PSI- Issue 9

Khadija Kimakh et al. / Procedia Structural Integrity 9 (2018) 243–249 Khadija. KIMAKH / StructuralIntegrity Procedia 00 (2018) 000–000

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Furrow

Streak

Tearing material

(a)

(b)

(c)

Fig. 5. Global observations of specimens machined with different feed rate (a) f 1 =0.25 mm/rev, (b) f 2 =0.15mm/rev and (c) f 3 =0.05 mm/rev.

According to the specimen observations, we notice that the feed rate changes the surface state. The specimens machined with a very high feed rate have a rougher surface state compared to those machined with low feed rate. So the surface roughness increases with the increase of feed rate. When the feed rate decreases, the number of streaks decreases and their widths increase. Also, the furrows become deeper with the increase of feed rate. On the other hand, we notice the presence of the tearing material which decreases with the decrease of the feed rate. All these geometrical irregularities represent defects which are