40 CFR §420.81

1. (a)The term salt bath descaling, oxidizing means the removal of scale from semi-finished steel products by the action of molten salt baths other than those containing sodium hydride.
2. (b)The term salt bath descaling, reducing means the removal of scale from semi-finished steel products by the action of molten salt baths containing sodium hydride.
3. (c)The term batch, sheet and plate means those descaling operations that remove surface scale from sheet and plate products in batch processes.
4. (d)The term batch, rod and wire means those descaling operations that remove surface scale from rod and wire products in batch processes.
5. (e)The term batch, pipe and tube means those descaling operations that remove surface scale from pipe and tube products in batch processes.
6. (f)The term continuous means those descaling operations that remove surface scale from the sheet or wire products in continuous processes.
7. (g)The term batch means those descaling operations in which the products are processed in discrete batches.