This research study articulates the joining of marine grade alloys Monel 400 and AISI 904L by pulsed current gas tungsten arc welding (PCGTAW) technique using ERNiCu-7 and ERNiCrMo-4 filler metals. Experimental studies were carried out to establish the structure-property relationships of the dissimilar weldments. Microstructure studies corroborated the formation of migrated grain boundaries at the fusion zone of ERNiCrMo-4 weldments. Also a partially melted zone (PMZ) was observed at the weld interface of Monel 400 while using ERNiCrMo-4 filler. Tensile studies corroborated that the joint strength was found better for the ERNiCu-7 weldments compared to ERNiCrMo-4 weldments. Tensile failures occurred at the HAZ of Monel 400 for ERNiCrMo-4 weldments which could be reasoned out to the presence of partially melted zone (PMZ). Charpy V-notch studies demonstrated that both the weldments absorbed higher amount of energy by showing ductile mode of fracture. The outcomes of the present study will be beneficial to the industries operating these metals. © 2015 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.

Devendranath Ramkumar K

Department of Manufacturing Engineering

School of Mechanical Engineering

Vellore Campus

Arivazhagan N

Naren S.V

Karthik Paga V.R

Tiwari A

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Manufacturing Processes

In the present study, three different fluxes namely NiO, MoO3 and SiO2 were employed to investigate the weldability of super-duplex stainless steel (UNS S32750). Bead on trial studies were conducted to determine the effect of welding current on the depth of penetration and depth to width (D/W) ratio. The studies demonstrated that complete penetration could be achieved in a single pass with the use of activated flux. Microstructure studies showed the formation of coarser grains of ferrite along with three different types of austenite which are Widmanstätten, intra-granular and grain boundary austenite in the fusion zones of all the weldments. Oxygen content and ferrite count analysis were also carried out at the fusion zones of the weldments. Tensile studies inferred that the tensile failures occurred at the weld zone for all the cases. The joint efficiencies of the activated flux tungsten inert gas (A-TIG) weldments employing NiO, MoO3 and SiO2 flux were reported to be 91.6%, 87.4% and 93.06%, respectively. The impact toughness of the A-TIG weldments was found to be lower than that of the base metal (82 J). Potentiodynamic polarization studies were also performed to investigate the corrosion behaviour of the welds in 3.5% NaCl environment. © 2016 The Society of Manufacturing Engineers

Studies on the structure–property relationships and corrosion behaviour of the activated flux TIG welding of UNS S32750

This research article reported the weldability, microstructure and mechanical properties of the dissimilar combinations of nickel alloys such as Monel 400 and Hastelloy C276. Multi-pass pulsed current gas tungsten arc (PCGTA) welding was employed for joining these dissimilar metals using ERNiCrMo-3 filler. Interface microstructures showed the absence of unmixed zone at the HAZ of both the sides. It was evident from the studies that all the tensile failures occurred at Monel 400 side. The average impact toughness portrayed by these dissimilar weldments was found to be 41. J. Bend test results showed that these dissimilar combinations offer augmented ductility. The outcomes of the study substantiated the use of current pulsing for the successful joints of Monel 400 and Hastelloy C276 by correlating the mechanical and metallurgical properties. © 2014 Elsevier Ltd.

Materials & Design

Investigations on the microstructure and mechanical properties of multi-pass pulsed current gas tungsten arc weldments of Monel 400 and Hastelloy C276

Dissimilar metal welding involving AISI 304 and Monel 400 finds widespread use in marine and offshore environments for the fabrication of heat exchangers, evaporators, piping and vessels in petrochemical and power generation industries. However studies on the performance of such weldments are scantly found in the literature even though the individual metals have higher corrosion resistance and strength. This paper reports the work carried out on welding of AISI 304 and Monel 400 using Gas Tungsten Arc Welding (GTAW) technique to examine the weldability, mechanical and metallurgical properties. Investigations have been carried out on the hot corrosion behavior of these joints subjected to cyclic air oxidation and K2SO4&nbsp;+&nbsp;NaCl (60%) molten salt environment at 600&nbsp;°C. A comparative analysis was carried out on these weldments for two different filler metals such as E309L and ENiCu-7. The oxide scales formed on the various zones of the weldment have been characterized systematically using surface analytical techniques. Weld zone was found to be more susceptible to degradation than base metals used. The effect of filler materials on the hot corrosion is discussed. The studies reported in this paper would be beneficial for fabricators embracing this type of dissimilar weldments in the petrochemical and power generation industries.

Journal	Data powered by TypesetJournal of Manufacturing Processes
Publisher	Data powered by TypesetElsevier BV
ISSN	1526-6125
Open Access	No