Utilising Titanium to Successfully Handle Chloride Process Environments

摘要

Titanium possesses an exceptional and wide-range resistance to chlorides and their compounds when compared to most corrosion-resistant engineering alloys (CRAs) used in the CPI. This natural resistance to chlorides stems from titanium's protective, tenacious, and readily rehealable titanium oxide surface film, which is chemically stable over a wide range of pH and redox potentials in aqueous environments. This passive film explains titanium's elevated resistance to anodic pitting, crevice and stress corrosion, and erosion-corrosion in aqueous chloride environments. Guidelines for successful selection and application of industrial titanium alloys are derived from an extensive laboratory test database and more than forty years of industrial/chemical service experience. These guidelines are simplified, and alloy corrosion performance is assessed with respect to four basic aqueous chloride service categories where selection or consideration of titanium is highly merited. An overview of historical titanium alloy applications in chloride-rich environments in a wide variety of process industries substantiates their exceptional chloride tolerance. These industrial titanium alloys are cost competitive with stainless steels and nickel alloys, readily commercially available, and routinely fabricated and welded in the shop and field via well established methods.