Improvement of Inner Surface Roughness of Multi-Stage Deep Drawn Stainless Steel Cups by Inner Ironing

摘要

To finish the inner surface of deeply drawn stainless steel cups, an inner ironing process is introduced. In the inner ironing, the inner surface roughness increased by the multi-stage deep drawing is improved by ironing the cup set in the container with a punch having a diameter larger than the inner diameter of the cup. The effects of the ironing ratio, punch coating treatments and lubricants on the improvement of the roughness are examined in the experiment. Although the outer surface roughness is improved by the conventional outer ironing, the reduction in inner surface roughness by the inner ironing is considerably larger than that by the outer ironing. It is found that the inner ironing process is effective in improving the inner surface roughness of the deeply drawn cup.