Some Clarifications Regarding Literature on Atmospheric Corrosion of Weathering Steels

Table 1

Guiding corrosion values for corrosion rates (𝑟_av, 𝑟_lin) of carbon steel and weathering steel in atmospheres of various corrosivity categories.

Metal	Average corrosion rate (𝑟av) during the first 10 years for the following corrosivity categories (ISO 9223)
	C1	C2	C3	C4	C5
Carbon steel	𝑟av≤0.5	0.5<𝑟av≤5	5<𝑟av≤12	12<𝑟av≤30	30<𝑟av≤100
Weathering steel	𝑟av≤0.1	0.1<𝑟av≤2	2<𝑟av≤8	8<𝑟av≤15	15<𝑟av≤80
Metal	Steady state corrosion rate (𝑟lin) for the following corrosivity categories (ISO 9223)
	C1	C2	C3	C4	C5
Carbon steel	𝑟lin≤0.1	0.1<𝑟lin≤1.5	1.5<𝑟lin≤6	6<𝑟lin≤20	20<𝑟lin≤90
Weathering steel	𝑟lin≤0.1	0.1<𝑟lin≤1	1<𝑟lin≤5	5<𝑟lin≤10	10<𝑟lin≤80