PSI - Issue 75

Carolina Payares-Asprino et al. / Procedia Structural Integrity 75 (2025) 489–500 C. Payares-Asprino et al./ Structural Integrity Procedia (2025)

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Figure 12 shows the fracture location of the fatigue specimens for a) the weld manufactured at 1.44 kJ/mm, b) the base metal and c) machined the weld bead. The figure shows that the fracture in welds with the weld bead occurred in the HAZ. The fracture in the machined weld specimen was far away from the weld bead because the machined weld bead increased the fatigue life concerning the weld bead welds.

HAZ Fatigue Fracture

a

BM Fatigue Fracture Machined weld fracture away from HAZ.

b

Figure 4 Fatigue Specimen a. Weld fatigue specimen fracture at HAZ weld at HI:1.44 kJ/mb; b. Base Metal fatigue specimen c

Fig. 12 Fatigue fracture specimens: a) Weld bead specimen; b) Base metal specimen; c) machined weld specimen

Machining after welding contributes to the overall quality and reliability of the final product. Essential factors include correcting distortions, achieving tight tolerances, and eliminating residual stresses in the weld, which is achieved using CNC machining after welding. CNC machining is crucial in welding applications. The process corrects distortions caused by welding, ensuring parts fit accurately and improving the fatigue behavior removing the weld bead. CNC machines handle intricate designs required in welded assemblies. Manufacturers must use CNC machining to refine welded parts, enhancing overall quality. The process supports various industries by delivering the precise components necessary for complex assemblies. Machining after welding finds application in multiple sectors requiring precision, such as aerospace, automotive, medical, and construction. 4. Conclusion An increase in the heat input produces an increase in the welding deformation, leading to an increase in the tensile residual stress adjacent to the transition zone location of the weld bead. The fatigue behaviour of Duplex Stainless Steel (DSS) is influenced by heat input, decreasing the fatigue life concerning the DSS parent metal. The fatigue life improved when the machining process removed the weld bead by a factor of two compared to the DSS weld with the weld bead, we conclude that the higher compressive residual stresses resulted in improving fatigue properties. Acknowledgements Authors wish to thank the Vermont Space Grant Consortium (VTSGC) and Vermont NASA EPSCoR Faculty Research Grant Program for funding the research and CIDESI (Centro de Ingeniería y Desarrollo Industrial, Santiago de Querétaro, México), for the use of the facilities to carry out the fatigue experimental test. References Muthupandi, V., Srinivassa, P.B., Asehadri, S.K., Sundaresam, S., 2003. Effect of weld metal chemistry and heat input of the structures and properties of duplex stainless steel welds. Material Science Engineering A 358 (1-2), 9-16. Sathiya, P., Aravindan, S., Noorul Haq, A., 2009, Effect of shielding gases on mechanical and metallurgical properties of duplex stainless-steel welds. Journal of Material Science 44 (3), 114 Callister, W. D., 1991. “ Materials Science and Engineering: An Introduction ”, 2nd edition New York: John Wiley & Sons Inc. Kuma, H., Thakur, M., Raj, J., Baghel, A., 2018. A review on Fatigue Life Estimation of Welded Joints. IJSTE. International Journal of Science Technology & Engineering, Vol. 4 (7). Shigley, J. E., Mischke, C.R., Budynas, R.G., 2011. “Mechanical engineering design”. McGraw-Hill, 2011.