Method for descaling metal strip utilizing anhydrous salt

Abstract

An improved salt and method of using such salt for conditioning scale on strip or sheet metal surfaces is provided. In more particular aspects, the invention provides an improved salt of alkali metal hydroxides and alkali metal nitrates which are used in their fused anhydrous form to condition scale on metal strip or sheet. The salt preferably contains from about 40% to about 70% potassium hydroxide, from about 20% to about 55% sodium hydroxide, and from about 2% to about 30% of an alkali metal nitrate. The salt is especially adapted to be sprayed onto a moving strip or sheet of metal as it passes a spray station, although it can also be used in conventional salt bath applications in which the salt is maintained in a fused condition in a tank, and the sheet, strip, bar, tubing or other form to be treated is immersed in the fused salt bath.

Dependencies are inferred from the claim text.