PSI - Issue 14

Neeta Paulose et al. / Procedia Structural Integrity 14 (2019) 649–655 Neeta Paulose etal./ Structural Integrity Procedia 00 (2018) 000–000

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The difference in UTS of Cycle A and CycleB reduced with increase in temperature due to less amount of strain induced martensite formation. The formation of sigma phase at high temperature could be the reason for the loss of ductility in Cycle A as compared to Cycle B, as % δ ferrite is more in Cycle A specimen and the distribution of phase is discrete in nature. Strength is similar and ductility of Cycle B is high at high temperature (550°C) compared to Cycle A and as cast specimen as shown in Fig.5 and Fig.8.Cycle B leads to tougher structure than Cycle A and as cast structure at 550°C. 4. Conclusion  Amount, size and shape of δ ferrite depend on processing conditions.  With increase in temperature both yield strength and UTS decreases till 150  C. Beyond that strength stabilizes till 550  C.  Water Quench specimen shows more toughness within 250  C -550  C. As cast specimen shows lower toughness in all tested temperature ranges. Acknowledgements The authors gratefully express their sincere gratitude to Sri MZ Siddique, Director, GTRE, and DRDO for the permission to publish these results. Authors also thank the Associate, Technical director for their constant encouragement and support. Authors also give their sincere thanks to SSEL team of GTRE and the entire team of AMTL, for their assistance during the execution of the work. References J.P.Shingledecker. P.J.Maziaz, N.D Evans, M L Santella , M J Pollard.,2006, CF 8C plus: a new high temperature austenitic casting alloy for advance power systems, Energy Material 1, 25-32 A. F. Padilha and P. R. Rios., 2002 , Decomposition of austenite in austenitic stainless steels, ISIJ International 42 , 325 - 337. Angelo Fernando Padilha1, Caio Fazzioli Tavares, Marcelo Aquino Martorano1., 2013, Delta Ferrite Formation in Austenitic Stainless Steel Castings Materials Science Forum Vols. 730-732 , 733-738. S Kozuh, M Gojic, L Kosec., 2009, Mechanical properties and microstructure of austentic stainless steel after welding and post-weld heat treatment, Kovove Mater. 47, 253-262 . G.Sui, E.A Charles , J Congleton., 1996, The Effect of Delta-Ferrite Content on the Stress Corrosion Cracking of Austentic Stainless Steels in Sulphate Solution, Corrosion Science, 38, 687-703. Adrian P. Mouritz., 2012, Introduction to aerospace materials; Woodhead Publishing Limited.134-143 A Molinari, M.Composta, C Menapace., 2008, Effect of Carbon and Nitrogen content on deformation and fracture of AISI 304 austenite stainless steel, Frattura ed Integrita Strutturale,4, 12-19 Guilherme Correa Soares, Mariana Crala Mendes Rodrigues, Leandro de Arruda Santos., 2017, Influence of Temperature on Mechanical Properties, Fracture Morphology and Strain Hardening Behaviour of a 304 Stainless Steel, Materials Research, 1-11.