C-Mn Steels

[R.G.]

According to DNV-OS-C101 and C201 PWHT is required on joints in C-Mn steels that have thicknesses greater than 50mm. I'm trying to understand what exactly defines "C-Mn" steels. I've read a number of similar threads that asked this similar question, but I've never seen a valid reply or conclusion. Can someone out there steer me in certain direction.
Thanks,
r

 

[kingnero]

Under EN/ISO, that would be steels from group 1, 2, 3, and 11 (ISO/TR 15608). Basically all typical structural steels that are not significantly alloyed (to consider it a Cr- or Ni- alloy).

 

[DekDee]

Generally slightly higher Manganese - 1.2 to 1.8 %