Title: Assessment of mechanical properties, microstructure and fracture mechanism of SA-508 Gr.3 Cl.1/SS 316L bimetallic joint

Authors: Tahir Rahim; Muhammad Ammar Anjum; Jahan Zeb; Amena Mohsin; Muhammad Farooq; Miraj M. Jan; Zaheer Ahmad

Addresses: National Center for Non-Destructive Testing (NCNDT), Islamabad, 44800, Pakistan ' Pakistan Institute of Engineering and Applied Sciences, Islamabad, 47721, Pakistan ' National Center for Non-Destructive Testing (NCNDT), Islamabad, 44800, Pakistan ' National Center for Non-Destructive Testing (NCNDT), Islamabad, 44800, Pakistan ' National Center for Non-Destructive Testing (NCNDT), Islamabad, 44800, Pakistan ' National Center for Non-Destructive Testing (NCNDT), Islamabad, 44800, Pakistan ' National Center for Non-Destructive Testing (NCNDT), Islamabad, 44800, Pakistan

Abstract: Bimetallic joints of carbon steel SA-508 Gr.3 Cl.1 and stainless steel SS-316L are extensively used in nuclear power plants (NPPs) and petrochemical industry. Severe service conditions during the operation of an NPP involving high temperature, pressure and corrosion rates; make these weldments of extreme importance. The objective behind the present study is to explore the weld quality and mechanical properties of these bimetallic joints prepared by shielded metal arc welding process, using inconel electrode. The prepared bimetallic joint showed improved strength and toughness as compared to the base metals. Fractography results obtained from stereomicroscopy and scanning electron microscopy proved that fracture was ductile due to coalescence of micro voids. X-Ray diffraction and X-Ray energy dispersive spectroscopy results showed the absence of second phase in the joint. The obtained fracture toughness of weld though acceptable is lesser than base metals.

Keywords: DMWJs; dissimilar metal welded joints; pressure vessel; shielded metal arc welding; buttering; elemental diffusion; fracture toughness; fractography; scanning electron microscopy; X-ray diffraction.

DOI: 10.1504/IJMMP.2020.115219

International Journal of Microstructure and Materials Properties, 2020 Vol.15 No.4, pp.298 - 315

Received: 06 Dec 2019
Accepted: 15 Sep 2020
Published online: 24 May 2021 *

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