NEN ISO 15626 : 2018 en

.Foreword.......................................................................................................................................................................................................................................iv
1 Scope.................................................................................................................................................................................................................................1
2 Normative references......................................................................................................................................................................................1
3 Terms and definitions.....................................................................................................................................................................................1
4 Symbols..........................................................................................................................................................................................................................1
5 Relation between quality levels and acceptance levels................................................................................................1
6 Definition and determination of length and height.........................................................................................................2
6.1 General........................................................................................................................................................................................................... 2
6.2 Determination of length.................................................................................................................................................................. 2
6.2.1 General...................................................................................................................................................................................... 2
6.2.2 Length sizing of elongated straight indications .................................................................................... 2
6.2.3 Length sizing of elongated curved indications ...................................................................................... 3
6.3 Determination of height.................................................................................................................................................................. 4
6.3.1 General...................................................................................................................................................................................... 4
6.3.2 Surface‑breaking discontinuities....................................................................................................................... 5
6.3.3 Embedded discontinuities....................................................................................................................................... 6
7 Acceptance levels .................................................................................................................................................................................................6
7.1 General........................................................................................................................................................................................................... 6
7.2 Indications from single discontinuities ............................................................................................................................. 7
7.2.1 General...................................................................................................................................................................................... 7
7.2.2 Acceptance level 1 .......................................................................................................................................................... 7
7.2.3 Acceptance level 2 .......................................................................................................................................................... 8
7.2.4 Acceptance level 3 .......................................................................................................................................................... 8
7.3 Total length of indications............................................................................................................................................................. 8
7.4 Grouping of indications................................................................................................................................................................... 9
7.5 Point‑like indications......................................................................................................................................................................... 9
Bibliography.............................................................................................................................................................................................................................11

This document specifies acceptance levels for the time‑of‑flight diffraction technique (TOFD) of full
penetration welds in ferritic steels from 6 mm up to 300 mm thickness which correspond to the quality
levels of ISO 5817.
These acceptance levels are applicable to indications classified in accordance with ISO 10863.