This revised Unified Requirements document (UR W31 Rev3 CLN) was published on March 1st, 2023, and will enter into force on July 1st, 2024.
The content of this document refers to the requirements on YP47 steels and brittle crack arrest steels as required by UR S33.
YP47 steels are steels with a specified minimum yield point of 460 N/mm2.
The purpose of this IACS document is to give the requirements for YP47 steels in thicknesses greater than 50 mm and not greater than 100 mm, intended for the upper deck region of ships carrying containers.
Brittle crack arrest steels
The thickness range of brittle crack arrest steels is between 50 mm and 100 mm. They are also intended for the upper deck region of container carriers.
The brittle crack designation can be assigned to YP36 and YP40 steels specified in UR W11 and YP47 steels specified in this Unified Requirements document.