Hard disk drive device forged shape material for case body, case body, method for producing forged shape material for case body, and method for producing case body

摘要

PROBLEM TO BE SOLVED: To provide a hard disk drive device case body forging roughly formed material, a case body and a manufacturing method of the case body forging roughly formed material, capable of obtaining a processing root part having a high notch fatigue strength required as use durability and strength satisfying reliability, in a portion predetermined so as to be used as an actuator attachment part of the aluminum hard disk drive device case body forging roughly formed material.SOLUTION: A hard disk drive device case body forging roughly formed material is characterized in that, on a portion predetermined so as to be used as an actuator attachment part by cutting processing of an aluminum hard disk drive device case body forging roughly formed material having a blind box-shape of which one side surface is opened, an average particle size of aluminum crystal grain is 15 to 80 times with respect to the average particle size of the portion predetermined so as to be used as a bottom part.