Performance Assessment of Ship Hull Metal in Seawater Media

Abstract

This research was undertaken to determine the effects of corrosion on material performance using mild steel and Aluminum as selected material in seawater media. The result from the experiment showed higher corrosion rate in uncoated mild steel coupon as higher corrosion rate ranges from 0.0494 mmpy, 0.0565 mmpy, and 0.0656 mmpy was evident, while a reduction in corrosion rate from 0.0369mmpy, 0.0432 mmpy and 0.0452mmpy was observed in the fourth week, fifth week and sixth week. Corrosion rate for coated mild steel ranges from 0.0396 mmpy in the first week and reduces to 0.0333 mmpy and continually reduces to 0.0206 mmpy in the sixth week. From the hardness testing device using MITECH 320, uncoated Mild steel metal specimen gave an average Brinell hardness reading of 112 before immersion and 105 after immersion to seawater. Also, the tensile strength of the uncoated mild steel specimen deteriorated from 414 Mpa before immersion to 403Mpa after immersion to seawater media. Also, uncoated Aluminum specimen gave a brinell average reading of 163 before immersion and 152 after immersion to the seawater media. Likewise, the tensile strength result of the aluminum specimen gave 776M pa before immersion and 744 Mpa after immersion to the seawater media. The overall result from weight loss technique and metal hardness using MITECH 320 showed aluminum metal is more resistive to corrosion attack.