New in-situ measurement technique to determine corrosion fatigue in components and pipes under cyclic load

摘要

In the field of water pipelines, geothermal energy production as well as carbon capture and storage technology (CCS) materials have tornprovide a high resistance to corrosion and mechanical stress. The combination of cyclic load and corrosive aqueous environment leadsrnto corrosion fatigue of pipes and components (e.g. pumps) and thus inevitably to the reduction of the lifetime of these components. Tornestimate the reliability of components from adjusted in-situ-laboratory experiments a corrosion chamber was designed and tested withrnCO_2-saturated corrosive aqueous media flowing at a steady rate. Unique feature of this special chamber is its installation directly ontornthe sample and thus providing flexible usability in almost every testing machine. This allows simultaneous mechanical loading of thernsample, operation at temperatures up to 100 ℃ and exposure to fluid flow of corrosive liquids and gases. The lifetime reduction of AISIrn420C (X46Cr13, 1.4034) is demonstrated at T=60 ℃, geothermal brine: Stuttgart Aquifer flow rate: 9 l/h, CO_2. S-N plots, micrographic-,rnphase-, fractographic- and surface analysis were applied to obtain sustainable information on the corrosion fatigue behavior. Maximumrnnumber of cycles (here 12.5 × 10~6 cycles to failure) is reached at sa =173 MPa. No typical fatigue strength exists and passive corrosionrnfatigue may be identified as failure cause.