What kind of material is the milling cutter?
45 carbon steelQuenching and tempering HB270 above canIf you demand a high degree of strengthIt can be machined with 42CrMo forgings (quenched and tempered HB300-330)
45# steel plus quenching and tempering can be, the cost is low.
42CrMo more, hardness HRC29 - 34.