Effect of Hot Rolling Temperature on Oxide Scale Formation, Grain Size, and Pickling of Stainless Steel

The pickling efficiency of hot‐rolled stainless steel is affected by oxide scale properties and hot rolling parameters. In this study, electrochemical and mixed‐acid pickling were used to remove oxide scales from AISI 304L, formed by different finishing rolling (FRT) and coiling temperatures (CT) and annealing. FRT varied based on the temperature differences between strip locations, and CT based on whether laminar or passive cooling was employed. Characterization of as‐received, annealed, and pickled surfaces was conducted using FESEM‐EDS microscopy. Gravimetric analysis of pickling was conducted to define differences in process parameters in terms of the amount of removed oxide scale, and digital microscopy was used to evaluate surface cleanliness. The results indicate that oxide scale formed with high FRT and CT differs from other scales by the chromium‐rich layer at the oxide‐steel interface and in the metallic phases inside the scale, while during annealing these disappeared and cracks formed for all scales. The efficiency of pickling was better for as‐received compared to annealed surfaces, while high FRT and CT surfaces were not undercut as well as other as‐received surfaces.