In doing analysis for a construction company many of their pieces of equipment are showing very high chromium levels along with very high iron levels. Anybody have any thoughts on what may be taking place(as to why chromium is showing up)? At times the dirt(Si) level is also very high.

Judging by what you've said it would appear dirt is/has worn your hydraulic cylinder rods. The chromium would be coming from the chrome coating on the cylinder rods, once this wears away you've exposed your iron which would be tearing your seals to bits and then letting even more dirt in to do more damage.

Its a vicious circle.

Hope this helps.

Lou,

Chrome can be due to Roller bearings distress.
Iron is an indication of Gear/Shaft/Retainer
plate wear.Silicon alone in the sample is not
Dirt.Dirt Ingression will show Al:Si in the
ratio of 1:3 or 1:4 ratio depends upon type of
soil.Dirt entry causes abrasive wear of Gear
Components,if not controlled could end up with
excessive wear and subsequent failures.

Break-in wear also initially shows high level
of wear elements,Should come down after two to
three oil changes.Simple patch test will tell
you the contaminant condition.

Regards

Bala.