GB/T 3323-1987 Radiography and quality classification of steel fusion welded butt joints
Some standard content:
National Standard of the People's Republic of China
Methods for radiographic inspectionlonand classification of radiographs for fusion welded butt joints in steelUDC 621.791.65,05
GB 3323-87
Replaces GB3323-82
1.1 This standard specifies the X-ray and radiographic methods and the quality classification of fusion welded butt joints in steel with a base metal thickness of 2 to 200 mm (hereinafter referred to as welds).
1.2 The photographic quality grade, photographic scope and quality grade of the weld shall be selected according to the product technical conditions and relevant regulations, and may also be determined by the design, manufacturing and user units according to the specific use of the product. 2 Requirements for personnel
2.1 Personnel engaged in radiographic inspection must hold a qualification certificate issued by the relevant national departments and suitable for their work. 2.2 The vision of the film reviewer should be checked once a year, and the corrected vision should not be less than 1.0. It is required that a group of printed letters with a height of 0.5mm and an interval of 0.5mm can be read at a distance of 400mm. 3 Radiographic quality classification
According to the required film image quality, the radiographic method is divided into A line (ordinary level), AB level (higher level) and B level (higher level). When using level B, the weld excess height should be ground flat. 4 Surface condition
The surface quality (including excess height) of the weld and heat-affected zone should be qualified after appearance inspection. The image of the irregular state of the surface on the film should not cover the defects in the weld or be confused with it, otherwise appropriate repairs should be made. 5 Selection of radiation source and energy
5.1 X-rays with tube voltage below 400kV
When using X-rays below 400kV to penetrate the weld, the maximum tube voltage (working range) allowed for different penetration thicknesses T is shown in Figure 1. Approved by the State Bureau of Standards on July 13, 1987
Implementation on July 1, 1988
5.2 X-rays and high-energy X-rays
GB3323—87
Irradiation thickness TA
Figure 1 Irradiation thickness and maximum tube voltage allowed for use The range of parent material thickness for Y-rays and X-rays above 1MeV is shown in Table 1 Table 1 Range of parent material thickness for X-rays and X-rays above 1MeV Parent material thickness T
Ray source
X-rays 1～2MeV
X-rays>2MeV
30~200
20~100
40~200
40 ~ 175
50~175
Note: When the internal penetration method (center method or eccentric method) is used, the thickness of the base material can be 1/2 of the lower limit value in Table 1.6 Industrial X-ray Film and Intensifying Screen
607080
50~150
60~150
6.1 Film
Films are divided into three types: "1", "2" and "3" according to the order of silver salt particle size from small to large, as shown in Table 2. They can be selected in order of image quality from high to low.
Film type
Intensifying screen
Sensitivity
GB3323-87
Film type
Fluorescent
Radiography can use metal intensifying screen or no intensifying screen. The selection of metal intensifying screen is shown in Table 3. In some cases, intensifying screen or metal fluorescent intensifying screen is used, but it is limited to Class A. Table 3 Selection of intensifying screen
Ray type
120250kv
250～400kv
3~8MeV
8 ～35MeV
Intensifying screen material
Copper, lead
Vanadium, tungsten, lead
Copper, steel, lead
(1) The flaw detection sensitivity obtained by molybdenum screen or tungsten screen is higher than that of lead screen. Front screen thickness
0.025~0.125
0.05~0.16
1.00 - 1.60
0.05-0.16
0.50~2.00
（2）The best detection sensitivity can be obtained by using copper or steel screen, but the exposure time is longer than that of lead screen. 6.3 Contact between film and intensifying screen
The film and intensifying screen should always be in close contact with each other during transillumination. Linear image quality meter
Back screen thickness
1.00~1.60
0.25~1.00
The image quality meter is used to check the quality of transillumination technology and film processing. The numerical value to measure this quality is the image quality index, which is equal to the line number of the thinnest steel wire that can be identified on the film.
7.1 Model and specification of linear image quality meter
The model and specification of linear image quality meter shall comply with the provisions of GB5618-85 "Linear Image Quality Meter" 7.2 Selection of image quality meter
GB3323-87
According to the image quality index required for the penetration thickness and image quality level, select the R10 series image quality meter specified in GB5618-85, see Table 4.
For the determination of penetration thickness, see Appendix A. The penetration thickness of double-wall single shadow shall be the thickness of the single-wall parent material plus a residual height. 7.3 Placement of image quality meter
The linear image quality meter shall be placed on the workpiece surface on the side of the radiation source at one end of the weld area to be inspected (1/4 of the length of the inspected area). The steel wire shall cross the weld and be perpendicular to the weld direction, and the thin steel wire shall be placed on the outside. When it is not possible to place an image quality meter on one side of the radiation source, it may be placed on the surface of the workpiece on one side of the film, but a comparative test should be conducted to ensure that the actual image quality index value meets the specified requirements. 7.3.1 When using the circumferential exposure technique with the radiation source placed at the center of the circle, the image quality meter should be placed on the inner wall, one every 90°. 7.3.2 The method of the comparative test is: cut a short test block that is exactly the same as the workpiece to be inspected, place an image quality meter at each end of the inner and outer surfaces of the inspected part, and use the same transillumination conditions as the workpiece for transillumination, and observe the resulting film to determine the corresponding image quality index. 7.3.3 When the image quality meter is placed on the surface of the workpiece on one side of the film, the image quality meter should be marked with "F" to distinguish it. Table 4 Selection of image quality meter
Required
Image quality index
8 Transillumination method
Line diameter
>8～10
> 10～16
> 16 ~ 25
>25 ~32
> 32 ~ 40
> 40 ～ 60
> 60 ～80
> 80 ～150
>150 ～170
≥170 ～180
>180 ～190
>190 ～ 200
Transillumination thickness
> 8～12
>12 ~16
> 16 ~20
> 20 ~25
> 25 ~ 32
> 32 ~ 50
> 50 ~80
> 80 ~120
>120~150
>150 ~ 200
> 8~10
> 10 ~16
> 16 ~25
> 25 ~32
>32 ~ 40
>40~50
> 50 ~80
>80-150
>150 ～200
According to the relative position between the radiation source, workpiece and film, the transillumination method is divided into five types: longitudinal seam transillumination method, annular seam external transillumination method, annular seam internal transillumination method, double-wall single shadow method and double-wall double shadow method, as shown in Figure 2. 50
Radiation source
C, the radiation source is not in the center of the component
GB $323—87
Longitudinal seam transillumination method
Radiation source
b) Circumferential seam external transillumination method
Radiation source
Radiation source in the center of the component
e) Circumferential seam internal transillumination method
Figure 2 Schematic diagram of transillumination method
9 Geometric conditions
GB3823-87
Radiation drift
Double wall single shadow method
Radiation source
Double wall double shadow elimination
Continued Figure 2
9.1 The relationship between the distance L1 from the radiation source to the workpiece surface, L1/d and the distance L2 from the workpiece surface to the film is shown in Figure 3. The nomogram of Li is shown in Figures 4 and 5. d is the effective focal size of the radiation source, which can be calculated according to Appendix B. 52
GB8323--87
Distance from work surface to whole film
7 9 100
Figure 3 Relationship between distance Lz from work surface to film and minimum L,/d value 4500
GB 3323--87
50 00
Figure 4 Nomogram for determining distance from focus to workpiece Wuantt
GB 8823-87
5 Nomogram for determining distance from focus to workpiece
GB 3823--87
9.2 One-time exposure length refers to the length of the weld tested by each light feeding when segmented exposure is adopted, and shall comply with the provisions of Articles 14.1 and 14.2.
9.3 The exposure thickness ratio of the weld is the K value, see Figure 6. The K value of the A and AB grades of the circumferential seam is generally not greater than 1.1, and the K value of the B grade is generally not greater than 1.06. The K value of the A and AB grades of the longitudinal seam is not greater than 1.03, and the K value of the B grade is not greater than 1.01. Radiation interference
Figure 6 Schematic diagram of weld penetration thickness ratio
Where: T--base material thickness, mm,
--maximum thickness of the oblique penetration of the ray beam, mm. T
9.4 The ray beam should be directed to the center of the inspected part and be perpendicular to the section of the plane or curved surface of the inspected area at this point, but when necessary, it can also be penetrated from other directions that are conducive to the discovery of defects. When the double-wall penetration method is used, the rays should generally be deviated from the plane where the weld axis is located for oblique penetration to avoid overlapping of the weld images on both sides. 10 Shielding of useless rays and scattered rays
10.1 In order to reduce the influence of scattered rays, appropriate shielding methods should be used to limit the irradiation area of the inspected part. 10.2 To check the backscatter, a lead mark of "B\" (the height of B is 13mm and the thickness is 1.6mm) should be attached to the back of the dark box. If a lighter image of "B" appears on a darker background, it means that the backscatter protection is insufficient and the film should be re-examined. If a darker image of "&B" appears on a lighter background, it will not be used as a basis for judging the film to be scrapped. 11 Positioning marks and identification marks
11.1 Positioning marks
The lead positioning marks indicating the transillumination area of the weld include the center mark (+) and the overlap mark (↑) (when spot checking, they are called valid section marks).
11.2 Identification marks
The following lead identification marks should be affixed near each section of the weld to be inspected: workpiece number, weld number and area number. The repair transillumination area should also have repair marks R, R (the footnotes 1 and 2 refer to the number of repairs). 11.3 Marking position
The above positioning marks and identification marks shall be displayed at the appropriate position of the film and at least 5mm away from the edge of the weld. The placement of the overlap mark is shown in Appendix C.
The workpiece surface shall be permanently marked as a basis for repositioning each film. When the workpiece is not suitable for printing marks, a detailed sketch of the transillumination part and other effective methods shall be used. Exposure curve
According to the equipment, film and intensifying screen, a suitable exposure curve shall be made or selected according to specific conditions, and the exposure specification shall be selected accordingly. In order to achieve the specified film blackness, the exposure is recommended to be not less than 15mA·min to prevent the adverse effects caused by short focal length and high voltage.
18 Film processing
Film processing shall be carried out according to the film instructions or recognized effective methods. The processing solution shall be kept in good condition, and attention shall be paid to the effects of temperature, time and shaking on the washing effect. During automatic washing, the transmission speed and the replenishment of the liquid should also be accurately controlled. 14 Film quality
14.1 Blackness
The selected exposure conditions should make the blackness in the effective evaluation area of the film meet the requirements of Table 5. Table 5 Blackness range of film
Ray type
X-ray
Y-ray
Note: The D value in the table includes the Do value.
14.2 Image quality index
Film blackness D
The minimum wire diameter that must be displayed on the film and the corresponding image quality index are shown in Table 4. 14.3 Image recognition requirements
Gray fog D.
The image of the image quality meter on the film is correctly positioned, the positioning mark and recognition mark are complete, and the image of the weld to be inspected is not covered. On the weld image, if the image of the image quality meter wire with a length of not less than 10 mm can be clearly seen, it is considered to be recognizable. 14.4 Impermissible illusions
There should be no defects caused by improper film processing or other defects that hinder film evaluation in the effective evaluation area of the film. 15 Film observation
15.1 Film evaluation environment
Film evaluation should be carried out in a dedicated film evaluation room. The light in the film evaluation room should be dim, but not completely dark, and the indoor lighting should not reflect on the surface of the film.
15.2 Film viewing light
The film viewing light should have a maximum brightness of 3.5 for observing the maximum blackness of the film, and the brightness of the diffuse light for observation should be adjustable. For parts that do not need to be observed or have too much light transmission, appropriate shading plates should be used to shield the strong light. The brightness of the film after illumination shall not be less than 30cd/m2. In order to observe the film with a maximum blackness of 3.5, the maximum brightness of the film viewing lamp shall not be less than 100.000cd/m2.57
16 Weld quality classification
GB 3323-87
16.1 According to the nature and quantity of defects, the weld quality is divided into four levels. There shall be no cracks, lack of fusion, lack of penetration and strip inclusions in the weld of level I. 16.1.1
16.1.2 There shall be no cracks, lack of fusion and lack of penetration in the weld of level II. 16.1.3 There shall be no cracks, lack of fusion and lack of penetration in double-sided welding and single-sided welding with backing plate in the weld of level III. The allowable length of lack of penetration in single-sided welding without backing plate shall be evaluated according to the length of strip inclusions in level III in Table 10. 16.1.4 Weld defects exceeding level III are level IV. 16.2 Classification of circular defects
16.2.1 Defects with an aspect ratio less than or equal to 3 are defined as circular defects. They can be circular, elliptical, conical or with irregular shapes such as tails (the tail should be included when measuring the size). Including pores, slag inclusions and tungsten inclusions. 16.2.2 Circular defects are evaluated using an assessment area. The size of the assessment area is shown in Table 6. The assessment area should be selected at the most serious defect. Table 6 Defect assessment area
Parent material thickness 7
Assessment area size
10×10
>25~100
10×20
16.2.3 When evaluating circular defects, the defect size should be converted into defect points according to Table 7, see Table 7. Table 7 Conversion table for defect points
Defect long diameter, mm
.1～2
For defect sizes not counted, see Table 8.
>2～3
>3～4
3Defect sizes not counted
Thickness of parent material7
10×30
Defect long diameter
16.2.5When a defect touches the boundary line of the assessment area, it shall be classified as a point in the assessment area. mm
16.2.6When there are few defects near the assessment area, and it is considered inappropriate to classify the level only by the size of the assessment area, the assessment area may be expanded to 3 times along the weld direction through consultation between the supply and demand parties, and the total number of defect points shall be calculated, and 1/3 of this value shall be used for assessment. For the treatment method of expanding the assessment area, see Appendix D.
16.2.7 The classification of circular defects is shown in Table 9.01. Radiation interference
Figure 6 Schematic diagram of weld penetration thickness ratio
Where: T--base material thickness, mm,
--maximum thickness of oblique penetration of a beam of rays, mm. T
9.4 The beam of rays should be directed to the center of the inspected part and be perpendicular to the section of the plane or curved surface of the inspected area at this point, but when necessary, it can also be penetrated from other directions that are conducive to the discovery of defects. When the double-wall penetration method is used, the rays should generally be deviated from the plane where the weld axis is located for oblique penetration to avoid overlapping of the weld images on both sides. 10 Shielding of useless rays and scattered rays
10.1 In order to reduce the influence of scattered rays, appropriate shielding methods should be used to limit the irradiation area of the inspected part. 10.2 To check the backscatter, a lead mark of "B\" (the height of B is 13mm and the thickness is 1.6mm) should be attached to the back of the dark box. If a lighter image of "B" appears on a darker background, it means that the backscatter protection is insufficient and the film should be re-examined. If a darker image of "&B" appears on a lighter background, it will not be used as a basis for judging the film to be scrapped. 11 Positioning marks and identification marks
11.1 Positioning marks
The lead positioning marks indicating the transillumination area of the weld include the center mark (+) and the overlap mark (↑) (when spot checking, they are called valid section marks).
11.2 Identification marks
The following lead identification marks should be affixed near each section of the weld to be inspected: workpiece number, weld number and area number. The repair transillumination area should also have repair marks R, R (the footnotes 1 and 2 refer to the number of repairs). 11.3 Marking position
The above positioning marks and identification marks shall be displayed at the appropriate position of the film and at least 5mm away from the edge of the weld. The placement of the overlap mark is shown in Appendix C.
The workpiece surface shall be permanently marked as a basis for repositioning each film. When the workpiece is not suitable for printing marks, a detailed sketch of the transillumination part and other effective methods shall be used. Exposure curve
According to the equipment, film and intensifying screen, a suitable exposure curve shall be made or selected according to specific conditions, and the exposure specification shall be selected accordingly. In order to achieve the specified film blackness, the exposure is recommended to be not less than 15mA·min to prevent the adverse effects caused by short focal length and high voltage.
18 Film processing
Film processing shall be carried out according to the film instructions or recognized effective methods. The processing solution shall be kept in good condition, and attention shall be paid to the effects of temperature, time and shaking on the washing effect. During automatic washing, the transmission speed and the replenishment of the liquid should also be accurately controlled. 14 Film quality
14.1 Blackness
The selected exposure conditions should make the blackness in the effective evaluation area of the film meet the requirements of Table 5. Table 5 Blackness range of film
Ray type
X-ray
Y-ray
Note: The D value in the table includes the Do value.
14.2 Image quality index
Film blackness D
The minimum wire diameter that must be displayed on the film and the corresponding image quality index are shown in Table 4. 14.3 Image recognition requirements
Gray fog D.
The image of the image quality meter on the film is correctly positioned, the positioning mark and recognition mark are complete, and the image of the weld to be inspected is not covered. On the weld image, if the image of the image quality meter wire with a length of not less than 10 mm can be clearly seen, it is considered to be recognizable. 14.4 Impermissible illusions
There should be no defects caused by improper film processing or other defects that hinder film evaluation in the effective evaluation area of the film. 15 Film observation
15.1 Film evaluation environment
Film evaluation should be carried out in a dedicated film evaluation room. The light in the film evaluation room should be dim, but not completely dark, and the indoor lighting should not reflect on the surface of the film.
15.2 Film viewing light
The film viewing light should have a maximum brightness of 3.5 for observing the maximum blackness of the film, and the brightness of the diffuse light for observation should be adjustable. For parts that do not need to be observed or have too much light transmission, appropriate shading plates should be used to shield the strong light. The brightness of the film after illumination shall not be less than 30cd/m2. In order to observe the film with a maximum blackness of 3.5, the maximum brightness of the film viewing lamp shall not be less than 100.000cd/m2.57
16 Weld quality classification
GB 3323-87
16.1 According to the nature and quantity of defects, the weld quality is divided into four levels. There shall be no cracks, lack of fusion, lack of penetration and strip inclusions in the weld of level I. 16.1.1
16.1.2 There shall be no cracks, lack of fusion and lack of penetration in the weld of level II. 16.1.3 There shall be no cracks, lack of fusion and lack of penetration in double-sided welding and single-sided welding with backing plate in the weld of level III. The allowable length of lack of penetration in single-sided welding without backing plate shall be evaluated according to the length of strip inclusions in level III in Table 10. 16.1.4 Weld defects exceeding level III are level IV. 16.2 Classification of circular defects
16.2.1 Defects with an aspect ratio less than or equal to 3 are defined as circular defects. They can be circular, elliptical, conical or with irregular shapes such as tails (the tail should be included when measuring the size). Including pores, slag inclusions and tungsten inclusions. 16.2.2 Circular defects are evaluated using an assessment area. The size of the assessment area is shown in Table 6. The assessment area should be selected at the most serious defect. Table 6 Defect assessment area
Parent material thickness 7
Assessment area size
10×10
>25~100
10×20
16.2.3 When evaluating circular defects, the defect size should be converted into defect points according to Table 7, see Table 7. Table 7 Conversion table for defect points
Defect long diameter, mm
.1～2
For defect sizes not counted, see Table 8.
>2～3
>3～4
3Defect sizes not counted
Thickness of parent material7
10×30
Defect long diameter
16.2.5When a defect touches the boundary line of the assessment area, it shall be classified as a point in the assessment area. mm
16.2.6When there are few defects near the assessment area, and it is considered inappropriate to classify the level only by the size of the assessment area, the assessment area may be expanded to 3 times along the weld direction through consultation between the supply and demand parties, and the total number of defect points shall be calculated, and 1/3 of this value shall be used for assessment. For the treatment method of expanding the assessment area, see Appendix D.
16.2.7 The classification of circular defects is shown in Table 9.01. Radiation interference
Figure 6 Schematic diagram of weld penetration thickness ratio
Where: T--base material thickness, mm,
--maximum thickness of oblique penetration of a beam of rays, mm. T
9.4 The beam of rays should be directed to the center of the inspected part and be perpendicular to the section of the plane or curved surface of the inspected area at this point, but when necessary, it can also be penetrated from other directions that are conducive to the discovery of defects. When the double-wall penetration method is used, the rays should generally be deviated from the plane where the weld axis is located for oblique penetration to avoid overlapping of the weld images on both sides. 10 Shielding of useless rays and scattered rays
10.1 In order to reduce the influence of scattered rays, appropriate shielding methods should be used to limit the irradiation area of the inspected part. 10.2 To check the backscatter, a lead mark of "B\" (the height of B is 13mm and the thickness is 1.6mm) should be attached to the back of the dark box. If a lighter image of "B" appears on a darker background, it means that the backscatter protection is insufficient and the film should be re-examined. If a darker image of "&B" appears on a lighter background, it will not be used as a basis for judging the film to be scrapped. 11 Positioning marks and identification marks
11.1 Positioning marks
The lead positioning marks indicating the transillumination area of the weld include the center mark (+) and the overlap mark (↑) (when spot checking, they are called valid section marks).
11.2 Identification marks
The following lead identification marks should be affixed near each section of the weld to be inspected: workpiece number, weld number and area number. The repair transillumination area should also have repair marks R, R (the footnotes 1 and 2 refer to the number of repairs). 11.3 Marking position
The above positioning marks and identification marks shall be displayed at the appropriate position of the film and at least 5mm away from the edge of the weld. The placement of the overlap mark is shown in Appendix C.
The workpiece surface shall be permanently marked as a basis for repositioning each film. When the workpiece is not suitable for printing marks, a detailed sketch of the transillumination part and other effective methods shall be used. Exposure curve
According to the equipment, film and intensifying screen, a suitable exposure curve shall be made or selected according to specific conditions, and the exposure specification shall be selected accordingly. In order to achieve the specified film blackness, the exposure is recommended to be not less than 15mA·min to prevent the adverse effects caused by short focal length and high voltage.
18 Film processing
Film processing shall be carried out according to the film instructions or recognized effective methods. The processing solution shall be kept in good condition, and attention shall be paid to the effects of temperature, time and shaking on the washing effect. During automatic washing, the transmission speed and the replenishment of the liquid should also be accurately controlled. 14 Film quality
14.1 Blackness
The selected exposure conditions should make the blackness in the effective evaluation area of the film meet the requirements of Table 5. Table 5 Blackness range of film
Ray type
X-ray
Y-ray
Note: The D value in the table includes the Do value.
14.2 Image quality index
Film blackness D
The minimum wire diameter that must be displayed on the film and the corresponding image quality index are shown in Table 4. 14.3 Image recognition requirements
Gray fog D.
The image of the image quality meter on the film is correctly positioned, the positioning mark and recognition mark are complete, and the image of the weld to be inspected is not covered. On the weld image, if the image of the image quality meter wire with a length of not less than 10 mm can be clearly seen, it is considered to be recognizable. 14.4 Impermissible illusions
There should be no defects caused by improper film processing or other defects that hinder film evaluation in the effective evaluation area of the film. 15 Film observation
15.1 Film evaluation environment
Film evaluation should be carried out in a dedicated film evaluation room. The light in the film evaluation room should be dim, but not completely dark, and the indoor lighting should not reflect on the surface of the film.
15.2 Film viewing light
The film viewing light should have a maximum brightness of 3.5 for observing the maximum blackness of the film, and the brightness of the diffuse light for observation should be adjustable. For parts that do not need to be observed or have too much light transmission, appropriate shading plates should be used to shield the strong light. The brightness of the film after illumination shall not be less than 30cd/m2. In order to observe the film with a maximum blackness of 3.5, the maximum brightness of the film viewing lamp shall not be less than 100.000cd/m2.57
16 Weld quality classification
GB 3323-87
16.1 According to the nature and quantity of defects, the weld quality is divided into four levels. There shall be no cracks, lack of fusion, lack of penetration and strip inclusions in the weld of level I. 16.1.1
16.1.2 There shall be no cracks, lack of fusion and lack of penetration in the weld of level II. 16.1.3 There shall be no cracks, lack of fusion and lack of penetration in double-sided welding and single-sided welding with backing plate in the weld of level III. The allowable length of lack of penetration in single-sided welding without backing plate shall be evaluated according to the length of strip inclusions in level III in Table 10. 16.1.4 Weld defects exceeding level III are level IV. 16.2 Classification of circular defects
16.2.1 Defects with an aspect ratio less than or equal to 3 are defined as circular defects. They can be circular, elliptical, conical or with irregular shapes such as tails (the tail should be included when measuring the size). Including pores, slag inclusions and tungsten inclusions. 16.2.2 Circular defects are evaluated using an assessment area. The size of the assessment area is shown in Table 6. The assessment area should be selected at the most serious defect. Table 6 Defect assessment area
Parent material thickness 7
Assessment area size
10×10
>25~100
10×20
16.2.3 When evaluating circular defects, the defect size should be converted into defect points according to Table 7, see Table 7. Table 7 Conversion table for defect points
Defect long diameter, mm
.1～2
For defect sizes not counted, see Table 8.
>2～3
>3～4
3Defect sizes not counted
Thickness of parent material7
10×30
Defect long diameter
16.2.5When a defect touches the boundary line of the assessment area, it shall be classified as a point in the assessment area. mm
16.2.6When there are few defects near the assessment area, and it is considered inappropriate to classify the level only by the size of the assessment area, the assessment area may be expanded to 3 times along the weld direction through consultation between the supply and demand parties, and the total number of defect points shall be calculated, and 1/3 of this value shall be used for assessment. For the treatment method of expanding the assessment area, see Appendix D.
16.2.7 The classification of circular defects is shown in Table 9.3 Marking position
The above positioning marks and identification marks shall be displayed at the appropriate position of the film and at least 5mm away from the edge of the weld. The placement of the overlap mark is shown in Appendix C.
The workpiece surface shall be permanently marked as a basis for repositioning each film. When the workpiece is not suitable for printing marks, a detailed sketch of the transillumination part and other effective methods shall be used. Exposure curve
According to the equipment, film and intensifying screen, a suitable exposure curve shall be made or selected according to specific conditions, and the exposure specification shall be selected accordingly. In order to achieve the specified film blackness, the exposure is recommended to be not less than 15mA·min to prevent the adverse effects caused by short focal length and high voltage.
18 Film processing
The film shall be processed according to the film instructions or recognized effective methods. The processing solution shall be kept in good condition, and attention shall be paid to the effects of temperature, time and shaking on the washing effect. During automatic washing, the transmission speed and the replenishment of the liquid should also be accurately controlled. 14 Film quality
14.1 Blackness
The selected exposure conditions should make the blackness in the effective evaluation area of the film meet the requirements of Table 5. Table 5 Blackness range of film
Ray type
X-ray
Y-ray
Note: The D value in the table includes the Do value.
14.2 Image quality index
Film blackness D
The minimum wire diameter that must be displayed on the film and the corresponding image quality index are shown in Table 4. 14.3 Image recognition requirements
Gray fog D.
The image of the image quality meter on the film is correctly positioned, the positioning mark and recognition mark are complete, and the image of the weld to be inspected is not covered. On the weld image, if the image of the image quality meter wire with a length of not less than 10 mm can be clearly seen, it is considered to be recognizable. 14.4 Impermissible illusions
There should be no defects caused by improper film processing or other defects that hinder film evaluation in the effective evaluation area of the film. 15 Film observation
15.1 Film evaluation environment
Film evaluation should be carried out in a dedicated film evaluation room. The light in the film evaluation room should be dim, but not completely dark, and the indoor lighting should not reflect on the surface of the film.
15.2 Film viewing light
The film viewing light should have a maximum brightness of 3.5 for observing the maximum blackness of the film, and the brightness of the diffuse light for observation should be adjustable. For parts that do not need to be observed or have too much light transmission, appropriate shading plates should be used to shield the strong light. The brightness of the film after illumination shall not be less than 30cd/m2. In order to observe the film with a maximum blackness of 3.5, the maximum brightness of the film viewing lamp shall not be less than 100.000cd/m2.57
16 Weld quality classification
GB 3323-87
16.1 According to the nature and quantity of defects, the weld quality is divided into four levels. There shall be no cracks, lack of fusion, lack of penetration and strip inclusions in the weld of level I. 16.1.1
16.1.2 There shall be no cracks, lack of fusion and lack of penetration in the weld of level II. 16.1.3 There shall be no cracks, lack of fusion and lack of penetration in double-sided welding and single-sided welding with backing plate in the weld of level III. The allowable length of lack of penetration in single-sided welding without backing plate shall be evaluated according to the length of strip inclusions in level III in Table 10. 16.1.4 Weld defects exceeding level III are level IV. 16.2 Classification of circular defects
16.2.1 Defects with an aspect ratio less than or equal to 3 are defined as circular defects. They can be circular, elliptical, conical or with irregular shapes such as tails (the tail should be included when measuring the size). Including pores, slag inclusions and tungsten inclusions. 16.2.2 Circular defects are evaluated using an assessment area. The size of the assessment area is shown in Table 6. The assessment area should be selected at the most serious defect. Table 6 Defect assessment area
Parent material thickness 7
Assessment area size
10×10
>25~100
10×20
16.2.3 When evaluating circular defects, the defect size should be converted into defect points according to Table 7, see Table 7. Table 7 Conversion table for defect points
Defect long diameter, mm
.1～2
For defect sizes not counted, see Table 8.
>2～3
>3～4
3Defect sizes not counted
Thickness of parent material7
10×30
Defect long diameter
16.2.5When a defect touches the boundary line of the assessment area, it shall be classified as a point in the assessment area. mmwww.bzxz.net
16.2.6When there are few defects near the assessment area, and it is considered inappropriate to classify the level only by the size of the assessment area, the assessment area may be expanded to 3 times along the weld direction through consultation between the supply and demand parties, and the total number of defect points shall be calculated, and 1/3 of this value shall be used for assessment. For the treatment method of expanding the assessment area, see Appendix D.
16.2.7 The classification of circular defects is shown in Table 9.3 Marking position
The above positioning marks and identification marks shall be displayed at the appropriate position of the film and at least 5mm away from the edge of the weld. The placement of the overlap mark is shown in Appendix C.
The workpiece surface shall be permanently marked as a basis for repositioning each film. When the workpiece is not suitable for printing marks, a detailed sketch of the transillumination part and other effective methods shall be used. Exposure curve
According to the equipment, film and intensifying screen, a suitable exposure curve shall be made or selected according to specific conditions, and the exposure specification shall be selected accordingly. In order to achieve the specified film blackness, the exposure is recommended to be not less than 15mA·min to prevent the adverse effects caused by short focal length and high voltage.
18 Film processing
The film shall be processed according to the film instructions or recognized effective methods. The processing solution shall be kept in good condition, and attention shall be paid to the effects of temperature, time and shaking on the washing effect. During automatic washing, the transmission speed and the replenishment of the liquid should also be accurately controlled. 14 Film quality
14.1 Blackness
The selected exposure conditions should make the blackness in the effective evaluation area of the film meet the requirements of Table 5. Table 5 Blackness range of film
Ray type
X-ray
Y-ray
Note: The D value in the table includes the Do value.
14.2 Image quality index
Film blackness D
The minimum wire diameter that must be displayed on the film and the corresponding image quality index are shown in Table 4. 14.3 Image recognition requirements
Gray fog D.
The image of the image quality meter on the film is correctly positioned, the positioning mark and recognition mark are complete, and the image of the weld to be inspected is not covered. On the weld image, if the image of the image quality meter wire with a length of not less than 10 mm can be clearly seen, it is considered to be recognizable. 14.4 Impermissible illusions
There should be no defects caused by improper film processing or other defects that hinder film evaluation in the effective evaluation area of the film. 15 Film observation
15.1 Film evaluation environment
Film evaluation should be carried out in a dedicated film evaluation room. The light in the film evaluation room should be dim, but not completely dark, and the indoor lighting should not reflect on the surface of the film.
15.2 Film viewing light
The film viewing light should have a maximum brightness of 3.5 for observing the maximum blackness of the film, and the brightness of the diffuse light for observation should be adjustable. For parts that do not need to be observed or have too much light transmission, appropriate shading plates should be used to shield the strong light. The brightness of the film after illumination shall not be less than 30cd/m2. In order to observe the film with a maximum blackness of 3.5, the maximum brightness of the film viewing lamp shall not be less than 100.000cd/m2.57
16 Weld quality classification
GB 3323-87
16.1 According to the nature and quantity of defects, the weld quality is divided into four levels. There shall be no cracks, lack of fusion, lack of penetration and strip inclusions in the weld of level I. 16.1.1
16.1.2 There shall be no cracks, lack of fusion and lack of penetration in the weld of level II. 16.1.3 There shall be no cracks, lack of fusion and lack of penetration in double-sided welding and single-sided welding with backing plate in the weld of level III. The allowable length of lack of penetration in single-sided welding without backing plate shall be evaluated according to the length of strip inclusions in level III in Table 10. 16.1.4 Weld defects exceeding level III are level IV. 16.2 Classification of circular defects
16.2.1 Defects with an aspect ratio less than or equal to 3 are defined as circular defects. They can be circular, elliptical, conical or with irregular shapes such as tails (the tail should be included when measuring the size). Including pores, slag inclusions and tungsten inclusions. 16.2.2 Circular defects are evaluated using an assessment area. The size of the assessment area is shown in Table 6. The assessment area should be selected at the most serious defect. Table 6 Defect assessment area
Parent material thickness 7
Assessment area size
10×10
>25~100
10×20
16.2.3 When evaluating circular defects, the defect size should be converted into defect points according to Table 7, see Table 7. Table 7 Conversion table for defect points
Defect long diameter, mm
.1～2
For defect sizes not counted, see Table 8.
>2～3
>3～4
3Defect sizes not counted
Thickness of parent material7
10×30
Defect long diameter
16.2.5When a defect touches the boundary line of the assessment area, it shall be classified as a point in the assessment area. mm
16.2.6When there are few defects near the assessment area, and it is considered inappropriate to classify the level only by the size of the assessment area, the assessment area may be expanded to 3 times along the weld direction through consultation between the supply and demand parties, and the total number of defect points shall be calculated, and 1/3 of this value shall be used for assessment. For the treatment method of expanding the assessment area, see Appendix D.
16.2.7 The classification of circular defects is shown in Table 9.
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