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The influence of cold rolling on the microstructural changes of 2205 duplex stainless steel was investigated. The steel samples revealed the presence of almost equal volume fraction of δ‐ferrite and austenite phase after hot rolling. During cold rolling, the above phase constituents became flattened, fragmented as well as transformed into acicular microstructural constituents with increasing amount of cold deformation. The transmission electron microscopy revealed the presence of strain‐induced α′ martensite, Moiré fringes, elongated worm‐like closed slip band channels and poorly developed dislocation cell structures. The volume percent of the constituent phases has been quantified by X‐ray diffraction analysis, which has also been substantiated by the image analysis result. The micro‐hardness measurement establishes that the work hardening capacity of austenite is more compared to ferrite.

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The present work aims to study the evaluation of the microstructure, tensile properties, hardness, corrosion behaviour of the various grades of rebars. The microstructures of all rebar samples comprise an outer tempered martensite ring with an inner core of ferrite-pearlite in between a narrow bainitic transition zone. Maximum hardness is achieved at the periphery which gradually decreases towards the centre. Chinese grade has a similarity with the Fe 600 rebar in terms of strength and % elongation, whereas Fe 500D and Fe 500 have lower strength but higher ductility. The EDS analyses of corrosion products obtained after immersion test in 5% NaCl solution for a period of 7 days apparently indicate the occurrences of iron oxy-hydroxides and iron oxides. X-ray diffraction and FTIR studies of the corrosion products formed on all thermomechanically treated (TMT) rebar surfaces after the aforesaid immersion test primarily indicate the presence of Lepidocrocite (γ-FeOOH), Goethite (α-FeOOH), Magnetite (Fe 3 O 4 ) and Maghemite (γ-Fe 2 O 3 ). Fe 500 (12 mm) and Chinese rebars have lower corrosion resistance as compared to the other rebars in 5% NaCl solution. Nevertheless, all the TMT rebars are corrosion resistant and can be satisfactorily used for construction purposes.