METHOD FOR FORGING PROJECTION PART OF FORGING PART HAVING U OR V SHAPED LUG PART AND FORGING DIE USABLE THEREFOR

摘要

PURPOSE:To improve the accuracy of a product and to reduce the cost by forming on a forging die the space part for forming a projection part, a lug part forming face and axial part forming face are constrained by a constraint die face as well and executing upsetting on the axial part. CONSTITUTION:A movable die 11 is made up of a die part 37 and die 38 and the space part 43 for forming a forging projection part is formed on the lower part end part of the die 38. The axial part of the preform W3 having an U shaped lug part 3 is set in the cavity 39 of the die 38 of the mobile die 11, an upper bolster 27 is descended and a punch die 31 is advanced downward. In this case, the inner opposing face 3a, tip face 3c and axial part 1 of the lug part 3 of the preform W3 are respectively constrained by constraint dies 40, 26. The projection part is formed via the die 38 and punch die 31 with the axial part 1 being upset in the axial direction. The accuracy of a product is improved and the cost is reduced because the project. ion part is formed by cold forging by constraining the lug part 3 and axial part 1.