Fatigue Crack Propagation in A533B Steels

1977 ◽  
Vol 99 (3) ◽  
pp. 459-469 ◽  
Author(s):  
A. D. Wilson

The influence of steelmaking practice on the fatigue crack propagation behavior of A533B low alloy plate steels is examined. Conventional practice, calcium-treated and electroslag-remelted steels were investigated in 6 specimen orientations. A significant improvement in the isotropy of fatigue crack growth rates and a consistent overall improvement in fatigue crack growth rate were found in going from the conventional practice, to the calcium-treated, to the electroslag-remelted materials. The fatigue crack growth rate differences within a material and between materials were attributed to material differences in nonmetallic inclusion quantities and morphologies.

2014 ◽  
Vol 1004-1005 ◽  
pp. 142-147
Author(s):  
Ming Liu ◽  
Kun Zhang ◽  
Sheng Long Dai ◽  
Guo Ai Li ◽  
Min Hao ◽  
...  

The fatigue crack propagation behaviors of an Al-Cu-Mg alloy are investigated in different environments and with varying stress ratios. Fatigue experiments are carried out via a fatigue crack growth rate test in laboratory air, a 3.5% (mass fraction) NaCl solution and a tank seeper. The results show that a corrosion environment has an obvious influence on the fatigue crack growth rate, and the degrees of influence of the two different corrosive environments are basically identical. When the stress ratio is R = 0.5 and 0.06 with a decrease of the stress intensity factor, the difference in the crack propagation rates for the corrosion and air environments gradually increases. However, the corrosion acceleration in each stage of crack propagation is obvious while R=−1.


2018 ◽  
Vol 165 ◽  
pp. 03009
Author(s):  
Luis Borja Peral ◽  
Sergio Blasón ◽  
Alfredo Zafra ◽  
Cristina Rodríguez ◽  
Javier Belzunce

In order to select the most appropriate steel to deal with pressurized hydrogen during long times, the fatigue crack propagation rate of quenched and tempered 2.25Cr1Mo and 2.25Cr1Mo0.3V steel grades was evaluated by means of tests performed on thermally pre-charged specimens in a hydrogen reactor at 195 bar and 450°C during 21 hours. Cylindrical samples to measure the hydrogen content and their desorption kinetics at room temperature and compact tensile specimens to determine the fatigue crack growth rate were used. Finally, scanning electronic microscopy was used in the study of fracture surfaces. Using the aforementioned pre-charging conditions, significant amounts of hydrogen were introduced, being much larger in the 2.25Cr1Mo0.3V steel grade (vanadium carbides provide strong hydrogen tramps). Regarding fatigue tests, the fatigue crack growth rate was increased notably due to the presence of hydrogen in the 2.25Cr1Mo grades for frequencies lower than 10 Hz. On the other hand, the presence of vanadium carbides has significantly improved the fatigue crack propagation performance in the presence of internal hydrogen.


2014 ◽  
Vol 891-892 ◽  
pp. 1212-1216
Author(s):  
Anghel Cernescu ◽  
Heikki Remes ◽  
Pauli Lehto ◽  
Jani Romanoff

The all-metal web-core sandwich structure consists of two face plates stiffened by one-directional system of web plates. These web core sandwich structures are used in many structural applications such as ship hulls, offshore platforms, bridge decks, and industrial platforms. However, the stress variation caused by the service loadings can be a determinant factor for crack initiation and growth until early failure of the entire structure. This paper presents an experimental study on fatigue crack growth rate in base material from a face plate after rolling and welding. The study is focused on the analysis of the stress ratio and crack closure effect on the fatigue crack growth rate in two directions. There is a significant stress ratio effect on fatigue crack growth rate, much more pronounced in the case of crack propagation in the longitudinal direction than in the transverse propagation. For all tests, the crack closure effect is more pronounced at low stress intensity factor range (in the threshold domain).


Author(s):  
Guang-en Luo ◽  
Jia-huan Dong

The extended McEvily model is adopted to predict the fatigue life of deepwater structures under cyclic compression. The three dimensional finite element analysis is performed to estimate the residual stress distribution along the crack surface during the crack propagation under cyclic compression. Then the stress intensity factors and crack growth rate are achieved based on extended McEvily model. The doubled edged specimen under cyclic compressive loading is taken for example to illustrate the analysis procedure, including fatigue crack growth rate prediction by Artificial Neural Networks (ANN), parameters estimation method of the extended McEvily model, calculation of the stress intensity factor and numerical simulation of fatigue crack propagation. By comparing the predicted results and the experimental results, it is found that the numerical simulation of fatigue crack growth under cyclic compression based on extended McEvily model is reasonable and feasible.


2015 ◽  
Vol 1096 ◽  
pp. 315-318
Author(s):  
Xu Dong Li ◽  
Hang Lv ◽  
Wen Xiu Wang

The present thesis made a research to evaluate fatigue crack growth rate subjecting to corrosion and cyclic fatigue loading, with the effect of load frequency on fatigue taken into account. A modified Paris’ law based model is proposed. An exponential modified expression of proportional parameter account for fatigue frequency is proposed based on the obvious fact that low frequency loading will lead to long fatigue life, thus prolong interaction time between corrosion media and specimen which will favor for crack propagation. Loading frequency higher enough will shorten that time, thus influence of corrosion will be significantly weaken, close to pure mechanical fatigue. Crack growth rate prediction from proposed formula is proved to be in good agreement with experimental results for steadily extended corrosion fatigue crack.


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