Modeling of the mechanical effects induced by the tungsten inert-gas welding of the IN718 superalloy

Dye, David; Hunziker, O.; Roberts, S.M.; Reed, Roger C.

doi:10.1007/s11661-001-0149-z

Cited by 50 publications

(63 citation statements)

References 10 publications

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“…Convergence studies have shown [4,20,21] that four elements through the thickness of the 4 mm plate, as modelled here, enable the distortions to be predicted accurately and efficiently.…”

Section: Finite Element Meshesmentioning

confidence: 91%

“…The filler metal addition has not been modelled explicitly by, e.g. element rebirth or using a lumped enthalpy term during solidification as such effects are incorporated into the heat source term, as in [4,24,29]. The enthalpy change during the solid state phase transformation is modelled, Figure 6b, although rate effects on cooling are ignored.…”

Section: Thermal-mechanical Materials Properties and Conditionsmentioning

confidence: 99%

“…However, distortion predictions have proved more difficult, although for idealised situations where restraint is not a concern good predictions can also be obtained, providing that appropriate element types are used [4]. The advantage of a model-based approach is that the sensitivity of the predictions to changes in parameters, such as welding process conditions, restraint and so forth can be examined in isolation.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Pre-existing Deformation on GMA Welding Distortion in Thin Steel Plates

Davies

Ahn

Tsunori

et al. 2014

J. of Materi Eng and Perform

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Weld distortion is particularly problematic for large thin structures that are used in the assembly of ships. The drive towards lighter ships and thinner plate is restricted by the significant increase in distortion as the plate thickness decreases. The influence of pre-existing deformation in the plates to be joined on the resultant distortion in gas metal arc (GMA) welded structure has been studied. DH-36 steel plate surface profiles were measured before and after the butt welding of two plates 1000 × 500 × 4 mm in size. Three dimensional finite element (FE) models that incorporate the initial plate profile have been created to simulate the welding process and to examine the relationship between the final welded plate profiles and the initial deformation present in the plates.Both symmetric and asymmetric models were considered. A significant variation in the unwelded base plates' initial distortion was observed. Generally, it has been found that if an out-of-plane deformation exists in a plate prior to welding, the level of distortion further increases in the same direction following welding. The final distortions are strongly related to the initial plate profiles. The residual stress distributions in the plates are also to some extent affected by the level of distortion initially present.

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“…Convergence studies have shown [4,20,21] that four elements through the thickness of the 4 mm plate, as modelled here, enable the distortions to be predicted accurately and efficiently.…”

Section: Finite Element Meshesmentioning

confidence: 91%

Section: Thermal-mechanical Materials Properties and Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Influence of Pre-existing Deformation on GMA Welding Distortion in Thin Steel Plates

Davies

Ahn

Tsunori

et al. 2014

J. of Materi Eng and Perform

Self Cite

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“…Temperature-dependent material properties were used, and heat loss on the surface by convection and radiation was considered. The thermal modeling results were calibrated by weld cross-section shape fit [7] corresponding to the weld geometry.…”

Section: Fig 2 Shape Of the Back (A) And Front (B) Side Of The Weldmentioning

confidence: 99%

Residual Stresses, Thermomechanical Behavior and Interfaces in the Weld Joint of Ni‐based Superalloys

Barabash¹,

Barabash²,

David³

et al. 2006

Adv Eng Mater

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In welds, in Ni based superalloys complex interactions between different physical processes are expected to occur. [1] On heating to a temperature close to the solidus temperature, the eutectic phases will dissolve ( Fig. 1(a)). Regions heated below solidus, but above the c′ solvus temperature will lead to complete dissolution of c′ precipitates. On cooling, re-precipitation of c′ phase results in a wide range of sizes of c′ precipitation. Due to thermal stresses, the dislocation activity occurs in different regions of the weld. The focus of the current research was to evaluate the structural changes that occur in the weld of Ni-based single crystal alloys.Results and Discussion: During heating and cooling the alloy passes through the single phase c region ( Fig. 1(a)). This creates complicated thermal mechanical conditions in the weld joint. [2,3] Two single crystal alloys, Rene N5 and CMSX-4, were investigated. Alloy compositions are shown in the Table 1.Positions of the alloys on the phase diagram are shown by a dashed line in Figure 1. Equilibrium temperatures for the alloys are shown in the Table 2. The very early stages of the weld process together with the base metal (BM) structure determine the properties of the weld. BM in both alloys had a dendrite structure ( Fig. 1(b)). Each dendrite contained Ni 3 Al based cuboidal c′-phase particles with their (001) plane aligned with matrix (001) plane ( Fig. 1(c)). SEM and OIM analysis shows that BM in both alloys had quasi single crystalline structure. Large angle boundaries were not observed ( Fig. 1(d)). Orientation of the BM was relatively homogeneious ( Fig. 1(e)) with surface normal in the [013] direction in RENE N5 and the [001] direction in CMSX superalloy.During welding the weld pool moves through the sample creating a complicated thermal mechanical field accompanying this movement. Formation of the quasi single crystalline structure of the weld joint at early stages of weld joint appearance is shown in Figures 2(a,b). Continuous nucleation of dendrites in the melted weld pool starts upon cooling at the fusion line (FL) separating BM within the heat affected zone (HAZ) (Fig. 2(c,d)). Therefore the BM structure together with the direction of temperature gradient G, determine the morphology of the FL (Fig. 2(e,f)) and the orientation of the nucleating dendrites.During dendrite formation the angle between the temperature gradient at the solidification front and the dendrite direction continuously increases. When the angle reaches 45°a change of the growth direction to the perpendicular one takes place ([100] ⇒ [010]) (Fig. 3(c)). This results in the formation of regions with different dendrites growth directions in the weld such as ([100],[100],[010]). Regions with the first two dendrite orientation are located in the left and the right sides of the FZ, and the third one with [010] dendrite direction is located in the central part of the joint as observed experimentally (Figs. 3(a,b)).According to OIM analysis the overall orientation change is much smaller i...

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“…However, such models demand knowledge of the temperature dependence of the thermophysical and mechanical properties of the material along with the distribution and magnitude of heat input into the material. Obtaining these data is again usually time-consuming and expensive, but has been performed in very many successful weld models in a range of materials, for example in the welding of steels [5,20], aluminium [19] and nickel [7,21] alloys.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Phase Transformations and Stresses During the Welding of a Ferritic Mild Steel

Dye

Stone

Watson³

et al. 2014

Metall Mater Trans A

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The transient stresses and phase evolution have been characterised in the quasi-steady state produced around a gas tungsten arc welding (GTAW) torch in a plain carbon (ASTM 1018) steel using in situ neutron diffraction. A novel method has been developed to isolate the deviatoric or plane stress state in the presence of isotropic contributions to the lattice parameter, such as thermal expansion and solute content. The stress state was found to evolve in the anticipated manner, with compressive stresses ahead of the weld and tensile stresses behind the weld, in the weld and heat affected zone, and compression in the far field behind the weld. In particular, the region of compression in the heat-affected zone adjacent to and just behind the welding torch expected from weld models was observed. The evolution of phase fraction around the weld was also determined using the technique and the stresses obtained from the ferrite phase.

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Modeling of the mechanical effects induced by the tungsten inert-gas welding of the IN718 superalloy

Cited by 50 publications

References 10 publications

The Influence of Pre-existing Deformation on GMA Welding Distortion in Thin Steel Plates

The Influence of Pre-existing Deformation on GMA Welding Distortion in Thin Steel Plates

Residual Stresses, Thermomechanical Behavior and Interfaces in the Weld Joint of Ni‐based Superalloys

Characterization of Phase Transformations and Stresses During the Welding of a Ferritic Mild Steel

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