Journal of Failure Analysis and Prevention

, Volume 8, Issue 1, pp 48–53 | Cite as

Stress-Corrosion Cracking and Galvanic Corrosion of Internal Bolts from a Multistage Water Injection Pump

Case History---Peer-Reviewed

Abstract

Nineteen out of 26 bolts (studs) used for assembly of multistage water pump showed severe corrosion and cracking after brief service in a severe working environment that contained saline water, CO2, and H2S. The failed bolts and intact nuts were supposed to be made out of a special type of austenitic stainless steel as per ASTM A 193 B8S and ASTM A 194, respectively. However, the investigation showed that bolts and nuts are made from two different alloys: an austenitic stainless steel and a nickel-base alloy. The difference in the corrosion resistance of these two alloys led to severe galvanic corrosion. The galvanic coupling between bolts and nuts in addition to the severe working environment played major role in the premature failure of bolts. The mechanisms of bolt failure were galvanic corrosion for bolts that were in direct contact with the environment and stress-corrosion cracking in the bolts remote from the severe environment. The stress-corrosion cracking was influenced by a bad fit between the bolts and nuts threads. This resulted in a crevice and the development of an aggressive chemistry between the engaged bolt/nut threads. All factors required to cause stress-corrosion cracking were available, namely, stressed bolts (bolts under tensile stress), temperatures above 60 °C, and chloride ions.

Keywords

Stress-corrosion cracking Galvanic corrosion Bolts 

References

  1. 1.
    Corrosion. Metals Handbook, vol. 13, 9th edn. American Society for Metals, Metals Park, OH (1987).Google Scholar
  2. 2.
    Failure Analysis and Prevention. Metals Handbook, vol. 11, 9th edn. ASM International, Materials Park, OH (2002).Google Scholar
  3. 3.
    Tuttle, R.N., Kochera, J.W.: H2S corrosion in oil and gas production. In: A Compilation of Classic Papers, p. 193. National Association of Corrosion Engineers, Houston, TX (1981).Google Scholar
  4. 4.
    International Standard, NACE MR0175/ISO 15156-1, Petroleum and natural gas industries—materials for Use in H2S containing environment in oil and gas production, Parts 1 through 3, National Association of Corrosion Engineers, Houston, TX.Google Scholar
  5. 5.
    Suess, S.J.: Stress corrosion cracking of various alloys. Mater. Perform. 46, 74 (2007).Google Scholar
  6. 6.
    Hara, T., Asahi, H., Kaneta, H.: Galvanic corrosion in oil and gas environment. Corrosion 96, paper no. 63, NACE International, Houston, TX (1996).Google Scholar
  7. 7.
    Tuttle, R.N., Tresder, R.S.: Life prediction of high pressure gas wells. Mater. Perform. 29, 34 (1991).Google Scholar

Copyright information

© ASM International 2008

Authors and Affiliations

  • F. Elshawesh
    • 1
  • K. Abusowa
    • 1
  • H. Mahfud
    • 1
  • H. Ezuber
    • 1
  1. 1.Libyan Petroleum InstituteTripoliLibya

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