According to Stahlschlussel (1995), the minimum RT Charpy V properties for the 1.7147 case hardening steel should be 34J and 34J for 11mm and 30mm section, respectively.
These values are identified as "after case hardening, in core". Clearly, the values of your actual material may be somewhat affected by the processing route.
If you need K1C/K1J values, I suggest you test some actual material (best), or ask your supplier for values.