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This article addresses applying a tensile test with a CCD camera to assess scale adhesion on hot-rolled steel as a function of hot-rolled coil position. The scale adhesion in this study was shown in the value of the strain initiating the first scale spallation. The result of strain initiating the first scale spallation was confirmed with an acoustic emission (AE) method. The as-received hot-rolled coil was studied at the head, middle, and tail positions. A scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to examine the scale morphology and phase identification respectively. The results show that the oxide scale comprises hematite and magnetite layers. It was found that the higher strain initiating the first scale spallation was revealed on the scale formed on the hot-rolled coil at the head and middle positions. This indicates that the oxide scale was more difficult to remove than at the tail position of the coil. The scale growth and cooling affects the stresses on the oxide layer and the steel substrate. A thin oxide layer on tail position of the hot-rolled coil will easily first crack and then buckle and followed by spallation, while a thick scale on head and middle positions of the hot-rolled coil was harder than that thin scale.

This article demonstrates the surface modification of sisal fibres by using NaOH in an ultrasonic medium. The fibres were soaked in 1.0 M NaOH, 60°C for 30, 60, and 90 min, respectively. The fibre surface was examined with a digital microscope camera and a scanning electron microscope (SEM). An elasticity test was used to examine the mechanical properties of composites, specifically between sisal and LLDPE. The results demonstrated the modification of the sisal fibres in NaOH solution by ultrasound producing a cleaner and smoother fibre surface. This was affected by a cavitation phenomenon, which produced high-speed impact jets that cleaned off the dirty particles from the fibre surface. The modified mixed materials had higher ultimate tensile strength. By using this method, the result of sisal fibre modification decreased in the diameter strand of the experimented fibres.

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