Yeah we don't make those out of aluminum (too soft and can't handle high pressures), they're usually carbon steel painted for corrosion resistance and we only using stainless or other alloys if handling corrosive fluids or needing to handle temperatures below -40C (and we don't paint those).
Also those covers are friction-fit, no way they wouldn't pop off during the impact of a plane crash had it actually been on the plane.
Yeah we don't make those out of aluminum (too soft and can't handle high pressures), they're usually carbon steel painted for corrosion resistance and we only using stainless or other alloys if handling corrosive fluids or needing to handle temperatures below -40C (and we don't paint those).
Also those covers are friction-fit, no way they wouldn't pop off during the impact of a plane crash had it actually been on the plane.
Looks like bead blasted Stainless to me. Nuke plant parts?