Monolithic metallic drive shafts which are resistant to corrosion and wear

摘要

A monolithic metallic drive shaft for a marine propulsion device is disclosed which is resistant to corrosion. The drive shaft comprises proximal and distal end portions, each of which has a predetermined surface hardness. The surface hardness of one of the proximal and distal end portions is greater than the surface hardness of the other of the proximal and distal end portions.