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M. Saadatmand et alii, Frattura ed Integrità Strutturale, 52 (2020) 98-104; DOI: 10.3221/IGF-ESIS.52.08

Effect of travel speed on thermal cycle of deposited layers The temperature distributions of p1 with different travel speeds are shown in Fig. 5. As shown in Fig 5, with increasing the travel speed, the maximum temperature for each point decreases. The reason is that as the travel speed reduces, the interaction time between arc and material increases. As a result, more energy transfers to the material, therefore temperature increases. Also, with increase in travel speed from 10 to 15 mm/s, the average cooling speed increases from 118°C/s to 136°C/s for the middle point in the first layer. Moreover, for the travel speed of 15mm/s, the second peak is approaching the melting point, so it influences the metallurgy bonding between deposited layers.

C ONCLUSIONS

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n this work, a 3D finite element model has been developed to study the thermal cycle during the WAAM process along with the effects of substrate preheating temperature and travel speed on the thermal cycle of WAAM manufactured wall of low carbon steel (ASTM A36). It has been found that, during the WAAM process, the peak temperature of newly deposited layers increases (from 2518 ℃ to 2640 ℃) but the average cooling speed decreases (from 123 °C/s to 115 °C/s) due to the influence of previously deposited layers. Moreover, with the increase of substrate’s preheating temperature, the peak temperature of first layer increases (from 2518 ℃ to 2600 ℃ ). In addition, the cooling rate of first layer decreases gradually from 123°C/s to 118°C/s with the increasing preheating temperature. Furthermore, from the obtained numerical results it can be concluded that the travel speed has a major impact on the thermal behavior and metallurgical bonding of deposited layers. [1] Wu, B., Pan, Z., Ding, D., Cuiuri, D., Li, H., Xu, J., Norrish, J. (2018). A review of the wire arc additive manufacturing of metals: properties, defects and quality improvement, J. Manuf. Process., 35(February), pp. 127–139, DOI: 10.1016/j.jmapro.2018.08.001. [2] Haden, C. V., Zeng, G., Carter, F.M., Ruhl, C., Krick, B.A., Harlow, D.G. (2017). Wire and arc additive manufactured steel: Tensile and wear properties, Addit. Manuf., 16(2010), pp. 115–123, DOI: 10.1016/j.addma.2017.05.010. [3] Hejripour, F., Binesh, F., Hebel, M., Aidun, D.K. (2019). Thermal modeling and characterization of wire arc additive manufactured duplex stainless steel, J. Mater. Process. Technol., 272(March), pp. 58–71, DOI: 10.1016/j.jmatprotec.2019.05.003. [4] Ding, J. (2012).Thermo-mechanical Analysis of Wire and Arc Additive Manufacturing Process. Cranfield University. [5] Kazanas, P., Deherkar, P., Almeida, P., Lockett, H., Williams, S. (2012). Fabrication of geometrical features using wire and arc additive manufacture, Proc. Inst. Mech. Eng. Part B J. Eng. Manuf., 226(6), pp. 1042–1051, DOI: 10.1177/0954405412437126. [6] Xiong, J., Lei, Y., Li, R. (2017). Finite element analysis and experimental validation of thermal behavior for thin-walled parts in GMAW-based additive manufacturing with various substrate preheating temperatures, Appl. Therm. Eng., 126, pp. 43–52, DOI: 10.1016/j.applthermaleng.2017.07.168. [7] Thompson, S.M., Bian, L., Shamsaei, N., Yadollahi, A. (2015). An overview of Direct Laser Deposition for additive manufacturing; Part I: Transport phenomena, modeling and diagnostics, Addit. Manuf., 8, pp. 36–62, DOI: 10.1016/j.addma.2015.07.001. [8] Colegrove, P.A., Coules, H.E., Fairman, J., Martina, F., Kashoob, T., Mamash, H., Cozzolino, L.D. (2013). Microstructure and residual stress improvement in wire and arc additively manufactured parts through high-pressure rolling, J. Mater. Process. Technol., 213(10), pp. 1782–1791, DOI: 10.1016/j.jmatprotec.2013.04.012. [9] Zhao, H., Zhang, G., Yin, Z., Wu, L. (2011). A 3D dynamic analysis of thermal behavior during single-pass multi-layer weld-based rapid prototyping, J. Mater. Process. Technol., 211(3), pp. 488–495, DOI: 10.1016/j.jmatprotec.2010.11.002. [10] Xiong, J., Li, R., Lei, Y., Chen, H. (2018). Heat propagation of circular thin-walled parts fabricated in additive manufacturing using gas metal arc welding, J. Mater. Process. Technol., 251, pp. 12–19, DOI: 10.1016/j.jmatprotec.2017.08.007. [11] Stamenkovic, D., Vasovic, I. (2009). Finite Element Analysis of Residual Stress in Butt Welding Two Similar Plates, Sci. Tech. Rev., LIX(1), pp. 57–60. [12] Goldak, J., Chakravarti, A., Bibby, M. (1984). A new finite element model for welding heat sources, Metall. Trans. B, R EFERENCES

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