14 Metallic Materials Optimisation Routes Available to Purchase

An overview of materials selection routes for different production scenarios is given in this chapter acting as a guide in a holistic strategy for materials optimisation. This provides a preferred route to the choice of appropriate materials for a particular application. A basic knowledge of materials and corrosion is nevertheless highly advisable so that a fitforservice solution is achieved. It is important to note that while carbon and low alloy steels (CLASs) are chosen primarily according to their general and localised metal loss corrosion resistance, with adequate resistance to sulphide stress cracking (SSC), corrosion resistant alloys (CRAs) are normally selected mainly based on their resistance to environmental cracking (EC). These latter threats include SSC and chloride stress corrosion cracking (Cl-SCC) or a combination thereof as affected by the operating temperatures and conditions. The exception for CRAs is under extreme conditions – typically a combination of high temperature, low pH, high CO₂, and H₂S – where general corrosion may also or exclusively have to be considered in the overall selection strategy. In this chapter, an integrated strategy to materials optimisation is illustrated to enable safe and trouble-free operations while maintaining economy.