NDT GUIDE
Non-destructive testing of ship hull steel welds
1. General
1.1 This document is intended to give guidance on the minimum requirements on the methods and quality levels that may be adopted for the non-destructive testing (NDT) of ship hull steel welds during new building and ship repair.
1.2 The quality levels given in this document refer to production quality and not to fitness for purpose of the welds examined.
1.3 The non-destructive testing is normally to be performed by the Shipbuilder or its subcontractors in accordance with these requirements. The Classification Society’s surveyor may require to witness some testing.
1.4 It should be the Shipbuilder’s responsibility to assure that testing specifications and procedures are adhered to during the construction and the report is made available to the Classification Society on the findings made by the NDT.
1.5 The extent of testing and the number of checkpoints are normally agreed between the ship yard and the Classification Society.
2. Limitations
2.1 Materials
2.1.1 This document applies to fusion welds made in normal and higher strength hull structural steels in accordance with UR W11, high strength quenched and tempered steels in accordance with UR W16 and connections welds with hull steel forgings in accordance with UR W7 and hull steel castings in accordance with UR W8.
2.2 Welding processes
2.2.1 This document applies to fusion welds made using shielded metal arc welding, flux cored arc welding, gas metal arc welding, gas tungsten arc welding, submerged arc welding, electro-slag welding and electro-gas welding processes.
2.3 Weld joints
2.3.1 This document applies to butt welds with full penetration, tee, corner and cruciform joints with or without full penetration, and fillet welds.
2.4 Timing of NDT
2.4.1 NDT should be conducted after welds have cooled to ambient temperature and after post weld heat treatment where applicable.
2.4.2 For steels with specified minimum yield stress of 420 N/mm2 and above, NDT should not be carried out before 48 hours after completion of welding. Where post weld heat treatment (PWHT) is carried out the requirement for testing after 48 hours may be relaxed.
