in/yr\text{in/yr}

inch per year

Corrosion rateexact by definition

The inch per year is a thousand mils per year, exactly 0.0254 m/yr by definition of the international inch. It is rarely used for ordinary corrosion, which never approaches an inch a year, and appears mainly for erosion-corrosion, acid attack on unprotected steel, and rapid degradation cases where the mpy figure would run into the thousands.

Watch out: An inch per year is 1000 mpy and 25.4 mm/yr. Seeing this unit at all in a report is a signal that something has gone badly wrong, so confirm the units before acting: a figure meant as mpy and typed as in/yr is off by a factor of a thousand.

1 in/yr\text{in/yr} 25.4 mm/yr\text{mm/yr}

One inch per year in every corrosion rate unit

25,400,000nanometer per year (nm/yr)
25,400micrometer per year (μm/yr)
1,000mil per year (mpy)
25.4millimeter per year (mm/yr)
1inch per year (in/yr)this unit
0.0254meter per year (m/yr)