Supervisor

Dr. Sushanta K Panda
Prof. Surjya K Pal

Doctoral Research Problem

Friction stir welding and deep drawing of aluminum tailored blanks for light weight automotive applications

Research Statement

The invention of friction stir welding had created good scopes of replacing steels by some aluminum alloys (particularly 5XXX series) in the fabrication of tailor welded blanks. However, there was very limited information available in open literature regarding formability (in particular, drawability) performance of tailor-made aluminum friction stir welded blanks. Therefore, two mostly used aluminum alloys, namely AA5754-H22 and AA5052-H32 with dissimilar gauge (2.0 and 2.5 mm) were initially friction stir welded using optimized parameters, to be ensured to get its maximum weld strength. Subsequently, the fabricated optimized aluminum tailor friction stir welded blanks (TFSWBs) were examined for its formability in terms of limiting drawing ratio (LDR) in a laboratory scale standard deep drawing test. The obtained results were found to be very close to that of the base metals; however, for further improvement in the LDR, a new die (named as modified conical tractrix die, MCTD) was designed, developed and tested by using the fabricated optimized TFSWBs. Significant improvement in the LDR was observed once using MCTD. Moreover, a finite element model of the LDR test was developed and validated using the experimental results with impressively high accuracy. This model was used to analyze the strain evolution pattern during the drawing of the fabricated TFSWBs, which revealed a new and more pronounced reason behind the improvement in the LDR obtained with MCTD.

Indusrial Application

Automotive industry: Fabrication of body-in-white, fuel tank, door and floor panel etc.

Publications

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• Email: ramkumar31kesharwani[at]gmail.com
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Supervisor

Prof. Surjya K Pal

Doctoral Research Problem

Novel Twin Tool Based Friction Stir Welding of Aluminum Alloys

Research Statement

Most of the research woks in FSW have been conducted using the traditional single tool system. This leads to non-unifrom temperature distribution across the weld plates. FSW also requires heavy clamping force abd high downward force to maintain the contact between the tool and the workpiece intact. To tackle this, a twin tool has been indignenously develeoped and farbicated. This consists of two tools rotating in opposite directions and moving simulateneously. The tool system requires less clamping force as the two tools counter each other. It disrupts and fragments the residual oxide layer remained in the first weld region by the follower tool, thus, enhancing the weld quality. Good quality welds can be achieved with higher welding speeds.

Publications

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• Email: kanchan.1087[at]gmail.com
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Supervisor

Prof. Surjya K Pal
Prof. Shiv B Singh

Doctoral Research Problem

Numerical modeling and validation of friction stir welding with different tool configurations

Research Statement

Study of material flow mechanism, forces and defect formation during FSW process are important as it could help in proper selection of process parameter and pin design. Their experimental study is exhaustive due to lots of post weld analyses. Numerical modeling could be an efficient method to study the material flow and defect formation. This will reduce the cost associated for material and development of infrastructure. In the current research work two different three-dimensional thermo-mechanical models are developed to simulate FSW.
(a) A three dimensional thermo-mechanically coupled model was developed based on Lagrangian theory. The developed model is used to model FSW for AA2024 and AA6061 aluminum alloys. For AA2024 material, the model is validated with the forces and spindle torque data obtained from the literature. Two different pin shapes viz. conical and threaded conical are compared in terms of forces, material flow, material velocity, effective strain and strain rate. Threaded conical pin produced higher deformation and vertical flow of the material among the two. For AA6061 material, in-house experiments are performed to validate the model with temperature, force and spindle torque. Three different pin shapes, namely, cylindrical, triflat and square are compared. For flat pin surfaces bulk material flow is prominent, while shearing or layer by layer material flow is more prominent for cylindrical pin. Distribution of the material is uniform across the stirred region for the triflat pin while it is stretched towards the advancing side for the square pin.
(b) Prediction of defect using Lagrangian model is difficult as void cannot be introduced in it. Therefore, another model based on coupled Eulerian Lagrangian is developed to predict the defect formation. The defect prediction is based on volume of fluid principle. Effect of tilt angle on defect formation is studied and simulation predicted defect is compared with the experiments. The developed model accurately predicted the defective as well as defective weld.

Indusrial Application

1. The developed model will help industry to pick the efficient tool geometry that will produce higher weld strength.
2. The model developed based on coupled Eulerian Lagrangian method can predict the defective or non-defective weld based on input process parameter.
3. This will reduce a lot of experimental requirement to come up with optimized process parameters.

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• Email: rahul[at]iitbhilai.ac.in
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Supervisor

Prof. Surjya K Pal

Doctoral Research Problem

Friction Stir Lap Welding of AA6061-T6 and AISI304 in Air and Underwater Media: Mechanical Studies and Material Characterizations

Research Statement

The joining of dissimilar materials such as AA6061-T6 and AISI34 has the potential for tailoring the properties of a structure. However, because of the differences in the mechanical and metallurgical properties of AA6061-T6 and AISI304, there exist several challenges in fabrication. Friction stir welding (FSW) is an advanced solid-state welding technique having the potential to produce a sound weld between aluminum and steel substrates. Microstructure, intermetallic compounds (IMC), crystallographic texture, corrosion, and weld defects are the main factors controlling the mechanical and metallurgical properties of the welds. These factors rely on process parameters and weld media. Scanty literature is available on the effect of process parameters on the FSW of AA6061-T6 and AISI304 in air and water media.

Indusrial Application

Sub-frame of Honda Accord


Ref:http://world.honda.com/automobiletechnology/FSW/topic7/20.03.2018

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• Email: rajukec1[at]gmail.com
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Supervisor

Dr. Jinu Paul

Doctoral Research Problem

Development of friction based solid-state processing strategies for the surface modification of Aluminium alloys

Research Statement

Solid state friction based strategies has the potential for locally enhancing the properties of various aluminium alloys for demanding applications within the automotive industry. The research aimed to increase the wear resistance of the aluminium alloys through impregnating various carbonaceous reinforcements such as Graphite, Graphene and CNTs through solid state friction stir processing and friction surfacing methodologies. Additionally, the novel powder metallurgy assisted friction surfacing technique is developed which facilitates the impregnation of amorphous materials on the substrate through friction surfacing.

Industrial Application

Hardfacing of the knife by FS

Publications

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• Email: abhi.foundry[at]iitkgp.ac.in
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Supervisor

Prof. Surjya K Pal

Doctoral Research Problem

Industry 4.0 based, monitoring and control of friction stir welding process

Research Statement

Applying digitization techniques to FSW is expected to improve the overall quality of the process. Integrating the machine with several sensors will provide a set of values of physical parameters which could be analyzed to monitor the process in real time and control it as required.

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• Email: debsmishra02[at]gmail.com
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Supervisor

Dr. Vikranth Racherla
Prof. Surjya K Pal

Doctoral Research Problem

Fabrication of open-celled copper foam using friction sintering

Research Statement

Metal foams have received considerable attention due to their low density, high strength to weight ratio, large compressive deformations at constant flow stress, high gas permeability, and large surface area. Sintering and dissolution process (SDP), sintering with blowing agents, direct gas blowing, sintering with hollow spheres, reaction sintering, investment casting, etc., can be used to create metal foams. While most methods listed above result in closed-cell foams, SDP results in open-cell foams. While closed-cell foams are used in structural applications, open-cell foams are used in the heat exchanger, sound absorption, catalysis, boiling, and filtration applications. Metal foam can be fabricated on a friction stir welding machine using friction sintering process.

Industrial Application

Multifunctional heat exchanger (University of Virginia)



Ref:https://www2.virginia.edu/ms/research/wadley/thermal-management.html

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• Email: vyasmani742014[at]gmail.com
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Supervisor

Prof. Surjya K Pal
Dr. Prakash Srirangam (WMG, UK)

Doctoral Research Problem

Fabrication of electronic components by friction stir welding in the Li-ion battery packs

Research Statement

With the increasing rate of pollution and globalization, industries are adopting innovative technologies that can be probable solutions towards these concerns. Electric vehicles (EVs) are one such example among these innovations. EVs consist of powerful batteries consisting of micro-thickness tabs and interconnected with busbars. They are intended to obtain a high current source by means of these battery packs. Copper (Cu) and aluminum (Al) are two such metals which are being widely used in this area owing to their high thermal conductivity. The joining of this sheets through conventional fusion welding techniques will not be feasible because of the high amount of temperature involved with these methods. Hence, advanced solid state welding techniques i.e. friction stir welding (FSW) was emerged. Thus, research on µ-friction stir welding (µ-Friction Stir Welding) process was become a necessity. As these materials (Al-Cu) have similar FCC crystal structure, it is very difficult to examine the diffusion mechanisms, so a molecular dynamics study is a potentially useful approach to studying the joining mechanisms.

Industrial Application

Battery cells and packs with electrode tabs for electric vehicles



Ref:https://link.springer.com/article/10.1007/s40430-018-1542-5

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• Email: omkar.mypati[at]gmail.com
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Supervisor

Prof. A K Nath
Prof. Surjya K Pal

Doctoral Research Problem

Development of tools for friction stir welding of high melting point materials using direct metal laser deposition technique

Research Statement

Friction stir welding (FSW) is a solid state welding process originally developed for joining of low melting point alloys like Al & Mg alloys, which are otherwise difficult to be joined by the conventional fusion welding processes. Further, it offers superior property in the welded joints as it does not involve melting. This inspired extending the application of FSW to high melting point materials like Cu, Fe, Ti and their alloys. One of the major problems of FSW of these materials is the tool wear. This necessitates the development of tool materials having high strength, toughness and wear resistance at elevated temperatures. One possible solution could be the coated tools having hard coating on tough base material. H13 tool steel is one of the most commonly used tool material in FSW of low melting point materials like Al and Mg alloys. However, high temperature involved during FSW of high strength and high melting point materials like Cu alloys leads to increased tool wear. Therefore, the current study focuses on direct metal laser deposition (DMLD) of Stellite-6, a hardfacing alloy having high temperature wear resistance property on H13 tool steel for the fabrication of tools for friction stir welding of copper alloys.

Indusrial Application

Cost reduction in FSW of high melting point materials like copper alloys through enhancement of tool life by Direct Metal Laser Deposition



Ref:http://www.iter.org

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• Email: sadhu.abhi4all[at]gmail.com
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Supervisor

Prof. Surjya K Pal
Dr. Parthasarathi Mandal (The University of Manchester, UK)

Doctoral Research Problem

Development of an integrated thermo-mechanical and metallurgical model of friction stir welding of pipes

Research Statement

Friction stir welding (FSW) has been successfully used to weld materials in various joint configurations such as butt, lap, and T, and recently it is being employed for joining of pipes. Industries like thermal power, hydro power, petroleum refineries, smelting plants, and rolling industries use pipelines for transportation of various fluids. There is an emerging need for establishing proper installation methodology and working of these pipes. The fabrication of these pipes is mostly being performed by using the fusion welding techniques, however, making use of FSW to fabricate them will not only be cost-effective but also will be environmental friendly. Further, an integrated thermo-mechanical and metallurgical model for FSW of pipes will be useful to predict various thermal properties such as strain, strain rate, temperature of the weld, mechanical properties such as force, torque, and metallurgical properties such as distribution of grain boundary, average grain size etc. In addition to the above, making use of modeling techniques prior to experiments optimizes the process, and increases the amount of process innovation.

Industrial Application

FSW can be directly implement to join the aluminum tubular bus-bars for HV substations and pipelines industries



Ref:https://www.123rf.com/stockphoto/pipe_welding.html?sti=ljt4ct9kw1yq24im9s|&mediapopup=33311652

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• Email: iqbal.iitkgp[at]gmail.com
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Supervisor

Prof. Surjya K Pal
Dr. Sushanta K Panda

Doctoral Research Problem

Fabrication of friction stir welded aluminium tubes and their formability performance

Research Statement

Tubular components made of aluminium are widely used as structural components in automobile and aerospace industries because of its low cost, higher energy absorption capability and better corrosion resistance. The tubular components can be manufactured by extrusion as well as different welding processes. The extrusion process is very expensive and is limited to fabrication of small diameter tubes. Hence for manufacturing tubes with large diameter to thickness ratio, welding is the possible solution. Fusion welding techniques create a lot of detrimental intermetallics and defects in the joints thus decreasing the quality of the tubes. Friction stir welding (FSW) process is an advanced welding technique where the welding takes place in its solid state i.e. without melting. Hence the joint formed is near to homogeneous in nature which enhances the joint properties and quality of the tubes. Tubular components which are employed in critical areas, needing good mechanical and metallurgical properties and can withstand failure can be manufactured by FSW. FSW of curved surfaces has got many challenges. Thus the objective of this research is to successfully weld tubular components using FSW process and study the forming properties of the welded tubes.

Industrial Application

Wheel rims



Ref:https://spinoff.nasa.gov/Spinoff2008/ip_4.html

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• Email: debolinasen90[at]gmail.com
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