D.H. Lammlein PhD Dissertation - Vanderbilt University

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Figure 29: Dynamic pressure trend lines for spindle speed N and depth y at weld speed a) v=30mm/min b)90 mm/min. Figure from [67]. Defects can be identified in the trend lines above by spikes, which correspond to perturbations. In chart a) defects occur in experimental welds of N=900 and N=1400 at a depth of y=3.5. In chart a) defects occur in experimental welds of N=900 at y=3.5 and N=1400 from y=3.5 to the surface. By correlating defects in experimental welds with dynamic pressure trend lines from Fluent CFD models the authors are able to accurately predict the parameters at which a tunnel-defect occurs for a given tooling and material along with the depth at which the defect occurs. References: [1] Thomas W.M., et al. 1991, Friction Stir Butt Welding. International Patent Application # PCT/GB92/02203, GB Patent Application #9125978.8, and GB Patent # 2,306,366. [2] Shercliff HR, Colegorve PA; "Modelling of friction stir welding", In Mathematical Modelling of Weld Phenomena, 6th Edition. H. Cerjak and H. Bhadeshia, Maney Publishing, London, UK, pp. 927-974. [3] Shercliff HR, Colegrove PA; Chapter 10: Process Modeling. In Friction Stir Welding and Processing, Rajiv SM, Mahoney MW (Editors), ASM International, 2007. [4] Threadgill PL; Terminology in friction stir welding; Sci. Technol. Weld. Join., 2007, 12, (4), 357-360. 42
[5] Taylor RE, Groot H, Goerz T, Ferrier J, Taylor DL: Measurement of the electric resistivity of metals up to and above the melting temperature; High Temp-High Pressures, 30 (1998) 269-275. [6] Sellars CM, Tegart WJM; Hot workability; Int. Metall. Rev., 1972, 17, 1-24 [7] R. Nandan, G. G. Roy, and T. Debroy, "Numerical Simulation of Three-Dimensional Heat Transfer and Plastic Flow During Friction Stir Welding," Metallurgical and Materials Transactions, vol. 37A, pp. 1247-1259, April 2006. [8] Simar A, Pardoen T, de Meester B; Influence of friction stir welding parameters on the power input and temperature distribution on friction stir welding; Proc. of the 5th International Symposium on Friction Stir Welding, 2004. [9] Simar A, Pardoen T, de Meester B; Effect of rotational material flow on temperature distribution in friction stir welds; Science and Technology of Welding and Joining, Vol.12, No.4, p324, 2007. [10] Santiago DH, Lombera G, Santiago U; Numerical modeling of welded joints by the friction stir welding process; Materials Research, Vol.7, Num.4, p569, 2004. [11] Pew JW, Nelson TW, Sorensen CD; Torque based weld power model for friction stir welding; Science and Technology of Welding and Joining,Vol.12, Num.4, p341, 2007. [12] Russell MJ, Shercliff HR; Analytical modeling of microstructure development in friction stir welding; Proc. of the 1st International Symposium on Friction Stir Welding, Session 08, 1999. [13] Milding OT, Grong O; A process model for friction welding of Al-Mg-Si alloys and Al-SiC metal matrix composites; Acta Metall. Mater, 42 (5), 1994, p1595. [14] Frigaard O, Grong O, Bjorneklett B, Midling OT; Modelling of thermal and microstructure fields during friction stir welding of aluminium alloys; Proc. of the 1st International Symposium on Friction Stir Welding, Session 08, 1999. [15] Gould JE, Feng Z; Heat flow model for friction stir welding of aluminum alloys; Journal of Materials Processing and Manufacturing Science, 7, p185, 1998. [16] Song M, Kovacevic R, Ouyang J, Valant M; A detailed three-dimensional transient heat transfer model for friction stir welding; 6 th International Trends in Welding Research Conference Proc., p212, 2002. [17] Colegrove P, Painter M, Graham D, Miller T; 3 Dimensional flow and thermal modelling of the friction stir welding process; Proc. of the 2nd International Symposium on Friction Stir Welding, 2001. [18] Chen H-B, Yan K, Lin T, Chen S-B, Jiang C-Y, Zhao Y; The investigation of a typical welding defects for 5456 aluminum alloy friction stir welds; Materials Science and Engineering A, 433, p64, 2006. [19] Linder K, Khandahar Z, Khan J, Tang W, Reynolds AP; Rationalization of hardness distribution in alloy 7050 friction stir welds based on weld energy, weld power, and time/temperature history; Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [20] Midling OT, Rorvik G; Effect of tool shoulder material on heat input during friction stir welding; Proc. of the 1st International Symposium on Friction Stir Welding, 1999. [21] Heurtier P, Jones MJ, Desrayaud C, Driver JH, Montheillet F, Allehaux D; Mechanical and thermal modeling of friction stir welding; Journal of Materials Proccessing Technology, 171, p348, 2006. 43
Page 1 and 2:
FRICTION STIR WELDING OF SPHERES, C
Page 3 and 4:
TABLE OF CONTENTS TABLE OF FIGURES
Page 5 and 6:
Appendix ..........................
Page 7 and 8:
Figure 16: Left(FE streamline), Mid
Page 9 and 10:
Figure 51: A thermal camera image t
Page 11 and 12:
for a similar conventional weld (3/
Page 13 and 14:
Figure 102: Tapered retraction proc
Page 15 and 16: setting are indicated. Note that st
Page 17 and 18: Unsupported welds of this kind with
Page 19 and 20: Figure 157: A thermal camera image
Page 21 and 22: ottom sample is a tungsten inert ga
Page 23 and 24: N - newton (force unit) n - visco-p
Page 25 and 26: INTRODUCTION Friction Stir Welding,
Page 27 and 28: educed conduction lengths. In small
Page 29 and 30: CHAPTER I LITERATURE REVIEW: COMPUT
Page 31 and 32: frictional condition at the interfa
Page 33 and 34: contact. The contact area can inclu
Page 35 and 36: For horizontal sections, a heat inp
Page 37 and 38: (1.11) where r p is the probe (pin)
Page 39 and 40: This efficiency term, η pd , is kn
Page 41 and 42: The heat input on the tool surface
Page 43 and 44: The added complication of these met
Page 45 and 46: Figure 5: Lateral cross sections of
Page 47 and 48: Flow stress in aluminum alloys is d
Page 49 and 50: Figure 8: Three flow fields a) rota
Page 51 and 52: and post-weld cool-down. This model
Page 53 and 54: Williams et al. [60] use a 2D-axisy
Page 55 and 56: Figure 16: Left(FE streamline), Mid
Page 57 and 58: Figure 18: Temperature contour over
Page 59 and 60: Figure 22: Temperature distribution
Page 61 and 62: Figure 24: Lateral velocity contour
Page 63 and 64: Figure 26: Experimental(white) vers
Page 65: Figure 28: Top view schematic of tu
Page 69 and 70: [41] Heinz B., Skrotzki B., Eggler
Page 71 and 72: CHAPTER II COMPUTATIONAL ANALYSIS O
Page 73 and 74: Figure 30: Blind t-joint setup with
Page 75 and 76: Figure 33: Process forces and later
Page 77 and 78: Figure 35: Experimental Welds, Axia
Page 79 and 80: Figure 37: FEA boundary conditions
Page 81 and 82: A 4500 N axial force is applied eve
Page 83 and 84: axial force with lateral offset dur
Page 85 and 86: Figure 42: Contour plot of von Mise
Page 87 and 88: Figure 44: Deformation contour for
Page 89 and 90: Figure 46: Quarter-plate model for
Page 91 and 92: Figure 49: Contour plot of deflecti
Page 93 and 94: where P is the weld power (W), Q is
Page 95 and 96: Figure 52: Fluent CFD model zones.
Page 97 and 98: Figure 55: Thermal contour of weld
Page 99 and 100: Figure 59: Thermal contour of weld
Page 101 and 102: Figure 61: Velocity vectors for 0.0
Page 103 and 104: Figure 65: Contour of velocity magn
Page 105 and 106: CHAPTER III THE APPLICATION OF SHOU
Page 107 and 108: Figure 66: A shoulder-less, conical
Page 109 and 110: Figure 68: Typical axial(Z-axis) fo
Page 111 and 112: Figure 71: 90° conical tool macros
Page 113 and 114: Figure 75: Run 3, 80° conical tool
Page 115 and 116: Figure 79: (90º tool) Ultimate ten
Page 117 and 118:
Figure 83: (90º tool) Lateral forc
Page 119 and 120:
Figure 87: (80º tool) Lateral forc
Page 121 and 122:
The Eulerian, finite volume, CFD so
Page 123 and 124:
Figure 92 shows the increasing elem
Page 125 and 126:
Figure 91: CFD model geometry consi
Page 127 and 128:
Figure 95: Lateral cross-section of
Page 129 and 130:
Figure 96: Attempts a probe tapered
Page 131 and 132:
CHAPTER IV THE FRICTION STIR WELDIN
Page 133 and 134:
applications for its high strength
Page 135 and 136:
Figure 97: Experimental weld sample
Page 137 and 138:
Figure 99: Split protrusion type de
Page 139 and 140:
with a cupped recess. It is however
Page 141 and 142:
of tapered retraction (i.e. move th
Page 143 and 144:
The adjustments in vertical positio
Page 145 and 146:
manners the assigned depth was main
Page 147 and 148:
Figure 108: Lateral macrosections f
Page 149 and 150:
Figure 110: (Supported, cupped tool
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
apparent strength of 26% parent whi
Page 157 and 158:
with a 100º conical tool (0.025”
Page 159 and 160:
Figure 119: Macrosection view of an
Page 161 and 162:
and tooling. Torque is highly depen
Page 163 and 164:
locally in proportion to the local
Page 165 and 166:
Figure 126: (threaded tool) Contour
Page 167 and 168:
Figure 128: (conical tool) Geometry
Page 169 and 170:
Figure 131: (threaded tool) Lateral
Page 171 and 172:
The results presented here show tha
Page 173 and 174:
Figure 136:(from left: Tapered retr
Page 175 and 176:
[8] Metallurgical analysis of ablat
Page 177 and 178:
CHAPTER V FRICTION STIR WELDING OF
Page 179 and 180:
Collaboration between Advanced Meta
Page 181 and 182:
eccentricity, the method of interio
Page 183 and 184:
gas tungsten arc welding of small d
Page 185 and 186:
Full penetration welds of 4.2” (1
Page 187 and 188:
Figure 143: The curvature of the pi
Page 189 and 190:
Figure 144: Experimental axial forc
Page 191 and 192:
Together, a fine wall thickness tol
Page 193 and 194:
Figure 147: Axial force history for
Page 195 and 196:
The weld macrosections show complet
Page 197 and 198:
Figure 154: Macrosections of welds
Page 199 and 200:
Figure 157: A thermal camera image
Page 201 and 202:
Figure 159: Average tool shank temp
Page 203 and 204:
471,146 faces. The meshes are fine
Page 205 and 206:
Figure 162: A closeup view of mesh
Page 207 and 208:
4 2 3 4 5 16 " 1.745 2 0.24
Page 209 and 210:
applied heat locally in proportion
Page 211 and 212:
Figure 164: Modeled temperature con
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Figure 172: Model pathlines for the
Page 219 and 220:
Figure 174: Model pathlines for the
Page 221 and 222:
later speed setting, the tool welds
Page 223 and 224:
Figure 178: Zoom view of a macro ta
Page 225 and 226:
Figure 180: The superficial appeara
Page 227 and 228:
Figure 182: The rotary welding appa
Page 229 and 230:
Figure 185: A diagram illustrating
Page 231 and 232:
CONCLUSION AND FUTURE WORK Conclusi
Page 233 and 234:
new FSW process environment is reso
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D.H. Lammlein PhD Dissertation - Vanderbilt University

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