NB/T 47013.2-2015Nondestructive testing of pressure equipments - Part 2: Radiographic testing (English PDF)

3.1 Penetrated thickness; W

Nominal thickness in radial irradiation direction. In multi-layer penetrating, the penetrated thickness shall be equal to the sum of nominal thickness of each layer of material passed.

3.2 Object-to-film distance; b

The distance between side surface of radiation source at object's inspected position measured along the central axis of the ray bundle.

3.3 Source-to-object distance; f

The distance between sides surfaces of radiation source at object's inspected position measured along the central axis of ray bundle.

3.4 Focal distance; F

The distance between radiation source inspected along the central axis of ray bundle and the film.

3.5 Source size; d

Effective focal size of radiation source.

4.1 Inspection personnel

4.1.1 The personnel engaging in radiographic testing shall meet relevant provisions of NB/T 47013.1.

4.2.2 Radiographic film

4.2.3 Film viewer

Main performance of the film viewer shall meet relevant provisions of GB/T 19802, and the maximum brightness shall meet the requirements of film evaluation.

4.2.4 Nigrometer (optical densimeter)

4.2.5 Film with standard density

The standard density film shall include 8 blackness criteria with certain intervals, which can cover the scope of 0.3 ~ 4.5 and the films shall be calibrated every two years at least. The storage and using conditions of standard density films must be specially paid attention to.

4.2.6 Intensifying screen

4.2.7 IQI

4.2.8 Determination for safety radiation time of the darkroom

The film shall be conducted darkroom processing in safety lamplight recommended by the film manufacturer; determination for safety radiation time of the darkroom can refer to Annex D.

4.3 Levels of the measurement technique

4.4 Process documents for inspection

4.5 Protection of radiation safety

4.5.1 The radiation protection shall meet relevant requirements of GB 18871, GBZ 117 and GBZ 132.

5.1 Inspection opportunity

5.1.1 The inspection opportunity shall relevant provisions, specifications, standards and design documents, at the same time; it shall meet other technical requirements agreed by the both parties.

5.1.2 Unless otherwise specified, radiographic testing shall be conducted after production of the welding joints being completed, for the materials with delayed cracks; the welding joints shall be made 24 h after the welding being completed.

5.2 Inspection zone

5.3 Surface requirements

Before radiographic testing, surface of the welding joints shall be qualified by visual inspection. The image of irregularity of surface on films shall not cover image of the flaw, or the surface shall be properly trimmed.

5.4 Selection of films

5.5 Arrangement of penetration

5.6 Ray energy

5.6.1 Under the premise of ensuring penetrating power, X-ray imaging shall adopt low tube voltage. If the high tube voltage is used, the proper exposure shall be ensured.

Figure 1 indicates the maximum X-ray tube voltage allowed for different materials and penetrating thicknesses.

5.8 The distance between the film and object inspected

In the period of exposure, the film shall be close to the object, unless special provisions or the penetrating arrangement can ensure to get better penetrating images of the inspected zone. When the source included penetrating of fillet welds is used, the film shall be close to welds on the inspected object as far as possible.

5.9 Exposure quantity

5.10 Exposure curve

5.13 Marks

5.14 Film processing and quality inspection

5.14.1 Film processing

In general, film processing is conducted according to instructions of the film. Which can be processed with automatic washing or manual washing, the automatic method is recommended. In general, the washing formula or drugs produced or recommended by the film manufacturer, and the requirements of GB/T 19348.

6.2 Radiographic testing

result evaluation and quality grading for melting welding joints of pressure equipment made of aluminum

6.2.1 Scope

This clause is suitable for the radiographic testing result evaluation and quality grading of the welding joints for pressure equipment made of aluminum and aluminum alloy with the thickness of 2 mm ~ 80 mm, types of the welding joints applied include the butt welds of two-side melting welding, the butt welds of full penetration equivalent to two-side welding, as well as single-side welding butt welds with sub-plate close to the base metal along whole length of the root welds.

6.2.2 Types of flaws

According to nature and forms, flaws in welding joints can be divided into 6 classes.

Cracks, incomplete fusion, incomplete penetration, copper inclusion, stripy flaws and round flaws.

6.2.3 Division of quality levels

According to nature, quantity and density of flaws in welding joints, the quality levels can be divided into level I, II, III and IV.

6.2.4 General provisions for quality grading

6.2.5 Grading evaluation of round flaws

6.3 Radiographic testing

result evaluation and quality grading for melting welding joints of pressure equipment made of tantalum and tantalum alloy

6.3.2 Types of flaws

According to nature and forms, flaws in welding joints can be divided into 5 classes. Cracks, incomplete fusion, incomplete penetration, stripy flaws and round flaws.

6.3.3 Basis of quality levels

According to nature, quantity and density of flaws in welding joints, the quality levels can be divided into level I, II, III and IV.

6.3.4 General provisions for quality grading

7 Radiographic testing result evaluation and quality grading for melting welding joints of pressure equipment's pipes and pressure pipelines made of steel, nickel and copper

7.1.1 Scope

This clause is suitable for the radiographic testing result evaluation and quality grading of the butt circular welding joints for pressure equipment's pipes and pressure pipelines made of steel, nickel and nickel alloy; copper and copper alloy with the thickness of T >= 2 mm, types of the welding joints applied include the butt welds of single-side welding added with sub-plate close to the base metal along whole length of the root welds, and the single-side butt welds without sub-plate.

7.1.2 Types of flaws

According to nature and forms, flaws in welding joints can be divided into 7 classes.

Cracks, incomplete fusion, incomplete penetration, stripy flaws, round flaws, indent at roots, and undercut at roots etc.

7.1.3 Division of quality grades

According to nature, size, quantity and density of flaws in welding joints, the quality levels can be divided into level I, II, III, and IV.

7.1.4 General provisions of quality grading

7.1.8 The grading evaluation of indent and undercut at roots

When the pipe's outer diameter Do is > 100 mm, the grading evaluation for root indent and undercut flaws of single-side welding without sub-plate is conducted according to Table 26. When the pipe's outer diameter Do is <= 100 mm, the quality grading evaluating for root indent and undercut flaws without sub-plate shall be conducted according to Table 27.

7.2 Radiographic testing

result evaluation and quality grading for melting welding circular joints of pressure equipment's pipes and pressure pipes made of aluminum and aluminum alloy

7.2.1 Scope

This clause is suitable for the radiographic testing result evaluation and quality grading of melting welding circular joints for pressure equipment's pipes and pressure pipe made of aluminum and aluminum alloy with the wall thickness T of >= 2 mm, types of the welding joints applied include the butt welds of single-side melting welding the sub-plate closed to basic metal along whole length of the welds root, and the single-side butt welds without sub-plate.

7.2.2 Types of flaws

According to nature and forms, flaws in welding joints can be divided into 8 classes.

Cracks, incomplete fusion, incomplete penetration, copper inclusion, stripy flaws, round flaws, root indent and root undercut etc.

7.2.8 Grading evaluation of root indent and undercut

The quality grading evaluation shall be conducted according to 7.1.8.

7.3 Radiographic testing result evaluation and quality grading for melting

welding circular joints of pressure equipment's pipes and pressure pipes made of tantalum and tantalum alloy