MANUFACTURE OF CYLINDRICAL FORMED PRODUCT

摘要

PURPOSE:To manufacture cylindrical formed products of good textural consolidation at a high yield by constituting a reduced part forming tapered faces that face the inner peripheral face of a die and the outer peripheral face of a core rod and pressing in a cylindrical powdery forming material by a punch. CONSTITUTION:A heated cylindrical powdery forming material 30 is inserted into an opening 49 formed by the inner peripheral face of a die 33 having an inner hole and the outer peripheral face of a core rod 45 which is inserted into the inner hole by the action of a lower die 42. Then, a punch 59 is lowered by the action of an upper ram 58, and inserted into the opening 49 to press the material 30 therein. A reduced part is constituted by forming tapered parts that project facing each other on the inner peripheral face of the die 33 and the outer peripheral face of the core rod 45. The material 30 is drawn in the reduced part to obtain a thin cylindrical formed product. Above-mentioned method is especially suitable for manufacturing a cylindrical formed product such as a cylinder liner material of an internal-combustion engine from a material made of aluminum group.