Abstract

The residual deformation and stress states, corresponding to a rolled product of AA 6082-T6 aluminium alloy used in naval structures, were comprehensively analyzed from data obtained using an optimized micro-indent method. A great advantage of using this method, which needs a measuring machine, is to avoid specific equipments and qualified personnel. Furthermore, the absolute measurement error of this technique is very small (±0.9 MPa). The results obtained through the analysis of Mohr's circles reveal compressive normal components prevailing in the residual deformation and stress states. A very important aspect is that the direction of the more compressive component is very close to the rolling direction. This may indicate the importance of the rolling process, which is previous to the thermal hardening process T6, in the final states of residual deformation and stress. Finally, the residual stress state of the evaluated material, which is quasi-isotropic, was compared with the failure stress by using the von Mises yield criterion for ductile materials.

Keywords:

Micro-indent method, naval alloy, rolling, residual deformations, residual stresses,

References

1. Almeida Bugio, T.M., R. Martins and L. Leal das Neves, 2013. Failure analysis of fuel tanks of a lightweight ship. Eng. Fail. Anal., 35: 272-285.
   CrossRef    
2. Budynas, R.G. and J.K. Nisbett, 2008. Shigley’s Mechanical Engineering Design. 8th Edn., McGraw-Hill, New York.
   
3. Curtis, M.A. and F. Farago, 2007. Handbook of Dimensional Measurement. Industrial Press Inc., New York.
   
4. Díaz, F.V. and C. Mammana, 2012. Study of Residual Stresses in Conventional and High-speed Milling. In: Filipovic, L. (Ed.), Milling: Operations, Applications and Industrial Effects. Nova Science Publishers Inc., New York, pp: 127-155.
   
5. Díaz, F.V., G. Kaufmann and G. Galizzi, 2000. Determination of residual stresses by hole drilling and digital speckle pattern interferometry with data automatic analysis. Opt. Laser. Eng., 33: 39-48.
   CrossRef    
6. Díaz, F.V., R. Bolmaro, A. Guidobono and E. Girini, 2010. Determination of residual stresses in high speed milled aluminium alloys using a method of indent pairs. Exp. Mech., 50: 205-215.
   CrossRef    
7. Díaz, F.V., C. Mammana, A. Guidobono and R. Bolmaro, 2011. Analysis of residual strain and stress distributions in high speed milled specimens using and indentation method. Int. J. Eng. Appl. Sci., 7: 40-46.
   
8. Díaz, F.V., C. Mammana and A. Guidobono, 2012. Evaluation of residual stresses induced by high speed milling using an indentation method. Modern Mech. Eng., 2: 143-150.
   CrossRef    
9. Dotson, C.L., R. Harlow and R. Thompson, 2003. Fundamentals of Dimensional Metrology. 5th Edn., Thompson Delmar Learning, New York.
   
10. Gere, J.M., 2001. Mechanics of Materials. 5th Edn., Brooks/Cole, Pacific Grove, CA.
    PMCid:PMC4781630    
11. Gupta, B., 1973. Hole-drilling technique: Modifications in the analysis of residual stresses. Exp. Mech., 13: 45-48.
    CrossRef    
12. Mammana, C.A., F. Díaz, A. Guidobono and R. Bolmaro, 2010. Study of residual stress tensors in high-speed milled specimens of aluminium alloys using a method of indent pairs. Res. J. Appl. Sci. Eng. Technol., 2: 749-756.
    Direct Link
13. Mao, W., 2003. Recrystallization and Grain Growth. In: Totten, G.E. and D. MacKenzie (Eds.), Handbook of Aluminum. Physical Metallurgy and Processes. Marcel Dekker Inc., New York, 1: 211-258.
    CrossRef    
14. Müller, E., 2005. Evolution of the residual stresses by stress rolling. Proceeding of the 9th International Conference and Exhibition on Shot Peening. Institute for Industrial Technology Transfer, Paris, pp: 436-441.
    PMid:16079795    
15. Noyan, I.C. and J.B. Cohen, 1987. Residual Stress Measurement by Diffraction and Interpretation. Springer-Verlag, Berlin.
    
16. Prevéy, P.S., 1987. X-ray Diffraction Residual Stress Techniques. Metals Handbook, American Society for Metals, USA, pp: 380-401.
    
17. Rendler, N.J. and I. Vigness, 1966. Hole-drilling strain-gage method of measuring residual stresses. Exp. Mech., 6: 577-586.
    CrossRef    
18. Rowlands, R.E., 1987. Residual Stresses. In: Kobayashi, A. (Ed.), Handbook on Experimental Mechanics. Prentice-Hall, New Jersey, pp: 768-813.
    
19. Schwach, D.W. and Y. Guo, 2006. A fundamental study on the impact of surface integrity by hard turning on rolling contact fatigue. Int. J. Fatigue, 28: 1838-1844.
    CrossRef    
20. Sielski, R.A., 2007. Aluminum marine structure design and fabrication guide. Ship Structure Committee Report SSC-452.
    
21. Suresh, S. and A. Giannakopoulos, 1998. A new method for estimating residual stresses by instrumented sharp indentation. Acta Mater., 46: 5755-5767.
    CrossRef    
22. Swadener, J.G., B. Taljat and G. Pharr, 2001. Measurement of residual stress by load and depth sensing indentation with spherical indenters. J. Mater. Res., 16: 2091-2102.
    CrossRef    
23. Timoshenko, S.P. and J. Goodier, 1970. Theory of Elasticity. 3rd Edn., McGraw-Hill, New York.
    CrossRef    
24. Toribio, J., 1998. Residual stress effects in stress-corrosion cracking. J. Mater. Eng. Perform., 7: 173-182.
    CrossRef    
25. Withers, P.J. and H. Bhadeshia, 2001. Residual stress. Part 1: Measurement techniques. Mater. Sci. Technol., 17: 355-365.
    CrossRef    
26. Withers, P.J., 2007. Residual stress and its role in failure. Rep. Prog. Phys., 70: 2211-2264.
    CrossRef    
27. Wyatt, J.E. and J. Berry, 2006. A new technique for the determination of superficial residual stresses associated with machining and other manufacturing processes. J. Mater. Process. Tech., 171: 132-140.
    CrossRef    

Competing interests

The authors have no competing interests.

Open Access Policy

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Copyright

The authors have no competing interests.