A Presentation on

Effect of Friction Stir Welding on mechanical properties and formability of thin commercial Al blanks

Submitted byManish Singh (2011MEP3270)

Under the guidance of 

Dr. S. Aravindan and Dr. D. Ravi Kumar

Department of Mechanical Engineering Indian Institute of Technology, Delhi

Contents

1. Introduction

2. Experimental setup

3. Experimental procedure

4. Results and discussion

5. Conclusion

6. Gantt chart

7. References

Friction stir welding : FSW is a solid–state, hot–shear joining process in which a rotating tool with a shoulder moves along the butting surfaces of two rigidly clamped plates placed on a backing plate as shown in Fig.

Schematic illustration of the Friction Stir Welding process[1].

Friction Stir Welding Set up:

1. Vertical Milling machine2. Fixture 3. Backing Plate4. Tool 5. Specimen

Fixture:

Backing Plate

Backing plate (200X100X8 mm) used in FSW process.

Tool dimensions Values

Shoulder length (mm) 10

Shank diameter (mm) 19.95

Shank length (mm) 57

FSW Tools

Table 1- Tools Used for Welding

Tool Tool 1 Tool 2 Tool 3

Tool

Figure

Tool pin

Diameter8 mm 12 mm 16 mm

Specimen:

Specimen (170X50X1.7 mm).

Yes

No

Experimental procedure

Welding Run

No.

Rotational

speed (rpm)

Welding speed

(mm/min)

Tool diameter

(mm)

Depth of

plunging (mm)

1 450 80 8 0.2

2 450 160 12 0.2

3 450 250 16 0.2

4 560 160 8 0.2

5 560 250 12 0.2

6 560 80 16 0.2

7 710 250 8 0.2

8 710 80 12 0.2

9 710 160 16 0.2

Process parameterThe welding was carried out by using the selected variations of parameters as shown in Table1 which is obtained by Taguchi’s orthogonal array method for minimizing the number of experiments.

Distance from Centre

Line

Sample no.Welding Run 1 Welding Run 4 Welding Run 7

-7 44.9 44.4 45.6

-6 43.4 44.6 43.6

-5 43.32 42.4 42.6

-4 40.7 41.7 41.5

-3 42.5 40.1 40.6

-2 39.8 40.8 37.6

-1 37.9 39.3 37.5

0 41.8 38.1 36.3

1 38.6 36.9 38.3

2 41.2 36.8 40.0

3 42.4 39.5 41.3

4 42.6 41.5 41.6

5 42.8 41.1 41.9

6 43.8 40.6 42.1

7 44.2 44.6 43.8

Table 4- Vickers Hardness values of all samples with respect to weld region

Microhardness profile of welded samples

Weld Run No.Welding

parametersLDH Test Samples LDH (mm) Remarks

Run No. 1

Rotational

Speed = 450

rpm

Welding

Speed = 80

mm/min

Shoulder

Diameter = 8

mm

11.04

Failure

occurs from

weld centre

line

13.76

Failure

occurs from

TMAZ/HA

Z

Limiting Dome Height Test of FS Welded Samples

Run No. 4

Rotational

Speed = 560

rpm

Welding

Speed = 160

mm/min

Shoulder

Diameter =

8 mm

Welding

parameters

12.72

Failure

occurs from

TMAZ/HAZ

11.32

Failure

occurs from

Weld centre

line

Weld Run No.Welding

parametersLDH Test Samples LDH (mm) Remarks

Run No. 7

Rotational

Speed = 710

rpm

Welding

Speed = 250

mm/min

Shoulder

Diameter = 8

mm

12.04

Failure

occurs in

Weld centre

line

14.28

Failure

occurs from

Weld centre

line

Weld Run No.Welding

parametersLDH Test Samples

LDH

(mm)Remarks

Tensile Sample along the Weld

Tensile Sample Transverse to

the Weld

Hardness Sample Transverse to the Weld

Weld Centre Line

Weld Nugget

Tensile test

Conclusion:

1. Hardness in advancing side is more than the retreating side in HAZ and TMAZ because the grain refinment is more in advancing side than retreating side.

2. From the LDH tests, it is observed that LDH in run 7(710 rpm, 250 mm/min, 8mm) is higher than the LDH in run 1(450 rpm, 160 mm/min, 8mm) and run 4(560 rpm, 160 mm/min, 8mm). As formability strongly depends on mechanical properties of the welded blank, further tests (tensile tests and LDH tests) have to be carried out to draw the conclusions.

3. In LDH tests the failure occurred in the weld region in some samples and in HAZ/TMAZ in other samples.

Work done till now Time

1. To study the literature and see the various aspect of project 25thJuly - 15th February

2. Weld specimen preparation by friction stir welding process. 10th January- 25th January

3. To study the micro-structure of weld specimen 25th January- 5th February

4. Performance of micro hardness test and LDH test. 5th February - 18th February

5. Report writing. 15th February -20th

February

Work to be done 1. Weld specimen for remaining runs is going to be prepared.2. LDH tests and microhardness tests will be performed after that.

Time

Activity

June Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May

Literature

review

Setup

preparation

TWBs

preparation by

FSWSample preparation & Mechanical testing

Forming test

Report

writing

Gantt chart

References

1. R. Nandan ,T. DebRoy ,H.K.D.H. Bhadeshia, Recent advances in friction-stir welding – Process, weldment structure and properties, Progress in Materials Science 53 (2008) 980–1023.

2. J. Jeswiet, M. Geiger, U. Engel, M. Kleiner, M. Schikorra, J. Duflou, R. Neugebauer, P. Bariani, S. Bruschi, Metal forming progress since 2000, CIRP Journal of Manufacturing Science and Technology 1 (2008) 2–17.

3. Amir Abbas Zadpoor, Jos Sinke, Rinze Benedictus, Raph Pieters, Mechanical properties and microstructure of friction stir welded tailor-made blanks, Materials Science and Engineering A 494 (2008) 281290.

4. Sushanta Kumar Panda, D. Ravi Kumar, Improvement in formability of tailor welded blanks by application of counter pressure in biaxial stretch forming, journal of materials processing technology 2 0 4 ( 2 0 0 8 ) 70–79.

5. R Ganesh Narayanan1 and K Narasimhan, Predicting the forming limit strains of tailor-welded blanks, The manuscript was received on 17 April 2008 and was accepted after revision for publication on 20 June 2008.

6. M.Sivashanmugam, S.Ravikumar, T.Kumar, V.Seshagiri Rao, D.MuruganandamA Review on Friction Stir Welding for Aluminium Alloys, 978-1-4244-9082-0/10/$26.00 ©2010 IEEE

7. D.M. Rodrigues, A. Loureiro, C. Leitao, R.M. Leal, B.M. Chaparro, P. Vilaça, Influence of friction stir welding parameters on the microstructural and mechanical properties of AA 6016-T4 thin welds, Materials and Design 30 (2009) 1913–1921.

8. Wonoh Lee, Kyung-Hwan Chung, Daeyong Ki, Junehyung Kim, Chongmin Kim, Kazutaka Okamoto, R.H. Wagoner, Kwansoo Chung, Experimental and numerical study on formability of friction stir welded TWB sheets based on hemispherical dome stretch tests, International Journal of Plasticity 25 (2009) 1626–1654.

9. Daeyong Kim, WonohLee, JunehyungKim, ChongminKim, KwansooChung, Formability evaluation of friction stir welded 6111-T4 sheet with respect to joining material direction, International Journal of Mechanical Sciences 52 (2010) 612–625.

10. Kwansoo Chung, Wonoh Lee, Daeyong Kim, Junehyung Kim, Kyung-Hwan Chung, Chongmin Kim, Kazutaka Okamoto, R.H. Wagoner, Macro-performance evaluation of friction stir welded automotive tailor-welded blank sheets: Part I – Material properties, International Journal of Solids and Structures 47 (2010) 1048–1062.