The use of a novel phosphonate corrosion inhibitor improves general steel corrosion and steel pitting corrosion in cooling water systems. This halogen stable phosphonate inhibitor shows efficacy for traditional continuous flow cooling systems and additionally for cooling systems characterized by low or no flow for extended periods of time. Case histories for performance at an air separation plant and at a plastic mold injection plant are documented.

94-13: The Control of Ferrous Metal Corrosion in Cooling Water by a Novel