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www.rsisinternational.org Page 27

Experimental Investigation of Aluminium Alloys through Friction Stir Welding

R.Ram Kumar

1

, J. Sebastin Joyal

2

, K.Ganesh

3

, I. Justin Antony Raj

4

1, 2, 3, 4 Assistant Professor, Department of Mechanical Engineering, Vandayar Engineering College, Thanjavur,

Tamil Nadu, India

Abstract: Gas metal arc welding (GMAW) was a welding process in which an electric arc formed between a consumable wire electrode and the work piece metals which heated the work piece metals and caused them melted and also joined along with the wire electrode. A shielding gas feeded through the welding gun which shielded the process from contaminants in the air. Most common welding problems in gmaw were weld porosity, improper weld bead profile, lack of fusion, faulty wire delivery related to equipment set-up and maintenance. Friction stir welding (FSW) was a welding process where two metals were joined with the help of heat generated by rubbing the metals against each other. The friction stir welding was mostly used for joining aluminium alloys. The main defects occurred in this welding were holes, material flow rate. These defects were mainly caused due to improper selection of machining parameters. In this work steps are taken reduces the defects by selecting suitable machining parameters, comparing the welding techniques and selecting the suitable weld process for the preferred aluminium alloy. The base metal considered for this work AA2014, AA5083, AA6082.weld joints were similar joints.

The experimental results were evaluated by DT (destructive test) and NDT (Non-destructive test).

Index Terms---Gas metal arc welding, Friction stir welding, aluminium alloys, welding techniques, Destructive test, Non destructive test.

I. INTRODUCTION 1.1. FSW TOOL

Fig 1. Friction stir welding tool

Improvements in tool design had been shown caused substantial improvements in productivity and quality. TWI had developed tools specifically designed increased the depth of penetration and so increased the plate thickness that could be successfully welded. Work was continuing best understood the effects of tool materials composition, structure, properties and geometry on their performance, durability and cost.

II. EXPERIMENTAL DETAILS 2.1. Materials Utilized

The Base metal under investigation was aluminium alloy of various grades namely 2014, 5083, 6082 under the form of plate of 6mm thickness with chemical composition as shown in table below.

Table.1.Chemical composition

Grades/Elements AA2014 AA5083 AA6082

Mg 0.8% 4.2% 1.2%

Mn 1.2% 0.60% 1.0%

Si 0.90% 0.25% 1.3%

Fe 0.50% 0.15% 0.50%

Zn 0.25% 0.09% 0.20%

Cr 0.08% 0.09% 0.25%

Cu 5.0% 0.06% 0.10%

Ti 0.15% 0.02% 0.10%

Al Bal (wt%) Bal (wt%) Bal (wt%).

Table 2. FSW tool dimensions.

Tool dimensions Values(mm)

Pin diameter, d 6

Shoulder diameter, D 18

Pin length, L 5

Friction stir welding tool used in the present investigation

Fig 2.High-chromium high-carbon tool

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Table. 3 .Summary of FSW parameters used for AA2014, AA5083, AA6082

NO. w (rpm) v (mm/min) F(kN)

F-1 1120 50 7 F-2 1120 50 7 F-3 1120 50 7

Friction stir welding machine used in this investigation shown below

Fig 3. FSW welding machine (side view)

Fig 4. FSW welding machine (Front view)

Table. 4 .Summary of MIG parameters used for AA2014, AA5083, AA6082

NO. Amperage(A) Voltage(V) wire feed(m/min)

M-1 18 8 110 M-2 18 8 110

M-3 18 8 110

Al 5356 filler metal under protection of argon was used to fabricate MIG welded joint .chemical composition of filler was shown below.

Table.5. Chemical composition of filler material

Elements percentage

Mg 5.6%

Mn 0.30%

Si 0.25%

Fe 0.40%

Zn 0.10%

Cu 0.05%

Ti 0.15%

Metal inert gas welding machine used in this investigation

Fig 5. MIG welding machine

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Fig 6. Materials before welding

Base materials were taken for experiments with 100X25X6mm size and welded through by FSW and GMAW processes.

Fig .7.Friction stir welded materials

Fig 8.Metal inert gas welded materials

2.2. Project methodology

Source selection

III. RESULTS AND DISCUSSION 3.1. Tensile Test

As the material was being pulled, you would find its strength along with how much it would elongate.Tensile tests were performed to determine the mechanical properties of the welded material. In FSW process with same rotational speed and welding speed different aluminium materials were welded

START

Machines Raw materials

Aluminium alloys

gmaw & fsw machines

NO

FEASIBLE YES

Welding of specimens

NON Destructive

testing Destructive testing

Data testing

Comparison of GMAW & FSW

Results and discussion Documentation

Stop

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and there tensile values were taken to investigate the welding

parameters for the suitable aluminium alloys.

TENSILE TEST SPECIMEN:

Fig 9.Tensile test specimen

Table.6. Friction weld of AA2014, AA5083, AA6082

AA w (rpm) v (mm/min) TS(Mpa) 2014

1120 50 350

1120 50 351

5083 1120 50 NA

1120 50 NA

6082 1120 50 230

1120 50 229

In FSW process at the selected welding and rotational speed AA5083 was not weldable, tunnel crack occurred in the weld region .AA2014 and 6082 was suitable for welding in the given parameters. Table 6 showed the tensile strength values of the welded specimens.

Fig 10.Tunnel crack in friction stir welding (AA5083)

Table 7. Metal inert gas welded of AA2014, AA5083, AA6082

AA amperage (A) wirefeed

(m/min) TS(Mpa)

2014 110 8 NA

110 8 NA

5083 110 8 301

110 8 300

6082 110 8 192

110 8 193

In metal inert gas welding process at the selected current and wire feed rate AA 2014 was unable to weld due to the formation of aluminium-copper intermetallics in weld metal rendered them brittle .They were tended to crack when welding was done. AA5083 and AA6082 were welded with care under the protection of argon with filler wire AL 5356.

Table 7 showed the tensile strength values of the welded specimens.

3.2. HARDNESS TEST:

The form of a right pyramid with a square base between opposite faces subjected to a load of 1 to 100 kgf.

Fig 11.Vickers hardness test method

Table 8. Friction weld of AA2014, AA5083, AA6082

AA w (rpm) v (mm/min) Hardness value (VHN)

2014 1120 50 109

1120 50 110

5083 1120 50 NA

1120 50 NA

6082 1120 50 71

1120 50 70

Table 8 showed the hardness value of the aluminium alloys AA2014 and AA6082 by friction stir welding.

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Table 9. Metal inert gas weld of AA2014, AA5083, AA6082

AA amperage (A) wirefeed (m/min)

Hardness value (VHN)

2014 110 8 NA

110 8 NA

5083 110 8 61

110 8 60

6082 110 8 59

110 8 58

Table 9 showed the hardness value of the aluminium alloys AA5083 and AA6082 by metal inert gas welding.

ADVANTAGES:

1. One scale covered the entire hardness range.

2. A wide range of test forces suited every application.

3. Non destructive, sample could normally be used.

3.3. Radiography Test:

Employs x rays or gamma rays penetrated an object and detected discontinuities by recording the difference on a recording device .It was used to detect internal flaws.

Radiation Safety was a major concern. X ray machines or Ir 192 or Co 60 main sources of radiation and used Penetrameters for ensured the quality of the radiography procedure. Penetrameters were hole type and wire type.

Sufficient radiographic density was required for the radiograph for proper evaluation.

RADIOGRAPHIC TESTING METHOD FOR INSPECTION

Fig: 12.Single wall single image Technique

Table 10 .Friction stir weld

AA ω

(rpm) v (mm/min) Radiographic results

2014 1120 50 Acceptable weld

1120 50 Acceptable weld

5083 1120 50 Tunnel defect

1120 50 Tunnel defect

6082 1120 50 Acceptable weld

1120 50 Acceptable weld

In friction stir welding AA 5083 was welded and tunnel defect was formed. AA2014 and AA6082 was welded and the radiographic test was taken and the report was good without any internal flaws and with proper surface finishing.

Table. 11 .Metal inert gas weld

AA amperage (A) wirefeed

(m/min) Radiographic results

2014 110 8 Unable to weld

110 8 Unable to weld

5083 110 8 Acceptable weld

110 8 Acceptable weld

6082 110 8 Acceptable weld

110 8 Acceptable weld

In metal inert gas welding AA2014 was not able to weld.

AA5083 and AA6082 was welded and radiographic test was taken. The weld was proper with good reinforcement.

IV. CONCULSION

 From the investigation made on aluminium alloys AA2014, AA5083, AA6082. It was concluded that AA5083 had tunnel defect with higher welding speed.

 AA 2014 was unable to weld because the formation of aluminium-copper intermetallics in weld metal.

Non-fusion techniques such as friction welding and friction stir welding might given some success.

 AA 2014 had high tensile strength and hardness value in friction stir welding and there was no internal defect in the weld zone.

 Fusion welding method (MIG) and solid state welding method (FSW) had been used for welding aluminium alloy 6082.

 Friction stir welded samples had shown higher strengths in comparison to the MIG samples.

REFERENCE

[1]. P.Janaki Ramulu ,R. Ganesh Narayanan ,Satish V. Kailas , Jayachandra Reddy,’Internal defects and process parameter analysis during friction stir welding of AA6061’. Adv Manuf Technology,2012.

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[2]. V. Fahimpour , SK.Sadrnezhad , F. Karimzadeh,’Corrosion behavior of aluminum 6061 alloy joined by friction stir welding and gas tungsten arc welding methods’. Materials and Design.

2012.

[3]. P. Kah , J. Martikainen, ‘Influence of shielding gases in the welding of metals’.Int . Advance Manufacturing Technology . 2012.

[4]. AR yazdipour, shafiei hjamshidi aval,’Microstructures and properties of metal inert gas welding and friction stir welding in AA5083’.Indian acadamy of sciences. 2011.

[5]. H.T. Zhang , J.Q. Song,’ Microstructural evolution of aluminum/magnesium lap joints welded using MIG process with zinc foil as an interlayer’, Materials. 2011.

[6]. Y. Ruan , W.B. Gong , D.Q. Sun , Y.P. Li , ‘Mechanical properties and microstructures ofAA6082 joints welded by twin wire metal inert gas welding with sio2 flux’. Materials and Design. 2011.

[7]. G.Madhusudhan Reddy, P. Mastanaiah, K. Sata Prasad , T.

Mohandas ,‘Microstructure,mechanical property in AA6061 aluminium alloy using friction stir welding. 2009,

[8]. Rakeshkumaar,ulrichdilthey, D.K.dwivedi,S.P.sharma,P.K.ghosh,’

Welding of thin sheet of Al alloy (6082) by using gas metal arc welding’, materials processing technology. 2009.

[9]. T. Sakthivel ,G. S. Sengar , J. Mukhopadhyay,’ Effect of welding speed on microstructure and mechanical properties of friction-stir- welded aluminum’, Int J Adv Manuf Technol . 2009.

[10]. P. M. G. P. Moreira, V. Richter-Trummer , P. M. S. T. de Castro,’

Fatigue Behaviour of FS, LB and MIG Welds of AA6061-T6 and AA6082-T6’, Journal of Materials Processing Technology,2009.

References

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