TWO-PIECE FRICTION-WELDED PISTON

摘要

A two-piece piston is formed by friction welding an upper member to a lower member, wherein the upper and lower members are precision cast to net final dimensions such that no post-casting machining is required prior to the friction-welding process. The upper member includes a substantially flat crown and combustion surface extending radially inward from the crown. The lower member includes a pair of opposing skirts, each having a bore formed therethrough for receiving a connecting rod pin. The upper member and lower member each include at least two corresponding connecting surfaces that form a welded joint therebetween when the upper and lower members are friction welded together. The finished piston includes an integral cooling oil reservoir adjacent to the combustion surface.