Effect of Grain Size on Micro Ball Punch Deformation of SUS 304 Stainless Steel

Abstract

Micro metal forming is widely interested due to its potential in manufacturing micro parts with low costs and high production rate as the demands of compact devices have been increasing in many fields. This study uses micro ball punch deformation tests to investigate the effect of grain size on the formability of SUS 304 stainless steel sheets. The study employed annealing treatments to change the grain size of the sheets. By using three punches in different diameters in associated with three dies having an inner diameter of 2 mm and different die radii, it was able to perform micro bulging tests and obtain the bulging depths which were used to assess the formability of the sheets. The study shows that the grain size does affect the depth of the deformed dome in the ball punch deformation test at the micro scale.