LR 无损检测标准.doc

Rulefinder Version 9.14 (July 2010) - Lloyd’s Register Rules and Regulations - Rules for the Manufacture, Testing and Certification of Materials, July 2010 - Requirements for Welded Construction - Specific requirements for ship hull structure and machinery Section 2 Specific requirements for ship hull structure and machinery 2.12 Non-destructive examination of welds 2.12.1. All finished welds are to be sound and free from cracks and substantially free from lack of fusion, incomplete penetration, porosity and slag. The surfaces of welds are to be reasonably smooth and substantially free from undercut and overlap. Care is to be taken to ensure that the specified dimensions of welds have been achieved and that both excessive reinforcement and under-fill of welds is avoided. 2.12.2. Welds forming part of the hull and superstructure may be coated with a thin layer of protective primer prior to inspection provided it does not interfere with inspection and is removed, if required by the Surveyor, for closer interpretation of possible defective areas. 2.12.3. All welds are to be visually inspected by personnel designated by the builder. Visual inspection of all welds may be supplemented by other non-destructive examination techniques in cases of unclear interpretation, as considered necessary. The acceptance criteria for visual testing are given in Table 13.2.4. Table 13.2.4 Acceptance criteria for visual testing, magnetic particle and liquid penetrant testingSurface discontinuity Classification according to ISO 6520-1Acceptance criteria for visual testingCrack 100 Not acceptedLack of fusion 401 Not acceptedIncomplete root penetration in butt joints welded from one side4021 Not acceptedSurface pore 2017 Single pore diameter d ≤ 0,25t, for butt welds, see Note 1d ≤ 0,25a, for fillet welds, with maximum diameter 3 mm, see Note 12,5d as minimum distance to adjacent pore Undercut in butt welds 501 Depth ≤ 0,5 mm, whatever the lengthDepth ≤ 0,8 mm, with a maximum continuous length of 90 mm, see Note 2 Undercut in fillet welds 501 Depth ≤ 0,8 mm, whatever the lengthNOTES1. t is the plate thickness of the thinnest plate, and a is the throat of the fillet weld. 2. Adjacent undercuts separated by a distance shorter than the shortest undercut are to be regarded as a single continuous undercut. 2.12.4. In addition to visual inspection, welded joints are to be examined using any one or a combination of ultrasonic, radiographic, magnetic particle, eddy current, dye penetrant or other acceptable methods appropriate to the configuration of the weld. 2.12.5. The method to be used for the volumetric examinations of welds is the responsibility of the builder. Radiography is generally preferred for the examination of butt welds of 8 mm thickness or less. Ultrasonic testing is acceptable for welds of 8 mm thickness or greater and is to be used for the examination of full penetration tee butt or cruciform welds or joints of similar configuration. 2.12.6. The acceptance criteria for radiographic testing are given in Table 13.2.5, and those for ultrasonic testing in Table 13.2.6. Alternative NDE acceptance criteria will be subject to special consideration provided that they are equivalent to these requirements. Table 13.2.5 Acceptance criteria for radiographic testingDiscontinuity Classification according to ISO 6520-1Acceptance criteria for radiographic testing, see Note 1 Crack 100 Not acceptedLack of fusion 401 Continuous maximum length t/2 or 25 mm, whichever is the less, see Note 2 Intermittent cumulative length maximum t or 50 mm, whichever is less, see Note 3 Lack of root fusion 4013 Not accepted in butt joints welded from one sideNot accepted in butt joint welded from one sideIncomplete root penetration4021Continuous maximum length t/2 or 25 mm, whichever is lesser, see Note 2 Intermittent cumulative maximum length t or 50 mm, whichever is less, see Note 3 Slag inclusion 301 Continuous maximum length t or 50 mm, whichever is less, see Note 2 Intermittent cumulative length maximum 2t or 100 mm, whichever is less, see Notes 3 and 4 Gas pore 2011 maximum dimension for a single pore: d ≤ 0,2t, max. 4,0 mm see Note 5 Uniformly distributed porosity2012 Maximum dimension of the area of imperfections: For single run welds: ≤ 1,5% For multi-run welds: ≤ 3% see Notes 6 and 7 Clustered (localised) 2013 Maximum dimension of the summation of the porosity projected area of the imperfection: ≤ 8% see Notes 6 and 7 Elongated cavity 2015 h ≤ 0,3t, max. 3,0 mm l ≤ t, max. 50 mm see Notes 8 and 9 Wormholes 2016 h ≤ 0,3t, max. 3,0 mm l ≤ t, max. 50 mm see Notes 8 and 9 Metallic inclusions other than copper304 h ≤ 0,3t, max. 3,0 mm see Note 8 Copper inclusions 3042 Not permittedNOTES1. t is the thickness of the thinnest plate. 2. Two adjacent individual discontinuities of length ld1 and ld2 situated on a line and where the distance ld between them is shorter than the shortest discontinuity are to be regarded as a continuous discontinuity of。