Investigation into the intergranular corrosion behaviour of electron beam welded Hastelloy C-276 sheet using laser displacement sensor

The laser displacement sensor scan technique proposed in the present study helps to calculate the corrosion rate (CR), and subsequently, determine the susceptibility to intergranular corrosion, without preparing separate samples for the weld zone (WZ), adjacent heat affected zone (HAZ) and unaffected base metal (BM). Processing of the displacement data collected during laser displacement sensor scan of the electron beam welded Hastelloy C-276 sample before and after the corrosion test shows that the (CR)(WZ) > (CR)(BM) > (CR)(HAZ). The (CR)(WZ) was found to higher due to the (a) lower concentration of Mo and Cr in the dendrite body (of WZ) and (b) higher non-uniformity in Mo concentration per unit length within the WZ. The weld thermal cycle did not cause sensitization of HAZ (i.e., the formation of Mo depleted regions), and hence, the intergranular attack was not evident along the grain boundaries of the HAZ and the (CR)(HAZ) was lower. (C) 2019 Elsevier Ltd. All rights reserved.