Analysis of Residual Stress by the Hole-Drilling Method and Hardness in Dissimilar Joints of Austenitic Stainless Steel AISI 316L and Inconel 718 Alloy by Autogenous GTAW Process

Abstract

Stainless steel and nickel alloy have high corrosion resistance in high-temperature environments due to the high Cr content present in their chemical composition, being widely used in components of nuclear reactors, petrochemical industries, etc. Through proper processes and procedures, it becomes possible to join these alloys. However, this union can generate detrimental factors in its performance, among them, the residual stresses. In this work, the residual stresses generated by the autogenous GTAW process, due to different interpass temperatures on the weld bead geometry, were analyzed by the Hole-Drilling technique in dissimilar welding joints of stainless steel AISI 316L and Inconel 718 alloy. In addition, the Vickers microhardness measurements were carried out to evaluate the hardness profile in the cross section of the weld bead covering base metal (BM), heat affect zone (HAZ) and weld metal (WM). We found that in the interface region between BM and HAZ of each dissimilar joint metal, residual stresses increased above 300 MPa, while hardness increased above 160 HV.

Influence of the Interpass Welding Temperature on Microstructure and Corrosion Resistance of Superduplex Stainless Steel SAF 2507

“…According to Ramirez et al 14 , intragranular austenite is obtained due to the thicker grains formed in this region. The explanation follows the classical mechanism confirmed by previous results 11, [18][19][20][21][22][23][24][25][26][27] .…”

“…Therefore, the phase balance represented by their volume fractions and spatial distributions besides their morphological characteristics is mainly related to their specific grain boundary area and the local cooling rates. These main key parameters strongly relate to the growth kinetics of the phases developed during the welding procedures, which in turn, are defined by the welding parameters and the local thermophysical properties of the material [11][12][13][14][15][16][18][19][20][21][22][23][24][25][26][27] . Consequently, larger regions in the center of the ferrite grains will be available for the nucleation and growth of austenite due to the resulting supersaturation with austenitizing elements of the ferrite phase.…”

Analysis of Dissimilar Welding Joint between Inconel 718 and AISI 316L by GTAW Multipass Process

“…Silva et al [10] studied the corrosion resistance of dissimilar joints of Inconel 718 and AISI 316L welded by GTAW process under different heat inputs and concluded that Inconel 718 and the fusion zone (FZ) have good resistance to pitting corrosion, although in the region close to AISI 316L steel may suffer localized corrosion. Gomes et al [11], using the Hole-Drilling technique, analyzed the presence of residual stresses in dissimilar joints of AISI 316L and Inconel 718, concluding that the interface between the base metal and heat-affected zone (HAZ) of each metal presented residual stress around 300 MPa. Using the multipass GTAW process, Ramkumar et al [12] compared the similar welding of AISI 316L and Inconel 718 with the dissimilar welding between AISI 316L and Inconel 718 and concluded that the dissimilar joint has better tensile strength than the similar joints of both materials.…”