Microstructure Analysis of Cold Worked Holes


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The cold expansion technique is often used to introduce beneficial compressive residual stresses at fastener holes that retard cracking in fatigue loaded material. The present investigation emphasizes micro structural changes along the radial section of holes after the holes are subjected to cold working. The experiment was conducted for two different materials, namely Steel85, EN-8D alloy steel with thickness 10mm. The holes are expanded to different percentages by split sleeve method and the microstructures are observed using SEM (Scanning Electron Microscope). It is observed from the micrographs that a zone of plastic deformation close to the hole followed by a zone of elastic compression induced by the split sleeve expansion. A comparative study of microstructure of the hole before and after expansion and also study the pattern after different extent of expansion of holes



Materials Science Forum (Volumes 539-543)

Main Theme:

Edited by:

T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran




S. Nagaraj and M. Krishna, "Microstructure Analysis of Cold Worked Holes", Materials Science Forum, Vols. 539-543, pp. 2222-2227, 2007

Online since:

March 2007




[1] Leitao, V.M.A., Aliabadi, M.H., Rooke, D.P. and Cook, R. Boundary element methods for the analysis of crack growth in the presence of residual stress fields. J. Mater. Engng and Performance, 1998, 7(3), 352-360.

DOI: 10.1361/105994998770347792

[2] Ball, D.L. and Lowry, D.R. Experimental investigation on the effects of cold expansion of fastener holes. Fatigue and Fracture of Engng Mater. Structs, 1998, 21(1), 17-34.

[3] FTI 8101C Cold Expansion of Holes Using the Standard Split Sleeve System (Cx) and Countersink Cold Expansion, 1994 (Engineering Process Specification, fatigue Technology Inc., Seattle, Washigton).

[4] Suresh, S. Fatigue of Materials, 1st edition, 1991, Cambridge Solid State Science Series (Cambridge University Press, Cambridge).

[5] Fitzpatrick, M.E. and Edwards, L. Fatigue crack/residual stress field interations and their implications for damage-tolerance design. J. Mater. Engng and Performace, 1998, 7(2), 190-198.

[6] Stefanescu, D. Experimental study of double cold expansion of holes. J. Strain Analysis, 2003, 38(4), 339-347.

[7] Stefanescu, D. Measurement and prediction of fatigue crack growth from cold expanded holes, Part 1: the effect of fatigue crack growth on cold expansion residual stresses. J. Strain Analysis, 2004, Vol. 39, 25-39.

DOI: 10.1177/030932470403900103

[8] Zhao, W., Wu, X. R. and Yan, M.G. Weight function method for threedimensional crack problems. Engng Fracture Mechanics, 1989, 34(3), 593-607.

[9] Stefanescu, D., Dutta, M., Wang, D., Edwards, L. and Fitzpatrick, M. E. The effect of high compressive loading on residual stresses and fatigue crack growth at cold expanded holes. J. strain Analysis, 2003, 38(5), 419-427.

DOI: 10.1243/03093240360713478

[10] Champoux, R.L., Overview of hole cold expansion methods. Proceedings of the International Conference on Fatigue Prevention and Design, Amsterdam, The Netherlands, 1986, pp.35-61.

[11] Landy, M. A., Armen, Jr., H., and Eidnoff, H. L., Enhanced stop-drill repair procedure for cracked structures. Fatigue in Mechanically Fastened Composite and Metal Joints. ASTM STP, 1986, 927, 190.

DOI: 10.1520/stp29061s

[12] N. Chandawanich and W.N. Sharpe Jr., Eng. Fract. Mech., (1979) 11.

[13] X. Su, M. Go and M. Yan. Fatigue Fract. Eng. Mater. Struct., (1986) 9.

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