GB/T 5677-1985 Radiography and film grade classification method for steel castings

This standard specifies the X-ray and gamma-ray radiography methods and radiographic film grade classification methods for steel castings with a thickness of 5 to 300 mm. GB/T 5677-1985 Radiography and film grade classification methods for steel castings GB/T5677-1985 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Radiographs and Films for Steel Castings
Classification Methods
Methods of radiographic testing and classificationof radiographs for steel castingsUDC 621.741.4
.001.33
GB 5677—85
This standard specifies the X-ray and radiographic methods and radiographic film classification methods for steel castings with a thickness of 5 to 300 mm. 1 Radiographic Methods
1.1 Requirements for Radiographic Methods
1.1.1 The surface of steel castings must be cleaned and radiographed only after passing the appearance inspection. 1.1.2 Permanent or semi-permanent marks should be used on the surface of the workpiece as the basis for repositioning each radiographic film. When printing marks are not suitable, detailed sketches of the perspective parts or other marking methods should be used. 1.1.3 The flaw detector must have the basic theory and operation technology of radiographic flaw detection, understand the casting process and use conditions of the workpiece to be inspected, and obtain the radiographic flaw detection qualification certificate from the relevant non-destructive testing personnel qualification appraisal agency. 1.2 Radiographic sensitivity
1.2.1 Radiographic sensitivity is expressed by the following formula: ×100
Where: K
-radiographic sensitivity expressed as a percentage, %, d
-diameter of the thinnest steel wire that can be identified on the radiographic film, mm, and the thickness of the steel casting at the irradiated part, mm.
1.2.2 Radiographic sensitivity is divided into Class A (normal sensitivity level) and Class B (high sensitivity level). Class A radiographic sensitivity K<2.0%.
Class B radiographic sensitivity Ks<1.5%.
However, when the irradiated thickness is less than 10mm, the image quality meter steel wire with a diameter of 0.2mm must be read on the film. 1.3 Selection of X-ray Sources
Selection of X-ray tube voltage is as shown in Figure 1. Other X-ray sources can be selected according to Table 1 based on the penetration thickness and sensitivity level. Issued by the National Bureau of Standards on December 4, 1985
Implementation on September 1, 1986
X-ray Sources
1r 192
1 ~ 2 MV X-rays
>2MV X-rayswww.bzxz.net
1.4 Selection of Films
GB 5677—8.5
Irradiation Thickness mm
Relationship between Tube Voltage and Irradiation Thickness
Table 1 X-ray Sources with Different Irradiation Thickness Ranges
Applicable Thickness Range for Class A
20 ~100
40~200*
50~ 200
Applicable thickness range for Class B
60~150
60~150
The type of film should be selected according to the thickness of the steel casting, photographic sensitivity and sensitization method within the appropriate exposure time. The A-level method should use type 3 or smaller film, and the B-level method should use type 2 or type 1 film. See Table 2 for the selection of film types. Table 2 Classification of X-ray Films
Film Type
Ultra-fine Film
Fine Film
Film with Medium Grains
Film with Large Grains
Sensitivity Speed
Medium Speed
*When the thickness range of the transillumination is 40~60mm, a front screen and rear screen made of steel (or alloy steel) or copper with a thickness of 0.4~0.7mm must be used. 19
1.5 Selection of intensifying screens
GB 5677—85
Metal and metal fluorescent intensifying screens should be used in this standard. The thickness of the metal screen can be selected according to Table 3. Table 3 Selection of metal screen thickness
Radiation source
6~12MV
0.02~0.25mmFront and rear screens are lead intensifying screens0.05~0.25mmFront and rear screens are lead intensifying screens0.1~0.5mmFront and rear screens are
Lead, steel or copper intensifying screens
0.4~0,7mmFront and rear screens are
Steel or copper intensifying screen
0.1～1.0mmThe front and rear screens are lead intensifying screens
1.0~1.5mmThe front and rear screens are copper or steel intensifying screens. The thickness of the front screen is 1.0～1.6mm, and the thickness of the rear screen is less than 1.5mm. The intensifying screen material can be copper, steel or molybdenum
1.0～1.5mmThe front screen is button or tungsten intensifying screen, and the rear screen is not required. Note: The material of the steel intensifying screen in the table can also be made of alloy steel. For radiation sources below 100kV, the front screen can be omitted. 1.6 Determination of focal length
Determine the minimum distance from the radiation source to the workpiece (}), plus the workpiece penetration thickness (t) to get the required focal length. The value can be determined by any of the methods in Appendix A (Supplement). 1.7 Shielding of scattered rays
1.7.1 In order to improve the sensitivity of radiography, the following methods can be used to shield scattered rays: a. Add a lead cover and a filter plate to the window of the radiation source; use thick lead plates to shield the non-transmitted parts of the workpiece; b.
The back of the dark box is shielded by a lead plate with a wall thickness greater than 2mm; c.
The transilluminated workbench is covered with a 6mm thick lead plate,
and shielded with lead shot, iron bean sand and compensation liquid. e.
1.7.2 In order to determine the influence of film backscattered rays, B-shaped lead characters can be attached to the back of the dark box. The B-shaped character image should not appear after the film is developed. 1.8 Arrangement of transillumination
1.8.1 The transillumination positions of the radiation source, image quality meter, steel castings and film shall be arranged as shown in Figure 2. 1.8.2 There should be an image of the image quality meter on each negative film. If the transillumination thickness varies greatly, an image quality meter can be placed on the thick and thin parts of the workpiece. If a 360° circumferential exposure method is used, an image quality meter can be placed on the workpiece in each quadrant. 1.8.3 The image quality meter must be placed on the radiation source side of the casting. When this is not possible, it can be placed on the film side of the casting and marked with the letter F. However, a comparative test must be conducted to ensure that the actual sensitivity meets the requirements of Article 1.2. 20
GB 5677-85
Figure 2 Layout of radiography positions
Radiation source
Image quality meter
1.9 Radiography direction and radiography thickness of steel castings
The radiography direction is required to be the direction of the minimum thickness of the steel casting. If it is impossible to radiograph from this direction, radiographs from other directions may be used. The radiography thickness refers to the actual radiography thickness. When the actual thickness measurement is impossible, it may be determined by drawing methods. 1.10 Image quality meter
The image quality meter shall be selected according to the thickness of the steel casting in accordance with GB5618--85 "Linear Image Quality Meter". 1. 11 Film darkroom processing and requirements for negatives 1.11.1 Film should be processed in the darkroom according to the formula recommended by the film factory. In order to ensure the quality of the negative, the tank development method should be used. 1.11.2 The photographic sensitivity of the negative must meet the requirements of Article 1.2. There must be permanent or semi-permanent casting part numbers and positioning marks on the workpiece. The part number on the negative must be consistent with the part number on the casting. Lead positioning marks should be placed at the positioning marks on the casting. This mark must be imaged on the film to verify the defect location. 1.11.3 There are no defective parts on the film. The blackness should meet the requirements of Table 5. The blackness range specified in Table 5 is the effective film evaluation range. When using double film exposure technology and thickness compensation technology, the effective film evaluation range of the blackness on the film can be expanded. Table 5 Blackness range of film
1.11.4 The film is not allowed to have defects such as scars and spots that hinder the film rating. Blackness range
1.12 Observation of film
When the blackness of the film is large, a film viewing lamp with appropriate brightness should be used for observation. The brightness of the film viewing lamp should be adjustable and should meet the requirements of Table 6. 21
GB 5677--85
The viewing screen of the film viewing lamp should be equipped with an adjustable shielding window, and the window size can be adjusted according to the film observation area when in use. Table 6 Brightness of film viewing lamp
Film blackness
Note: When the film blackness is less than or equal to 2.5, the brightness of the illumination through the film should not be less than 30cd/m2. When the film blackness is greater than or equal to 3, the brightness of the illumination through the film should not be less than 10cd/m2. 2 Classification method of X-ray film grade
Brightness of film viewing lamp
10 000
30 000
2.1 This standard is one of the general standards for quality rating of steel castings. When using this standard, the manufacturer and the user can negotiate and select a certain level of this standard as the qualified level based on the use requirements, manufacturing possibilities and other conditions of the steel castings. Different qualified levels can also be selected for different parts of the same steel casting, and different qualified levels can also be selected for different types of defects in the same part. 2.2 Casting defects on the film are divided into five categories: pores, sand and slag inclusions, shrinkage cavities and shrinkage, unfused internal cold iron and unfused mud core support, hot cracks and cold cracks.
2.3 The size of the defect is determined according to the size of the defect image on the film. For shrinkage cavities, only the size of the obvious part of each defect is measured, excluding the size of the surrounding blurred shadow part. When two or more defects overlap on the film, their sizes should be measured separately. 2.4 Classification method for pores and sand and slag inclusion defects For the classification of pores and sand and slag inclusion defects, the evaluation field of view should first be selected in the area with the most defect points on the film. The size of the evaluation field of view is determined according to Table 9 and Table 11 according to the thickness of the transillumination. 2.4.1 The number of points of a single defect should be found according to Table 7 according to the size of the defect. However, the number of defect points may not be calculated for defects smaller than those specified in Table 8.
The number of points of more than two defects is the sum of the number of defect points in the evaluation field of view. If the defect is on the boundary of the assessment field of view, the part outside the defect line shall also be included in the calculation of the number of points. 2.4.3
2.4.4 The level of defects such as pores and sand and slag inclusions shall be assessed according to the total number of defect points in accordance with Table 9 and Table 11 respectively. However, the maximum size of pores and sand and slag inclusions allowed in the first level shall not exceed the provisions of Table 10 and Table 12 respectively. Table 7 Conversion between defect size and defect point count
Defect size, mm2
Defect point count
Defect size, mm
Defect point count
>10.0～15.0
>2.0～4.0
15.0~20.0
>20.0 ~25.0
>25.0 ~30.0
>8.0～10.0
>30. 0 ~60.0
Transillumination thickness
Scope of application
Below level 2
Transillumination thickness
(diameter)
Transillumination thickness
Maximum size of pores
GB5677—85
Maximum size of defects without points counted
>10～20
>20～40
>40～80
>80~120
>120～200
Table 9 Maximum point values ​​allowed for pores in different levels10
Below level 3
>10～20
>20~40
>40~80
>80 ～120
>200～300
>120 ~ 200
200 ~ 300
Number of defects exceeds 5 levels; defect size exceeds 1/2 of wall thicknessTable 10
Transmissive thickness
Evaluation field of view
(diameter)
Maximum pore size allowed for level 1
>10~20
>20 ~40
>40~80
80～120
The maximum number of sand and slag inclusions allowed in different grades<10
5 or less
>10～20
>20~40
>40~80
≥120～200>200～300
>80 ~120>120 ~200[200 ~300
The number of defect points exceeds 5 levels; the defect size exceeds 70% of the wall thickness
Transparent thickness
The maximum size of sand and slag inclusions
GB5677-85
The maximum size of sand and slag inclusions allowed in the first grade>10~20
>20～40
≥>40 ~80
[≥80 ～120
>120~200≥200 ~300
2.5 Method for classification of shrinkage defects
2.5.1 When classifying shrinkage defects, first select the part with the largest shrinkage length and area on the film as the evaluation field of view. The size of the evaluation field of view should be determined according to the thickness of the exposure according to Table 14. 2.5.2 Shrinkage defects can be divided into strip shrinkage, dendritic shrinkage and large-area shrinkage according to their shapes. 2.5.3 Calculation of the length of strip shrinkage defects: The maximum length of a strip shrinkage is the defect length, and the sum of the lengths of the shrinkages of more than two strip shrinkages is the defect length. When the shrinkage is on the boundary line of the evaluation field of view, the part outside the defect line should also be included. However, the defect length can be excluded if the length is less than that specified in Table 13. Table 13 Shrinkage defects may not be calculated. Maximum values ​​of defect length and area. Transillumination thickness
Scope of application
Below level 2
Strip, mm
Dendrite, mm2
Strip, mm
Dendrite, mm2
>10~20
>20~40
>40~80
>80 ~120
>120~200 /200~300
2.5.4 Calculation of the defect area of ​​dendritic shrinkage: The defect area of ​​a dendritic shrinkage is the product of the maximum length of the defect and the maximum width orthogonal to it. The defect area of ​​more than two dendritic shrinkages is the sum of the areas of each. When the shrinkage cavity is on the boundary line of the assessment field of view, the part outside the defect line should also be included in the area calculation. 2.5.5 When both dendritic shrinkage cavities and strip shrinkage cavities exist in the assessment field of view, the strip shrinkage cavities should also be calculated as dendritic shrinkage cavities. Its length is the length of the strip shrinkage cavities, and its width is one third of the length. 2.5.6 Calculation of large-area shrinkage defect area: The defect area is the product of the maximum length of the defect and the maximum width orthogonal to it.
2.5.7 The grade of shrinkage defects should be assessed based on the sum of defect lengths or areas. Strip shrinkage cavities are assessed based on the sum of defect lengths in accordance with Table 14. Dendritic shrinkage cavities are assessed based on the sum of defect areas in accordance with Table 15. Large-area shrinkage cavities are assessed based on the sum of defect areas in accordance with the values ​​in brackets in Table 15. When the casting thickness is greater than 40mm, it is not easy to find such defects by radiography.
Transillumination thickness
GB567785
Table 14 Maximum length of defects allowed for strip shrinkage holes in different grades 410
Evaluation field of view
(diameter)
>10～20
12 or less
Transillumination thickness
Evaluation visual exposure
(diameter)
>20 ～40
>40 ~80
>80~120
For those with a length exceeding grade 5
Maximum area of ​​defects allowed for dendritic shrinkage holes in different grades 10
>10 ～ 20
250(1000)
450(2000)
800(3000)
1600(6000)
3 600 (10 000)
≥20~40
600(1600)
900(3000)
1650(5000)
2700(9000)
6300(16000)
≥40~80
120~200>200-300
80~120120~200
Those with an area exceeding level 5
12 000
When the film shows defects such as complete non-fusion of the inner cold iron and complete non-fusion of the mud core support, it should be rated as level 6. 2.6
2.7When the film shows hot cracks and cold cracks, it should be rated as level 6. 100
>200 300
2.8 Comprehensive rating of defects
2.8.1 When there are more than two types of defects in the assessment field of view, the comprehensive assessment method should be carried out according to the type of defects, and the lowest level should be determined as the comprehensive assessment level. 2.8.2 When there are more than two types of defects of the same level in the assessment field of view, if the number, length and area of ​​the defects exceed the middle value specified for the level, the comprehensive assessment level should be reduced by one level. However, the comprehensive assessment level of those that have been rated as level 6 will still be level 6. 2.8.3. On the negative film with the first-level requirement, defects such as pores or sand and slag inclusions appear in the evaluation field. The size of a single defect exceeds the provisions of Table 10 or Table 12, but the total value of its points does not exceed the value specified in the first level. In this case, if other similar defects that are rated as second level appear in this evaluation field, the comprehensive evaluation level is still second level. Record
When radiography is recorded, the following records should be made:
Name and manufacturer of the steel casting;
Date and number of flaw detection,
Material and penetration thickness;
Name of flaw detection instrument, focus, focal length, tube voltage, tube current and exposure time.
Type and intensity of the ray source,
Type of film, intensification method, development and fixing conditions, flaw detection sensitivity and film blackness,
Result of grade classification.
A.1 Diagram method
GB 5677—85
Appendix A
Method for determining the minimum distance (f) from the radiation source to the workpiece (supplement)
According to the thickness of the workpiece to be irradiated, find the f/d value from Figure A1. f=(f/d)·d
Where: f-
-minimum distance from the radiation source to the workpiece, mm,
-effective size of the radiation source, mm.
Calculation of the effective size d of the radiation source:
. Square focus d=α (a is the side length of the square). Rectangular focus d= (a, b are the side lengths of the rectangle). b.
Elliptical focus d=
(a, b are the major and minor axis lengths of the ellipse). 2
d. Circular focus d is the diameter of the circular focus. B-level
Transillumination thickness tmm
200300
Relationship between transillumination thickness t and minimum f/d value
A.2 Graphical method
According to Figure A2, according to the known effective focal spot size d and the thickness of the transillumination workpiece t, it is divided into two levels, A and B, and the f/d value is calculated by the graphical method. Legend: The transillumination thickness t=37mm is known. The effective size of the radiation source d=3mm. The intersection of the line connecting point 3 of the d scale and point 37 of the t scale on the f scale 27
GB 5677--85
can determine the f value. A-level f=250mmB-level f=500mm. 10
—2000
100—-
Figure A2 Nomogram of the minimum distance from the radiation source to the workpiece (Legend d=3mm, t=37mm, then f=500mm for Class B) Additional notes:
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Shanghai Materials Research Institute of the Ministry of Machinery Industry. This standard is drafted by the Shenyang Foundry Research Institute of the Ministry of Machinery Industry. u
The main drafters of this standard are Li Yuda, Yang Jiping, and Huang Mingshan. This standard mainly refers to the Japanese JCSSG2 standard and the American ASTME446/E186/E280 standard. 28
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