Search

The dissolution–ionization–diffusion–deposition (DIDD) model was used for developing a corrosion–resistant stainless steel (SS) by the means of alloying and the guidelines for the process were proposed. The novel HP–13Cr–Cu SS was designed to resist corrosion in H 2 S–containing geothermal environment. The results indicated that the preferential deposition of CuS promoted the heterogeneous nucleation rate of Cr 2 O 3 , FeCr 2 O 3 , and FeS, which formed denser corrosion product layer. As a result, this alloy exhibited a low corrosion rate and a high sulfide stress cracking (SSC) resistance. The results were consistent with the theoretical calculation conducted by the DIDD model. • The DIDD model established the bridge between thermodynamics and kinetics of electrochemical corrosion. • The guidelines for designing corrosion–resistance stainless steel were proposed by means of micro–alloying. • A novel HP–13Cr–Cu SS was designed based on the DIDD model to resistant the H 2 S corrosion. • The testing results verified HP–13Cr–Cu SS gained the low corrosion rate and high SSC resistance. [ABSTRACT FROM AUTHOR]

The dissolution-ionization-diffusion-deposition (DIDD) model is corrected by a cathodic process with the feature of complex equilibrium and deposition competition. CO 2 /H 2 S corrosion of steel is taken as an example to better understand whether the main factor controlling the corrosion is CO 2 , H 2 S or both. The preliminary assessment reveals that when the rate of nuclei is less than 10 % of the total, the corrosion is controlled by only one factor. Furthermore, the calculated results also have a good agreement with morphology and weight loss experiments. This study makes a significant contribution to promoting the application of DIDD model. • The DIDD model is corrected with a complex cathodic process and deposition competition. • When the FeCO 3 nuclei rate is less than 10 %, the corrosion is controlled by H 2 S. • When the FeS nuclei rate is less than 10 %, corrosion is controlled by CO 2 , otherwise controlled by both. • Taking CO 2 /H 2 S corrosion of 20 steel as an example to validate the corrected model. [ABSTRACT FROM AUTHOR]

• The effect of temperature and CO 2 pressure on the stress corrosion cracking of HP-13Cr stainless steel was proposed. • The stress and strain concentration in pitting area was studied by finite element analysis. • A pitting-to-cracking model has been built to elucidating the initiation of stress corrosion cracking. • A "HTHP-SCC electrochemical system" was developed to conduct the electrochemistry measurement under applied stress. The stress corrosion cracking of HP-13Cr stainless steel in the geothermal environment was studied by experimental measurements and modeling calculations. The stress corrosion cracking susceptibility of HP-13Cr stainless steel increases with both temperature and CO 2 pressure, and shows a synergistic effect greater than the temperature or CO 2 pressure does singly. The fracture morphologies presented quasi-cleavage fracture characteristic in the geothermal environment. The stress corrosion cracking mechanism is dominated by the anodic process. The critical stress intensity factor for stress corrosion cracking was measured and the pitting-to-cracking process was clarified by a mechanism model. [ABSTRACT FROM AUTHOR]

• TG201 inhibitor contains Cu2+, and would acquire electrode prior to H+ to form Cu film in the process of acidizing. • The galvanic corrosion between HP-13Cr SS and Cu film could be neglected. • The failure mechanism resulted in the synergistic effect resulted from the Cu film among the process of well completion. • With the temperature and pressure increased, the corrosion rate and the synergistic effect would be enhanced obviously. TG-201 inhibitor could minimize corrosion of HP-13Cr SS in the process of live acid. Moreover, it accelerated the probability of serious corrosion of SS during the well completion. The failure mechanism of TG-201 inhibitor was investigated using surface analysis and electrochemical measurements. TG201 inhibitor contains amounts of Cu2+, which would acquire the electrons prior to H+ to form Cu film. The failure mechanism was due to the synergistic effect attributed to the Cu film. Cu film promoted the formation of the occluded cell and the changes of fluid state evoked by the increase in interfacial roughness during the well completion. [ABSTRACT FROM AUTHOR]