The goals of the study were to determine how cold rolled perforated steel reacts to drawing operations and develop the following relationships:

1. Effect of the open area on Formability.

2. Effect of the hole size on Formability.

3. Differences between commercial quality and drawing quality cold rolled steel in their Formability.

4. Differences in Formability according to the orientation of the work piece with respect to the punching tool, i.e., when applying drawing forces perpendicular to straight rows of holes or parallel to straight rows of holes.

The Effect of Hole Size and Sheet Thickness
In Charts 1 through 4, it can be seen that increasing the hole size has very little effect in the 10 to 20 percent open area range. Looking at Chart 5, in the 30 to 40 percent range, increasing the hole size could slightly increase the formability for the same percent
open area. For a particular hole size and percent open area, the formability actually decreases slightly with increasing thickness. This can be seen in Chart 6.

The Effect of Draw Quality Versus Commercial Quality Steel
A comparison of the formability of draw quality versus commercial quality steel is shown in Chart 7. Generally, draw quality has higher formability. Chart 7 compares four thicknesses of steel with a perforated pattern with a hole size of .1875” and 17.01% open area.

The Effect of Orientation
The effect of orientation changes the formability by about 30%. A perforated pattern that has the straight row of holes parallel to the straight punch (B orientation) has less formability than having the straight row of holes perpendicular to the punch (A orientation).