Rust degrees (corrosion rate)

Rust degrees are an expression of the extent to which there are millscale on a topic

Assessment of rust degrees are an important prerequisite for the evaluation of cleaning the form and extent of a steel surface before being corrosion protected. A thorough and accurate assessment is a prerequisite for a long life span.

According to the standard ISO 8501-1 rust grades are divided from A to D:

A: Steel surface completely covered with adherent millscale and with virtually no rust

B: Steel surface which has begun to rust and from which millscale is beginning to peel off

C: Steel surface where millscale is rusted away, but where corrosion is not significantly visible

D: Steel surface where millscale is rusted away and corrosion is visible to the naked eye