Applicability: designers, shipbuilders and steel manufacturers.
Amendments are being made to Brittle Crack Arrest (BCA) steel designation within Lloyd’s Register (LR) Rules. This is to accommodate changes necessitated by IACS UR W31 (Revision 2) of YP47 Steels and Brittle Crack Arrest Steels, which will be implemented by LR from 1 January 2021.
Please note the following:
- The following applicable steel grades with designated Brittle Crack Arrest properties will now have a suffix notation of ‘BCA’ (either BCA1 or BCA2):
BCA1 or BCA2 notations confirm Brittle Crack Arrest properties either in terms of crack arrest temperature (CAT), or crack arrest toughness Kca with a minimum value for BCA1 of Kca≥6000 N/mm1.5 and for BCA2 of Kca≥8000 N/mm1.5, at -10°C.
- Introduction of a new designation for EH47 / YP47 grade as non-BCA steel. This means EH47 grade1 without BCA suffix notation does not have designated Brittle Crack Arrest properties. This non-BCA grade is intended for container ships that do not utilise Brittle Crack Arrest design criteria.
Note 1: EH47 grade which was certified prior to 1 January 2021 is deemed as having Brittle Crack Arrest properties (to BCA1).
The new Rules clearly differentiate between BCA steels and non-BCA steels. Attention is therefore made to EH47 BCA1/BCA2, and EH47 (without BCA suffix notation).
- LR Rules have also been updated with the inclusion of welding procedure qualification ranges based on the new BCA notations.
- For any design plans which have been approved in accordance with LR Rules prior to 1 January 2021 where EH47 grade steel is specified, the shipyard needs to ensure that the correct material is specified and sourced. The LR Technical support office should be contacted to confirm the material specification.