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

Hastelloy X develops hot fissuring during fusion welding, which could be precluded using single-pulsed gas metal arc welding (SP-GMAW) and double-pulsed gas metal arc welding (DP-GMAW). The outcome of this research is to provide a better insight into microstructural characteristics, and mechanical properties of Hastelloy X welded by GMAW, SP-GMAW, and DP-GMAW techniques. GMAW depicts the cellular dendrites, whereas DP-GMAW and SP-GMAW displayed fine equiaxed dendrites. Mo-rich segregation is identified in the interdendritic region of GMAW owing to high solidification time. Mo-rich segregation is reduced for SP-GMAW, whereas it is completely precluded for DP-GMAW due to the existence of refined grain. The development of M3C (Fe2MoC) and M6C (Fe2Mo4C) carbide precipitates is identified in GMAW and SP-GMAW. But, DP-GMAW displays the absence of Mo-rich carbides and the development of Mo1Ni4 intermetallic precipitates. DP-GMAW provides better joint efficiency (96.32%), UTS, and ductility, which is followed by SP-GMAW and GMAW. DP-GMAW shows higher mean microhardness (7.31% and 3.52%) and impact toughness (49.01% and 26.67%) on comparison with GMAW and SP-GMAW, respectively. Inverse pole figure (IPF) maps of SP-GMAW weldment confirmed that the broad and straight dendrites formed tend to grow along &lt; 100 &gt; direction during the entire solidification process. DP-GMAW also displays the major intensity shift from &lt; 100 &gt; to &lt; 111 &gt; direction. Evidence for the formation of equiaxed grains of random orientation along with dendrites is confirmed by IPF maps from DP-GMAW weldments. The presence of these equiaxed grains in the DP-GMAW weldment might have contributed to the enhancement of tensile properties. © 2021, ASM International.

World University root node

Department of Design and Automation

School of Mechanical Engineering

Vellore Campus

Department of Manufacturing Engineering

Journal of Materials Engineering and Performance

Investigation of Double-Pulsed Gas Metal Arc Welding Technique to Preclude Carbide Precipitates in Aerospace Grade Hastelloy X

The present study investigates the metallurgical, mechanical and corrosion behavior on 6 mm plate, friction stir welded aluminium alloy (AA) 7475-T761. The process parameters of the welding process were optimized by using Box Behnken Method with a minimum number of trials. Optical and Scanning electron microscope (SEM) were used to evaluate the microstructure of weldment in different zones. Energy Dispersive X-ray Spectroscopy (EDS) analysis was carried out to analyze the extent of microsegregation of alloying elements in the different zones of the weldment. X-Ray diffraction (XRD) analysis was carried out to evaluate the phase formation and calculate the crystallite size, microstrain and dislocation density in the stir zone and base metal. Exfoliation corrosion was performed to evaluate the corrosion behavior of the weldment in the different zones. The results illustrate the defect-free welding was obtained by a combination of rotational speed (ω) 600 RPM, traverse speed (ν) 40 mm min-1 and axial force (p) 10 kN. The fine equiaxed microstructure was observed in the stir zone. EDS analysis shows the extent of Cu rich microsegregation in the stir zone. Weldment produced by the above combination of parameters exhibit 76% joint efficiency. Hardness value along the weldment reveal 26% improvement in stir zone compared to the base metal due to refined microstructure. X-Ray diffraction analysis point out the high dislocation density and strain induced in stir zone is caused by dynamic recrystallization. Corrosion study confirms the stir zone has higher resistance to corrosion compared to adjacent thermos-mechanical affected zone. © 2019 IOP Publishing Ltd.

VIT Unitversity

Materials Research Express

Friction based joining process for high strength aerospace aluminium alloy

Digital data extraction is the most important and advance informative system that are embedded in the modern world functioning machinery to acquire the most precise feedback about the real-time operational situation of the machine to the control centre of operation. This data that is acquired from the machinery can be used to increase the efficiency, operational timing, production-cost and the overall human effort that is required for the operation. This paper focuses on the development on the advanced telemetry system that is capable to acquire real-time data of the modern vehicle wirelessly during its motion. A mobile automotive telemetry system for installation on-board a vehicle, includes: diagnostic structure for monitoring operational functions of the vehicle and generating operational information; memory for storing the generated operational information; and a server, in communication with the diagnostic structure and the memory. The server includes: (a) structure to receive a request from a remote client for the generated operational information; (b) structure to retrieve the generated operational information from the memory; and (c) structure to transmit the generated operational information to the remote client. © 2019 SAE International. All Rights Reserved.

SAE Technical Paper Series

Development of Data Acquisition and Analysis System: Telemetry in Automotive

Alloy C-276 susceptible to hot cracking. The microsegregation occurs during solidification is the largely responsible for the hot cracking in the alloy. The present study investigates the microstructure and mechanical properties of alloy C-276 weld joint fabricated by ATIG welding technique. The macro examination was carried out assess the defects in the weld joints. Optical and scanning electron microscope examination was carried out to see the structural changes in the fusion zone. The tensile test was performed to evaluate the strength of the weld joints. The results show the defect free welding was achieved in the established process parameters. The macrograph shows the full depth of penetration was obtained in the single pass by the effect of Marangoni convection. Energy Dispersive X-ray spectroscopy (EDS) analysis illustrates the absence of microsegregation in the interdendritic zone. The tensile test shows the improved mechanical properties compared to the base metal. © Published under licence by IOP Publishing Ltd.

Fulltext

IOP Conference Series: Materials Science and Engineering

Investigation on Microstructure and Mechanical Properties of ATIG welded alloy C-276 with Fe2O3 flux

The present study investigates the dissimilar weld joints between AISI 316L and Duplex 2205 stainless steel. The joints were fabricated with the Pulsed current gas tungsten arc welding with ER316L and ER309L filler wire. The weld joints were subjected to metallurgical and mechanical characterization. The macro examination and optical microstructure examination were carried out to see the defect in the weld joints and structural changes in the fusion zone. The results show that the defect free welding was achieved in the both the filler wire. The optical microstructure shows the ferritic structure in both filler wire. The strength of the weld joints was tested with the tensile test. The results indicate the fracture occurred in the base metal in both cases. © Published under licence by IOP Publishing Ltd.

Department of Thermal and Energy Engineering

Investigation on microstructure and tensile properties of dissimilar weld joints between AISI 316l and duplex 2205 stainless steel

The present study investigates the microstructure, microsegregation, and microhardness of alloy C-276 plates by a bead on trials of plasma arc welding (PAW). The bead - on welds were carried out by autogenous plasma welding using melt in mode technique. Microstructural characterization studies were performed using optical and scanning electron microscopy (SEM) techniques. The studies showed the presence of close networks of fine equiaxed dendrite structures while employing lower heat inputs. Whereas the increasing heat energy input demonstrates the occurrence of columnar dendrite structures. SEM/EDAX analysis demonstrates the presence of secondary phases of P and μ in the fusion zone. Energy Dispersive X-Ray Analysis (EDAX) analysis was performed to infer the microsegregation of alloying elements. Microhardness study was carried out to evaluate the hardness of the weld zones in different heat input. The hardness test revealed that on increasing the heat input, the hardness values were impoverished. © 2017 Elsevier Ltd.

Materials Today: Proceedings

Investigations on the Microstructure, Microsegregation and Hardness Properties of Bead on Plasma Arc Welded C-276 Alloy

Design for manufacture and assembly, DFMA, is a set of tools or applications, when incorporated on a particular product helps reduce the number of parts ,bring about a change in the material used, and even the process/operation used. This indirectly helps in the overall cost reduction of the product and hence improve the productivity on the whole. DFMA is usually used during the initial design stages of a product, so that if any changes can be brought about in the product to help improve its efficiency and cost, simultaneously, it can be done in the beginning itself. This helps the designer plan out his entire schedule for production of the product depending on its work volume. DFMA is a combination of two basic principles, namely, Design for Manufacture (DFM) and Design for Assembly (DFA). Design for manufacture helps to ease out the manufacturing processes used in the production cycle of a product, whereas, Design for assembly helps ease out the assembly line once done with the production stage. Improper design decisions are responsible for higher manufacturing cost for a product. Thus it is important to include DFMA by combining principles of both DFM and DFA principle early in the design process. This paper presents a case study of the manufacturing and assembly cost's estimation during the design stages of a hand pressure mob, with the help of a DFMA tool.

International Journal of Mechanical Engineering and Technology

Early cost estimation of hand pressure mop using design for manufacture &amp; assembly (DFMA)

This article investigated the weldability, metallurgical and mechanical properties of Inconel 625 and AISI 316L stainless steel weldments obtained by continuous current (CC) and pulsed current (PC) gas tungsten arc welding (GTAW) processes employing ERNiCr-3 and ER2209 fillers. Microstructure studies showed the migrated grain boundaries at the weld zone of ERNiCr-3 weldments and multi-directional grain growth for ER2209 weldments. It was inferred from the tension tests that the fracture occurred at the parent metal of AISI 316L in all the cases. Charpy V-notch impact tests accentuated that the CCGTA weldments employing ERNiCr-3 filler offered better impact toughness of 77 J at room temperature. Further a detailed study has been carried out to analyze the structure â property relationships of these weldments using the combined techniques of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. Â© 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Journal of Mechanical Science and Technology

Characterization of metallurgical and mechanical properties on the multi-pass welding of Inconel 625 and AISI 316L

This investigation has been performed to characterize the microstructure and mechanical properties of the GTA and PCGTA welded dissimilar combinations of Inconel 625 superalloy and AISI 304 austenitic stainless steel. These welds were obtained by employing ERNiCrMo-3 filler metal. The weldments were characterized by the combined techniques of optical microscopy and SEM/EDAX analysis. Hardness and tensile studies were conducted to assess the mechanical properties of the weldments. Tensile studies showed that the fracture had occurred at the parent metal of AISI 304 side in both the cases.

ISIJ International

Characterization of Microstructure and Mechanical Properties of Inconel 625 and AISI 304 Dissimilar Weldments

This Experimental research article presents a bead on plate welding of AISI 316L welded with continuous Laser Beam Welding (LBW). An attempt is made to find a process parameter for a full penetration weld bead profile; with less segregation effect. The experiments were carried out in two sets on an AISI 316L austenitic stainless steel plate (200 × 150 × 5 mm). In the first set, trial welds were carried out by keeping the laser speed at 400 mm/min and in the second set; it was kept at 800 mm/min. In both the cases, the laser power was varied from 1000 W, 1500 W and 2000 W. Metallurgical and mechanical characterizations were carried to evaluate the weld beads. Macro and micro structural analysis is carried done to evaluate the bead profile and microstructures. Ferrite content in terms of ferrite number (FN) in the weld zone is evaluated using Fischer Feritscope. Scanning Electron Microscope (SEM)\Energy Dispersive X-ray Spectroscopy (EDS) was used to characterize the weld beads for segregation effect. Vickers micro hardness test was carried out across the cross section of the weld beads to find the hardness distribution. Better result was obtained for the trial bead with parameter 800 mm/min and 2000W. © 2014 The Authors.

Procedia Engineering

Micro-segregation Studies on the Continuous Nd: YAG Laser Beam Welded AISI 316L

This paper presents the experimental investigations carried out to study the influence of addition of Tungsten Carbide (WC) on the scratch resistance and high-temperature corrosion behaviour of flame-sprayed EWAC 1001 coatings on the AISI H13 steel substrate. The improvement in properties was analysed by conducting various tests such as microstructural analysis, microhardness, and scratch tests. Moreover, high-temperature corrosion tests were carried out on the coated as well as uncoated AISI H13 steel by exposing the material to air oxidation at 700°C under cyclic conditions. The thermogravimetric technique was used to establish kinetics of corrosion, whereas XRD and SEM/EDAX techniques which were used to analyze the AISI H13 steel with EWAC 1001 coating containing WC showed better resistance to high-temperature corrosion as compared to that of uncoated AISI H13 steel. It is observed that the formation of Cr2O3, NiO, and NiCr2O4 contributes to the enhancement of high temperature corrosion resistance of the coating. The formation of unprotective Fe2O3 oxide leads to intense spalling and peeling of the scales in the uncoated material. The results presented in this paper would be beneficial for improving properties of tools used in the die-casting industry.