For my Manufacturing Processes Lab, we took a steel plate and punched holes in it with a punch press to make a mounting plate. The plate was 1/2″ thick and the press delivered around 60 tons of force towards the punch. These are pictures of the hole that was cut out. Even though this was for a different class, I decided to discuss this using Physical Metallurgy concepts.
Note the ridges in the center. This indicates a ductile fracture.
The smooth surface at the top and bottom show a more brittle fracture mode in this area.
These deep ridges in the center are semi-chevron shaped, which is characteristic of steel failure. The initial crack began in the direction of the point of the chevron.