Material Characterization on the Nickel-Based Alloy 600/82 NeT-TG6 Benchmark Weldments

The NeT-TG6 project examines the behaviour of a three-pass slot-welded benchmark made from Alloy 600 base material and Alloy 82 weld metal. This paper reports the material characterization studies conducted as part of the extensive round-robin activities performed to characterise the residual stress state in the TG6 benchmark using both measurement and simulation. An additional three slot specimen with one, two and three pass welds was manufactured to allow extensive characterization studies and comparison with the actual NeT-TG6 specimen, which contains only a single three-pass weld. Optical metallography and chemical composition studies examined the variability of the chemical composition and microstructure between parent material and weld metal with varying levels of dilution and differing thermo-mechanical behaviour. Micro indentation measurements were used to acquire hardness maps of the welded samples and reveal the impact of thermo-mechanical cyclic history. Electron microscopy and in particular electron back scattered diffraction (EBSD) was used to estimate the grain size variation, and, in the deformed parent and each weld bead, to assess the accumulation of plastic deformation.