Internal residual stress measurement on inertia friction welding of nickel-based superalloy

Abstract

The internal residual stress in the narrow inertia friction welding (IFW) welds of FGH96 nickelbased superalloy was measured with the contour method (CM). The as-welded internal hoop and axial residual stresses were obtained after two cuts and the detailed steps of the CM measurement were described. In addition, the hole-drilling method was used to obtain the surface stress. Furthermore, the internal hoop residual stress of a FGH96 superalloy IFW specimen after post-weld heat treatment (PWHT) was also measured with the CM after a single cut. The measured results show that the peak hoop residual stress is not symmetrical about the weld centreline. Axial residual stress on the outer surface at the weld centreline is compressive stress, while tensile stress appears on the inner surface, and it varies linearly along the thickness. The peak values of hoop tensile and compressive stresses decrease dramatically after PWHT.

Direct Friction Welding of TiAl Alloy to 42CrMo Steel Rods

“…It is agreed that if the interface in dissimilar materials weld is thinner than 10 mm, the resultant joint strength could be reasonably high [19]. Especially, the compressive residual stress in the friction welded joint also benefits the joint strength [20]. Figure 6 reveals the fracture morphology of the specimen after PWHT.…”

Experimental investigation on residual stress distribution in an engineering-scale pipe girth weld

“…Because the first cut can induce part of the axial stress release, then supposition [15] was employed and additional steps were implemented to account for the stress relaxation effects from the first cut accomplished by applying the displacement boundary conditions applied to the FE model created for determining the hoop stress [7]. The detailed procedure of the stress measurement in a pipe specimen with the two-cut CM can be found in reference [19].…”

Effects of ultrasonic impact treatment on weld microstructure, hardness, and residual stress

“…While theoretical details for the CM can be found in the references [20][21][22], we provide a summary of implementation here for the three key stages of the contour measurements: (1) cutting of the part, (2) measuring and fitting of cut surface contours, and (3) computing residual stress. The cuts for CM were made using a wire electric discharge machine (EDM) (Sodick AQ400Ls) with a 250 μm diameter brass wire at a nominal cutting speed of 0.15 mm s −1 .…”

“…The second cut provides a 2D map of the transverse stress in the second cut plane, σ yy (x, z), which requires a modest extension of the typical CM [21,22] that relies on superposition of transverse stresses found in the first and second cuts.…”