| 摘要 |
PURPOSE:To improve the life and productivity of dies by bending the projections formed by forming process by sizing process and erecting them by ironing. CONSTITUTION:A blank material 2 is subjected to spheroidization annealing, shot blasting, and bonderizing and is forward extruded to form a part 6a, and form a recess 6b in the head part, to a semifinished product 6. This semifinished product 6 is bonderized, after which it is headed to form a part 7a, recess 7b and a raised part 7c. After this semifnished product 7 is soft-annealed, it is shot blasted and bonderized, and three projections 8a are formed by forming. Next, the projections of the semifinished product are bent by soft-annealing, shot blasting and bonderizing followed by sizing, and are erected axially by ironing, whereby a semifinished product 9 is formed. The end face of the head part, the part for containing inboard rollers, the stem part, etc. are worked by slight machining to this semifinished product 9, whereby the finished product is obtained. |
