Method of producing polygonal ring-shaped machine parts having complex cross-section

摘要

Disclosed is a method of producing a polygonal, ring-shaped machine part having a complex cross-section starting from a metal rod with improved productivity and remarkably increased material yield. The method comprises the steps of: forging a rod to prepare a notched blank 1 having large diameter parts 11 and the remaining small diameter parts 12; bending the large diameter parts 11 to form a first intermediate 3 of polygonal, open ring-shape and a complex cross-section with confronting ends; butting and welding the confronting ends of the first intermediate 3 to form a second intermediate 5; die-forging the second intermediate 5 to form a ring-shaped product 7; and subjecting the product 7 to necessary finishing step such as machining to obtain the final product.