A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 11 in.2 and

Question

A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 11 in.2 and that approximately 2.3 kg had corroded away during the submersion. Assuming a corrosion penetration rate of 200 mpy for this alloy in seawater, estimate the time of submersion in years. The density of steel is 7.9 g/cm3.

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Thiên Hương 5 years 2021-07-23T18:39:38+00:00 1 Answers 335 views 0

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  1. danthu
    0
    2021-07-23T18:41:02+00:00
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    Answer:

    The time of the submersion is t_{years} = 9 years

    Explanation:

    From the question we are told that

       The area of the plate is  A = 11 in^2

        The mass of the corroded plate m = 2.3 \ kg = 2.3 * 1*10^{6}= 2.3 *10^{6} mg

        The corrosion penetration rate is R = 200 mpy

         The density of steel is  \rho = 7.9 g/cm^3

    Generally the corrosion penetration rate   can be mathematically represented as

                 R = \frac{K m}{A \rho t}

    Where K is the corrosion imperial unit constant   whose value is  K = 534 mpy

               t is the exposure time of the plate

       Making t the subject of the formula

                  t = \frac{K m}{R \rho A}      

          Substituting value

                 t = \frac{534 *2.3*10^{6}}{200 * 7.9 * 10 }

                 t = 77734 hrs

    Converting to years

                  t_{years} = \frac{77734}{365 * 24}

                 t_{years} = 9 years

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