The Influence of Environment on High Frequency Fatigue Crack Propagation in High Strength Steel PDF Download

Author: C. E. Nicholson
Publisher:
ISBN:
Category :
Languages : en
Pages : 16

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Author: Thomas Charles Babcock
Publisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 166

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Book Description

Author: GA. Miller
Publisher:
ISBN:
Category : Corrosion fatigue
Languages : en
Pages : 8

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Book Description
An experimental program was carried out to further determine the range of applicability of the superposition model, proposed by Wei and Landes, for estimating the effects of cyclic loading variables and chemical environment on fatigue crack growth. AISI 4340 steel, tempered at 200°F and 500°F, and RQ360A steel were used in this investigation. The influences of frequency, stress ratio, and cyclic-load waveform were examined. The results showed that the superposition model provides correct estimates of the trend and the order of magnitude for the influences of these variables within the applicable range (that is, for Kmax > KIsee) provided that steady-state crack growth data are used. Data on the AISI 4340 steel suggest the presence of some synergistic effect of fatigue and environmental attack. Modification of this model will be needed to incorporate this effect and to improve the accuracy of predictions.

Author: Roger Charles Rowlands
Publisher:
ISBN:
Category : Steel
Languages : en
Pages : 152

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Author: R. P. Wei
Publisher:
ISBN:
Category :
Languages : en
Pages : 57

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Book Description
The current state of understanding of the phenomenology and mechanism(s) for corrosion fatigue of high-strength steels is reviewed. Particular attention is directed towards corrosion fatigue in hydrogen and in water/water vapor environments. Available experimental data indicate that fatigue crack growth in high-strength steels is influenced by loading variables, such as frequency, stress ratio and waveform in regions above and below KIscc. The influences of these variables are directly attributed to interactions with the external chemical environment. Possible synergistic interactions and their relation to chemical reaction kinetics are indicated. Pertinent information on oxygen-metal and water-metal reactions is summarized. Initial results from a coordinated program of study for determining the water-metal reaction kinetics and the kinetics of crack growth on a single high-strength steel are discussed. (Author Modified Abstract).

Author: AK. Vasudevan
Publisher:
ISBN:
Category : Constant amplitude loading
Languages : en
Pages : 13

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Book Description
A study was conducted to identify the environmental influence on fatigue crack growth behavior of three high strength steels: AerMet 100, 300M, and 4340. These steels were subjected to fatigue tests under constant amplitude loading of frequency 10 Hz and stress ratios R = 0.1 and 0.9, in vacuum, air, and 3.5% NaCl solution. The fatigue crack growth was characterized with two driving force parameters, stress intensity range, ?K, and maximum stress intensity, Kmax. Especially, the variation of fatigue crack growth per time, da/dt, with Kmax in 3.5% NaCl solution was evaluated with respect to R, environment, and threshold stress intensity for environmentally assisted cracking (EAC), KIEAC. In addition, the environmental influence on fatigue crack growth was examined with the fractographic features and trajectory path, drawn with the limiting values of ?K and Kmax, ?K* and Kmax*.

Author: Institution of Mechanical Engineers (Great Britain). Applied Mechanics Group
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 196

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Author: P. S. Pao
Publisher:
ISBN:
Category :
Languages : en
Pages : 19

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Book Description
The effect of cyclic load frequency on the room-temperature fatigue crack growth response of AISI 4340 steel (tempered at 205 C) in water vapor at 585 Pa (4.4 torr) has been investigated. The water vapor pressure was chosen to avoid capillary condensation at the crack tip. Crack growth tests were conducted over a frequency range from 0.1 to 10 Hz, and a range of stress intensity factors (K). The maximum K in these tests was below the apparent threshold K for sustained-load crack growth in this environment. Fatigue crack growth rates were found to increase with the reciprocal of frequency (that is, with the period at load), and exhibited transient behavior when the test frequency was altered. By separating the growth rate into an environment independent component (pure fatigue) and an environment dependent component, it was found that the environment dependent component varied linearly with period over the frequency range 0.1 to 10 Hz. The results are correlated with the kinetics for water vapor/metal surface reactions, and with other fatigue crack growth data on high-strength steels tested in aqueous and H2S containing environments. The frequency and transient effects are discussed in terms of possible crack-tip processes. (Author).

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 300

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Book Description

Author: John J. Burke
Publisher: Springer
ISBN:
Category : Medical
Languages : en
Pages : 440

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Book Description
The Army Materials and Mechanics Research Center in coop eration with the Materials Science Group of the Department of Chemical Engineering and Materials Science of Syracuse University has been conducting the Annual Sagamore Army Materials Research Conference since 1954. The specific purpose of these conferences has been to bring together scientists and engineers from academic institutions, industry and government who are uniquely qualified to explore in depth a subject of importance to the Department of Defense, the Army and the scientific community. These proceedings entitled, FATIGUE - ENVIRONMENT AND TEMPER ATURE EFFECT, address the overview of temperature and environmental effects of fatigue, room temperature environmental effects, high temperature and environmental effect - mechanisms, high tempera ture and environmental effect - mechanisms, materials and design-engineering applications. We wish to acknowledge the assistance of Messrs. Joseph Bernier and Dan McNaught of the Army Materials and Mechanics Research Center and Helen Brown DeMascio of Syracuse University throughout the stages of the conference planning and finally the publication of the book. The continued active interest and support of these conferences by Dr. E. Wright, Director of the Army Materials and Mechanics Research Center, is appreciated.