BALL, BALL SCREW, AND ELECTRIC INJECTION MOLDING APPARATUS AND ELECTRIC PRESS MACHINE INCLUDING THE BALL SCREW

摘要

PROBLEM TO BE SOLVED: To impart appropriate hardness and toughness to a ball of a ball screw. SOLUTION: The ball 9 is used in the ball screw 1 employed in a high load drive section of an electric injection molding apparatus or the like. The ball 9 has a surface hardened layer formed by tempering after carbonitriding. The amount of residual austenite in the surface hardened layer is 35 vol.% to 45 vol.%. COPYRIGHT: (C)2008,JPO&INPIT