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 5 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.

Answer 1

the estimated time of submersion is 17.7 years

Step-by-step explanation:

Given the data in the question;

estimate the time of submersion in years.

we write down the relation between time of submersion and corrosion penetration as follows;

CPR(mpy) = K × W(mg) / [ A(in²) × p(g/cm³) × t(hr) ]

we solve for t

t = (K × W) / ( AP × CPR )

given that;

Area A = 5 in²

W = 2.3 kg = 2.3 × 10⁶ mg

density of steel p = 7.9 g/cm³

CPR = 200

we know that K is 534

so we substitute

t = (534 × 2.3 × 10⁶ mg) / ( 5 in² × 7.9 g/cm³ × 200 mpy )

t = 1,228,200,000 / 7900

t = 155468.3544 hr

t = 155468.3544 hr × ( 1 yrs / ( 365 × 24 hrs )

t = 17.7 years

Therefore, the estimated time of submersion is 17.7 years