*3.2.2 SEM micrographs*

**Figures 2** and **3** reveal the SEM microstructures of the Fe 600 rebar and galvanized rebar samples, respectively, consisting of the tempered martensitic rim at the periphery as shown in **Figures 2(c)** and **3(c)**, along with a transition zone consisting of bainite as shown in **Figures 2(a)** and **3(a)**, followed by a ferritepearlite mixed microstructure in the core as shown in **Figures 2(b)** and **3(b)**. In this context, it is noteworthy to mention here that the pearlite microstructure that is shown in **Figure 2(d)** reveals the presence of degenerated pearlite in the case of the Fe 600 rebar sample, which can be correlated with inadequate carbon diffusion during cooling. Detailed discussion on the formation of degenerated pearlite and bainite is available in the literature [23, 33, 39–44]. **Figure 3(d)** primarily reveals pearlite microstructure at a higher magnification with greyish ferrite and whitish cementite flake-like structures, which is completely distinguishable for galvanized rebar samples.

### **Figure 3.**

*SEM micrographs of galvanized rebar sample showing (a) transition zone, (b) core region, (c) outer rim region, and (d) pearlite at higher magnification.*

*Study on the Perspective of Mechanical Properties and Corrosion Behaviour of Stainless… DOI: http://dx.doi.org/10.5772/intechopen.101388*

**Figure 4.**

*SEM micrographs of stainless steel rebar sample showing (a) no transition zone and (b) higher magnification micrograph showing equiaxed ferrite grain.*

SEM microstructures of stainless steel rebar and plain rebar samples are shown in **Figures 4** and **5**, respectively. These microstructures mainly consist of equiaxed grains of ferrite separated by clearly visible distinct grain boundaries in the case of stainless steel rebar sample as shown in **Figure 4(b)**. It cannot be overruled that as the carbon percentage is very low and chromium (ferrite stabilizer) percentage is high for the investigated stainless-steel rebar, hence the microstructure is ferritic. However, mixed ferrite-pearlite microstructures with no transition zone throughout the sample have been observed for plain rebar. The lamellar configuration of pearlite with some amount of resolved pearlite has been shown at a higher magnification at the inset of **Figure 5(b)**.
