Influence of Stress Ratio on the Fatigue Crack Propagation Behavior of K55 Casing-drilling Steel
The influence of stress ratio on the fatigue crack growth (FCG) behaviour of K55 casing-drilling steel was investigated by means of scanning electron microscopy (SEM) and fatigue tests. The results show that stress ratio possesses a remarkable influence on Delta K responding to starting point of cra...
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Published in | Cai liao gong cheng = Journal of materials engineering Vol. 43; no. 6; pp. 79 - 84 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | Chinese |
Published |
20.06.2015
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Subjects | |
Online Access | Get full text |
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Summary: | The influence of stress ratio on the fatigue crack growth (FCG) behaviour of K55 casing-drilling steel was investigated by means of scanning electron microscopy (SEM) and fatigue tests. The results show that stress ratio possesses a remarkable influence on Delta K responding to starting point of crack unstable zone. The FCG rates responding to starting point of crack unstable zone exhibit a significant decrease with the increase of stress ratios, and the FCG threshold value possesses a significant decrease. The average load, which is gradually instead of Delta K, turns into the dominant drive force of the FCG when the fatigue crack propagates into the unstable zone from Paris region bit by bit. The fatigue fracture surface exhibits obviously impact facture characterization, when the crack propagates into overload tensile zone. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1001-4381 |
DOI: | 10.11868/j.issn.1001-4381.2015.06.013 |