Two competing crack growth mechanisms in very high pressures tubes

This work addresses the influence of autofrettage in the occurrence of repeated leaks of thick wall straight and curved 4333M4 steel tubes from a high pressure petrochemical reactor, comprised by straight and curved tubes subjected to autofrettage. Recent leaks in straight tubes are due to fatigue t...

Full description

Saved in:
Bibliographic Details
Published in:Engineering failure analysis 2011-03, Vol.18 (2), p.564-571
Main Authors: Otegui, J.L., Kunert, H.G., Booman, J., Barcia, P., Guidi, G.
Format: Article
Language:English
Subjects:
Crack propagation
Cracks
Cumulative damage
Curved
Fatigue cracking
Fatigue failure
Fracture mechanics
Leaks
Residual stress
Stress concentrations
Temper Embrittlement
Tubes
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This work addresses the influence of autofrettage in the occurrence of repeated leaks of thick wall straight and curved 4333M4 steel tubes from a high pressure petrochemical reactor, comprised by straight and curved tubes subjected to autofrettage. Recent leaks in straight tubes are due to fatigue transgranular growth of cracks initiating from machining groves in the inner surface, driven by pressure cycles during many years of normal operation. Experimental measurement of residual stresses verified that high temperature service relieved most of the compressive residual stresses imposed by the autofrettage. Previous failures in curved tubes were found to be due to metallurgical susceptibility to intergranular cracking, related to a phenomenon similar to Temper Embrittlement. Repeating autofrettage to mitigate fatigue failures would reproduce the deformation mechanisms that favored intergranular cracking of the tubes. Recently developed life extension strategies include early detection of leaks by acoustic emission and an improved manufacturing method of replacement bends.
ISSN:1350-6307
1873-1961
DOI:10.1016/j.engfailanal.2010.09.019