Effect of beam oscillation on borated stainless steel electron beam welds

Guttikonda RajaKumar; G. D. Janaki Ram; S. R. Koteswara Rao

doi:10.3139/120.110740

Article

Effect of beam oscillation on borated stainless steel electron beam welds

Guttikonda RajaKumar , G. D. Janaki Ram and S. R. Koteswara Rao

Published/Copyright: May 15, 2015

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From the journal Materials Testing Volume 57 Issue 6

Abstract

Borated stainless steels are used in nuclear power plants to control neutron criticality in reactors as control rods, shielding material, spent fuel storage racks and transportation casks. In this study, bead on plate welds were made using gas tungsten arc welding (GTAW) and electron beam welding (EBW) processes. Electron beam welds made using beam oscillation technique exhibited higher tensile strength values compared to that of GTA welds. Electron beam welds were found to show fine dendritic microstructure while GTA welds exhibited larger dendrites. While both processes produced defect free welds, GTA welds are marked by partially melted zone (PMZ) where the hardness is low. EBW obviate the PMZ failure due to low heat input and in case of high heat input GTA welding process failure occurs in the PMZ.

Kurzfassung

Borierte hochlegierte austenitische Stähle werden in Kernkraftwerken verwendet, um die Neutronenkritikalität in Reaktoren zu kontrollieren, zum Beispiel für Steuerstangen, als Schutzmaterial, für Speichereinheiten für verbrauchte Kernbrennstäbe und für Transportbehälter. In der diesem Beitrag zugrunde liegenden Studie wurden Auftragsschweißungen mittels Wolfram-Inertgasschweißen (WIG) (Gas Tungsten Arc Welding (GTAW)) und Elektronenstrahlschweißens (Electron Beam Welding (EBW)) hergestellt. Die Elektronenstrahlschweißungen, die mittels Strahloszillationstechnik hergestellt wurden, wiesen höhere Festigkeitswerte auf als die WIG-Schweißungen. Die Elektronenstrahlschweißverbindungen zeigten eine feine dendritische Mikrostruktur, während die WIG-Schweißungen größere Dendriten aufwiesen. Während mit beiden Verfahren defektfreie Schweißungen hergestellt werden konnten, waren die WIG-Schweißungen durch eine teilweise aufgeschmolzene Zone (Partially Melted Zone (PMZ)) mit geringer Härte gekennzeichnet. In den Elektronenstrahlschweißungen konnte ein Versagen der PMZ durch eine geringe Wärmezufuhr verhindert werden, wobei im Fall hoher Wärmezufuhr beim WIG-Schweißen ein Versagen in der PMZ auftrat.

§Correspondence Address, Assistant Prof. Guttikonda RajaKumar, Department of Mechanical Engineering, Tagore Engineering College, Rathinamangalm, Melakottayiur Post, Chennai, India, 600127, E-mail: rajkumardotcom@yahoo.com

Senior Assistant Prof. Guttikonda RajaKumar, born in 1980, completed his M. Tech. in Machine Design at JNT University Kakinada, India. He worked as Assistant Professor in Sree Kavitha Engineering College, AP, India from June 2003 to October 2010. Since November 2010, he is working as Senior Assistant Professor in the Department of Mechanical Engineering, Tagore Engineering College, Chennai, India. He is pursuing his PhD in the Faculty of Mechanical Engineering at Anna University, Chennai.

Associate Professor G. D. Janaki Ram, born in 1968, received his PhD in Metallurgical and Materials Engineering from IIT in Madras, Chennai, India in 2005. He completed his post doctoral studies at the Utah State University, USA. He has published more than 53 publications in international journals so far. He has around 20 years of professional experience in teaching, industry and research. Presently, he is working as Associate Professor in the Department of Metallurgical & Materials Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India.

Prof. S. R. Koteswara Rao, born in 1966, received his PhD in Metallurgical and Materials Engineering from IIT Madras, Chennai, India in 2005. He has published more than 35 publications in international journals so far. He has around 20 years of professional experience in teaching and research. Currently, he is working as Professor of Mechanical Engineering at SSN College of Engineering, Chennai, Indiaa.

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Published Online: 2015-05-15

Published in Print: 2015-06-01

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https://doi.org/10.3139/120.110740