Iron oxide scale formed on steel during hot working processes, cooled in air

The "rust" or iron oxides which forms on red hot ingots, slabs, blooms billets, etc., which is knocked off by water streams (and other methods) in steel mills. It contains a percentage of iron, usually over 65%, but should be tested for average iron content prior to negotiations.

An almost invisible surface scale of oxide formed when iron is heated.

See scale, mill.