In the corrosion rate equation CR = (K × W) / (A × t), what does K represent?

• A. The exposed area.
• B. The time period.
• C. A constant chosen to yield the desired units.
• D. The weight loss.

Answer: (C)

K is a conversion factor that adjusts the raw rate into the desired corrosion-rate units. It isn’t the exposed area, the time period, or the weight loss itself; rather, it scales the result so that, with the units you’re using for W (weight loss), A (area), and t (time), the final CR comes out in the standard units you want (for example, mm/year or mils/year). The exact numeric value of K depends on the unit system you’re using, so it’s essentially a tool to convert the computed rate into the preferred units.