2. WELDING
Welding is a permanently joining process of metals and alloys. Welding uses
temperature, pressure and metallurgical condition to mixed two materials
together.
Firstly forge welding is used as a metal joining process. In forge welding,
metals are joined by hammering and heating.
Today lots of welding processes are available.
The principle difference between the welding processes is the method which is
used to generate heat for melt the metals.
Welding is used as a fabrication process for small and large industries.
This process used in air, space and under water also.
3. FRICTION STIR WELDING
Friction Stir Welding a solid state joining process was invented and
experimentally perform by Wayne Thomas and a team of his colleagues at The
Welding Institute UK
Initially the process was developed for aluminum alloy, but since then found
that FSW was suitable for welding a large number of materials.
When FSW is developed, it becomes appropriate alternative technology due
to low distortion, high processing speed and high strength of joint.
In FSW process, a non-consumable rotating tool, consisting of a shoulder and
a profile probe or pin, is forced down into the joint line under conditions where
the frictional heating is sufficient to raise the temperature of the material to the
range where it is plastically deformed as shown in next slide.
6. The progress of the tool through the joint, also
showing the weld zone and the region affected by the
tool shoulder
7. Advantages & Disadvantages of friction stir welding
Advantages of friction stir welding
It is environment friendly process. Aluminum alloys can be welded without the need of shielding gas.
Can operate in all position (vertical, horizontal, etc.).
Generally good weld appearance obtained.
Easily automated on simple milling machine and lower set up cost.
Improve strength, ductility, resistance to corrosion and fine grain structure has been obtained.
Welded surface is free of porosity void defect, cracks and with lower distortion etc.
Fatigue life of welded joint is high.
Disadvantages of friction stir welding
Exit hole left when tool is withdrawn.
Large downward force required with heavy duty clamping necessary
to hold the plate together.
Less flexible than manual and arc welding.
Often slower traverse rate than some fusion welding process.
8. APPLICATIONS OF FRICTION STIR WELDING.
Railway Industry- FSW is mostly used in the construction of railway carriages,
building container bodies, railway tanker etc.
Automotive Industry- FSW process is very applicable in automation industries
and fabrication work like to manufacture tail light panels, automotive suspension
arms etc.
Shipping And Marine Industry- Some of the applications included panels for
decks, railings and also used in the construction of marine vessels.
Aerospace Industry- At present, Aerospace Industry is using production parts valid
by FSW are body and fuel tanks for space aircrafts etc.
Construction Industry- The use of portable FSW is possible for aluminum bridges
,window frames, aluminum pipe lines, aluminum reactors for power plant and
air conditioners, heat exchangers, pipe fabrication and chemical industry.
9. FSW PROCESS PARAMETERS
FSW process parameters such as tool geometry rotational speed, welding
speed and tilt angle significantly influence the process and play a major role in
deciding the quality of the weld.
The detailed list of FSW process parameters are listed below:
1. Rotational speed of the tool (rpm)
2. Welding speed (mm/min)
3. Axial load (KN)
4. Tool geometry
(i) D/d ratio of tool (ii) Pin length
(iii) Tool shoulder diameter, D (mm)
(iv) Pin diameter, d (mm) (v) Tool inclined angle (◦)
10. CHALLENGES IN FSW
An inappropriate rate of heating can result in the formation of FSW defects such
as lack of penetration, lack of fusion, tunnels, voids, surface grooves,
excessive flash, nugget collapse.
These are primarily determined by the main parameters of FSW, which are the
tool rotational speed (TR), welding speed (WS), and tilt angle and axial force.
A large mass of flash due to the excess heat input,
Cavity or groove-like defect caused by an insufficient heat input.
Cavity produced by the abnormal stirring.
11. THE TAGUCHI METHOD
Taguchi, a Japanese quality engineer widely recognized as the father of
quality engineering
He addresses quality in two main areas: off-line and on-line quality
control
Off-line quality control refers to the improvement in quality in the product
and process development stages.
On-line quality control refers to the monitoring of current
manufacturing processes to verify the quality levels produced .
The Taguchi method considers the minimization of the variance of the
characteristic of interest.
Taguchi statistical design is a powerful tool to identify significant factor
from many factors by conducting relatively less number of experiments.
12. STEPS TO BE FOLLOWED FOR PROCESS
PARAMETER OPTIMIZATION
Step 1: Determine the quality characteristic to be optimized.
Step 2: Identify the noise factors and test conditions.
Step 3: Identify the control factors and their alternative levels.
Step4: Design the matrix experiment and define the data analysis
procedure.
Step 5: Conduct the matrix experiment.
Step 6: Analyze the data and determine optimum levels for control
factors.
Step 7: Predict the performance at these levels
13. LITERATURE REVIEW
R.S. Mishra et al (2005) : studied Friction stir welding (FSW),its
advantages and disadvantages and its applications of metallic
alloys, that are difficult to weld by traditional fusion welding
Huseyinet al.(2005): studied fatigue properties; hardness and the
microstructure of aluminum alloy and stainless steel by using
friction stir welding process.
Optical microscopy (OM) is used to characterize the
microstructures of HAZ, WNZ, BM and TMAZ.
Research result show that fatigue properties of
dissimilar metal welded joint are approximately 30% lower than that
of the Al alloy base metal
14. Benyounis et al. (2008) : considered that welding input parameters
play a major role in determine the quality of a weld joint.
(DOE), and evolutionary algorithms are vastly used to develop a
mathematical relationship between the welding process input
parameters and the output variables of the weld joint in order to
regulate the welding input parameters that lead to the desired
welded joint quality.
Jayaraman et al. (2009) investigate that Taguchi technique are used
to determine the tensile strength of FSW joint .
Determine the optimum welding condition for maximizing tensile
strength of cast aluminum alloy and with the help of Signal to Noise
ratio we find out the optimal results for friction stir welding.
15. Vidal et al. (2010): studied the comparative analyses between welded
joints and the base material joints for the improvement of FSW of the
aerospace aluminum alloy joint.
The test shows that the ground joints gave higher fatigue strengths in
comparison with the base material joints.
K.Elangovan et al (2007): AA6061 aluminum alloy joint studied with
Five different tool pin profiles (straight cylindrical, tapered cylindrical,
threaded cylindrical, triangular and square) .
From this research it is found that the square pin profiled tool with 18mm
shoulder diameter produced mechanically sound and metallurgically
defect free welds compared to other tool pin profiles.
16. Elatharasan et al. (2012) : examine the effect of axial force, rotary speed
and welding speed on tensile strength, displacement and yield strength
The test result show that ultimate tensile strength of friction stir welding joint
increase as the rotational speed increase and as the axial force increase
then ultimate tensile strength start decreasing.
Bisadi H. et al. (2013) investigate the effect of rotational and transverse
speeds on mechanical properties and microstructures of friction stir welding
joint and lap joint of pure copper joint.
Rajkumar et al. (2014) study the effect of welding parameters and tool
structure on friction stir welding of for joining dissimilar aluminum alloy.
It is noticed that when both the sample welded at lower feed rate they will
perform better in term of ductility.
17. Chaitanya Sharma et al (2011) : studied the effect of varying welding
parameters of FSW on microstructure and mechanical properties of
AA7039.
Results showed that optimal combination of welding and rotational speed to
provide a comprehensive and defect free joint with microstructure that
produces maximum mechanical properties.
Palanivel et al. (2011) develop the mathematical model for determine the
ultimate tensile strength (UTS), percentage of elongation and yield strength
of aluminum alloy joints.
Response surface methodology (RSM) is used to develop the
mathematical model.
Analysis of variance (ANOVA) method is used to ensure the capability of
the developed mathematical model.
18. Lakshminarayanan et al. (2008) study the improve value of rotary speed,
axial force and welding speed for the friction stir welding (FSW).
In this study work that Taguchi method was used to calculate better tensile
strength of friction stir welded aluminum alloy joint.
The method was based on Taguchi’s technique, analysis of variance
(ANOVA) and signal to noise ratio (S/N Ratio) to improve the Friction stir
welding process parameters for effective welding.
As welding force, the rotational speed and axial force are increase,
tensile strength will increase but up to a definite limit. Then tensile
strength starts decreasing.
The predicted optimum value of tensile strength for friction stir welded
aluminum alloy is 303 MPa.
19. Elatharasan et al.(2013): study the enhance value of welding
parameters for the friction stir welding(FSW).
Central composite design technique and mathematical model was
developed by Response Surface Methodology (RSM).
The results of this study shows that the increase in tool rotary speed
and axial force result in the increase in tensile strength (TS) of the
welded joints up to a maximum value, while tensile strength(TS)
start increase when decrease in welding speed.
The study shows that at higher axial forces and higher rotary
speeds and lower transverse speed result to removal of the
defects and so the yield strength (YS) is higher.
20. RESEARCH GAPS
Literature review revealed that many researchers has done work on many similar and
dissimilar aluminum alloy, but limited study has been reported on friction stir welding of
aluminum alloy 6105 yet.
Literature review revealed that many studies has done on parametric optimization on
aluminum alloy like AA6061, AA6063, AA6061-T6, AA319, AA2219, AA7075, and AA7039, but
parametric optimization of friction stir welding on AA6105 is still required.
Many researchers has studied the microstructure of friction stir welding joints on other similar
and dissimilar aluminum alloys, but no study has been done on AA6105 yet.
From studying the literature review it is found that several methods has used for optimization
of process parameter such as RSM, ANN, FEA, CFD.
Taguchi Method has been used for aluminum alloy like AA319, AA6061,
AA6063 and other dissimilar materials like AA7075 and AA6061 etc.
but parametric process optimization of FSW on AA6105 by
Taguchi Method is still required.
21. PROBLEM FORMULATION
Aluminium alloy 6105 is vastly being used in automotive connector stock, seamless
and structural tubing, structural members, ladder structures and hand rail tubing.
Aluminum alloys (AA6105), many difficulties are associated with the fusion welding. It
also suffers from poor welded joint strength, hardness, porosity, voids and cracks.
This loss of mechanical properties is due to low heating temperature and some other
factors.
The process of FSW will be used to reduce the loss of mechanical properties.
An inappropriate rate of heating can result in the formation of FSW defects such as
lack of penetration, lack of fusion, tunnels, voids, surface grooves, excessive flash,
nugget collapse. For these defects, the welding parameters are
responsible, so there is need of optimization of FSW parameters of AA6105.
22. PROBLEM FORMULATION
Though research work applying Taguchi method on various processes have
been reported in literatures .
It appears that the optimization of FSW process parameters of aluminum
alloy 6105 using Taguchi method has not been reported yet.
The noise factors are ignored completely in other techniques, due to which
their impact have not been analyzed, as far as mechanical properties of
AA6105are concerned.
Considering the above facts, the Taguchi method is adopted to analyze the
effect of each processing parameters of AA6105.
23. THESIS OBJECTIVES
The objectives of present research are listed below:-
Prepare Design of Experiment & Select the Orthogonal Array.
To set up Experiment.
To conduct an experiment accordingly.
Apply the Taguchi Method, ANOVA & optimize the parameters.
Analysis of test results for investigating the influence of various process parameters
on tensile strength, and hardness of the joint and joint efficiency.
Reduction of impact of noise factors by applying S/N ratio.
Analysis of microstructure studies to determine internal structure
properties like (Grain size, Defects etc.) and effects on mechanical
properties.
Results and Discussion.
24. PROPOSED METHODOLOGY
Methodology is the proposed procedure that will be followed during research
work The methodology undertaken to carry out the research work has been
developed on the basis of objectives of research.
1. Study the friction stir welding, its applications and its parameters.
2. Study the applications and properties of AA 6105.
3. Selection of CTP like (welding speed, tool rotary speed, axial force, tilt
angle, tool geometry) which
have considerable impact on the mechanical
properties of welded joints.
25. 4. Define the range of CTP parameters.
5. After defining and selection of CTP parameters .
6. Conduction of experimentation.
7. After actual experimentation, mechanical properties testing would be
conducted.
8. Then optimization of CTP would be done by applying Taguchi Method.
9. Microstructure testing would be done to determine internal structure
properties (like Grain size, structure, defects etc.)
10. In the end, conclusions of experimentations will be drawn and
future scope of work will be proposed.
26. SHORT LISTED PROCESS & RESPONSE PARAMETERS
PROCESS PARAMETERS : Rotational Speed, welding speed and Tilt Angle.
RESPONSE VARIABLES :
Tensile Strength
Hardness
Joint Efficiency
Micro structural study will be done by
OM- To find average grain size
SEM-To carry out failure analysis
TEM-To examine dislocation and precipitates
Experiment will be conducted on vertical milling machine at Geeta
Institute of Management & Technology, Kanipla- Kurukshetra.
Testing will be done at Chandigarh Industrial & Tourism Developed
Corporation limited (CITCO) Chandigarh.
28. Size and specification of vertical milling machine
Make Pacmill (semi automatic)
Spindle position Vertical
R.P.M range 90 – 4600
Longitudinal bed range 950 mm
Cross bed range 400 mm
Diameter of tool holder 50 mm
Longitudinal feed range 14 – 900 mm/min
Motor 3 HP, 2300 rpm
30. SIZE AND SPECIFICATION OF UTM
UTE 100
Capacity 100 KN
Resolution 0.01 KN
Make FIE
Calibrated by Blue star
Minimum test speed 0.1mm/min
Maximum test speed 500 mm/min
32. Name Vicker Hardness Tester
Model VM 50
Make F.I.E
Maximum capacity 50 Kgf
Optical Measuring range 0.1 – 1
Scale least count (mm) 0.001
Weight (approximate) 70 kg
Throat depth (mm) 135
Name Vicker Hardness Tester
Model VM 50
Make F.I.E
Maximum capacity 50 Kgf
Optical Measuring range 0.1 – 1
Scale least count (mm) 0.001
Weight (approximate) 70 kg
Throat depth (mm) 135
Size and specification of Vicker hardness testing machine
33. SEM CITCO AT CHANDIGARH
The scanning electron microscope (SEM) uses a focused
beam of high-energy electrons to generate a variety of
signals at the surface of solid specimens. The signals that
derive from electron-sample interactions reveal
information about the sample including
external morphology (texture), chemical
composition, and crystalline structure and
orientation of materials making up the
sample. In most applications, data are collected over a
selected area of the surface of the sample, and a 2-
dimensional image is generated that displays spatial
variations in these properties.
34. OPTICAL MICROSCOPE
OM is performed to verify:
Grain Size, Locational Density and
Inter-granular distance among
material grains.
35. RESOURCE PLANING
Sr. No. Work Time Period
1 Course work July 2014-Jan
2015
2 Synopsis Feb.2015-August
2015
Introduction to welding & FSW Feb 2015
Welding of AA6105& their Applications March 2015
Literature Review April 2015-June
2015
Research Gap & problem formulation July 2015
Write up of Synopsis & Submission August 2015
3 Design of Experiment Sept.2015-
Oct.2015
Selection of Process parameters, Response
parameters, levels
Sep 2015
36. 4
Purchasing of material Nov. 2015-Jan. 2016
5
Experimental set up Feb.2016-May2016
6
Conduct of Experiment June2016- Dec. 2016
7
Microstructure studies Jan 2017-March 2017
8
Mechanical properties testing April2017-July 2017
9
Parameters optimization& microstructure
analysis
August 2017-Oct. 2017
10
Results and Discussion Nov. 2017-Dec. 2017
11
Write-up and submission of work Jan. 2018-May 2018
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