Effect of Burr Grinding on Fatigue Strength of Steel Butt-Welded Connections

Document Type: Original Article

Authors

Bu-Ali Sina University

Abstract

Among assembling methods, welding is most widely used in various industries. During the welding operation, material is heated to a temperature above the melting point and melted material forms a weld pool. This leads to the formation of tensile residual stresses in the weld toe. In this paper, effect of burr grinding technique on fatigue strength of butt-welded joint has been evaluated. Burr grinding is one of the weld geometry modification methods that with removing small crack-like defects at the weld toe and increasing weld toe radius leads to reduction of stress concentration factor (SCF) and improvement of fatigue strength of weld. Also, the finite element simulation was performed by using ABAQUS software and stress concentration factor was chosen as a criterion. This factor was calculated using analytical and numerical methods for samples before and after grinding. Burr grinding procedure on welded samples was done using an electric grinder and different conical burrs. Burrs with different radii have been selected in order to provide a better comparison. Fatigue life of samples before and after grinding was determined by fatigue tests under constant amplitude loading. The results show 43.72 percent improvement in stress concentration factor and 50.61 percent improvement in fatigue life of samples. In experimental study, the best result belongs to grinding with a 3 mm tapered burr leading to an improvement of 50.61% in fatigue life while grinding with 1 mm tapered gives the worst result of 8.88% improvement in fatigue life.

Keywords

Main Subjects


[1]     Kirkhope, K. J., Bell, R., Caron, L., Basu, R. I. and Ma, K. T., Weld Detail Fatigue Life Improvement Techniques: Part 1- Review, Marine Structures, Vol. 12, No. 6, 1999, pp. 447- 474.

[2]     Haagensen, P. J., Maddox, S. J., Recommendations on Methods for Improving the Fatigue Strength of Welded Joints, International Institute of Welding, Commission XIII-1815-00, 2013.

[3]     Clegg, R. E., Mcleod, A. J. and Ruddell, W., Effect of Toe Treatment on the Fatigue Resistance of Structural Steel Welds, Australasian Welding Journal, Vol. 58, No.3, 2013, pp. 34-41.

[4]     Pedersen, M. M., Mouritsen, O. O., Hansen, M. R., Andersen, J. G. and Wenderby, J., Comparison of Post Weld Treatment of High Strength Steel Welded Joints in Medium Cycle Fatigue, International Institute of Welding, XIII-2272-09, 2010.

[5]     Tai, M., Miki, C., Improvement Effects of Fatigue Strength by Burr Grinding and Hammer Peening under Variable Amplitude Loading, Welding in the world, Vol. 56, No. 7, 2012, pp. 109-117.

[6]     Baptista, R., Infante, V., and Branco, C. M., Study of the Fatigue Behavior in Welded Joints of Stainless Steels Treated by Weld Toe Grinding and Subjected to Salt Water Corrosion, International Journal of Fatigue, Vol. 30, No. 3, 2008, pp. 453-462.

[7]     Knight, J. W., Improving the Fatigue Strength of Fillet Welded Joints by Grinding and Peening, Welding Research International, Vol. 9, No. 6, 1978, pp. 519-540.

[8]     Mohr, W. C., Tsai, C. and Tso, C. M., Fatigue Strength of Welds with Profile and Post-Weld Improvements, Proceedings of fourth International Conference Offshore Mechanics and Arctic Engineering, Copenhagen, 1995.

[9]     Kirkhope, K. J., Bell, R., Caron, L., Basu, R. I. and Ma, K. T., Weld Detail Fatigue Life Improvement Techniques: Part 2- Application to Ship Structures, Marine Structures, Vol. 12, No. 6, 1999, pp. 477-496.

[10]  Pang, H. L. J., Analysis of Weld Toe Radius Effects on Fatigue Weld Toe Cracks, International Journal of Pressure Vessel and Piping, Vol. 58, No. 2, 1994, pp. 171-177.

[11]  Huther, I., et al., The Influence of Improvement Techniques on Welded Joint Fatigue Strength, IIW Document XIII-1562-94, 1994.

[12]  Nguyen, T. N., Wahab, M. A., The Effect of Weld Geometry and Residual Stresses on the Fatigue of Welded Joints under Combined Loading, Journal of Materials Processing Technology, Vol. 77, No. 1-3, 1998, pp. 201-208.

[13]  American Welding Society AWS-D1 Committee on Structural Welding, Structural Welding Code- Steel, 22th ed. American National Standards Institute, 2010.

[14]  PFERD Tool Selection Manual, 22th ed., Section 203, Germany, August Rüggeberg GmbH & Co. KG, 2014.

[15]  Fanous, I. F. Z., Younan, M. and Wifi, A., 3D Finite Element Modeling of the Welding Process Using Element Birth and Element Movement Techniques, International Journal of Pressure Vessel Technology, Vol. 125, No. 2, 2003, pp. 144-150.

[16]  Barsoum, Z., Barsoum, I., Residual Stress Effects on Fatigue Life of Welded Structures Using LEFM, Engineering Failure Analysis, Vol. 16, No. 1, 2009, pp. 449-467.

[17]  Goldak, J., Akhlaghi, M., Computational Welding Mechanics, New York, Springer, 2005.

[18]  Gill, J., Singh, J., Effect of Welding Speed and Heat Input Rate on Stress Concentration Factor of Butt Welded Joint, International Journal of Advanced Engineering Research and Studies 2012, Vol. 1, No. 3, 2012, pp. 98-100.