Hydrogen-induced cracking behaviors of Incoloy alloy 825

Abstract

The effect of hydrogen on the fracture behaviors of Incoloy alloy 825 was investigated by means of slow strain rate testing (SSRT). Hydrogen was introduced into the sample by electrochemical charging. The results show that surface microcracks form gradually during aging at room temperature when desorption of hydrogen takes place after hydrogen charging at a current density of 5 mA/cm² for 24 h. SSRT shows that the increase of ductility loss is significantly obvious as the hydrogen charging current density increases. Scanning electron microscopy (SEM) images reveal ductile fracture in the pre-charged sample with low current densities, while the fracture includes small quasi-cleavage regions and tends to be brittle fracture as the hydrogen charging current density increases to 5 mA/cm².

Keywords

Incoloy alloy / hydrogen-induced cracking / diffusible hydrogen / slow strain rate testing

References

[1] Zhang S.C., Zhu G.Y., Liang Y.B. Probe into formation mechanism of H2S and high-quality reservoirs of Puguang large gas field in Sichuan Basin. Geol. Rev. (in Chinese), 2006, 52(2): 46.

[2] J. Kolts, Laboratory evaluation of corrosion resistant alloys for the oil and gas industry, [in] The NACE International Annual Conference and Exposition 1986, Houston, 1986, paper No.323.

[3] P.R. Rhodes, Stress cracking risk in corrosive oil and gas wells, [in] The NACE International Annual Conference and Exposition 1986, Houston, 1986, paper No.322.

[4] H.E. Chang, M. Watkins, and G.A. Vaughn, Stress-corrosion cracking resistance of stainless alloys in sour environments, [in] The NACE International Annual Conference and Exposition 1985, Houston, 1985, paper No.227.

[5] A. Ikeda, M. Ueda, and H. Tsuge, Environmental cracking of evaluation of corrosion resistant alloys in H₂S-CO₂-Cl⁻ environment by slow strain rate tensile test, [in] The NACE International Annual Conference and Exposition 1989, Houston, 1989, paper No.7.

[6] H. Miyuki, J. Murayama, T. Kudo, and T. Moroishi, Effect of Cr, Ni and Mo on corrosion resistance of highly alloyed materials in sour well environments, [in] The NACE International Annual Conference and Exposition 1984, Houston, 1984, paper No.209.

[7] Chu W.Y. Hydrogen Attack and Delayed Fracture (in Chinese), 1988 Beijing, Metallurgical Industry Press, 17.

[8] Zhang X., Li Z.M., Zhong X.Z., et al. Experiment on H₂S stress corrosion of tube in deep well. Pet. Explor. Dev., 2004, 31(6): 95.

[9] Wayman M.L., Smith G.C. The hydrogen embrittlement of Fe-Ni martensites. Metall. Mater. Trans., 1970, 1, 1189.

[10] Foct F., de Bouvier O., Magnin T. Stress corrosion cracking mechanism of alloy 600 polycrystals and single crystals in primary water: influence of hydrogen. Metall. Mater. Trans. A, 1999, 30, 2025.

[11] Rios R., Magnin T., Noel D., de Bourier O. Critical analysis of alloy 600 stress corrosion cracking mechanisms in primary water. Metall. Mater. Trans. A, 1995, 26A, 925.

[12] El kebir O.A., Szummer A. Comparison of hydrogen embrittlement of stainless steels and nickel-base alloys. Int. J. Hydrogen Energy, 2002, 27, 793.

[13] Boniszewski T., Smith G.C. A note on nickel hydride. J. Phys. Chem. Solids, 1961, 21, 115.

[14] Chu W.Y., Qiao L.J., Chen Q.Z., Gao K.W. Fracture and Environmental Fracture (in Chinese), 2000 Beijing, Science Press, 82.

[15] Zhang R.Y., Dong C.F., Li X.G., et al. Hydrogen induced cracking behaviors of X70 pipeline steel and its welds under electrochemical charging. Acta Metall. Sin., 2006, 42(5): 521.