The line is designed with capacity of 500,000t/a. The strip surface is impinged by mortar (mixture of steel sand & water) to remove the scales, and the descaled strips are used as substitutes for some cold-rolled & pickled sheets. Compared with coupled pickling line - tandem cold mills, the surface treatment line features higher environmental friendliness, less land occupancy and lower cost, representing the trend of surface treatment technology development.