What is steel corrosion in cooling towers mainly caused by?

Steel corrosion in cooling towers is primarily caused by dissolved oxygen. When water in cooling systems is exposed to air, the oxygen it contains can react with the steel components of the cooling system. This reaction leads to oxidation, whereby iron from the steel combines with oxygen to form iron oxide, commonly known as rust. Rusting can lead to pitting, thinning of material, and ultimately structural failure if not controlled.

Dissolved oxygen is especially problematic in cooling towers due to the constant movement and aeration of water, which increases the exposure of steel to oxygen. Additionally, in scenarios where water is repeatedly cycled and not properly treated, the levels of dissolved oxygen can become elevated, further accelerating corrosion.

While factors like chlorinated chemicals, high temperatures, and water hardness are also critical in cooling system maintenance, they typically exacerbate corrosion or influence other chemical reactions rather than being the primary cause of corrosion in steel due to the specific nature of how oxygen interacts with metals in aqueous environments.