"过渡圆半径" can be translated as "radius of the transition fillet" or "radius of the transition round" in English.
"Transition fillet" is often used in engineering contexts to describe a rounded corner or edge that facilitates a smooth transition between two surfaces or features.
"Transition round" is a more straightforward translation, emphasizing the rounded shape used for transition.
Both terms are acceptable, and the choice between them may depend on the specific context or industry preference.