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Title: Hydrogen-Assisted Cracking Fracture Analysis using High-Speed Camera and Delayed Hydrogen Cracking Test
Dissimilar metal welds (DMWs) are commonly used when a high strength steel is overlaid with a corrosion resistant alloy (CRA) for petrochemical applications. There have been reported failures of these DMWs during subsea service while under cathodic protection (CP). These failures are caused by local hydrogen embrittlement of susceptible microstructures that form at the weld fusion boundary. Hydrogen-assisted cracking (HAC) occurs as a result of the local embrittlement and is influenced by base/filler metal combinations, and welding and post-weld heat treatment (PWHT) procedures. A delayed hydrogen cracking test was used to simulate tensile load and hydrogen charging on 8630-FM 625 weld. The failure of this sample was recorded using a high-speed camera to capture the crack initiation and propagation during failure. Fractography was performed using a scanning electron microscope (SEM) along with energy dispersive spectroscopy (EDS). The fracture surfaces, EDS measurement and video timestamps revealed brittle fracture nucleation in the planar growth and CGHAZ regions of the weld. The cracking continued to propagate through the same regions of the weld leading to final ductile failure (microvoid coalescence) in the cellular dendritic region of the weld.  more » « less
Award ID(s):
2052747
PAR ID:
10506955
Author(s) / Creator(s):
;
Publisher / Repository:
Springer
Date Published:
Journal Name:
Journal of Failure Analysis and Prevention
Volume:
22
Issue:
1
ISSN:
1547-7029
Page Range / eLocation ID:
385 to 399
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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