FRICTIONAL STIRRING SURFACE TREATMENT METHOD AND APPARATUS

摘要

Two beams 17 and 18 perpendicular to a moving trajectory Q are formed in an intake port opening 14 of a cylinder head material to serve as margins for interfering with deformation of the opening 14 due to softening of the material, thereby a deformation of the material and a void caused by the deformation can be prevented in the frictional stirring with the rotary tool.