TY - JOUR A1 - Pfennig, A. A1 - Wiegand, Reiner A1 - Bork, Claus-Peter T1 - Corrosion and corrosion fatigue of AISI 420C (X46Cr13) at 60 °C in CO2-saturated artificial geothermal brine JF - Corrosion science N2 - The lifetime reduction of cyclically loaded AISI 420C (X46Cr13, 1.4034) constantly exposed to highly corrosive CO2-saturated hot thermal water is demonstrated in in situ-laboratory experiments (60 °C, brine: Stuttgart Aquifer, flowing CO2: 30 L/h). S–N plots, micrographic-, phase-, fractographic- and surface analysis were applied to obtain sustainable information on the corrosion and corrosion fatigue behavior. Maximum number of cycles (here 12.5 × 106 cycles to failure) is reached at σa = 173 MPa. Hydroxide and siderite layers were found on pits and crack surfaces. No typical fatigue limit exists and pit corrosion prior to crack initiation may be identified as failure cause. KW - A. Stainless steel KW - C. Corrosion fatigue KW - C. Pitting corrosion KW - C. Kinetic parameters KW - B. SEM PY - 2013 DO - https://doi.org/10.1016/j.corsci.2012.11.005 SN - 0010-938X VL - 68 SP - 134 EP - 143 PB - Elsevier CY - Orlando, Fla. AN - OPUS4-27541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bork, Claus-Peter A1 - Wolf, Marcus A1 - Pfennig, A. A1 - Trenner, S. A1 - Wiegand, Reiner T1 - Comparison between X5CrNiCuNb16-4 and X46Cr13 under corrosion fatigue T2 - Corrosion 2014 N2 - In geothermal power plants materials e.g. pumps are exposed to extremely corrosive thermal water. This results in corrosion fatigue and so inevitably the reduction of the lifetime of these components. Also in the field of the carbon dioxide storage technology (carbon capture and storage CCS) components are exposed to a corrosive environment and mechanical stress. In order to gain knowledge upon the corrosion fatigue strength of materials a corrosion chamber for "in situ" conditions was designed and successfully applied.Two different steels X46Cr13 and X5CrNiCuNb16-4 have been tested and their corrosion fatigue behavior was compared. To simulate the frequency of operating pumps (30 – 40 Hz) a resonant testing machine was used. In addition technical CO2 was introduced into the closed system at a rate close to 9 L/h to keep stable environmental conditions. The samples have a surface roughness of Rz = 4 to simulate technical machined surfaces. The calculated tensile strength of X46Cr13 with soft annealed microstructure (coagulated cementite in ferrite-perlite matrix) is about 680 MPa and the yield strength is about 345 MPa. The tensile strength of X5CrNiCuNb16-4 is about 1078 MPa and the yield strength about 928 MPa. Testing parameters are: corrosion media: saline aquifer water (Stuttgart Aquifer) temperature of the brine at 60 °C and load ratio of R=-1. For X46Cr13 a stress amplitude between 160 MPa to 270 MPa and for X5CrNiCuNb16-4 a stress amplitude between 150 to 500 was chosen. Cycles until crack initiation differ strongly and were found to start at 5 x 104 up to 12.5 x 106 cycles.X46Cr13 has reached a maximum number of cycles (12.5 x 106) at a stress amplitude of 173 MPa. X5CrNiCuNb16-4 has reached the maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa. The range of scatter for X5CrNiCuNb16-4 is very high (1:34) in comparison the range of scatter for X46Cr13 (1:3.5). T2 - Corrosion 2014 CY - San Antonio, TX, USA DA - 09.03.2014 KW - Steel KW - Corrosion chamber KW - Geothermal power KW - CCS KW - Corrosion fatigue PY - 2014 SP - Paper 3776, 1 EP - 6 PB - NACE AN - OPUS4-31085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -