METHOD OF EVALUATING SURFACE MACHINING CRACK SUSCEPTIBILITY AND DEVICE THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a method of evaluating surface machining crack susceptibility during cold forging and a device therefor of a cylinder workpiece material and a device therefor, both of which can properly evaluate surface machining crack susceptibility during cold forging of a thick diameter cylinder workpiece material without using a press apparatus with large load capability.

SOLUTION: Flange formation of a cylinder workpiece material 10 having a diameter (mm) D0in which a bar steel material is cut perpendicularly with respect to a rolling direction is performed by lateral extrusion using a die including an upper die 7 and a lower die 8; a flange diameter (mm) DCis measured when the accumulated cracking ratio generated on flange sides is 50%; the limit diameter expansion ratio defined by formula (1) is calculated; and the surface machining crack susceptibility during cold forging is evaluated based on the limit diameter expansion ratio. Limit diameter expansion ratio=DC/D0(1).

COPYRIGHT: (C)2013,JPO&INPIT