Effect of pre-corrosion on fatigue life of high strength steel 38CrMoAl

Abstract

The effect of pre-corrosion on fatigue behavior of high strength steel 38CrMoAl was investigated with a fatigue test method using the accelerated pre-corrosion specimen in the neutral salt spray environment. The methods of weight-loss and energy dispersive spectrum (EDS) were adopted. The corrosion weight-loss rate was fitted with the test time using power law, and the relationship between the corrosion weightloss rate and the time was formulated. Moreover, the fatigue behaviors of the steel for different pre-corrosion time were investigated by the axis-direction tensile fatigue test. The fatigue life distribution characteristics of the pre-corrosion specimens were studied using the statistical probability methods, and the mathematical expectations and the standard tolerances of the material fatigue lives after different pre-corrosion time were obtained. It was found that the crack initiation of the high strength steel was accelerated by the preferential corrosion at the local plastic deform areas. The fatigue life obeys the lognormal distribution perfectly. Furthermore, within the common time range of the engineering, the standard tolerances of the logarithm of the fatigue life were independent of the pre-corrosion time.

Keywords

pre-corrosion / fatigue life / 38CrMoAl steel

References

[1] Kermanidis Al Th, Petroyiannis P V, et al. Fatigue and Damage Tolerance Behavior of Corroded 2024 T351 Aircraft Aluminum Alloy[J]. Theoretical and Applied Fracture Mechanics, 2005, (43): 121–132

[2] Wanhill R J H. Aircraft Corrosion and Fatigue Damage Assessment[R]. NLR Technical Publication TP 94401 L, National Aerospace Laboratory, Amsterdam, 1994

[3] Hoffman M E, Hoffman P C. Corrosion and Fatigue Researchstructural Issues and Relevance to Naval Aviation[J]. Int. J.Fatigue, 2001, (23): S1–S10

[4] DuQuesnay D L, Underhill P R, Britt H J. Fatigue Crack Growth from Corrosion Damage in 70752-T6511 Aluminum Alloy under Aircraft Loading[J]. Int.J.Fatigue, 2003, (25): 371–377

[5] Zhang J. Y., Fei B. J. Probability Damage Tolerance Analysis for Structures with Multiple Fatigue Cracks under Corrosive Environment[J]. Journal of Beijing University of Aeronautics and Astronautics, 2002, 4(28): 202-204.

[6] Jiang Z. G., Jin S., Liu W. B., . Aircraft Structure of Corrosion Fatigue[M], 1992 Beijing Aviation Industry Press 90-101.

[7] Ishihara S, Nan Z Y, et al. On the Initiation and Growth Behavior of Corrosion Pits during Corrosion Fatigue Process of Industrial Pure Aluminum[J]. Int.J.Fatigue, 2008, (30): 1 659–1 668

[8] Zhao H. J., Jin P., Liu W. L., . Research on a Model of the Influence Coefficient for Pre-corrosion Fatigue life[J]. Corrosion Science and Protection Technology, 2006, 18(4): 265-267.

[9] He X. F., Liu W. T., Wang Z. B., . A Study of Distribution Characteristic and Parameter Analysis of Pre-corrosion Fatigue Life[J]. Journal of Aeronautical Materials, 2007, 27(6): 21-26.

[10] Chen Q. Z., Yang R. Q., Li G. Y., . Influence of Corrosion on Fatigue Life of 30CrMnSiNi2A Steel Structure[J]. Equipment Environmental Engineering, 2007, 4(5): 7-10.

[11] Walde K V, Hillberry B M. Characterization of Pitting Damage and Prediction of Remaining Fatigue Life[J]. Int.J.Fatigue, 2008, (30):106–118

[12] Tong W. P., Han Z., . Low-temperature Nitriding of 38CrMoAl Steel with a Nanostructured Surface Layer Induced by Surface Mechanical Attrition Treatment[J]. Surf.Coat. Technol., 2008, 202(20): 4 957-4 963.

[13] Shangguan Q. Q., Cheng X. H. Effect of Rare Earth Elements on Erosion Resistance of Nitrocarburized Layer of 38CrMoAl Steel[J]. Journal of Rare Earths, 2004, 22(3): 406-409.

[14] Cheng X. H., Xie C. Y. A Study on Mechanisms of the Effect of Rare Earths on Thermo-chemical Treatments of Steels[J]. Journal of the Chinese Rare Earth Society, 1994, 12(4): 336-341.

[15] Natesan M, Venkatachari G, Palaniswamy N. Kinetics of Atmospheric Corrosion of Mild Steel, Zinc, Galvanized Iron and Aluminum at 10 Exposure Stations in India[J]. Corros. Sci., 2006, (48): 3 584–3 608

[16] Li S. Y., Jung S. W., Park K. W., Lee S. M., . Kinetic Study on Corrosion of Steel in Soil Environments Using Electrical Resistance Sensor Technique[J]. Mater.Chem.Phys., 2007, 103(1): 9-13.

[17] Melchers R. E. A New Interpretation of the Corrosion Loss Processes for Weathering Steels in Marine Atmospheres[J]. Corros. Sci., 2008, 50(12): 3 446-3 457.