Sulphuric Acid Non Corrosive to Cast Iron 1

[ak1965]

Could someone out here help me in knowing that what prevents sulphuric acid corroding cast iron?

 

[moltenmetal]

Wow, what an open question!

What concentration of sulphuric acid? What temperature? Flowing, or stagnant?

CONCENTRATED sulphuric acid can be handled in carbon steel and cast iron components if there is next to no velocity. The surface becomes passivated with ferrous sulphate, but it is not strongly retained. Even bubbles of hydrogen (from corrosion) can disturb the passive layer and expose fresh metal to corrosion.

Dilute sulphuric acid eats cast iron like sugar candy.

 

[EdStainless]

There are also some high Si cast irons that are regularly used in acid service, but again temperature and concentration and flow must be very carefully defined.

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P.E. Metallurgy, Plymouth Tube