Reduction in Pickling Time Induced by Surface Application of KCl and CaCl2 on Hot-Rolled Stainless Steel Prior to Annealing

摘要

The beneficial effects of application of potassium and calcium chloride onto thesurface of hot-rolled stainless steel prior to annealing were investigated in order to reduce pickling time. Three types of stainless steels were examined: 304L, 253 MA and 654 SMO. The specimen were immersed in an aqueous solution of the metal chlorides, dried and subsequently annealed at 1150 C for a maximum of 30 minutes. Upon annealing the surface of the specimen underwent severe oxidation. The oxide layer was voluminous and spalled cooling. The irregular ruptured scale promoted the penetration of pickle solution into regions where descaling initiates. Complications such as extension of the Cr-depleted zone and internal oxidation were also observed.