Hi
Not sure what code you are talking about? In general, I find the EN materials specs difficult to work with, but generally the information is there, as long as you are prepared to search. The mechanical properties for this grade is found in part 2 of EN10025. Can't actually find a required hardness value, but this is not necessarily unusual. Many material specs do not give hardness limits as a standard requirement, but can be specified as a supplementary test if required. I will attach as section of the relevant mechanical property table below, just to give some info, but not sure if this is what you were asking about.
If the code you are asking about is ASME IX, then you will not find it there, because this spec is for structural steel, not pressure quality.
If I am missing your question, please clarify.
Regards
Niekie