A couple of issues I would address at first glance.
The ID of this material may not be round. If there is any TIR callout between the ID/OD, this could force you to machine the inside just to grip it either on a mandrel or otherwise to control it. Same goes for the OD before cutting the groove.
Why a 4.5mm radius helical groove? As if this were for a ball screw function, then grinding may be in order.
Knowing its intended purpose might help in regard to how critical the end result will be and so direct the process of manufacture. Any heat treat, like case hardening could also influence portions of the process.
If I read your dimensions correctly, 30mm wall thickness is not thin is it? Chatter should not be a problem, but might be reduced if you rough the groove with a smaller radius tool, then finish it to spec with the majority of the finish material removed from the leading edge.
DC
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