Tatsuo Maekawa1, Sadayoshi Nagata1, Nobuo Nakajima1 and Masaru Kagawa1
1Engineering and Research Laboratory, Mitsubishi Atomic Power Industries Incorporated, Saitama
The potentiostatic etching technique for austenitic stainless steels was studied to observe the variation of the structure by cold-rolling. The etching potentials of each phase (ferrite, austenite and grain boundary) were determined from the etching figures of an annealed AISI 321L stainless steel. 1 N H2SO4 (containing 0.01 g/L NH4SCN) and conc HNO3 solutions were selected as etching solutions. The ferrite phase caused by cold-working was etched at a potential of -0.35 V (vs S.C.E.) in H2SO4, and the distribution of ferrite phase was observed by an electron microscope. The slipping band was etched at -0.2 V, the etching potential of austenite phase. The grain boundary was etched at 1.2 V in conc HNO3, and the deformation of the grain by rolling was observed.
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