Contents
What is the chemical symbol of chloride?
Cl-
Chloride/Formula
Cl (chloride): Cl is the chemical symbol for chloride, the major anion found in the fluid outside of cells and in blood. An anion is the negatively charged part of certain substances such as table salt (sodium chloride or NaCl) when dissolved in liquid.
What is chloride corrosion?
Low levels of chloride tend to cause general corrosion while high levels of chloride likely induce localized corrosion. However, no strict boundaries exist between the general and localized process along with higher chloride concentrations and prolonged exposure time.
How to prevent chloride corrosion of carbon steel pipe?
I am specifying pipes for a water system with 500 ppm chloride in solution. Ordinarily we would specify 316L stainless steel to limit the corrosion, but I was asked if we could instead specify carbon steel pipe with a corrosion allowance. So instead of the typical schedule 40 pipe, could I realistically use schedule 80 or 120 etc?
Can aqueous chloride cause pitting in carbon steel?
Cl- definitely can cause pitting in carbon steel. Jones, “Principles and Prevention of Corrosion” has a nice schematic of the pitting mechanism in iron. But SCC is not also a worry: Jones says “…hot aqueous chloride solutions readily crack stainless steels but do not have the same effect on carbon steels, aluminum or other nonferrous alloys.”
What is the effect of chloride on corrosion?
Chlorides increase the conductivity of the fluid and increase the catohidc areas in the corrosion cell. The consequence is an higher general corrosion and possibility of localized corrosion (not pitting) due to the destruction of passive films.
How often does chloride ion attack carbon steel?
Therefore, the action of the chloride ion, which destabilizes passive films in stainless, is not very important to carbon steel. The rate of attack of carbon steel in both fresh water and tropical sea water is between 5 and 10 mils/year ( 2 and 4 mm/year).