Optimization of FSW Process Parameters for AlSiCp PRMMC Using ANOVA

Optimization of FSW Process Parameters for AlSiCp PRMMC Using ANOVA

Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 2 (2015) 2504 – 2511 4th International Conference on Materials ...

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Available online at www.sciencedirect.com

ScienceDirect Materials Today: Proceedings 2 (2015) 2504 – 2511

4th International Conference on Materials Processing and Characterization

Optimization of FSW process parameters for AlSiCp PRMMC using ANOVA Chinmay Shaha,Bhupesh Goyalb,Vijay Patela,b,* a b

Parul Institute of Technology,Vadodara-391760,India Parul Institute of Technology,Vadodara-391760,India

Abstract In recent years, composite materials have gained more and more attention in aerospace, automotive and structural applications. In many engineering applications, high strength-weight ratio of materials are important while designing the components. Now a days, to fulfil the above requirements conventional materials are replaced by composite materials. In present work, stir casting method is used for uniform distribution of the reinforcement material (SiC) in Aluminium as a matrix material. Friction stir welding (FSW) is a relatively new solid-state joining process. In particular, it can be used to join high-strength aerospace aluminium alloys that are hard to weld by conventional fusion welding. For analysis, L9 orthogonal array is used with four different variables (Wt % of Sic, welding speed, tool rotation speed and tool geometry) for the analysis of UTS. ANOVA is performed for the optimization of the process parameters. ©2015 2014Elsevier The Authors. Ltd. All rights reserved. © Ltd. AllElsevier rights reserved. Selectionand andpeer-review peer-review under responsibility the conference committee the 4th International conference Selection under responsibility of theof conference committee membersmembers of the 4thof International conference on Materials on Materials and Processing and Characterization. Processing Characterization. Keywords: Metal Matrix Composite,FSW,ANOVA,Taguchi,Stir Casting;

1. Introduction The term ‘‘composite’’ originally arose in engineering when two or more materials were combined in order to rectify some shortcoming of a particularly useful component. Recently, the composite materials are brought into

* Corresponding author. Tel.: +91-9033361466; E-mail address: vijaypatel.2612gmail.com

2214-7853 © 2015 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the conference committee members of the 4th International conference on Materials Processing and Characterization. doi:10.1016/j.matpr.2015.07.195

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greater use in the industries of aircraft, automobiles and especially solar vehicles, because of their light density and high specific strength. In these applications the fracture strength and fatigue loads are usually unavoidable. For this reason resent designs do not specify static strength alone as a primary design criterion but also include fatigue analysis. The demand for improved performance of structural materials in transportation industries, particularly in aircraft, makes strength analysis is an important consideration. In a stir casting process, the reinforcing phases (usually in powder form) are distributed into molten Aluminum by mechanical stirring. Stir casting of metal matrix composites was initiated in 1968, when S. Ray introduced alumina particles into aluminum melt by stirring molten aluminum alloys containing the ceramic powders. In general, Stir casting is a primary process of composite production whereby the reinforcement ingredient material incorporated into the molten metal by stirring. This involves stirring the melt with ceramic particles and then allowing the mixture to solidify. This can usually be prepared by fairly conventional processing equipment and carried out on a continuous and semi continuous basis by the use of stirring mechanism. Friction-stir welding (FSW) is a solid-state joining process (the metal is not melted) that uses a third body tool to join two faying surfaces. Heat is generated between the tool and material which leads to a very soft region near the FSW tool. Nomenclature FSW ANOVA PRMMC AlSiCp

Friction Stir Welding Analysis Of Variance Particulate Reinforced Metal Matrix Composite Aluminium Silicon carbide particulate

2. Experimental details Two materials are used in MMC, one is matrix material and other is reinforced material. Al6061 was used as a matrix material and SiCp as reinforcement material. 2.1. Stirrer manufacturing Stirrer is designed according to dimensions of crucible and height of furnace. Material selection for stirrer is very important due to work at high temperature. So, SS 304 is selected for stirrer. 2.2. Design of experiments Four input variables and three levels, according to the full factorial design 34 = 81 no of experiments require to perform. To reduce the no of experiment Taguchi method is used. Taguchi L9 array is used for design of experiments. Taguchi array is developed by MINITAB 16 software. Table 1. Coded values of input variables with levels

coded values

Units

Lower level

Middle

Input parameters

Notation

C1

Wt % of SiC

W

mg

10

15

20

C2

Tool Geometry

T

NA

Cylindrical

Tapered

Threaded Tapered

C3

Welding Speed

V

mm/min

3

6

14

C4

Tool Rotation Speed

N

RPM

1110

1320

1750

level

Upper level

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2.3. Stir casting process A stir casting setup as shown in figure, consisting of coal fired furnace and a stirrer assembly was used to synthesize the composite. Aluminum in solid form was melted at liquids temperature in coal fired furnace. Preheating of reinforcement Sic at 8000 C was done to remove moisture from the surface of the particulates. The stirrer was then introduced up to 1/3 height of crucible.

Fig. 1. (a) Stirring of mixture (b) Prepared of casting plate

2.4 Tool Design The design of the tool is a critical factor as a good tool can improve both the quality of the weld and the maximum possible welding speed. It is desirable that the tool material is sufficiently strong, tough and hard wearing, at the welding temperature. Further, it should have good oxidation. Tool steels have been widely used for welding aluminium alloys within thickness ranges of 0.5 - 50 mm, but more advanced tool materials like Carbides, Polycrystalline Cubic Boron Nitride (PCBN) and tungsten rhenium (W-Re) alloys are necessary for more demanding applications such as highly abrasive metal matrix composites or higher melting point materials like steel or titanium. Considering above characteristics, we decided to use H13-Hot Die Tool Steel.

Fig.2 (a) Cylindrical (b) Tapered Cylindrical (c) Tapered Cylindrical with Threaded tool

Chinmay Shah et al. / Materials Today: Proceedings 2 (2015) 2504 – 2511

2.5 Friction Stir Welding 1. Initial setup is to mount work piece on a vertical milling machine. The work piece was held in position by fixture as shown below. 2. Initial setup of tool on a vertical milling machine having various RPM and feeds. The tool was held by spring collet.

Fig.3 (a) Initial setup of work piece (b) Tool gripped by spring collet

3. 4. 5.

Initial phase of friction stir welding which is penetration of the tool in the work piece to be weld. Intermediate phase of FSW which is giving feed to the work piece/tool in longitudinal direction. Final phase of FSW which is lifting up the tool from work piece at the end of welding.

Fig.4 (a) Intermediate Phase of FSW process (b) Final phase of FSW process

Fig.5 Condition of the tools after performing FSW

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2.6 Tensile Testing

Fig. 6 Tensile specimens after test

3.1 Tensile Test Result Table 2. Tensile Test Result Variables DOE

Response

C1

C2

C3

C4

Wt% SiC

Rotation Speed (RPM)

Welding Speed (mm/min)

Tool Geometry

1

10

1110

3

1

35.5

2

10

1320

6

2

59.7

3

10

1750

14

3

74.0

4

15

1110

6

3

98.1

5

15

1320

14

1

59.0

6

15

1750

3

2

58.1

7

20

1110

14

2

88.6

8

20

1320

3

3

75.6

9

20

1750

6

1

93.3

Here, For Tool Geometry, 1 = Cylindrical Tool, 2 = Taper Tool, 3 = Threaded Tool.

UTS

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3.2 Taguchi Analysis Main Effects Plot for SN ratios Data Means

Wt% SiC

39

Rotation Speed (RPM)

38

Mean of SN ratios

37 36 35 1

2

3

1

Welding Speed (mm/min)

39

2

3

Tool Geometry

38 37 36 35 1

2

3

1

2

3

Signal-to-noise: Larger is better

Fig. 7 Main effects plot of S/N ratio for UTS

Main Effects Plot for Means Data Means

Wt% SiC

90

Rotation Speed (RPM)

80

Mean of Means

70 60 1

2

3

1

Welding Speed (mm/min)

90

2

3

Tool Geometry

80 70 60 1

2

3

1

2

3

Fig. 8 Main Effect plot of Means of Means for UTS

From the plot of S/N Ratio and from the plot of Mean of Means, it is observed that Tensile Strength value increases with increase in SiC percentage from 10% to 20%. It is observed that Tensile Strength value decreases with increase in RPM till 1320 RPM and then increases till 1750 RPM. It can be noted that Tensile Strength value increases with increase in Transverse Speed till 6 mm/min and then decreases till 14 mm/min. For the tool geometry, it is observed that threaded tool is better for getting maximum tensile strength compare to cylindrical and taper tool. 3.2 ANalysis Of VAriance (ANOVA) ANOVA (ANalysis Of VAriance) method is used for confirm the result obtained from Taguchi method and also to get Significance contribution of process parameters in Response factor.

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Chinmay Shah et al. / Materials Today: Proceedings 2 (2015) 2504 – 2511 Table 3. ANOVA Table Source

DF

Wt% of SiC Rotational Speed Transverse Speed Tool Geometry

Seq SS

Adj SS

Adj MS

F-Value

2

1300.24

1300.24

650.12

22.71

2

195.10

195.10

97.55

3.41

2

1147.07

1147.07

573.53

20.03

1

598.00

598.00

598.00

20.89

28.63

28.63

Error

1

28.63

Total

8

3269.04

P-Value

Contribution

0.147

39.77%

0.358

5.97%

0.156

35.09%

0.137

18.29% 0.88% 100%

Table 4. Model Summary of ANOVA Table S

R-sq

R-sq(adj)

5.35044

99.12%

92.99%

ANOVA is performed at 95% confidence level. From above analysis table we can observe that Wt% of SiC has highest contribution 39.77% on UTS followed by Transverse Speed (35.09%) and Tool Geometry (18.29%). Rotational Speed has very less contribution only 5.97%. 3. Conclusion Within the frame of current research work the following conclusions can be derived. a) Experimental result shows that Wt% of SiC, Transverse Speed, Tool Geometry and Rotational Speed influence the tensile strength of Friction Stir Welding. b) UTS of Friction Stir Weld is highly influenced by Wt% of SiC. As the Wt% of SiC increases, UTS increases. c) From Taguchi analysis conclusions can be drawn out that Rotational Speed have not more effects on tensile compared to Wt% of SiC, Transverse Speed and Tool Geometry. d) Friction Stir Welding done by using Threaded tool have more UTS than compare to Cylindrical & Taper tool. e) From the ANOVA, it is concluded that the Variation in Wt% of SiC having Highest significant influence on UTS of FSW followed by Transverse Speed and then Tool Geometry. References [1] H. K. Mohanty, D.Venkateswarlu, Pradeep Kumar, Modeling the Effects of Tool Probe Geometries and Process Parameters on Friction Stirred Aluminum Welds, Journal of Mechanical Engineering and Automation 2012. [2] A. S. Vagh, S. N. Pandya, Influence Of Process Parameters On The Mechanical Properties Of Friction Stir Welded Aa 2014-T6 Alloy Using Taguchi Orthogonal Array, International Journal of Engineering Sciences & Emerging Technologies, April 2012. [3] Gopi, Manonmani, K1 Australian Journal of Mechanical Engineering. 2012, Vol. 10 Issue 2, p129-140. 12p. [4] Neelima Devi. C, Mahesh.V , Selvaraj. N ," Mechanical characterization of Aluminium silicon carbide composite", International journal of applied engineering research, dindigul, Volume 1, No 4, 2011. [5] Yufeng Wu, Gap Yong Kim, Carbon nanotube reinforced aluminum composite fabricated by semi-solid powder processing ,Journal of Materials Processing Technology, Volume 211, Issue 8, August 2011, Pages 1341–1347. [6] G. B. Veeresh Kumar1, C. S. P. Rao, N. Selvaraj, M. S. Bhagyashekar," Studies on Al6061-SiC and Al7075Al2O3 Metal Matrix Composites, Journal of Minerals & Materials Characterization & Engineering", Vol. 9, No.1, pp.43-55, 2010. [7] Ahmed Khalid Hussain, Evaluation Of Parameters Of Friction Stir Welding For Aluminium Aa6351 Alloy, International Journal ofEngineering Science and Technology, Vol. 2(10), 2010.

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[8] P.K.Mallik, "Composite materials handbook". [9] FSW- Technical hand book. [10] Hand Book Of Composites, Second Edition. Edited by S.T.Paters Process Research, Maountain View, California, USA. [11] Design of Experiment by Douglas Montgomery.