Oil Staining
Surface staining caused by the partial decomposition during thermal treatment of residual lubricant.
Orange Peel
A roughening, on subsequent cold deformation, of the surface of sheet or strip when the grain size is too coarse. Has the appearance of an orange skin.
Ore
Bauxite - A red rock found in the earth's crust, close to the surface. Extracted by open-cast mining it is a very rich ore with a 25% yield.
Ovality
Any variation from a true circle of the cross section of a round tube, bar or wire.
Over-ageing
Artificial ageing treatment at too high a temperature, or for too long a time, after the maximum hardening effect has been achieved. It causes some loss of properties.
In some cases it may be a deliberate act, e.g. to improve resistance to stress corrosion or to minimise any further loss of properties in alloys operating at higher temperatures.