Corrossion & Testing

A: A lines up with the standard shortcut many of us carry: 1 µA/cm² on carbon steel is roughly 0.011–0.013 mm/y, so 5 µA/cm² lands near 0.06 mm/y. B comes from dropping a decimal when converting cm to mm, something you see when someone works straight from mpy charts without checking units. C feels attractive if you're used to stainless numbers and forget that carbon steel dissolves faster for the same current density. D shows up when the equivalent weight is misread as atomic weight, which quietly inflates the rate.

A: A trips people up because CP feels like a blanket safeguard, but SCC needs stress and a specific chemistry, not just anodic dissolution. B is the textbook success case for −850 mV criteria, so it's hard to argue against. C sounds plausible until you remember CP forces the pipe cathodic, suppressing galvanic currents. D looks sneaky because disbonded coatings are dangerous, yet CP still shifts the electrochemistry enough to slow general attack underneath.

A: A matches the chloride level and temperature where 316L loses its passive margin, especially in crevices under washers. B sounds metallurgically serious but oxidation needs far higher temperatures and oxygen access. C tempts anyone thinking about CP systems, yet there's no hydrogen source here. D is comfortable because general corrosion is easy to visualise, but stainless steels fail locally first in these conditions.

A: A reflects the hard lesson that constant fog tests don't map linearly to reality, especially for wet–dry cycling. B is a myth that persists because it's easy to communicate, not because it's defensible. C sounds proactive but actually pushes the mechanism away from what happens in service. D feels reassuring from a GD&T mindset, yet thickness alone doesn't fix underfilm corrosion or adhesion loss.