文档介绍：International
Journalof
Fatigue
ELSEVIER International Journal of Fatigue 23 (2001) 103-113
ate/ijfatigue
Sulfide stress corrosion cracking and fatigue crack growth of
welded TMCP API 5L X65 pipe-line steel
. Tsay a,*, . Chen a, . Chan b
a Institute of Materials Engineering, National Taiwan Ocean University, Zpei-Ning Road, 202 Keelung, Taiwan, ROC
b Institute of Materials Science and Engineering, National Taiwan VniversiQ, Taipei, Taiwan, ROC
Received 8 March 2000; received in revised form 9 June 2000; accepted 28 August 2000
Abstract
Slow strain rate tensile test and fatigue crack growth (FCG) test were performed to evaluate the fracture behavior of API 5L
X65 steel weldments after hydrogen-charging. Regardless of the testing environments, tensile fracture of all welds was located at
the weld metal (WM), which had the lowest hardness pared to that of the other parts of the weld. When hydrogen-charged
in an H,S-saturated solution, all specimens suffered a small drop in tensile strength pared to those tested in air; however,
the loss in ductility was more significant. The susceptibility to hydrogen embrittlement of the welds could be reduced significantly
by subjecting the welds to 6OOTY2 h tempering treatment. With the tempering treatment, the number of surface cracks in the WM
after hydrogen-charging decreased and the tensile properties improved. Results of FCG test demonstrated that in a higher stress
intensity factor range (AK), tempered steel plates with a severely banding structure had the higher fatigue crack growth rates
(FCGRs) than those of as-received ones. The WM of an uncharged weld had the lower FCGRs pared to the parent metal
within the same AK range. However, the enhancement of crack growth in the WM was very pronounced after hydrogen-charging.
SEM fractographs of tensile and fatigue-fractured surfaces revealed a quasi-cleavage fracture in the embrittled region. 0 2001
Elsevier Scienc