Metal hollow member and method for manufacturing the same

摘要

A metal hollow member having a plurality of hollow portions extending in a longitudinal direction thereof and communication apertures formed in a partitioning wall partitioning adjacent hollow portions is formed by: extruding a molten extrusion material through a die comprising a female die for forming an outer peripheral portion of the metal hollow member and a male die including a plurality of hollow-portion-forming protrusions corresponding to the plurality of hollow portions; and intermittently supplying fluid insoluble in the molten extrusion material into the partitioning wall from a bottom portion of a groove formed between the adjacent hollow-portion-forming protrusions while extruding the molten extrusion material, whereby the plurality of communication apertures are formed by fluid-released-apertures from which the fluid is released.