108.030.129-79 "Shaped parts and assembly units of station and turbine pipelines of thermal power plants General technical conditions", GOST 20415-75 "Non-destructive testing. Acoustic methods. General provisions", GOST 21105-75 "Non-destructive testing. Magnetic particle method", OST 108.030.40-79 "Tubular elements of heating surfaces. Connecting pipes within the boiler "Collectors of stationary steam boilers. General technical conditions." 1.5. The Instructions take into account the recommendations of GOST 14782-76 "Non-destructive testing. Welded seams. Ultrasonic methods", GOST 17410-78 "Seamless cylindrical metal pipes. Ultrasonic flaw detection method", "Basic provisions for ultrasonic flaw detection of welded joints of boiler units and pipelines of thermal power plants (OP No. 501-CD-75)" (M.: SPO Soyuztekhenergo, 1978). The introduction period was set from January 1, 1982.

2. GENERAL PROVISIONS

2.1. The instruction defines methods for flaw detection of bends of unheated pipes within boilers, station pipelines for steam and hot water, pipelines within a turbine and other pipes made of pearlitic steel with an outer diameter of 57 mm or more, a wall thickness of 3.5 mm or more. The instructions do not apply to cast elbows. (Modified edition, Rev. 1987). 2.2. The instructions are intended to identify defects such as pores, scratches, sunsets, delaminations, cracks*, corrosion pits, cavities on the outer and inner surfaces of bends and in their sections. * If it is necessary to identify defects such as transverse cracks, inspection is performed according to the method of Appendix 1. 2.3. The volumes and frequency of monitoring of pipeline bends are determined by the relevant instructional documents of the USSR Ministry of Energy and the Ministry of Energy. 2.4. Control includes: - visual inspection and measurement of ovality; - magnetic particle flaw detection (MPD); - measurement of wall thickness using the ultrasonic method; - ultrasonic flaw detection (USD). 2.5. Inspection of new bends is carried out over the entire surface of the bent section using the methods according to clause 2.4, except for MTD. Pipe bends with a diameter of 273 mm and more are additionally subjected to MPD. 2.6. Bends in operation are subject to control using methods according to clause 2.4, except for MTD. Pipe bends with a diameter of 273 mm or more, as well as bends with a diameter of 133 mm or more with an ambient temperature of 450 °C or higher are additionally subjected to MPD. Inspection of bends in operation is carried out on at least two thirds of the bend surfaces, including the stretched and neutral zones (Fig. 1).

Rice. 1. Bending sketch:

1 - controlled surface; 2 - uncontrolled surface; 3 - line connecting the bent section with the straight pipe; I - stretched zone; II, IV - neutral zone; III - compressed zone

2.7. Bends included in the control groups are subject to all types of control, according to clause 2.4 over the entire surface of the bend (in stretched, compressed and neutral zones). 2.8. Inspection of bends according to clause 2.4 (except for visual) is carried out by flaw detectors of at least the 4th category, trained and certified in accordance with the established procedure according to the “Rules for the inspection of welded joints of pipe systems of boiler units and pipelines of thermal power plants” (PK-03-TSS-66) and OP No. 501 CD-75. 2.9. Visual inspection and measurement of ovality in factory conditions is carried out by inspectors.

3. VISUAL INSPECTION AND OVALITY MEASUREMENT

3.1. A visual inspection of bends is carried out in order to identify defects on the outer surface that are not permissible according to TU-14-3-460-75 for the manufacture of pipes and OST 108.030.129-79 for the manufacture of bends. A visual inspection of the surface is carried out without the use of magnifying devices after cleaning performed for new bends in accordance with OST 108.030.129-79, and for bends in operation, after cleaning performed in accordance with clause 6.16 of these Instructions. 3.2. Based on the results of a visual inspection, bends are rejected if stains, sunsets, cracks, delaminations, flaws, deep scratches and rough ripples are found on the outer or inner surface. (Modified edition, Rev. 1987). 3.3. Surface defects without sharp corners (dents from scale), small ripples and other small defects due to the production method that do not interfere with inspection are allowed, with a depth of no more than 5% of the nominal wall thickness, but not more than 2 mm for hot-deformed pipes and 0.2 mm for cold- and heat-deformed pipes with a ratio of outer diameter to wall thickness of more than 5 and 0.6 mm for cold- and heat-deformed pipes with a ratio of diameter to wall thickness of 5 or less, provided that the wall thickness does not exceed the limits of the nominal permissible values. 3.4. On the concave (compressed) part of the bends, irregularities such as corrugations are allowed, and in places where bent sections transition into straight single smooth irregularities. In this case, the permissible dimensions of corrugations and irregularities are determined by OST 108.030.129-79. 3.5. Non-roundness (ovality) control is carried out in accordance with OST 108.030.129-79 by measuring the largest and smallest diameters: for bends with a rotation angle equal to or less than 30° - in the middle section; for bends with a rotation angle of more than 30° - in at least three sections, bend; on average and at distances equal to 1/6 of the arc length (but not less than 50 mm) from the beginning and end of the bend, while the ovality of the bend is determined by the maximum of three measured values. 3.6. At manufacturing plants, ovality control is carried out by direct measurement or by using no-go templates for each pipe size according to factory instructions approved by the chief engineer of the plant. 3.7. At repair plants and power plants, ovality is determined by direct measurement using micrometric instruments with a division value of no more than 0.01 mm. 3.8. The ovality value is fixed as a percentage for each bend separately and is determined by the formula

Where DMax , Dmin- the largest and smallest outer diameters measured in one section. The bend ovality value should not exceed the values specified in OST 108.030.129-79. 3.9. The results of ovality measurement are presented in accordance with clause 7 of these Instructions.

4. MAGNETIC POWDER DEFECTOSCOPY (MPD)

4.1. Magnetic particle flaw detection is carried out before ultrasonic testing in order to identify surface defects such as cracks, sunsets, looseness, etc. Under operating conditions at thermal power plants, instead of MPD, it is allowed to use ultrasonic testing with surface waves, the methodology of which is set out in Appendix 2. Inspection is performed after cleaning the bend surface in accordance with clause 6.16 of this Instructions. 4.2. Magnetic particle flaw detection is carried out in accordance with GOST 21105-75 using the method of circular magnetization by passing current through the controlled part of the product or longitudinal (pole) magnetization with an electromagnet. 4.3. Magnetic particle testing is carried out according to the method outlined in Appendix 3. (Modified edition, Rev. 1987). 4.4. Defective areas can be selected with a grinder and re-inspected by MPD or etching or penetrant flaw detection. The decision on the suitability of bends after removal of defects is made based on the results of wall thickness measurements at the sampling site according to clause 5.5. (Modified edition, Rev. 1987) 4.5. The results of the MTD are formalized in accordance with clause 7 of these Instructions. 4.4, 4.5. (Modified edition, Rev. 1987).

5. ULTRASONIC THICKNESS

5.1. Ultrasonic thickness gauging is carried out in order to determine the minimum thickness of the bend wall, including in sampling areas, if any were made. 5.2. Ultrasonic thickness gauging of bends is carried out using ultrasonic thickness gauges "Kvarts-6", "Kvarts-14", "TIC-3" and others according to the operating instructions for the devices with measurement accuracy: ± 0.15 mm for thicknesses up to 10 mm; ± 0.3 mm - up to 25 mm; ± 0.6 mm - more than 25 mm. It is allowed to carry out thickness gauging using UDM-1m and UDM-3 devices according to the method recommended in Appendix 4. Thickness measurements are made after preparing the surface in accordance with clause 6.16 of these Instructions. 5.3. Before carrying out thickness gauging, the devices must be prepared for operation: configured according to the factory operating instructions for the device and tested on a test sample used for ultrasonic testing of bends of a given standard size (Fig. 2). 5.4. The bend wall thickness is measured on the stretched part along the entire length of the bend. Under thermal power plant conditions (installation, incoming inspection), additional wall thickness measurements are carried out on both neutrals in sections 100-150 mm long, 30-50 mm wide in places where ovality is measured and in one of the straight sections near the bend along the perimeter on a ring 30-50 mm wide . 5.5. For connecting pipelines within the boiler, turbine and station pipelines, the value of wall thinning is determined by the formula

Where S- nominal pipe wall thickness; Smin- minimum pipe wall thickness at the bending point on the stretched side. The thinning of the wall of bends for pipes made with deviations from the nominal dimensions in thickness should not exceed the values specified in OST 108.030.40-79. (Modified edition, Rev. 1987). 5.6. Thickness measurement results are presented in accordance with clause 7 of these Instructions.

Rice. 2. Test sample for bend inspection:

1 - external risks; 2 - marking

Note. On samples of pipe bends up to 15 mm thick, the upper reflector is located in section II, the lower - in section I; over 15 mm - the upper and lower reflectors are located in section I. (Modified edition, Rev. 1987).

6. ULTRASONIC DEFECTOSCOPY

6.1. Ultrasonic flaw detection of bends is carried out to identify defects both on the internal and external surfaces, and in the cross section of the bend, without identifying the type of defect. 6.2. The most common defects in bends can be: delaminations, risks, looseness, corrosion-fatigue cracks, corrosion pits. 6.3. Ultrasonic flaw detection of bends is recommended to be carried out after visual inspection, measurement of ovality, IVD and wall thickness measurement. 6.4. The quality of bends is assessed based on a comparison of the parameters of the echo signals from the defect and the corner reflector of the “notch” type on a test sample of the appropriate standard size. 6.5. Test specimens for bend inspection are made from straight sections of pipes. The material of the samples must correspond to the material of the controlled bending. When inspecting bends that have been in operation for more than 50 thousand hours, it is recommended to make samples from pipes that have worked for the same period. To adjust the flaw detector, corner reflectors (“notches”) are made on the inner and outer surfaces of the test sample (see Fig. 2) using the technology given in Appendix 5 of OP No. 501-PD-75. The dimensions of the corner reflectors and bend control parameters depending on the wall thickness are given in Table. 1. Table 1

Pipe wall thickness, mm

Dimensions of the corner reflector (“notches”), mm

Operating frequency, MHz

Emitter diameter, mm

Up to 15.0 incl.

St. 15.0 to 18.0 incl.

St. 18.0 to 22.0 incl.

Note. When inspecting bends with a wall thickness of up to 15.0 mm, it is permissible to use prisms at a frequency of 2.5 MHz with a piezoelectric plate at a frequency of 5.0 MHz. When using piezoplates with a diameter of 8.0 mm (5.0 MHz) in a finder prism at 2.5 MHz, it is recommended to use a centering washer made of textolite or getinax of appropriate thickness.

(Modified edition, Rev. 1987). It is recommended to check the correct manufacture of reflectors using the lead impression method. Based on the shape of the impression, the angular and linear dimensions of the reflector are checked using an instrumental microscope. The following tolerances are established for the deviation of the angular and linear dimensions of reflectors: ± 0.1 mm - for the width and height of the reflector; ±2.0° - according to the angle of inclination of the reflective face. A marking is applied to the sample containing the outer diameter, wall thickness, steel grade, offset marks of the location of the reflective edges, reflector, reflector area, sample registration number according to the logbook. 6.6. For ultrasonic testing of bends, UDM-1M, UDM-3, DUK-66P (DUK-66PM) and other ultrasonic devices equipped with prismatic finders are used. To control bends with a ratio of the nominal wall thickness to the nominal pipe diameter less than or equal to 0.1, finders with a prism angle of 40 or 30° are used, more than 0.1 - 30°. 6.7. Inspection of bends with a diameter of less than 273 mm is carried out using ground finders. Before grinding, it is allowed to select finders according to Appendix 5. It is recommended to select the optimal angle of the finder prism from Fig. 9. (Modified edition, Rev. 1987). 6.8. To increase the sensitivity of the finder at a frequency of 5 MHz, it is possible to improve the piezoplate mounting unit in accordance with Appendix 6. 6.9. The finder is suitable for monitoring if the amplitude values A B The echo signal from the upper notch of the test sample meets the requirements of Table 2. In this case, the amplitude of the echo signal from the lower notch is set equal to 25 divisions. scale 1 of the "Distance" regulator in the mode Himp for flaw detectors of the UDM type or 20 dB for flaw detectors with an amplitude scale in decibels. table 2 (Modified edition, Rev. 1987). 6.10. It is recommended to check the quality of the finder's work during the process of adjusting the sensitivity of the flaw detector and control according to Table. 2. 6.11. The flaw detector is adjusted using notches made on the outer and inner surfaces of the test sample (see Fig. 2) in accordance with the selected scheme (Fig. 3, a). For ultrasonic testing of bends, a control scheme is used with a direct and once reflected beam (positions I, II in Fig. 3, a). For ultrasonic testing of bends with a wall thickness of less than 12 mm, it is permissible to use a testing scheme with a direct, once and twice reflected beam (positions I, II, III in Fig. 3, a). 6.12. The setting is carried out after installing the regulators in the following positions: - for a device of the UDM type: TVR - left, “Power” - right; “Cut-off” - zero; "Type of measurement" - Himp; “Distance, cm” - left; “Sensitivity” - right; “Frequency” - according to Table 1; - for the DUK-66P device: VARU - left; “Cut-off” - zero; “Weakening” - left; “Operating mode” - I; “Frequency” - according to Table 1; “Sweep smoothly” - left; "Delay" - "off". When operating with devices such as UDM and DUK-66P, the sound range is set according to Table 3.

Rice. 3. Flaw detector setup diagram:

a - setting according to the test sample; b - oscillogram of the flaw detector; finder position when playing:

I - notches with a straight beam; II - once reflected beam; III - twice reflected beam; b - angle of inclination of the finder prism; a is the angle of insertion of the ultrasonic beam; D x- distance from the insertion point to the plane of the notch location; A, B - sound zones (A - for positions I, II; B - for positions II, III) Table 3 (Modified edition, Rev. 1987). 6.13. The sequence of operations when setting up a flaw detector: - install the finder on the test sample and, moving it in a reciprocating motion perpendicular to the generatrix, make sure that there is an echo signal from the lower and upper notches. The scan speed is set using the “Smooth Sweep” controls so that the echo signal from the top notch is in the second half of the screen. The position of the echo signal on the scan line is recorded on the screen scale or on a strip of graph paper pasted below the scan line; - establish a rejection sensitivity level for defects located in the lower two-thirds of the bend section. To do this, the finder is set to the position of the maximum signal from the lower notch (position I in Fig. 3, a). With the “Distance, cm” regulator in a fixed position - 25 parts of scale I (UDM) or “Attenuation” - 20 dB, the signal height is reduced to 10 mm across the device screen using the “Cut-off”, “Power”, “Sensitivity” regulators; - the “Distance, cm” (UDM) or “Attenuation” (DUK) regulators are set to zero with the remaining positions of the other regulators unchanged; - establish a rejection sensitivity level for defects located in the upper third of the bend section. To do this, the finder is moved to the position of the maximum signal from the upper notch (position II in Fig. 3, a) and its amplitude is reduced to a height of 10 mm along the flaw detector screen using the “Distance, cm” or “Attenuation” regulators; - set the control level of sensitivity in accordance with Table 4 and measure the distance of the echo signal (conventional height) from the upper and lower notches in millimeters along the flaw detector screen. Table 4 (Modified edition, Rev. 1987). 6.14. In the process of setting up the flaw detector, the following control parameters are recorded: - amplitude of the echo signal from the top ( A B) and lower ( A N) notch; - distance of the echo signal from the top ( P V) and lower ( P N) notch. 6.15. Ultrasonic flaw detection of bends is carried out using a combined scheme with one finder. It is allowed to use a separate and combined monitoring scheme with two detectors. Appendix 7 shows the control method using an acoustic unit. 6.16. Before carrying out ultrasonic testing of bends, preparatory work is carried out in accordance with the requirements of OP No. 501 TsD-75 (clauses 1.4.1; 1.4.2; 1.4.7-1.4.10). In order to ensure the reliability of acoustic contact, the surface of the controlled bend along the entire length (up to the junction with straight sections plus 100 mm) is freed from insulation, flaking scale, dirt, and cleaned with metal brushes or sandpaper. To remove dense scale, it is allowed to use a thermal method (see Appendix 3 of OP No. 501 CD-75). Before inspection, the prepared bending surface is wiped with a rag and coated with a thin layer of contact lubricant (autol, machine oil). Solidol is not recommended for use. Surface preparation and removal of contact lubricant after ultrasonic testing is performed by specially designated personnel. 6.17. Scanning of the bend surface is carried out by reciprocating movements of the finder, oriented perpendicular to the bend generatrix, with simultaneous rotation by 10-15° in both directions relative to its own axis (Fig. 4). In places with increased curvature compared to the nominal one, it is recommended to slightly rock the finder relative to the beam entry point in a plane perpendicular to the bend generatrix. 6.18. Control of bends is carried out at a search sensitivity level, which is set using the “Distance” (UDM) or “Weakening” (DUK-66P) regulators as follows: - when monitoring new bends: 8 parts. H imp scale (UDM); 8 dB scale "Attenuation" (DUK-66P); - when monitoring bends in operation: 5 cases. H imp scale (UDM); 4 dB scale "Attenuation" (DUK-66P). (Modified edition, Rev. 1987).

Rice. 4. Bend control scheme:

1 - input point; 2 - control on the left; 3 - control on the right

Note. The sides of control are determined in relation to the course of the environment. 6.19. A sign of a defect in the bending metal is the appearance of an echo signal in the scanning area limited by the working area (see Fig. 3, b): zone A - when testing with a direct and once reflected beam; zone B - when controlled once and twice by a reflected beam. The appearance of an echo signal near the leading edge of the working area (position I in Fig. 3, b) or the rear edge (position III in Fig. 3, b) indicates the location of the defect near the inner surface. The echo signal in the working area (near position II in Fig. 3, b) indicates the location of the defect near the outer surface. In this case, the location of the defect can be determined by probing the surface of the bend with a finger dipped in oil. 6.20. When a defect is detected, its location is determined along the perimeter of the bend and parameters are measured: the amplitude of the echo signal A when testing from opposite sides and the path of the echo signal P when testing from opposite sides. The amplitude of the echo signal is measured by reducing the height of the echo signal on the device screen to 10 mm using the “Distance, cm” (UDM) or “Attenuation” (DUK-66P) regulator. The measured amplitude values are recorded. The range of the echo signal is measured in millimeters on the screen scale at the control sensitivity level (according to Table 4). If the envelopes of echo signals at the search sensitivity level (according to clause 6.18) from two defects are superimposed on one another, then it is considered that one defect has been detected. The location of the defect(s) along the perimeter of the bend approximately relates to one of the zones - tensile, neutral or compressed. If it is necessary to accurately indicate the location of defects, their coordinates are measured D x relative to the middle of each zone during transverse scanning on the right and left (see Fig. 4) after adjusting the scan speed recommended in Appendix 8. 6.21. The quality of bends based on the results of ultrasonic testing is assessed by two ratings: “Unfit” (defect) and “Pass”. The notch is unfit (rejected) if: - defects are detected, the amplitude or range of the echo signal from which is equal to or exceeds the rejection values for the corresponding notch. In this case, defects in the lower two-thirds of the bend section are assessed by a notch on the inner surface of the test sample, the rest - by the upper notch; - a defect was detected on the inner surface of the neutral zone, the amplitude exceeding the control sensitivity level (see Table 4). The final assessment of the continuity of the bending metal is made after removal of external defects and repeated ultrasonic testing. The bends are acceptable if no defects with rejection characteristics are found during the inspection process. In case of difficulties in assessing defects detected at a frequency of 5 MHz on bends in service with a wall thickness of up to 15 mm, it is recommended to additionally carry out inspection at a frequency of 2.5 MHz. If the amplitude of the echo signal from the defect during testing at a frequency of 2.5 MHz exceeds the amplitude of the echo signal from the notch, the defect is considered unacceptable. (Modified edition, Rev. 1987).

7. PREPARATION OF TECHNICAL DOCUMENTATION BASED ON THE RESULTS OF DEFECTOSCOPY

7.1. Based on the results of flaw detection, documentation is drawn up separately by type of control (see clause 2.4). 7.2. At manufacturing plants, information on each type of control is presented in the form established at the plant. Documentation can be issued for a group of bends. 7.3. The amount of information in documents is determined by the types of control. The results of control during the manufacture of bends are presented without deciphering the nature of the defects. When inspecting bends at thermal power plants, the size and location of defects must be presented. 7.4. The documentation for each type of control indicates: - the date of the control and the number of the conclusion (or journal entry); - factory mark (or number, position at the installation site) and standard size of the bend; - steel grade; - place of inspection (in the workshop, on the plaza, on the boiler, etc.); - name of the document regulating the need and scope of control; - control results and quality assessment; - name and signature of the person conducting the control. Certificate number of the flaw detector (for inspection at thermal power plants); - name and signature of the engineer responsible for carrying out the control (head of the laboratory, group, etc.). (Modified edition, Rev. 1987). 7.5. The scope of information recorded in control documents: - when measuring ovality - type of tool, device; - for MTD - magnetization method, type (brand) of device or device; characteristics of detected defects (dimensions and location areas), method of eliminating defects, dimensions of the sampling area; - for ultrasonic thickness gauging - type (brand), serial number of the device, type of finder, frequency of ultrasonic vibrations (except for manufacturers), registration number of the test sample, measurement results (minimum wall thickness in the neutral and stretched zones, straight section near the bend); for ultrasonic testing - type (brand) serial number of the flaw detector, type of finder, prism angle, frequency, diameter of the piezo plate, registration number of the finder, registration number of the test sample, settings according to clause 6.14, size and location of detected defects. (Modified edition, Rev. 1987). 7.6. An example of drawing up a conclusion on bend control is given in Appendix 9.

8. SAFETY PRECAUTIONS

8.1. Persons who have undergone safety training and are registered in a special journal are allowed to work on flaw detection testing of bends. 8.2. Instruction is carried out within the time limits established by the order of the enterprise (organization). 8.3. In the conditions of a power plant, flaw detection inspection is carried out by a team of two people (when using circular magnetization - at least three people - one worker and two operators) according to an assigned system of access to work. 8.4. Before any switching on, flaw detectors (for ultrasound or MTD) must be reliably grounded with a non-insulated flexible copper wire with a cross-section of at least 2.5 mm 2 (for circular magnetization, at least 10 mm 2). 8.5. If there are no plug sockets at the workplace indicating the voltage, connecting the flaw detectors to the network and disconnecting them from it is carried out by the electrical shop staff on duty (at the plant - by the electrician on duty). 8.6. Flaw detectors must work in protective clothing that does not restrict movement and in hats. 8.7. It is prohibited to carry out inspections near the welding site. 8.8. When carrying out ultrasound examination, occupational hygiene requirements when working with oils must be observed. 8.9. To prevent fire, oil rags should be stored in a metal box.

Annex 1
METHODOLOGICAL INSTRUCTIONS FOR ULTRASOUND OF BENDS FOR THE PRESENCE OF TRANSVERSE CRACKS

1. Inspection for transverse cracks is carried out after ultrasonic testing in accordance with Section 6 of these Instructions. 2. For testing, ultrasonic echo-pulse flaw detectors UDM-1M, UDM-3, DUK-66P with prismatic finders are used according to Table 5. When inspecting bends with a wall thickness of 20 mm or more, flaw detectors must have applied scales in accordance with clause 1.3.2 of OP No. 501 TsD-75. Table 5 The use of flaw detectors of other types is allowed if there are additional guidelines that take into account the specifics of the equipment. 3. Ultrasonic flaw detection of pipe bends with a diameter of up to 200 mm is carried out using a ground finder in accordance with clause 1.4.6 of OP No. 501 CD-75. 4. The duration of the scan must be set so that twice the thickness of the wall of the controlled bend fits within the limits of the flaw detector screen. The depth gauge is adjusted in accordance with the flaw detector operating instructions. 5. The sensitivity of the flaw detector is adjusted: - when testing bends with a thickness of over 20.0 mm - using a side cylindrical reflector with a diameter of 6 mm at a depth of 44 mm in standard sample No. 2 according to GOST 14782-76. In this case, the knobs that regulate the sensitivity of the flaw detector and the power of the probing pulse set the maximum amplitude of the echo signal from this reflector at the level of 10 mm across the screen when installing the attenuator in accordance with Table 1 of OP No. 501 TsD-75 on the control points (for UDM flaw detectors) or attenuation values corresponding to these points in decibels (for flaw detectors DUK-66P); - when inspecting bends with a thickness of 5.0 to 20.0 mm - along notches on test specimens for inspection of welded joints of pipelines without backing rings in accordance with Table 6 and in accordance with clause 2.4 of OP No. 501 TsD-75. In this case, the knobs that regulate the sensitivity of the flaw detector and the power of the probing pulse set the maximum amplitude of the echo signal from a notch on the inner surface of the sample at a level of 10 mm on the screen when installing the attenuator: - 25 mm on the “Distance I” scale in mode Himp for flaw detectors type UDM; - 20 dB for flaw detectors DUK-66P. Table 6 6. In the mode of searching for defects, the attenuator is set to the following positions: 0-5 div. - for flaw detectors of the UDM type; 0 dB - for flaw detectors DUK-66P. The control is carried out according to the scheme of a direct and once reflected beam. Scanning is carried out along the bend generatrix with a transverse step of no more than 5 mm. 7. When an echo signal from a defect is detected, the bends are rejected if: - when testing bends up to 20 mm thick, the amplitude of the echo signal from the defect is equal to or exceeds 15 mm on the “Distance I” scale for flaw detectors of the UDM type or 14 dB for flaw detectors DUK -66P; - when inspecting bends with a thickness of 20 mm or more, the amplitude of the echo signal from a defect is equal to the value of the control level, determined taking into account the depth of the defect, or exceeds it (on an internal scale of 3 for flaw detectors of the UDM type, or 6 dB less than the level value set for given depth according to the additional scale on the coordinate ruler of the DUK-66P flaw detector). 8. The results of control are documented in accordance with the requirements of Section. 7 of these Instructions.

Appendix 2
METHODOLOGICAL INSTRUCTIONS FOR ULTRASONIC CONTROL OF BENDING WITH SURFACE WAVES

1. Ultrasonic surface wave testing is used to detect cracks on the outer surface of the stretched part of steam pipe bends. 2. For monitoring, UDM-1M, UDM-3 devices are used, equipped with non-serial prismatic finders at a frequency of 1.8 MHz with a prism angle of 68° (Fig. 5), and test samples used for ultrasonic testing (see Fig. 2) . 3. Finder prisms are made of plexiglass. The piezoelement mounting unit is used from serial prismatic finders at a frequency of 1.8 MHz. 4. Constancy of the ultrasound entry point into the metal is achieved using a U-shaped clamp made of a metal plate 1-2 mm thick. The clamp is fixed to the prism with screws in the slots of the plate. 5. The flaw detector is adjusted using test samples by moving the clamp until an echo signal 40 mm high is received on the screen from the top notch of the established area. The clamp is secured with screws. The location of the echo signal on the device screen is marked with a strobe pulse and measured by the distance from the finder to the notch ( D x). The maximum signal from the notch and from the defect must be measured at a constant distance of the finder from the notch (for example, 50 mm along the surface). Control is carried out by longitudinal movement of the finder, oriented perpendicular to the bend (Fig. 6). 6. A sign of defects is a series of pulses with a height of more than 10 mm appearing on the flaw detector screen in the inspection area. The location of the defects is determined after combining the pulses from the defects with the mark on the screen. In this case, the defect will be located at a distance D x from the seeker. 7. Defective areas are sanded and checked again by MPD or etching; if the defect is confirmed, it is sampled or sanded, followed by checking the completeness of the sample using the MPD method or etching.

Rice. 5. Search head

Rice. 6. Scheme for sounding bends:

1 - creep zone

Appendix 3

1. Means for magnetic particle testing 1.1. Flaw detectors DMP-ZM, MD-10Ts, MD-50P and other types that provide similar parameters can be used as magnetizing devices for circular and longitudinal magnetization. 1.2. For longitudinal (pole) magnetization, alternating current electromagnets are used with the parameters specified in the “Instructions for the use of portable magnetizing devices for magnetic particle flaw detection of power equipment parts without cleaning surfaces” (M.: SPO Soyuztekhenergo, 1978), DME-20Ts and others, ensuring the magnetic field strength in the center of the interpolar space on the product is not lower than the value calculated according to the recommended Appendix 2 of GOST 21105-75 (conditional sensitivity level "B"). Longitudinal magnetization of a pipeline bend section for the presence of transverse defects can be carried out using a flexible power cable wound around the pipe on both sides of the controlled section. 1.3. Equipment for magnetic particle testing must provide an applied magnetic field strength of at least 30 A/cm for soft magnetic materials (coercive force N s< 10 А/см, остаточная индукция B r >1 T) steels. 1.4. Magnetic powders and pastes are used as an indicator of defects, which are applied to the controlled bending surface in the form of a suspension. The dispersion medium of the suspension is water with anti-corrosion and wetting agents. 1.5. The content of magnetic powder in 1 liter of dispersion medium is: black (TU 5-14-1009-79) or colored - 25 ± 5 g magnetic-luminescent - 4 ± 1 g The compositions of the magnetic suspension are given in the recommended Appendix 4 OST 108.004.109-80 "Products and seams of welded joints of power equipment of nuclear power plants. Magnetic particle testing technique." The viscosity of the dispersion medium should not be higher than 30·10 -6 m 2 /s (30 cSt) at the control temperature. 2. Control technology 2.1. During magnetic particle inspection of pipeline bends, the following operations are performed: preparing the equipment and surface of the pipeline bend for inspection; magnetization; applying an indicator in the form of a powder or suspension to the controlled area; marking defective areas and evaluating inspection results. 2.2. Before testing, the functionality of the magnetizing device components is checked. The operation is performed using measuring instruments included in the device kit, magnetic field meters and a control sample made in accordance with the recommended Appendix 6 of OST 108.004.109-80, or a sample with cracks selected from among the rejected pipe bends. At the same time, the technological properties of the magnetic suspension are checked on a controlled sample based on signs of the presence of a dense bead of powder on existing cracks. 2.3. The choice of the value of the applied field for the controlled steel grade is made according to the recommended Appendix 2 of GOST 21105-75 (conditional sensitivity level "B"). When calculating the value of the magnetizing current based on the value of H pr for circular and longitudinal magnetization, you can be guided by the recommendations of Appendix 8 (clauses 2, 3, 4) OST 108.004.109-80. 2.4. The surface of pipeline bends to be inspected must have a roughness no worse than R a= 10 µm ( R z= 40 µm) according to GOST 2789-73. 2.5. The bend is magnetized in sections using the applied field method. With circular magnetization, the distance l between electrical contacts should be within 70-250 mm; in this case, the width of the control zone should be no more than 0.6 l. 2.6. To identify differently oriented defects, the bending section is magnetized in mutually perpendicular directions. 2.7. Application of a magnetic suspension to the controlled area using the applied field method should stop 2-3 seconds before turning off the field source. 2.8. The illumination of the controlled surface must be at least 500 lux (when using incandescent lamps). 2.9. The control results are assessed by the presence of a dense bead of magnetic powder on the controlled surface, which is reproducible each time with multiple (2-3 times) checks. 2.10. The results of magnetic particle testing are recorded in a journal (clause 7 of these Instructions), and if necessary, the defective area is photographed or a defectogram is taken using transparent adhesive tape. The location of the defect is marked with paint, chalk and other means. 2.11. After inspection, if necessary, the installation sites of electrical contacts are cleaned. Appendix 3. (Changed version, Rev. 1987).

Appendix 4
THICKNESS METHOD USING UDM-1M and UDM-3 DEVICES

1. When measuring the thickness of bends with UDM-1M or UDM-3 devices, the following finders are used: - separate and combined at a frequency of 5 MHz for a thickness of up to 20 mm; - separate and combined (PC) at a frequency of 2.5 MHz with a thickness of 20-45 mm; - direct normal, combined at a frequency of 1.8 (1.25) MHz with a thickness of more than 45 mm. In this case, if normal finders are used, the adjustment of the depth-measuring device and thickness measurements are carried out in accordance with the factory operating instructions, when using RS finders - in accordance with clause 4 of this appendix. 2. Before using flaw detectors with RS detectors, their suitability is checked, for which the device regulators are set to the following positions: - “Power”, “Sensitivity”, “Smooth sweep” - far right; - “Cut-off”, “VRF”, “Distance” - leftmost; - "Measurement type" - smooth sweep; - "Sound range" - 1; - the “Type of measurements” switch is set to the “Smooth sweep” position and the alignment of the leading edges of the probing and strobe pulses is checked. If there are overlaps, the leading edge of the strobe pulse must be between the sweep start point and the leading edge of the probing pulse when the “Distance, cm” control is set to zero. If the pulses are combined, the “Type of measurements” switch is switched to the “Du” position and the device is set up. If there is no alignment, the device should be replaced. 3. The flaw detector is adjusted using stepped samples made of steel of the same grade as the controlled bending. To control bends with a diameter of up to 133 mm inclusive, samples are made according to Fig. 7, a, for bends with a diameter of more than 133 mm - fig. 7, b. Markings are applied to the surface of the test sample indicating the nominal diameter and thickness of the pipe, steel grade, numerical values of the step height, as well as the minimum and maximum wall thicknesses of the sample. 4. Setting up flaw detectors for measuring thickness up to 20 mm is carried out in the following order: - the finder is installed on the step of the test sample with a maximum negative tolerance ( Smin). Using the “Cutoff” and “Sensitivity” regulators, the signal amplitude is reduced to 15-20 mm across the device screen; - the “Distance, cm” regulator is moved to the mark corresponding to the nominal value of the thickness of the measured step on the appropriate scale; - using the “Start Du” potentiometer, the leading edge of the strobe pulse is combined with the leading edge of the echo signal; - the finder is installed on the step of the test sample with a maximum positive tolerance ( SMax). Using the “Cutoff” regulator, the elo-signal increases to a height of 15-20 mm across the screen; - the “Distance, cm” regulator is moved to the mark corresponding to the nominal value of the thickness of the measured step on the appropriate scale; - the “End Du” potentiometer combines the leading edges of the strobe pulse and echo signal. To ensure the required adjustment accuracy, all of the above operations are repeated several times. 5. Thickness measurement using RS finders is carried out in the following order: - through a layer of contact lubricant, the finder is applied to the surface being measured so that the radiation-reception plane is oriented along the generatrix and there is a clear bottom echo signal; - use the “Power” and “Sensitivity” knobs to set the height of the echo signal to 10-15 mm on the device screen; - using the "Distance", cm" regulator, the leading edge of the strobe pulse is combined with the leading edge of the echo signal. The value of the measured thickness is recorded on scale 1 "Distance, cm".

Rice. 7. Test samples for thickness gauging of bends with diameter:

a - up to 133 mm; b - over 133 mm; 1 - marking

Appendix 5
METHOD FOR CHECKING THE SUITABILITY OF FINDERS FOR CONTROL OF BENDS

1. The methodology determines the method of selecting finders by sensitivity and checking the correctness of their grinding in accordance with Table 2. 2. The test is carried out according to a standard sample (GOST 14782-76). In this case, the amplitude of the echo signal from the side drillings of the S.O. is measured. N 1 with control sensitivity adjusted by a hole with a diameter of 6 mm at a depth of 44 mm to a given level according to S.O. N 2 in accordance with table 7. Table 7

Finder nominal frequency, MHz

Finder prism angle, degrees.

The sensitivity level of the device adjusted according to S.O. N 2

Signal amplitude H imp from lateral drilling S.O. N 1, located at a depth, mm

Difference in signal amplitudes (dB) from side drilling S.O. N 1, located at a depth, mm

St. 3 to 10 incl.

(Modified edition, Rev. 1987). The finder is considered suitable for testing if the amplitude of the echo signal from side drillings with a diameter of 2 mm S.O. N 1 corresponds to the values in Table 7. To measure the amplitude of the echo signal with devices such as UDM, the "Type of measurements" switch is set to position " Himp". The amplitude is measured on a scale of 1 "Distance, cm", the total value of which is taken equal to 100 divisions, " Himp". Measuring the sensitivity of finders is carried out with prisms with angles of 30 and 40° that are not ground in along the curvature of the bends. If it is necessary to check the sensitivity of finders with ground prisms, the carriage with the piezoelectric plate is moved to a non-ground prism and the operations listed in paragraph 2. 3 are performed. The working surface of the finders is ground in along the curvature of the pipe as follows: - determine the position of the entry point according to S.O. N 3 GOST 14782-76; - on a sheet of paper, depict the full contour of the finder prism on a scale of 1: 1 (Fig. 8), on which the entry point (m) is marked ); - according to the graph (Fig. 9), set the value of the optimal prism angle (b 0) to control a given standard size of bends; - draw a straight line on the contour of the finder (see Fig. 8) Kn) at an angle b 0 to the surface of the electroacoustic contact ( Kl) through the vertex of the right angle of the rear part of the prism; - at the intersection point B of the specified straight line with the line dm connecting the center of the piezoplate d with the finder input point m, the perpendicular is restored; - along the perpendicular from point B, lay a segment equal to the radius of curvature of the working surface of the finder R, and from the resulting point 0 draw a circular arc abc ;

R = R T ,

Where R T- pipe radius; - the resulting contour is transferred to the finder prism; - the prism is filed along the contour and then ground in on an emery cloth placed on the surface of a test sample of a given size. Example. It is required to control a bend with a diameter of 159 mm and a thickness of 12 mm. The ratio of wall thickness to diameter is 0.075. From the graph in Fig. 9 (solid line) determine that the optimal prism angle (at which a meeting angle with the defect is equal to 45° is ensured) is 30°. (Modified edition, Rev. 1987).

Rice. 8. Scheme of constructing the working surface of the finder

Rice. 9. Graph for choosing optimal prism angles

Appendix 6
IMPROVEMENT OF THE PIEZO PLATE ATTACHMENT UNIT

The unit body is made of plexiglass according to TU 26-57, TU 1783-53 or class 1 GOST 9389-60. Plexiglas is cut into 15 × 15 mm bars with a length of 150-250 mm and turned on a lathe to a diameter of 10 mm. Further processing is carried out in the following order (Fig. 10, a): - the cylindrical workpiece is machined to a diameter of 9 mm and trimmed; - hole 1 is drilled with a drill with a diameter of 5 mm; - cavity 2 is bored to a diameter of 7 mm; - cavity 3 is bored along the diameter of the piezo plate, taking into account its tight fit. After the piezoelectric plate is seated on the shoulder of cavity 3, the outer edge of the housing must be machined flush with the surface of the piezoelectric plate; - the processed part of the workpiece is cut along line 4-4; - a contact pad 5, a spring 6 and a piezoelectric plate 7 are inserted into the housing 4 (see Fig. 10, b);

Fig. 10. Piezo plate mounting unit:

a - manufacturing technology; b - assembly technology

To install the unit in a standard finder at a frequency of 5 MHz, the tension sleeve of the piezoplate mounting unit is cut off and an M6x0.75 thread is cut in the central hole. A sketch of the piezoplate mounting unit is shown in Fig. 11. To increase the reliability of electrical contact, a feeder connector is used, shown in Fig. 12.

Rice. 11. Sketch of the piezo plate mounting unit:

1 - prism; 2 - carriage; 3 - tension nut; 4 - body; 5 - contact pad; 6 - contact spring; 7 - piezo plate

Rice. 12. Sketch of the finder connector:

1 - central core of the feeder; 2 - insulation of the central core of the feeder; 3 - feeder braid;

4 - feeder insulation; 5 - contact sleeve; 6 - centering washers; 7 - clamping sleeve; 8 - connector body; 9 - connector shank

Appendix 7
METHOD FOR CONTROL OF BENDS USING AN ACOUSTIC BLOCK

1. The acoustic unit (Fig. 13) consists of a housing 1, which contains two seekers 2, placed in a magnetic circuit 3. One of the seekers is fixed in the housing, and the other can move in the grooves 4. 2. The operating frequency of the seekers must correspond to the values given in Table 1. 3. Finders must have the same sensitivity and should not differ from one another in echo signal amplitude by more than 2-3 units. scale "Distance, cm" or by 1 dB scale "Attenuation". 4. Finder prism angles should not differ by more than ±2° from the nominal values determined from the graph (see Fig. 9). 5. The block finders are switched on according to a separate-combined scheme (clause 3.1, drawings 15, 16 GOST 14782-76) in accordance with Fig. 14. Bends with a wall thickness of over 10 mm are controlled by a direct beam (Fig. 14, a), and bends with a wall thickness of up to 10 mm are controlled by a once reflected beam (see Fig. 14, b). 6. Inspection of bends using an acoustic unit is carried out using devices such as UDM or DUK. When operating with devices of the UDM type, control is carried out in the N pulse mode. The use of devices of other types is allowed if there are additional guidelines that take into account the specifics of the equipment. 7. The flaw detector is adjusted according to the test sample after setting the regulators to the following positions: “VRF”, “Cut-off” (DUK/66P) and “VRF”, “Cut-off” (UDM) - to the far left, “Power” - to the far right for all types. Sound range - "1", "Attenuation" controls - 4 dB (DUKP), "Distance, cm" (UDM) - 5 div. N imp. 8. The acoustic unit is mounted on the test sample and held on it using magnetic circuits. Finder 2 is moved along the guides until pulse F appears on the screen of the device, conventionally called “service”, and at its maximum value it is fixed with screws 5 of finder 2 (see Fig. 13). 9. By moving the block along the test sample, a signal is received from the lower reflector F, the “Distance” or “Attenuation” regulators are set to position 25. N imp(or 20 dB) and the “Sensitivity” regulator of a device of the UDM type or the “Power” (“Cutoff”) of a device of the DUK type set the amplitude of the echo signal at a level of 10-15 mm across the device screen. 10. With the sensitivity adjusted, the amplitude is measured from the upper reflector. 11. If the location of the echo signal from the reflector and the “service” pulse coincide, they are separated by moving the finder 2 in one direction or another, after which the amplitude of the echo signal from the reflectors is again measured. 12. The quality of the surface of the controlled bend is assessed by comparing the amplitude of the “service” pulse on the test sample and on two or three sections of the controlled surface. 13. If the amplitude of the “service” pulses on the test sample and on the controlled bend differs by more than 5 points. N imp(4 dB) due to peeling oxides, poor acoustic contact, roughness, then the bend surface must be additionally cleaned with a file, sandpaper or thermal method. 14. Control of bends is carried out by moving the block along the surface perpendicular to the generatrix in a reciprocating motion. The “service” pulse must be on the device screen during the entire sounding time. If it disappears, it is necessary to establish the cause (poor contact, malfunction of the device, finder, cable, etc.). 15. If an echo signal from a defect is detected, it is assessed in accordance with paragraphs. 6.20, 6.21 of these Instructions.

Rice. 13. Acoustic block

Rice. 14. Bending control schemes

Appendix 8
METHOD FOR SETTING THE SCANNING SPEED OF DEVICES TYPE UDM AND DUK

1. The scanning speed of the devices is adjusted to establish correspondence between the distance values from the point of entry of the finder to the defect, measured on the scale of the device “Distance, cm” and on the surface of the controlled product. The scan speed when working with prismatic finders is adjusted using the corner reflectors of the test sample in accordance with the selected control scheme. 2. The scan speed of a UDM type device is adjusted in the following order: - the “Cut-off” and “VRF” regulators are set to the left position, “Power” - to the right; "Type of measurement" - D X; "Frequency" - to the position corresponding to the operating frequency of the selected finder; - the finder is installed on the test sample in the position of the maximum signal from the lower reflector (position I in Fig. 3, a); - use a ruler to measure distance D X 1 from the point of entry of the finder to the plane in which the reflective surface of the lower notch is located, and this value is set on the “Distance, cm” scale; - potentiometer "Start of scale D X " combine the leading edge of the strobe pulse with the leading edge of the echo signal; - the finder is set to the position of the maximum signal from the upper reflector (position II in Fig. 3, a). Using the "Sensitivity" regulator, the amplitude of the echo signal is reduced to 10-15 mm above the scan line; - using a ruler, measure the distance D X2 from the point of entry of the finder to the reflective surface of the upper notch, and this value is set on the “Distance, cm” scale; - using the potentiometer “End of scale D X”, combine the leading edge of the echo signal with the leading edge of the strobe - pulse; - to ensure adjustment accuracy (± 1 mm), all the above operations should be repeated several times. After setting the coordinates D X, the scan speed is coordinated in the “D X" and " modes N imp". To do this, the location of the echo signals from the upper and lower reflectors is noted on the UDM screen. The "Type of measurements" switch is set to N imp, and with the “Ultrasonic Speed” regulator the sweep is set so that the echo signals are in the positions fixed when setting D X. (Modified edition, Rev. 1987). 3. The scanning speed of the DUK-66P device is adjusted in the following order: - the finder is installed on the test sample in the position of the maximum signal from the upper reflector (position II in Fig. 3, a); - use a ruler to measure the distance from the insertion point to the reflective surface of the upper notch D X2 and mark it in a convenient scale on the screen scale. The scale should be chosen so that the echo signal is in the second third of the scale; - using the “Smooth sweep” knob, the echo signal from the upper notch is combined with the mark (position I, in Fig. 3, b); - the finder is set to the position of the maximum signal from the lower reflector (position I in Fig. 3, a); - using a ruler, measure the distance D X1 from the entry point to the plane in which the reflective surface of the lower notch is located; - on the screen scale in the selected scale, mark the value D X1; - if mark D X1 on the screen scale does not coincide with the position of the echo signal from the bottom notch, the device must be replaced.

Appendix 9
METHODOLOGICAL INSTRUCTIONS FOR ULTRASOUND BENDS WITH THE RATIO OF WALL THICKNESS TO OUTER DIAMETER MORE THAN 0.17

1. To control bends with a ratio of nominal wall thickness to nominal outer diameter of more than 0.17, standard piezoelectric transducers with a frequency of 1.8 (1.25) and 2.5 MHz are used, providing a meeting angle (g) of the ultrasonic beam with the defect equal to 90°. The optimal angles of inclination of the prism are selected according to the attached graph (Fig. 15). 2. The flaw detector is adjusted using a test sample made from a straight section of pipe. The sample material must match the material of the controlled bend (Fig. 16). 2.1. When testing bends with a wall thickness of up to 30 mm, a corner reflector (“notch”) is made on the inner surface of a sample of the appropriate size; when testing bends with a wall thickness of more than 30 mm, a hole with a diameter of 2 mm and a depth of 15 mm is made on the side surface of the sample (see Fig. . 16). 2.2. The dimensions of the corner reflectors and the parameters of the piezoelectric transducer, depending on the wall thickness of the bends, are given in Table. 8.

Rice. 15. Graph for choosing optimal prism angles:

b - prism tilt; g - encounters with a defect; a - input

Note. When the angle of inclination of the prism is less than the 1st critical angle, due to the presence of a curved surface, the longitudinal wave does not play a role and the main one is the transverse (shear) wave.

Rice. 16. Test sample:

R H - nominal radius of the pipe; S H - nominal pipe thickness; a - notch height; b - notch width

Table 8 3. The flaw detector is configured in the following order: 3.1. In accordance with the operating instructions for the device, the depth gauge is adjusted by lateral drilling and notching on the inner surface of the test sample (Fig. 17).

Rice. 17. Setting up the depth gauge:

Beginning, - end

3.2. The scan speed is adjusted by smoothly moving the transducer along the surface of the sample. In this case, echo signals from notching and side drilling are found and placed on the device screen, as shown in Fig. 18. The position of the echo signal on the scan line is recorded on a scale on the device screen.

Rice. 18. Setting the sweep speed

3.3. Setting sensitivity involves setting control sensitivity levels: 3.3.1. Search level - at which defects are searched. 3.3.2. Control level - at which the admissibility of a defect detected on the inner surface of the neutral zone is assessed by the amplitude of the echo signal or by the range of the echo signal (conditional height) in any place. 3.3.3. The first rejection level is at which the admissibility of a defect detected on the inner surface is assessed based on the amplitude of the echo signal. 3.3.4. The second rejection level is at which the admissibility of a defect detected in the upper 3/4 of the bend section is assessed based on the amplitude of the echo signal. 3.4. The 1st rejection level of sensitivity is adjusted according to the notch. To do this, by smoothly moving the transducer along the working surface of the sample, the position of the maximum echo signal from the notch is found with the “Distance, cm” regulator in a fixed position - 25 divisions of scale 1 (UDM) or “Attenuation” - 20 dB (DUK). The height of the echo signal is reduced to 10 mm across the device screen using the “Cutoff”, “Power”, “Sensitivity” regulators. The control level is 14 dB, or 15 units, the 2nd rejection level is 26 dB, or 35 units. 3.5. Control of bends is carried out at the search sensitivity level, which is set using the “Distance, cm” or “Attenuation” regulators as follows: - when monitoring new bends: 8 scale divisions N imp(UDM), 8 dB scale "Attenuation" (DUK); - when inspecting bends in operation: 5 scale divisions N imp(UDM), 4 dB scale "Attenuation" (DUK). 4. The quality of bends is assessed based on the results of ultrasonic testing as follows: “Unfit” (defect) and “Pass”. Unfit (defective) if: - defects are found on the outer surface of the bend, the amplitude or range of the echo signal from which is equal to or exceeds the 1st rejection level; - a defect exceeding the control sensitivity level in amplitude was detected on the inner surface of the neutral bending zone; - a defect was detected in the bend section, the amplitude exceeding the 2nd rejection sensitivity level. Bends are considered acceptable if no defects with rejection characteristics are found during the inspection process. Appendix 9. (Introduced additionally, Amendment 1987). Appendix 10 The control was carried out: with an ultrasonic device UDM-3 (serial number 1705), a thickness gauge "Kvarts-6" (serial number 1407), a magnetic particle device DMP-2 (serial number 1211), a micrometer clamp (no. 325). Based on Circular No. T-3/77, in accordance with the “Instructions for flaw detection of pipeline bends made of pearlitic steel (I No. 23 SD-80) (M.: SPO Soyuztekhenergo, 1981) Inspection was carried out by: Ultrasonic inspection - flaw detectorist of the 4th category Ivanov I.I. (certificate No. 127-19k); MPD - I.I. Ivanov (magnetization method - circular); thickness gauging I.I. Ivanov; ovality measurement senior engineer KTC Petrov P.P.

Bend number according to the diagram

Nominal-
Pipe diameter, mm

Steel grade

Operating parameters of the bending environment

Number of starts/including from cold

Ovality measurement, %

Wall thickness measurement, mm

Ultrasonic testing and magnetic particle flaw detection

Control results and locations
marriage discovered
defects (based on the results of IVD, ultrasound and wall thickness measurements)

Method for eliminating defects

Prime -
desire

Pressure MPa (kgf/cm2)

Tempera-
round, °С

Operating hours, thousand hours

Straight Section Ring

Stretched zone

Neutral zones

Finder type

Frequency, MHz

Prism angle, deg.

Piezo diameter
plates, mm

Evaluation of control results

Prismatic

On the outer surface of the stretched part of the bend

Removed with a sample measuring 21x10x1.0 mm. Left in service

On the inner surface of the right neutral there are defects A d = 32 parts. at a length of 30 mm

Gib replaced

Not carried out

Rejected and replaced

Not carried out

Unacceptable wall thinning

Prismatic

No defects

Signature of the person who carried out the control __________________________ (surname, signature). Signature of the person responsible for control ______________________ (last name, signature) Head of the metals laboratory (section) ______________________ (last name, signature) (Modified edition, Rev. 1987).

In accordance with SNiP 3.05.03-85, the contractor carries out ultrasonic flaw detection of pipeline joints during the construction of a category IV heating route. The costs of quality control of welds are determined according to the prices of the GESNm-2001 Collection No. 39 “Control of installation welded joints”.

There were disagreements with the customer regarding the source of financing. The customer believes that compensation for these costs should take place through overhead costs under the article “Costs for the maintenance of production laboratories - payment for services provided to laboratories by other organizations (Appendix 6, section III, paragraph 9).

Is the Customer right?

Answer:

The customer is wrong, since there is an additional clarification from Rosstroy on this issue, which states that if non-destructive testing of welded joints is carried out by specialized organizations, then these costs are included in Chapter 9 of the consolidated estimate as a separate line in columns 7 and 8 and are paid to these organizations on the basis of the submitted accounts with the conclusion of an agreement.

Letter from Rosstroy dated January 28, 2005. No. 6-35 is given below. The “Guidelines for determining the amount of overhead costs in construction”, Appendix 6, section III, clause 9 “Costs for the maintenance of production laboratories” states that the overhead cost standards provide for the costs of paying for services provided to laboratories by other organizations.

The clarification of this provision is due to the fact that when these Guidelines were being prepared, Rosstroy believed that budgetary organizations would provide services free of charge. However, in fact, budgetary service organizations created private intermediaries and Rosstroy was forced to clarify this issue. It must be borne in mind that if there are discrepancies in the current documents on any issue, one should be guided by the document that was most recently published (Rosstroy’s letter No. 6-99 dated February 25, 2005 is given below).

The Federal Agency for Construction and Housing and Communal Services reports on this issue. In cases where ultrasonic testing and other types of non-destructive testing of welded joints are carried out by contracting construction organizations, the costs of their implementation are included in the overhead costs of the contracting organizations and are compensated by overhead costs accrued in the estimate documentation and acceptance certificates for work performed when the customer pays for the work to the contractor.

In cases where ultrasonic testing and other types of non-destructive testing of welded joints are carried out by specialized organizations, the costs of organizing testing of welded joints using non-destructive methods performed by specialized organizations are included in Chapter 9 of the consolidated estimate calculation as a separate line in gr. 7 and 8 and are paid to specialized organizations on the basis of submitted invoices with the conclusion of an agreement to perform work on monitoring welded joints using non-destructive methods.

The same applies to concrete testing using non-destructive methods.

The costs of stamp testing of soils are included in the overhead costs of contractors. The costs of geodetic control over the construction of buildings and structures and their structural elements, including channel supports, are included in the overhead costs of contractors. The costs of developing work projects, including the technological regulations for performing these works, are included in the overhead costs of contractors.

Letter from the Federal Agency for Construction and Housing and Communal Services

The Federal Agency for Construction and Housing and Communal Services reports on this issue.

With the approval of the Methodology for determining the cost of construction products on the territory of the Russian Federation - the Code of Rules for determining the cost of construction as part of pre-project and design estimate documentation - SP 81-09-94 - became invalid.

Regarding the determination of the amount of funds, one should be guided by the above-mentioned Methodology and the Collection of estimated cost standards for the construction of temporary buildings and structures -.

If there are discrepancies in the current documents on any issue, the most recently published document should be used.

Head of the Construction Department R.A. Maksakov

Visual inspection

Using an external examination, you can identify not only visible seam defects, but also invisible ones. For example, the unevenness of the seam in height and width indicates that there were interruptions in the arc during the welding process. And this is a guarantee that the seam inside has lack of penetration.

How to properly conduct an inspection.

The seam is cleaned of scale, slag and drops of metal.
Then it is treated with technical alcohol.
After another treatment with a ten percent solution of nitric acid. It's called etching.
The surface of the seam is clean and matte. The smallest cracks and pores are clearly visible on it.

Attention! Nitric acid is a material that corrodes metal. Therefore, after inspection, the metal weld must be treated with alcohol.

The magnifying glass has already been mentioned. Using this tool you can detect tiny flaws in the form of thin cracks less than a hair thick, burns, small cuts and others. In addition, using a magnifying glass you can check whether the crack is growing or not.

During inspection, you can also use calipers, templates, and a ruler. They measure the height and width of the seam, its even longitudinal location.

Magnetic inspection of welds

Magnetic flaw detection methods are based on the creation of a magnetic field that penetrates the body of the weld. For this purpose, a special apparatus is used, the operating principle of which is based on the phenomena of electromagnetism.

There are two ways to determine a defect within a connection.

Using ferromagnetic powder, usually iron. It can be used both dry and wet. In the second case, iron powder is mixed with oil or kerosene. It is sprinkled on the seam, and a magnet is installed on the other side. In places where there are defects, powder will collect.
Using ferromagnetic tape. It is laid on the seam, and the device is installed on the other side. All defects that appear at the junction of two metal workpieces will be displayed on this film.

This option for flaw detection of welded joints can be used to control only ferromagnetic joints. Non-ferrous metals, steels with chrome-nickel coating and others are not controlled in this way.

Radiation control

This is essentially fluoroscopy. Expensive devices are used here, and gamma radiation is harmful to humans. Although this is the most accurate option for detecting defects in a weld. They are clearly visible on film.

Ultrasonic flaw detection

This is another accurate option for detecting flaws in a weld. It is based on the property of ultrasonic waves to be reflected from the surface of materials or media with different densities. If the weld has no defects within itself, that is, its density is uniform, then sound waves will pass through it without interference. If there are defects inside, and these are cavities filled with gas, then inside you get two different environments: metal and gas.

Therefore, ultrasound will be reflected from the metal plane of the pore or crack, and will return back, displayed on the sensor. It should be noted that different flaws reflect waves differently. Therefore, the results of flaw detection can be classified.

This is the most convenient and fastest way to control welded joints of pipelines, vessels and other structures. Its only drawback is the difficulty of decoding the received signals, so only highly qualified specialists work with such devices.

Penetrant control

Methods for monitoring welds using the capillary method are based on the properties of certain liquids to penetrate into the body of materials through the smallest cracks and pores, structural channels (capillaries). The most important thing is that this method can control any materials of different densities, sizes and shapes. It doesn’t matter if it’s metal (black or non-ferrous), plastic, glass, ceramics and so on.

Penetrating liquids seep into any imperfections in the surface, and some of them, for example, kerosene, can pass right through fairly thick products. And most importantly, the smaller the size of the defect and the higher the absorption of the liquid, the faster the process of detecting the defect occurs, the deeper the liquid penetrates.

Today, specialists use several types of penetrating liquids.

Penetrants

From English this word is translated as absorbent. Currently, there are more than a dozen penetrant compositions (aqueous or based on organic liquids: kerosene, oils, and so on). They all have low surface tension and strong color contrast, making them easy to see. That is, the essence of the method is this: a penetrant is applied to the surface of the weld, it penetrates inside, if there is a defect, it is painted on the same side after cleaning the applied layer.

Today, manufacturers offer different penetrating liquids with different flaw detection effects.

Luminescent. From the name it is clear that they contain luminescent additives. After applying such a liquid to the seam, you need to shine an ultraviolet lamp on the joint. If there is a defect, then the luminescent substances will shine and this will be visible.
Colored. The liquids contain special luminous dyes. Most often these dyes are bright red. They are clearly visible even in daylight. Apply this liquid to the seam, and if red spots appear on the other side, then a defect has been detected.

There is a division of penetrants according to sensitivity. The first class is liquids that can be used to determine defects with a transverse size from 0.1 to 1.0 microns. Second class – up to 0.5 microns. It is taken into account that the depth of the flaw must be ten times greater than its width.

Penetrants can be applied in any way; today we offer cans of this liquid. The kit includes cleaners for cleaning the defective surface and a developer, with the help of which penetration of the penetrant is detected and the pattern is shown.

How to do it correctly.

The seam and heat-affected areas must be thoroughly cleaned. Mechanical methods cannot be used; they can cause dirt to enter into the cracks and pores themselves. Use warm water or soap solution, the last step is cleaning with a cleaner.
Sometimes it becomes necessary to etch the surface of the seam. The main thing is to remove the acid after this.
The entire surface is dried.
If quality control of welded joints of metal structures or pipelines is carried out at sub-zero temperatures, then the seam itself must be treated with ethyl alcohol before applying penetrants.
An absorbent liquid is applied, which must be removed after 5-20 minutes.
After that, a developer (indicator) is applied, which draws out the penetrant from the weld defects. If the defect is small, you will have to arm yourself with a magnifying glass. If there are no changes on the surface of the seam, then there are no defects.

Kerosene

This method can be described as the simplest and cheapest, but this does not reduce its effectiveness. It is carried out using this technology.

Clean the joint of two metal blanks from dirt and rust on both sides of the seam.
On one side, a chalk solution is applied to the seam (400 g per 1 liter of water). You must wait for the applied layer to dry.
Kerosene is applied to the reverse side. It is necessary to moisten generously in several approaches for 15 minutes.
Now you need to observe the side where the chalk solution was applied. If dark patterns (spots, lines) appear, it means there is a defect in the weld. These drawings will only expand over time. Here it is important to accurately determine where the kerosene comes out, so after the first application of it to the seam, you need to immediately carry out observation. By the way, dots and small spots will indicate the presence of fistulas, lines - the presence of cracks. This method is very effective for connecting connections, for example, pipe to pipe. It is less effective when welding overlapping metals.

Methods for quality control of welded joints for permeability

This control method is mainly used for containers and tanks that are made by welding. To do this, you can use gases or liquids that fill the vessel. After which excess pressure is created inside, pushing the materials out.

And if there are defects in the places where the containers are welded, then liquid or gas will immediately begin to pass through them. Depending on which control component is used in the verification process, four options are distinguished: hydraulic, pneumatic, air-hydraulic and vacuum. In the first case, liquid is used, in the second, gas (even air), and the third – combined. And the fourth is the creation of a vacuum inside the container, which, through defective seams, will draw coloring substances applied to the outside of the seam into the tank.

With the pneumatic method, gas is pumped into the vessel, the pressure of which exceeds the nominal pressure by 1.5 times. A soap solution is applied to the seam from the outside. Bubbles will indicate the presence of defects. During hydraulic flaw detection, liquid is poured into the vessel under pressure 1.5 times higher than the working pressure, and the heat-affected area is tapped. The appearance of liquid indicates the presence of a flaw.

These are the options for flaw detection of pipelines, tanks and metal structures that are used today to determine the quality of the weld. Some of them are quite complex and expensive. But the main ones are simple, which is why they are often used.

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