|Title:||The influence of environment on the fatigue behavior of HF-80 HSLA steel|
|Doctoral Committee Chair(s):||Lawrence, Frederick V., Jr|
|Department / Program:||Materials Science and Engineering|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Engineering, Materials Science|
|Abstract:||Single-pitted specimens of HF-80, a HSLA steel, were tested in laboratory air and in 1 M NaCl solution to study the influence of a corrosive environment on its fatigue life.
The growth of fatigue cracks and the partitioning of the fatigue life into fatigue crack initiation and fatigue crack propagation were studied by photographing the pit and the cracks developing on it periodically during testing. Non-propagating or dormant surface cracks were not observed in this study. Fractography using SEM showed the locations of fatigue crack initiation.
The mechanisms of corrosion fatigue were studied by performing tests in 1 M NaCl at different test frequencies. Corrosion pits proved to be crack initiation sites. Hydrogen embrittlement was found to be insignificant in the corrosion fatigue of HSLA steel in this study. The 1 M NaCl corrosive environment appeared to reduce the fatigue life of this material by a dissolution mechanism.
The effect of pit depth was studied by testing specimens having various pit depths. An effect of pit size was apparent. Fatigue life decreased with increasing pit depth. Pit depth, rather than the ratio of pit depth to pit diameter, influenced fatigue behavior. A non-damaging pit depth was found.
|Rights Information:||Copyright 1990 Ahn, Seung-Ho|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9021645|
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This item appears in the following Collection(s)
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Materials Science and Engineering
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