Types of electrical wiring installation technology. Coursework: Technology of installation of electrical wiring. Technological stages of installation

TESTING NON-DESTRUCTIVE

WELDED CONNECTIONS

RADIOGRAPHIC METHOD

GOST 7512-82

STANDARDS PUBLISHING HOUSE

Moscow

STATE STANDARD OF THE UNION OF THE SSR

Introduction date 01.01.84

This International Standard specifies a radiographic inspection method welded joints from metals and their alloys, made by fusion welding, with a thickness of welded elements from 1 to 400 mm, using X-ray, gamma and bremsstrahlung radiation and radiographic film.

1. GENERAL PROVISIONS

1.1. Radiographic control is used to detect cracks, lack of penetration, pores, slag, tungsten, oxide and other inclusions in welded joints.

1.2. Radiographic control is also used to detect burns, undercuts, assess the magnitude of the convexity and concavity of the root of the seam, which are unacceptable for external examination.

any discontinuities and inclusions with a size in the direction of transmission less than twice the sensitivity of the control;

lack of penetration and cracks, the opening plane of which does not coincide with the direction of translucence and (or) the opening value is less than the values \u200b\u200bgiven in;

any discontinuities and inclusions, if their images on the pictures match the images of foreign parts, sharp corners or sudden changes cracks in translucent metal.

1.1 - 1.3.

Table 1

1.4. Welded joints with a ratio of the radiation thickness of the deposited weld metal to the total radiation thickness of at least 0.2 are subjected to radiographic control, having bilateral access, which makes it possible to install a cassette with a radiographic film and a radiation source in accordance with the requirements of this standard.

(Introduced additionally, Rev. No. 1).

2. REQUIREMENTS FOR CONTROL ACCESSORIES

Markings of sizes established by GOST 15843-79 should be used.

2.2. During radiographic control, radiographic films that meet the requirements of the technical specifications for them should be used.

The type of radiographic film must be set technical documentation for inspection or acceptance of welded joints.

The type of radioactive source, the voltage on the X-ray tube and the energy of accelerated electrons must be established depending on the thickness of the material being scanned by the technical documentation for the control or acceptance of welded joints.

2.4. Metal and fluorescent screens should be used as intensifying screens for radiographic testing.

The type of intensifying screen must be established by the technical documentation for the control or acceptance of welded joints.

The thickness of metal intensifying screens and methods for loading film into cassettes using screens are given in.

2.5. Screens must have a clean, smooth surface. The presence of wrinkles, scratches, cracks, tears and other defects on the screens is not allowed.

2.6. Film loading cassettes must be opaque and provide a tight hold of the intensifying screens to the film.

2.7. To protect the film from scattered radiation, it is recommended to shield the film cassette from the side opposite to the radiation source with lead screens.

The thickness of the protective screens is given in.

1 - insert; 2 - cover.

2.8. To determine the sensitivity of the control, wire, groove or plate sensitivity standards should be used.

2.9. Sensitivity standards should be made of a metal or alloy whose base is similar in chemical composition to the base of the welded joint being tested.

2.10. The shape and dimensions of the wire sensitivity standards are given on and in. The length of the wires in the standards is (20 ± 0.5) mm. Limit deviations for wire diameters:

up to 0.2 mm... + 0.01 mm

St. 0.2 to 1.6 mm... ± 0.03 mm

» 1.6 » 4.0 mm... ± 0.04 mm.

table 2

Limit deviations of other sizes - ± 0.5 mm. The insert and case for wire standards should be made of flexible transparent plastic.

(Revised edition, Rev. No. 1).

2.11. The shape and dimensions of the groove gauges are shown on and in .

2.12. The shape and dimensions of the plate sensitivity standards are given on and in.

Groove depth

Previous off groove depths

R, no more

Previous off

(Revised edition, Rev. No. 1).

Table 4

Previous off

Symbols for the material of the sensitivity standard: for alloys based on iron - 1, aluminum and magnesium - 2, titanium - 3, copper - 4, nickel - 5.

2.14. For marking groove standards, it is allowed to use cutouts and holes, or only the holes specified in. In this case, the thickness of the standard at the place of marking should be equal to h.

When marking standards with holes, the length of standard No. 1 is 27-0.52 mm, No. 2 - 38.5-0.62 mm, No. 3 - 53-0.74 mm.

2.15. For welded products intended for export, it is allowed to use other types of sensitivity standards, if it is provided for by the export conditions.

3. PREPARATION FOR CONTROL

3.1. Radiographic control should be carried out after removing external defects found during external examination of the welded joint and cleaning it from bumps, slag, metal splashes, scale and other contaminants, the images of which in the image may interfere with the interpretation of the image.

3.2. After stripping the welded joint and eliminating external defects, the welded joint should be marked into sections and marked (numbered) of the sections.

3.1, 3.2. (Changed edition, Rev. No. 1).

3.3. The system for marking and marking sections is established by technical documentation for the control or acceptance of welded joints.

3.4. During the control, sensitivity standards and markings should be installed at each site.

3.5. Sensitivity standards should be installed on the controlled area from the side facing the radiation source.

3.6. Wire standards should be installed directly on the seam with the direction of the wires across the seam.

3.7. Groove standards should be installed at a distance of at least 5 mm from the seam with the direction of the grooves across the seam.

3.8. Plate standards should be installed along the seam at a distance of at least 5 mm from it or directly on the seam with the direction of the standard across the seam so that the images of the marking marks of the standard do not overlap with the image of the seam in the picture.

3.9. When inspecting the circumferential welds of pipelines with a diameter of less than 100 mm, it is allowed to install groove standards at a distance of at least 5 mm from the weld with the grooves directed along the weld.

3.10. If it is impossible to install standards from the side of the radiation source when testing welded joints of cylindrical, spherical and other hollow products through two walls with deciphering only the area of the welded joint adjacent to the film, as well as during panoramic transillumination, it is allowed to install sensitivity standards from the side of the film cassette.

3.11.(Deleted, Rev. No. 1).

3.12. Markings, used to limit the length of the sections of welded joints controlled in one exposure, should be installed at the boundaries of the marked sections, as well as at the boundaries of the deposited and base metal when testing welded joints without reinforcement or with the weld reinforcement removed.

3.13. The markings used for numbering the controlled areas should be installed on the controlled area or directly on the film cassette so that the images of the marks on the pictures do not overlap with the image of the seam and the heat-affected zone according to .

3.14. If it is impossible to install sensitivity standards and (or) markings on the controlled area of the welded joint in accordance with the requirements of this standard, the procedure for testing without installing sensitivity standards and (or) markings should be provided in the technical documentation for the control or acceptance of welded joints.

4. CONTROL SCHEMES

4.1. Welded joints should be controlled by and.

4.2. With a limited width of the element to be welded, it is allowed to inspect tee welded joints with the direction of radiation along the generatrix of this element in accordance with.

4.2a. When testing circumferential welded joints of cylindrical and spherical hollow products, as a rule, it is necessary to use schemes of transillumination through one wall of the product (diagrams of Fig. 5 a, b, e, well, h). In this case, it is recommended to use transmission schemes with the location of the radiation source inside the controlled product:

5.1, 5.2 (Revised edition, Rev. No. 1).

for butt and lap joints:

not less than 5 mm - with a thickness of welded edges up to 5 mm;

not less than the thickness of the edges to be welded - with the thickness of the edges to be welded St. 5 to 20 mm;

not less than 20 mm - with a thickness of welded edges of St. 20 mm;

for tee and corner joints - is established by the technical documentation for the control or acceptance of these joints.

6. IMAGE INTERPRETATION

6.1. Viewing and interpretation of images should be done after they have completely dried in a darkened room using special illuminators-negatoscopes.

Negatoscopes with adjustable brightness and illuminated field size should be used. The maximum brightness of the illuminated field should be at least 10D+2 cd/m2, where D- optical density of the image. The dimensions of the illuminated field should be adjusted using movable shutters or mask screens within such limits that the illuminated field is completely covered by the image.

(Revised edition, Rev. No. 1).

6.2. Photographs approved for decoding must meet the following requirements:

the pictures should not have spots, stripes, pollution and damage to the emulsion layer, making it difficult to decipher them;

images of limit marks, markings and sensitivity standards should be visible on the pictures;

the optical density of the images of the controlled section of the weld, the near-weld zone and the sensitivity standard must be at least 1.5;

decrease optical density image of a welded joint in any part of this image, compared with the optical density of the image of the sensitivity standard, should not exceed 1.0.

6.3. Control sensitivity (the smallest diameter of the wire standard detected in the picture, smallest depth the groove of the groove standard detected in the image, the smallest thickness of the plate standard, at which a hole with a diameter equal to twice the thickness of the standard is detected in the image), should not exceed the values \u200b\u200bgiven in.

Table 6

	Sensitivity class


St. 5 to 9 incl.







» 100 » 140 »
» 140 » 200 »
» 200 » 300 »
» 300 » 400 »

Note. When using wire standards of sensitivity, values of 0.30; 0.60; 0.75 and 1.50 mm are replaced by 0.32; 0.63; 0.80 and 1.60 mm.

(Revised edition, Rev. No. 1).

Specific sensitivity values should be established by technical documentation (requirements of drawings, specifications, rules of control and acceptance) for controlled products.

For nuclear power plants, sensitivity requirements are established by the relevant regulatory documents.

6.4. In accordance with the requirements of technical documentation for controlled products, it is allowed to determine the sensitivity ( k) as a percentage according to the formula

where To- sensitivity, mm;

S- thickness of translucent metal, mm.

6.5. Interpretation and evaluation of the quality of welded joints from images that do not have images of sensitivity standards is allowed:

during panoramic transillumination of circumferential welded joints with simultaneous exposure of more than four films. In these cases, regardless of total number pictures, it is allowed to set one sensitivity standard for each quarter of the circumference of the welded joint;

when it is impossible to use sensitivity standards.

In these cases, the sensitivity is determined on the simulators of the welded joint during processing of control modes.

6.6. When deciphering the images, the dimensions of the images of cracks, lack of penetration, pores and inclusions are determined, and, if necessary, the magnitude of the concavity and convexity of the root of the weld is estimated (in cases where the root of the weld is not available for external examination).

The list of dimensions to be determined and the method for assessing the concavity and convexity of the weld root should be given in the technical documentation for the control and acceptance of welded joints.

6.7. When documenting the results of image interpretation, the sizes determined from the images should be rounded up to the nearest values from the range of 0.2; 0.3; 0.4; 0.5; 0.6; 0.8; 1.0; 1.2; 1.5; 2.0; 2.5; 3.0 mm or the nearest integer value in millimeters if the size determined from the image exceeds 3.0 mm.

6.8. If during the control the film is located at a distance H from the surface of the controlled welded joint facing the film and the relation

it is recommended to multiply the dimensions determined from the image before rounding them by the coefficient

where f- distance from the radiation source to the surface of the controlled section of the welded joint facing the source, mm;

s- radiation thickness, mm.

6.6 - 6.8. (Changed edition, Rev. No. 1).

6.9. When measuring the size of defects up to 1.5 mm, a measuring magnifier with a division value of 0.1 mm, St. 1.5 mm - any measuring device with a scale division of 1 mm.

6.10. The results of interpretation of images and the sensitivity of the control must be recorded in the conclusion or logbook of the results of control, the form of which should be established by the technical documentation for the control or acceptance of welded joints.

6.11. To indicate defects in the conclusion or log of control results, the symbols given in.

Examples of abbreviated recording of defects when deciphering images are given in.

7. SAFETY REQUIREMENTS

7.1. The main hazards for personnel during radiographic control are exposure to the body of ionizing radiation and harmful gases formed in the air under the influence of radiation, and electric shock.

7.2. Radiographic control and recharging of radioactive sources should be carried out only with the use of equipment specially designed for these purposes and in good condition, the documentation for the manufacture and operation of which, if issued in more than three copies, must be agreed with the USSR State Committee for the Use of Atomic Energy and the Chief Sanitary - epidemiological department of the Ministry of Health of the USSR; up to three copies - with local bodies of the sanitary and epidemiological service.

APPENDIX 4

1. Distance f from the radiation source to the surface of the controlled welded joint facing the source (when girth welded joints are translucent through two walls - to the surface of the ring joint adjacent to the source) should not be less than the values determined by the formulas given in Table. one.

Table 1

Transmission scheme

D - outside diameter controlled welded joint, mm;

t- the ratio of the inner and outer diameters of the controlled welded joint;

F- maximum size of the focal spot of the radiation source, mm;

To- required control sensitivity, mm.

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TESTING NON-DESTRUCTIVE

WELDED CONNECTIONS

RADIOGRAPHIC METHOD

IPK STANDARDS PUBLISHING HOUSE

Moscow

INTERSTATE STANDARD

Date of introduction 01.01.84

This standard specifies a method for radiographic testing of welded joints made of metals and their alloys, made by fusion welding, with a thickness of the welded elements from 1 to 400 mm, using x-ray, gamma and bremsstrahlung radiation and radiographic film.

1. GENERAL PROVISIONS

1.1. Radiographic control is used to detect cracks, lack of penetration, pores, slag, tungsten, oxide and other inclusions in welded joints.

1.2. Radiographic control is also used to detect burns, undercuts, assess the magnitude of the convexity and concavity of the root of the seam, which are unacceptable for external examination.

1.3. Radiographic control does not reveal:

Any discontinuities and inclusions with a size in the direction of transmission less than twice the sensitivity of the control;

Lack of penetration and cracks, the opening plane of which does not coincide with the direction of translucence and (or) the opening value is less than the values \u200b\u200bgiven in Table. one;

Any discontinuities and inclusions, if their images on the pictures coincide with the images of foreign parts, sharp corners or sharp changes in the cracks of the translucent metal.

1.1 - 1.3.

Table 1

2. REQUIREMENTS FOR CONTROL ACCESSORIES

2.1. For radiographic inspection, markings should be used which are made of a material that ensures that they are clearly visible on radiographic images.

Markings of the sizes established by GOST 15843 should be used.

2.2. During radiographic control, radiographic films that meet the requirements of the technical specifications for them should be used.

The type of radiographic film must be established by the technical documentation for the control or acceptance of welded joints.

2.3. During radiographic control, radiation sources provided for by GOST 20426 should be used.

2.4. Metal and fluorescent screens should be used as intensifying screens for radiographic testing.

The type of intensifying screen must be established by the technical documentation for the control or acceptance of welded joints.

The thickness of metal intensifying screens and methods for loading film into cassettes using screens are given in Appendix 1.

2.5. Screens must have a clean, smooth surface. The presence of wrinkles, scratches, cracks, tears and other defects on the screens is not allowed.

2.6. Film loading cassettes must be opaque and provide a tight hold of the intensifying screens to the film.

2.7. To protect the film from scattered radiation, it is recommended to shield the film cassette from the side opposite to the radiation source with lead screens.

The thickness of the protective screens is given in Appendix 2.

2.8. To determine the sensitivity of the control, wire, groove or plate sensitivity standards should be used.

2.9. Sensitivity standards should be made of metal or alloy, the basis of which is according to chemical composition similar to the basis of a controlled welded joint.

1 - insert; 2 - case

2.10. The shape and dimensions of the wire sensitivity standards are shown in Fig. 1 and in table. 2. The length of the wires in the standards is (20 ± 0.5) mm. Limit deviations for wire diameters:

up to 0.2 mm… ± 0.01 mm

St. 0.2" 1.6 mm… ± 0.03 mm

» 1.6 » 4.0 mm… ± 0.04 mm.

table 2

Reference number

Limit deviations of other sizes - ± 0.5 mm.

The insert and case for wire standards should be made of flexible transparent plastic.

2.11. The shape and dimensions of the groove sensitivity standards are shown in Fig. 2 and in table. 3.

Table 3

Reference number

Groove depth

Previous off groove depths

R, no more

Previous off

Prev off

Previous off

2.12. The shape and dimensions of the plate sensitivity standards are shown in Fig. 3 and in table. 4.

Table 4

Reference number

Previous off

2.13. Marking of sensitivity standards should be carried out with lead numbers in accordance with GOST 15843 in accordance with Appendix 3. The first digit of the marking should indicate the material of the standard, the next (one or two digits) - the number of the standard.

Symbols for the material of the sensitivity standard: for alloys based on iron - 1, aluminum and magnesium - 2, titanium - 3, copper - 4, nickel - 5.

2.14. For marking groove standards, it is allowed to use cutouts and holes or only the holes specified in Appendix 3. In this case, the thickness of the standard at the place of marking should be equal to h.

When marking standards with holes, the length of standard No. 1 is 27 -0.52 mm, No. 2 - 38.5 -0.62 mm, No. 3 - 53 0.74 mm.

2.15. For welded products intended for export, it is allowed to use other types of sensitivity standards, if it is provided for by the export conditions.

3. PREPARATION FOR CONTROL

3.2. After stripping the welded joint and eliminating external defects, the welded joint should be marked into sections and marked (numbered) of the sections.

3.3. The system for marking and marking sections is established by technical documentation for the control or acceptance of welded joints.

3.4. During the control, sensitivity standards and markings should be installed at each site.

3.5. Sensitivity standards should be installed on the controlled area from the side facing the radiation source.

3.6. Wire standards should be installed directly on the seam with the direction of the wires across the seam.

3.7. Groove standards should be installed at a distance of at least 5 mm from the seam with the direction of the grooves across the seam.

3.11. (Deleted, Rev. No. 1).

3.12. Markings used to limit the length of sections of welded joints inspected in one exposure should be installed at the boundaries of the marked sections, as well as at the boundaries of the deposited and base metal when testing welded joints without reinforcement or with the weld reinforcement removed.

3.13. The markings used for numbering the controlled areas should be installed on the controlled area or directly on the film cassette so that the images of the markings in the pictures do not overlap with the image of the seam and the heat-affected zone according to clause 5.7.

3.14. If it is impossible to install sensitivity standards and (or) markings on the controlled area of the welded joint in accordance with the requirements of this standard, the procedure for conducting control without installing sensitivity standards and (or) markings should be provided in the technical documentation for the control or acceptance of welded joints.

4. CONTROL SCHEME

4.1. Welded joints should be controlled according to the drawing. 4 and 5.

4.2. With a limited width of the welded element, it is allowed to test tee welded joints with the direction of radiation along the generatrix of this element in accordance with Fig. 6.

4.2a. When testing circumferential welded joints of cylindrical and spherical hollow products, as a rule, it is necessary to use schemes of transillumination through one wall of the product (diagrams of Fig. 5 a, b, f, g, h). In this case, it is recommended to use transmission schemes with the location of the radiation source inside the controlled product:

Damn scheme. 5 e(panoramic transillumination) - for testing products with a diameter of up to 2 m, regardless of the volume of control and a diameter of 2 m or more with 100% control;

Damn scheme. 5 well- at 100% and selective control, if the use of the scheme features. 5 e impossible;

Damn scheme. 5 h- at selective control of products with a diameter of 2 m and more;

Damn schemes. 5 a, b- for products with an internal diameter of 10 m or more, if the use of the scheme of features. 5 e impossible.

4.3. When controlling through two walls, the diagram is fig. 5 in recommended for transillumination of products with a diameter of up to 100 mm; hell schemes. 5 d, d- for transillumination of products with a diameter of more than 50 mm.

Control schemes for butt, lap, corner and tee joints

1 - radiation source; 2 - controlled area; 3 - film cassette

Inspection schemes for circumferential (butt, lap, fillet and tee) welded joints

1 - radiation source; 2 - controlled area; 3- film cassette

4.4. During the control of butt welded joints according to the schemes of fig. 5 a, b, f, g, h the direction of radiation must coincide with the plane of the controlled welded joint. When checking according to these schemes, fillet welds of pipes, fittings, etc. the angle between the direction of radiation and the plane of the welded joint must not exceed 45°.

4.5. During the control of welded joints according to the schemes of fig. 5 c, d, d the direction of radiation should be chosen so that the images of opposite sections of the weld in the image do not overlap.

In this case, the angle between the direction of radiation and the plane of the weld should be minimal and in any case not exceed 45°.

4.3 - 4.5. (Revised edition, Rev. No. 1).

4.6. (deleted, rev.№ 1).

4.7. In addition to control according to the schemes shown in Fig. 4 - 6, depending on the design features of the welded joints and the requirements for them, other schemes and directions of radiation can be used.

These schemes and directions of radiation must be provided for by the technical documentation for the control and acceptance of welded joints.

4.8. To reduce the difference in optical densities of different areas of the image when testing welded joints with a large difference in thickness, and also in the case when the controlled welded joint does not protect the radiographic film from direct radiation (for example, when monitoring the end welds of pipe welding into tube sheets, when testing surfacing edges for welding, etc.), control should be carried out using attachments-compensators.

It is allowed to use compensators from any material that provides the required radiation attenuation.

4.9. When choosing a scheme and direction of radiation, the following should be taken into account:

The distance from the controlled welded joint to the radiographic film should be minimal and in any case not exceed 150 mm;

The angle between the direction of radiation and the normal to the radiographic film within the area of the welded joint controlled in one exposure must be minimal and in any case not exceed 45°.

4.7 - 4.9. (Revised edition, Rev. No. 1).

5. SELECTION OF RADIOGRAPHIC CONTROL PARAMETERS

5.1. The distance from the radiation source to the surface of the controlled area of the welded joint closest to the source (when transilluminating welded joints of cylindrical and spherical hollow products through two walls - to the surface of the controlled welded joint adjacent to the source) and the size or number of areas controlled in one exposure for all transillumination schemes ( with the exception of the diagram of Fig. 5 e) should be chosen such that the following requirements are met during transillumination:

The geometrical blurring of images of defects in the images when the film is located close to the inspected welded joint should not exceed half of the required sensitivity of the control with a sensitivity of up to 2 mm and 1 mm - with a sensitivity of more than 2 mm;

The relative increase in the size of images of defects located on the side of the radiation source (in relation to defects located on the side of the film) should not exceed 1.25;

The angle between the direction of radiation and the normal to the film within the area of the welded joint controlled during one exposure should not exceed 45°;

The decrease in the optical density of the image of the welded joint in any part of this image in relation to the optical density at the installation site of the wire sensitivity standard or in relation to the optical density of the image of the groove or plate sensitivity standard should not exceed 1.0.

5.2. Formulas for determining the minimum allowable distances from the radiation source to the inspected welded joint, as well as the maximum dimensions and minimum number of areas inspected in one exposure when inspected according to the schemes of features. 4 - 6 are given in Appendix 4.

5.1, 5.2. (Revised edition, Rev. No. 1).

5.3. When inspecting welded joints according to fig. 5z (panoramic transillumination) inner diameter ratio d to outside diameter D controlled connection should not be less than 0.8, and the maximum focal spot size F radiation source should not be more than where K- control sensitivity.

5.4. In cases where the dimensions of defects are not determined (for example, defects are not allowed regardless of their size), the ratio between the inner and outer diameters of the controlled joint given in clause 5.3 may not be observed.

5.5. In the absence of a radiation source that meets the requirements of clause 5.3, it is allowed during control according to fig. 5 h use radiation sources with maximum size focal spot that satisfies the relation

In this case, the sensitivity standard should be installed on the weld or weld simulator used in determining the sensitivity, only on the side of the radiation source.

5.6. The length of the images should provide overlapping images of adjacent sections of welded joints with a length of the controlled section up to 100 mm, at least 0.2 of the length of the section, with a length of the controlled section over 100 mm - not less than 20 mm.

5.7 The width of the images should provide images of the weld, sensitivity standards, markings and heat-affected zones with a width of:

For butt and lap joints:

not less than 5 mm - with a thickness of welded edges up to 5 mm;

not less than the thickness of the edges to be welded - with the thickness of the edges to be welded St. 5 to 20 mm;

not less than 20 mm - with a thickness of welded edges of St. 20 mm;

For tee and corner joints - it is established by the technical documentation for the control or acceptance of these joints.

6. IMAGE INTERPRETATION

6.1. Viewing and interpretation of images should be carried out after they have completely dried in a darkened room using special illuminators - negatoscopes.

Negatoscopes with adjustable brightness and illuminated field size should be used. The maximum brightness of the illuminated field should be at least 10 D+2 cd/m2, where D is the optical density of the image. The dimensions of the illuminated field should be adjusted using movable shutters or mask screens within such limits that the illuminated field is completely covered by the image.

6.2. Photographs approved for decoding must meet the following requirements:

The pictures should not have spots, stripes, pollution and damage to the emulsion layer, making it difficult to decipher them;

The photographs must show images of limit marks, markings and sensitivity standards;

The optical density of the images of the controlled section of the weld, the near-weld zone and the sensitivity standard must be at least 1.5;

The decrease in the optical density of the image of the welded joint in any part of this image in comparison with the optical density of the image of the sensitivity standard should not exceed 1.0.

6.3. The sensitivity of the control (the smallest diameter of the wire standard detected in the image, the smallest depth of the groove of the groove standard detected in the image, the smallest thickness of the plate standard, at which a hole with a diameter equal to twice the thickness of the standard is detected in the image), should not exceed the values given in Table. 6.

Table 6

Radiation thickness (at the installation site of the sensitivity standard)	Sensitivity class


St. 5 to 9 incl.







» 100 » 140 »
» 140 » 200 »
» 200 » 300 »
» 300 » 400 »

Note. When using wire standards of sensitivity, values of 0.30; 0.60; 0.75 and 1.50 mm are replaced by 0.32; 0.63; 0.80 and 1.60 mm.

Specific sensitivity values should be established by the technical documentation (drawing requirements, specifications, control and acceptance rules) for the controlled products.

For nuclear power plants, sensitivity requirements are established by the relevant regulatory documents.

6.4 In accordance with the requirements of the technical documentation for controlled products, it is allowed to determine the sensitivity (k) as a percentage according to the formula

where K- sensitivity, mm;

S- thickness of translucent metal, mm.

6.5. Interpretation and evaluation of the quality of welded joints from images that do not have images of sensitivity standards is allowed:

With panoramic transillumination of circumferential welded joints with simultaneous exposure of more than four films. In these cases, regardless of the total number of shots, it is allowed to set one sensitivity standard for each quarter of the circumference of the welded joint;

When it is impossible to use sensitivity standards.

In these cases, the sensitivity is determined on the simulators of the welded joint during processing of control modes.

6.7. At documenting the results of image interpretation, the sizes determined from the images should be rounded up to the nearest values from the range 0.2; 0.3; 0.4; 0.5; 0.6; 0.8; 1.0; 1.2; 1.5; 2.0; 2.5; 3.0 mm or the nearest integer value in millimeters if the size determined from the image exceeds 3.0 mm.

6.8. If during the control the film is located at a distance H from the surface of the controlled welded joint facing the film and the relation

it is recommended to multiply the dimensions determined from the image before rounding them by the coefficient

where f- distance from the radiation source to the surface of the controlled section of the welded joint facing the source, mm;

s- radiation thickness, mm.

6.6. - 6.8. (Revised edition, Rev. No. 1).

6.9. When measuring the size of defects up to 1.5 mm, a measuring magnifier with a division value of 0.1 mm, St. 1.5 mm - any measuring device with a division value of 1 mm.

6.11. To designate defects in the conclusion or log of control results, the symbols given in Appendix 5 should be used.

Examples of abbreviated recording of defects when deciphering images are given in Appendix 6.

7. SAFETY REQUIREMENTS

7.2. Radiographic control and recharging of radioactive sources should be carried out only using equipment specially designed for these purposes and in good condition, the documentation for the manufacture and operation of which, if more than three copies are produced, should be agreed with State Committee USSR on the use of atomic energy and the Main Sanitary and Epidemiological Directorate of the Ministry of Health of the USSR; up to three copies - with local bodies of the sanitary and epidemiological service.

7.3. The electrical equipment of operating stationary and portable installations for radiographic control must comply with the requirements of GOST 12.2.007.0 and the "Rules for the Construction of Electrical Installations" approved by the Main Technical Directorate for the Operation of Energy Systems and the State Energy Supervision Authority of the USSR Ministry of Energy.

7.4. When carrying out radiographic control, storage and recharging of radioactive radiation sources, the safety of work must be ensured in accordance with the requirements of the Basic Sanitary Rules for Working with Radioactive Substances and Other Sources ionizing radiation"OSP-72/80 No. 2120-80, approved by the Chief State Sanitary Doctor of the USSR on January 18, 1980, "Radiation Safety Standards" NRB-76 No. 141-76, approved by the Chief State Sanitary Doctor of the USSR on June 7, 1976, " Sanitary regulations for Radioisotope Defectoscopy” No. 1171-74, approved by the Deputy Chief State Sanitary Doctor of the USSR on August 7, 1974 and GOST 23764.

7.5. When operating stationary and portable installations for radiographic control connected to an industrial power grid, the safety of work must be ensured in accordance with the requirements of the "Rules for the technical operation of consumer electrical installations" and the "Safety Rules for the operation of consumer electrical installations", approved by the State Energy Supervision Authority on April 12, 1969.

7.6. When transporting radioactive radiation sources, the requirements of the “Safety Rules for the Transportation of Radioactive Substances” PBTRV-73 No. 1139-73, approved by the Chief State Sanitary Doctor of the USSR on December 27, 1973, must be observed.

7.7. Enterprises performing radiographic testing of welded joints develop, in accordance with the safety requirements of this section, documentation that defines the rules and methods for the safe organization of work, the scope and means of radiographic testing, taking into account local production conditions, and bring them to the workers in the prescribed manner.

8. METROLOGICAL SOFTWARE

8.1. The groove and plate sensitivity standards used in the control must be subjected to metrological verification upon their release and subsequent verification at least once every 5 years. When these standards are produced, the reverse side of each standard should be electrochemically marked with the trademark of the enterprise that produced the standard and the year of issue; at the next verification - commercial or symbol the company that carried out the verification, and the year of verification.

8.2. Wire standards of sensitivity are not subject to verification, however, they should be withdrawn from circulation in case of any damage to the plastic cover or if traces of corrosion of the wires of the standard are found during visual inspection.

8.3. Densitometers and sets of optical densities used to determine the optical density of images are subject to verification at least once a year with the obligatory execution of a document (certificate) on the verification results.

8.4. Negatoscopes are subject to verification only upon their release with the obligatory indication in the passport (certificate) of the negatoscope of the maximum brightness of the illuminated field and the optical density of the image.

8.5. Measuring tools used to determine the dimensions of the images of cracks, lack of penetration, pores and inclusions in the images (measuring rulers and magnifiers) are subjected to verification in accordance with the provisions in force that apply to these tools.

8.6. non-standardized measuring tools, used to determine the size of the images of cracks, lack of penetration, pores and inclusions in the images (measuring templates, stencils, etc.), must be verified at least once a year with the obligatory execution of a document on the verification results.

Sec. eight. (Introduced additionally, Rev. No. 1).

APPENDIX 1 Thickness of metal intensifying screens

Table 1

Radiation source	Screen thickness, mm
X-ray machine with X-ray tube voltage up to 100 kV
X-ray machine with X-ray tube voltage over 100 to 300 kV
X-ray machine with X-ray tube voltage over 300 kV




Electron accelerator with radiation energy from 1 to 15 MeV

Cassette charging methods

table 2

radiographic film;

Reinforcing metal screen;

Intensifying fluorescent screen.

APPENDIX 2

Reference

Thickness of protective lead shields

Radiation source	Screen thickness, mm
X-ray machine with X-ray tube voltage up to 200 kV

X-ray machine with X-ray tube voltage over 200 kV	1.0 to 2.0
192 Ir; 137Cs; co	1.0 to 2.0
Electron accelerator with radiation energy from 1 to 15 MeV

APPENDIX 3

Mandatory

Table 1

Markings for sensitivity standards

table 2

Marking groove standards

Reference number

Based alloys

aluminum and magnesium

Table 1

Transmission scheme	Distance from the source to the surface of the controlled welded joint, mm, not less than
Heck. 4 and 6


	0.5D
	0.5 [C (1.4 - m) - 1] D

where at and C = 4 at

s- radiation thickness, mm;

D- outer diameter of the controlled welded joint, mm;

t - the ratio of the inner and outer diameters of the controlled welded joint;

F- maximum size of the focal spot of the radiation source, mm;

K- required control sensitivity, mm.

Note. If for the scheme hell. 5 d, d the conditions 1.5 С (1 - m) > 1 and С (1.4 - m) > 1 are not met, the distance f can be taken equal to zero (i.e., the radiation source can be placed directly on the wall of the product opposite to the controlled area).

2. The length of the areas controlled for one exposure when controlled according to the schemes of features. 4 and 6 should not be more than 0.8 f.

3. The number of sites (exposures) during the control according to the schemes of features. 5 a, c, d, e should not be less than the values determined by the formulas given in table. 2.

table 2

d- internal diameter of the controlled welded joint, mm.

4. For the scheme of traits. 5 b choose the length of the picture l and distance f, which must satisfy the relations

and determine the auxiliary coefficient

If the ratio is not met, reduce l or increase f until this ratio is met, after which the number of N areas controlled for one exposure, which must satisfy the ratio

5. For the scheme of features. 5 well determine the maximum possible (based on the inner diameter of the controlled product and the dimensions of the radiation or collimating head of the gamma flaw detector or the dimensions of the emitter of the X-ray machine) distance / (over the diameter of the product), which must satisfy the ratio

f ≥ 0.5C (1 - m) D.

If this relation is not fulfilled, it is necessary to use a source with smaller focal spot sizes for which this relation is fulfilled.

When this ratio is fulfilled, the auxiliary coefficient is determined

choose quantity N areas controlled for one exposure, which must satisfy the ratio

6. The angle between the directions of radiation for individual exposures when controlled according to the scheme of fig. 5 in should be

and when controlled according to the schemes of hell. 5 a, b, d, e, g -

7. The distance from the radiation source to the controlled welded joint and the length of the sections controlled in one exposure during the control of circumferential welded joints of cylindrical and spherical hollow products with a diameter of more than 2 m are determined in the same way as for welded joints controlled according to the schemes of features. 4 and 6.

APPENDIX4 . (Revised edition, Rev. No. 1).

APPENDIX 5

Mandatory

CONDITIONAL RECORDING OF DEFECTS WHEN INTERPRETATION OF IMAGES AND DOCUMENTATION OF THE RESULTS OF RADIOGRAPHIC CONTROL

1. For an abbreviated record of defects, when deciphering images and documenting the results of control, the symbols given in the table should be used.

Type of defect	Symbol		The nature of the defect	Symbol
Type of defect	Russian alphabet	Latin alphabet	The nature of the defect	Russian alphabet	Latin alphabet
			Crack along the seam
			Crack across the seam
			The crack is branched
lack of fusion			Failure at the root
			Lack of penetration between rollers
			Lack of cutting
			Separate time

			Cluster
Slag inclusions			Separate inclusion

			Cluster
Tungsten inclusions			Separate inclusion

			Cluster
oxide inclusions
Weld root concavity
Convexity of the root of the seam

Edge offset

2. For abbreviated notation of the maximum total length of defects (on a section of the image 100 mm long or on the entire image with its length less than 100 mm), the symbol Σ should be used.

3. After symbol defects are indicated by their dimensions in millimeters:

For spherical pores, slag and tungsten inclusions - diameter;

For elongated pores, slag and tungsten inclusions - width and length (through the multiplication sign);

For chains, accumulations, oxide inclusions, lack of fusion and cracks - length.

4. For chains and accumulations of pores, slag and tungsten inclusions, after the symbol for defects included in the chain or accumulation, the maximum diameter or width and length of these defects (through the multiplication sign) are indicated.

5. If there are identical defects in the image (defects of the same type with the same size) it is allowed not to write down each of the defects separately, but to indicate their number before the defect symbol.

6. After the symbol of the maximum total length of defects (in the area of the image 100 mm long), this length is indicated in millimeters.

7. In the absence of images of defects in the image, as well as in cases where the length, width and total length of defects do not exceed the specified maximum allowed values, in the column of the documentation “Meets the requirements”, “yes” is written, otherwise - “no”.

8. If defects not listed in paragraph 1 are found in the image, the full name of the defects should be indicated in the conclusion or log of inspection results.

APPENDIX5 . (Revised edition, Rev. No. 1).

APPENDIX 6

Reference

EXAMPLES OF REDUCED RECORDING OF DEFECTS WHEN INTERPRETATION OF IMAGES AND DOCUMENTATION OF THE RESULTS OF RADIOGRAPHIC CONTROL

1. The image contains images of five pores with a diameter of 3 mm each, a chain of pores with a length of 30 mm and a maximum length and width of pores in the chain of 5 and 3 mm, and a slag inclusion with a length of 15 mm and a width of 2 mm.

The maximum total length of defects in a 100 mm image section is 20 mm. Documentation entry: 5P3; Ts30P5 × 3; W15 × 2; Σ20.

2. Images of two accumulations of pores (the length of each accumulation is 10 mm, the maximum diameter of pores is 0.5 mm) and an accumulation of slag inclusions (the length of the accumulation is 8 mm, maximum length and width of inclusions 2 and 1 mm).

The maximum total length of defects in a 100 mm image section is 18 mm. Documentation entry: 2S10P0.5; S8Sh2 × 1; Σ18.

3. Images of two lacks of penetration 15 mm long each and cracks 40 mm long were found in the image. Record documentation: 2H15; T40.

4. Images of five pores with a diameter of 4 mm each and a lack of fusion 20 mm long were found in the image. The maximum total length of pores in a 100 mm image section is 12 mm.

Documentation entry: 5P4; Σ12; H20.

INFORMATION DATA

1 . APPROVED AND INTRODUCED BY Decree of the USSR State Committee for Standards No. 4923 of December 20, 1982

3 . REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

4 . The validity period was lifted according to protocol No. 3-93 of the Interstate Council for Standardization, Metrology and Certification

5 . EDITION (May 2004) with Amendment No. 1 approved March 1988

1. General provisions. 1

2. Requirements for control accessories. 2

3. Preparation for control.. 6

4. Control scheme. 7

5. Choice of radiographic control parameters. ten

6. Deciphering pictures. eleven