Welding Metallurgy. Sindo Kou

Microsegregation across boundary between cells or dendrite arms ...Figure 7.18 Coarsening of secondary dendrite arms revealed by quenching duri...Figure 7.19 Columnar dendrites growing along the weld centerline of IN 718, ...Figure 7.20 Secondary dendrite arm spacing vs. local solidification time of ...Figure 7.21 Effect of cooling rate or solidification time on dendrite arm sp...Figure 7.22 Effect of temperature gradient G and growth rate R on the morpho...Figure 7.23 Solutal undercooling ΔT _C and curvature undercooling ΔT _R at tip o...Figure 7.24 Smaller tip radius (r_t) and greater curvature undercooling (ΔT _R)...Figure 7.25 Compositions of ternary alloys shown by: (a) Gibbs triangle; (b)...Figure 7.26 Solidification paths: (a) binary A‐B phase diagram showing ce as...Figure 7.27 Solidification paths of Mg‐4Al‐3Sr (dmnqe) and Mg‐6Al‐1.5Sr (bpq...Figure 7.28 Ternary ally Mg‐4Al‐3Sr: (a) solidification path; (b) cast micro...Figure 7.29 Ternary ally Mg‐6Al‐1.5Sr: (a) solidification path; (b) cast mic...Figure 7.30 3‐dimentional ternary Fe‐Cr‐Ni phase diagram, calculated using t...Figure 7.31 Calculated liquidus projection of Fe‐Cr‐Ni ternary phase diagram...Figure 7.32 Calculated solidus projection of Fe‐Cr‐Ni ternary phase diagram....Figure 7.33 Calculated (L + δ + γ) three‐phase equilibrium in the Fe–Cr–Ni t...Figure 7.34 Calculated vertical cross‐sections of Fe‐Cr‐Ni ternary phase dia...Figure 7.35 Calculated vertical cross‐sections of Fe‐Cr‐Ni phase diagrams at...Figure 7.36 Solidification path of Fe‐25Cr‐20.5Ni alloy (which is close to 3...Figure 7.37 Solidification path of Fe‐23Cr‐14Ni alloy (which is close to 309...Figure 7.38 Solidification path of Fe‐18Cr‐8Ni alloy (which is close to 304 ...Figure 7.39 Solidification of 310 stainless steel: (a) schematic vertical se...Figure 7.40 Solidification of 309 stainless steel: (a) schematic vertical se...Figure 7.41 Microstructure of 309 stainless steel: (a) no quenching; (b) wat...Figure E7.1 Binary phase diagrams: (a) Al‐Mg; (b) Al‐Cu.Figure E7.2 Liquidus projection of the Fe‐Cr‐Ni ternary phase diagram.Figure P7.3Mg‐4Al‐1.5Sr alloys: (a) solidification path () shown on the liquidus...

      8 Chapter 8Figure 8.1 Effect of constitutional supercooling on solidification mode duri...Figure 8.2 Relationship between growth rate R and travel speed V.Figure 8.3 Variation in growth rate along pool boundary.Figure 8.4 Variations in temperature gradient G and growth rate R along pool...Figure 8.5 Variation in solidification mode across the fusion zone.Figure 8.6 Planar‐to‐cellular transition in an autogenous weld of Fe‐49Ni....Figure 8.7 Planar‐to‐cellular transition in as‐cast Al‐4.5Cu plate welded wi...Figure 8.8 Planar‐to‐cellular and cellular to dendritic transition in 1100 A...Figure 8.9 EB weld of single crystal Fe‐15Cr‐15Ni with sulfur showing transi...Figure 8.10 EB weld of single crystal of pure Fe‐15Cr‐15Ni made in a [110] d...Figure 8.11 Variation in dendrite arm spacing across fusion zone: (a) phase ...Figure 8.12 Transverse cross‐section of GTA weld in 6061 Al alloy: (a) finer...Figure 8.13 Effect of welding processes on microstructure in 6111 Al welds m...Figure 8.14 Effect of welding speed on cell spacing in electron beam welding...Figure 8.15 Effect of heat input per unit length of weld on dendrite arm spa...Figure 8.16 Microstructures near fusion line of GTA welds of 2014 aluminum: ...Figure 8.17 Tensile testing of two GTA welds of 2014 aluminum made without a...Figure 8.18 Increase in welding pool travel speed due to transverse arc osci...Figure E8.1 Al‐Cu phase diagram.Figure P8.3 Schematic sketch of top view of mushy zone.

      9 Chapter 9Figure 9.1 Spherical cap of a crystal nucleated on a planar substrate from a...Figure 9.2 Epitaxial growth at fusion line: (a) growth of columnar grains fr...Figure 9.3 Transverse cross‐section showing epitaxial growth of columnar gra...Figure 9.4 Top view of weld of 430 stainless steel (bcc) showing epitaxial g...Figure 9.5 Transverse cross‐section showing epitaxial growth from fusion lin...Figure 9.6 Nonepitaxial growth shown by welding 430 ferritic stainless steel...Figure 9.7 Nondendritic equiaxed grains in fusion zone next to HAZ of 2A97 A...Figure 9.8 Formation mechanism of nondendritic zone near fusion line by Al₃Z...Figure 9.9 Competitive growth of columnar grains in bulk fusion zone.Figure 9.10 Competitive growth in weld of 310 stainless steel (~Fe‐25Cr‐20Ni...Figure 9.11 Top surface of pure Cu weld made by EBW showing growth of curved...Figure 9.12 Effect of travel speed on pool shape and columnar grains: (a) lo...Figure 9.13 Gas–tungsten arc welds of 99.96% Al: (a) 250 mm/min welding spee...Figure 9.14 Effect of welding speed on columnar grains in weld metal: (a, b)...Figure 9.15 Axial grains in GTAW: (a) 2014 Al (~Al4.4Cu) at 3.6 mm/s welding...Figure 9.16 Axial grain in 316 stainless steel quenched with Woods metal dur...Figure 9.17 Oscillated arc Al welds (welding from right to left): (a) alloy ...Figure 9.18 Microstructure around weld pool: (a) pool; (b) partially melted ...Figure 9.19 Microstructure around the weld pool boundary: (a) phase diagram;...Figure 9.20 Nucleation mechanisms for equiaxed grains in fusion zone: (a) th...Figure 9.21 Carbon tetrabromide alloyed with salol (solute) showing necking ...Figure 9.22 Quenching during welding of 310 stainless steel induced cracking...Figure 9.23 Grain refining of 2219 Al (~Al‐6.3Cu) by adding (Al‐5Ti‐B) as gr...Figure 9.24 Heterogeneous nucleation and formation of equiaxed grains in fus...Figure 9.25 TiB₂ nuclei in 6061 Al welded by GTAW: (a) two grains nucleated ...Figure 9.26 Evidence of heterogeneous nucleation by TiN in GTAW of ferritic ...Figure 9.27 Growth restriction factor Q = m _L C _o(k − 1) and consti...Figure 9.28 Schematic diagrams showing how the relationship between grain si...Figure 9.29 Grain size plotted against 1/Q for Al alloys: (a) different leve...Figure 9.30 Effect of welding conditions on temperature gradient G at growth...Figure 9.31 Effect of welding conditions on grain structure of 6061 Al weld:...Figure 9.32 Effect of grain size on weld metal ductility of a Cr‐Ni iron bas...Figure 9.33 Schematic sketch showing application of external magnetic field ...Figure 9.34 Grain refining by stirring weld pool with an ultrasonic probe: (...Figure 9.35 Effect of ultrasonic oscillation amplitude on grain refining in ...Figure 9.36 Effect of offset of ultrasonic probe on grain refining in AZ31 M...Figure 9.37 AZ31 Mg (~Mg‐3Al‐1Zn) welded by gas–tungsten arc welding at 3.18...Figure 9.38 Effect of arc oscillation frequency and amplitude on grain refin...Figure 9.39 Identification of the nucleation mechanism of equiaxed grains in...Figure 9.40 Overlap welding similar to Figure 9.39b, suggesting either dendr...Figure 9.41 Overlap welding similar to Figure 9.40d, suggesting dendrite fra...Figure 9.42 Effect of arc oscillation on cooling curve during welding of AZ3...Figure 9.43 Arc oscillation helping grain refining: (a) no arc oscillation; ...Figure 9.44 Grain‐boundary (GB) migration in 310 stainless steel weld: (a) n...Figure E9.1 End of crater of a gas−tungsten arc weld of a 430 stainless stee...Figure P9.1 Schematic sketch of grain structure in an arc weld.Figure P9.2 A two‐pass weld with the second pass made normal to the first we...Figure P9.3 Schematic sketches of welds made normal to the coarse grains in ...Figure P9.4 Schematic sketch of the weld pool and its adjacent fusion zone d...

      10 Chapter 10Figure 10.1 Microsegregation caused by Case III solute redistribution: (a) p...Figure 10.2 Microsegregation across columnar dendrites near quenched weld po...Figure 10.3 Microsegregation in weld metal of 308 stainless steel: (a) phase...Figure 10.4 Microsegregation in laser weld of superaustenitic stainless stee...Figure 10.5 Increasing dendrite‐core solute contents with increasing travel ...Figure 10.6 Calculated microsegregation in Fe‐3.3Nb weld showing dendrite ti...Figure 10.7 Growing dendrites quenched during GTAW of stainless steels: (a) ...Figure 10.8 Growing dendrites quenched with Wood's metal during GTAW of 312 ...Figure 10.9 Calculated microsegregation: (a) Fe‐23Cr‐12Ni (solid‐state diffu...Figure 10.10 Micrographs of Al welds made by GTAW: (a) 2014 Al (~Al‐4.4Cu) s...Figure 10.11 Binary phase diagrams of Al alloys: (a) Al‐Cu; (b) Al‐Mg. At eu...Figure 10.12 2014 Al (~Al‐4.4Cu) quenched with Wood's metal during welding: ...Figure 10.13 2014 Al (~Al‐4.4Cu) quenched with Wood's metal during welding: ...Figure 10.14 5086 Al (~Al‐4Mg) quenched with Wood's metal during welding: (a...Figure 10.15 SEM images near ends of quenched mushy zones: (a) 2014 Al (~Al‐...Figure 10.16 Grids for composition measurements by EPMA: (a) 2014 Al at 5.78...Figure 10.17 Cu microsegregation near end of quenched 2014 Al (~Al‐4.4Cu) mu...Figure 10.18 Mg microsegregation near end of quenched 5086 Al (~Al‐4.0Mg) mu...Figure E10.1 Al‐Si phase diagram.Figure E10.2 Ternary alloy Fe‐15Cr‐15Ni: (a) vertical section of Fe‐Cr‐Ni ph...Figure P10.1 Al‐Cu phase diagram.

      11 Chapter 11Figure 11.1 Macrosegregation reported by Savage and Szekeres. Formation of b...Figure 11.2 Fusion boundary of a low‐alloy steel welded