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A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 10 in2 and that approximately 2.6 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. (convert the time from hours to years). The density of steel is 7.9 g/cm3. K

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Answer:

10 years

Explanation:

The rate of corrosion (R) is given as:

[tex]R=\frac{KW}{\rho At}[/tex]

Given that:

R = 200 mpy,

W is the weight loss of the metal after exposure in mg = 2.6 kg = 2.6 × 10⁶ mg,

t = time,

A = surface area of the metal exposed = 10 in²,

ρ = the density of the metal in g/cm³ =  7.9 g/cm³ and

constant K= 534 for CPR in mpy

From the rate of corrosion equation, rearranging to get:

[tex]t=\frac{KW}{\rho AR}[/tex]

Substituting to get:

[tex]t = \frac{534*2.6*10^{6} }{7.9*10*200} =8.8 *10^4hours = 10yrs[/tex]

The time of submersion of the steel plate in years is; 10 years

Corrosion Penetration Rate Calculation

We are given;

  • Corrosion penetration rate; CPR = 200 mpy
  • Weight of the corroded portion of plate; W = 2.6 kg = 2.6 × 10⁶ mg
  • Exposed surface area; A = 10 in²
  • Density of the metal plate; ρ =  7.9 g/cm³

The time of submersion of the steel plate is given by the formula;

t = KW/(ρA*CPR)

Now K is a constant and is equal to 534 provided CPR is in mpy and

A is in square inches.

Thus;

t = (534 * 2.6 × 10⁶)/(7.9 * 10 * 200)

t = 8.8 × 10⁴ hours

Now, 24 hours makes one day and there are 365 days in a year. Thus;

number of hours in a year = 24 * 365

Thus;

t in years = (8.8 × 10⁴)/(24 * 365)

t ≈ 10 years

Read more about corrosion at; https://brainly.com/question/5168322

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