Molten metal rotor with hardened blade tips

A rotor for use in molten metal, the rotor comprising (a) a body portion, and (b) a plurality of rotor blades, wherein each rotor blade comprises (i) a leading edge on a leading surface, wherein the leading surface has a height, (ii) a trailing edge, (iii) a top surface between the leading edge and the trailing edge, and (iv) a separate hardened tip different from and not connected to a hardened tip on any of the other plurality of rotor blades and comprising material at least twice as hard as the body portion, wherein the hardened tip extends along the top surface 30%-50% of a distance between the leading edge and the trailing edge and 30%-50% of the leading edge.