Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Bourgeois Dissertation.pdf (25.99 MB)

ETD Abstract Container

Abstract Header

Hydrogen Assisted Crack in Dissimilar Metal Welds for Subsea Service under Cathodic Protection

Bourgeois, Desmond
http://rave.ohiolink.edu/etdc/view?acc_num=osu1437668334

Abstract Details

2015, Doctor of Philosophy, Ohio State University, Welding Engineering.
Dissimilar metal welds (DMWs) are routinely used in the oil and gas industries for structural joining of high strength steels in order to eliminate the need for post weld heat treatment (PWHT) after field welding. There have been reported catastrophic failures in these DMWs, particularly the AISI 8630 steel - Alloy 625 DMW combination, during subsea service while under cathodic protection (CP). This is due to local embrittlement that occurs in susceptible microstructures that are present at the weld fusion boundary region. This type of cracking is known as hydrogen assisted cracking (HAC) and it is influenced by base/filler metal combination, and welding and PWHT procedures. DMWs of two material combinations (8630 steel – Alloy 625 and F22 steel – Alloy 625), produced with two welding procedures (BS1 and BS3) in as welded and PWHT conditions were investigated in this study. The main objectives included: 1) evaluation of the effect of materials composition, welding and PWHT procedures on the gradients of composition, microstructure, and properties in the dissimilar transition region and on the susceptibility to HAC; 2) investigation of the influence of microstructure on the HAC failure mechanism and identification of microstructural constituents acting as crack nucleation and propagation sites; 3) assessment of the applicability of two-step PWHT to improve the resistance to HAC in DMWs; 4) establishment of non-failure criterion for the delayed hydrogen cracking test (DHCT) that is applicable for qualification of DMWs for subsea service under cathodic protection (CP).
Boian Alexandrov (Advisor)
John Lippold (Committee Member)
Antonio Ramirez (Committee Member)
367 p.
Engineering; Materials Science

Recommended Citations

Citations

  • Bourgeois, D. (2015). Hydrogen Assisted Crack in Dissimilar Metal Welds for Subsea Service under Cathodic Protection [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437668334

    APA Style (7th edition)

  • Bourgeois, Desmond. Hydrogen Assisted Crack in Dissimilar Metal Welds for Subsea Service under Cathodic Protection. 2015. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1437668334.

    MLA Style (8th edition)

  • Bourgeois, Desmond. "Hydrogen Assisted Crack in Dissimilar Metal Welds for Subsea Service under Cathodic Protection." Doctoral dissertation, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437668334

    Chicago Manual of Style (17th edition)

osu1437668334
733
© 2015, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.