Selecting alloys for severely corrosive service

Selecting the most suitable, cost‐efficient alloy for a given application should not be difficult if the methodology described in this paper is followed. The first step is to identify those alloys with the desired corrosion resistance. Factors other than chemical composition have a bearing on an alloy’s corrosion resistance. Service environment and nature of the product application must also be considered. These conditions are discussed in the text. Consideration should be given to other key issues such as mechanical properties required as well as method of fabrication, design, condition and availability of the candidate alloy. To simplify selection, the author discusses severe corrodents and aggressive environments that are commonly encountered in the process industries, and describes the characteristics of alloys that might be considered for each type of corrosive service. Cross referenced charts position these alloys to show their relative resistance to each type of corrosion attack. While the paper is not designed to replace the technical expertise of a corrosion engineer, the author feels it can serve as a good starting point in the alloy selection process.