Influence of Heat Treatments on Microstructure, Mechanical Properties and Corrosion Behaviour of Alloy 625 Forged Rod

Abstract

Influence of heat treatments between 500 and 1125°C on forged alloy 625 has been studied. Hardening between 650 and 800°C results of dislocation glidings of matrix, zf" precipitation and maximum of intergranular precipitation of fine M23C6 carbides. Tensile strength and intergranular corrosion through ASTM G 28 test become maxima, impact strength and reduction of area become minima, in the field of M23C6 and M6C intergranular precipitation : between 700 and 950°C.

Characterization of Microstructure, Strength, and Toughness of Dissimilar Weldments of Inconel 625 and Duplex Stainless Steel SAF 2205

“…SEM fractographs however showed the presence of dimples with the ductile tearing ridges on the fractured surface of ERNiCrMo-3 weldments. As reported by Vernot-Loier and Cortial [19], the lower toughness values indicated in the weldments could be attributed to the presence of M 6 C, M 23 C 6 carbides which were also witnessed from the EDS results.…”

“…The presence of Nb increases the fragility of the welds. Similar observations indicated that Nb addition reduces the formation of ductile tear ridges and therefore suggests that increasing Nb content encourages inter-dendritic fracture in the cap [19]. The specimens with high Nb addition did not show large deformations, although there is evidence that the ruptured mechanism was still governed by void connection; i.e., the Nb-rich precipitates between the dendrites (Fig.…”

Temperature- and Time-Dependent Mechanical Behavior of Post-Treated IN625 Alloy Processed by Laser Powder Bed Fusion

“…In particular, the embrittlement has been attributed to intergranular precipitates, grain boundary shearing or sliding, gas phase embrittlement, dynamic strain aging, grain boundary segregation, and glide plane decohesion [22]. For IN625 alloy, this phenomenon is mostly associated with precipitates (carbides, M 23 C 6 and M 6 C, and δ phase) distributed along grain boundaries [2,24,39,40]. More specifically, according to Reference [24], cracks preferentially propagate along grain boundaries containing M 6 C carbides.…”

Laser Welding of 422 Stainless Steel with Inconel 625 Filler Metal

“…Although Inconel 625 was originally designed as a solid solution strengthened alloy, the precipitation of Ni 3 Nb intermetallic particles has seen found after tempering in the temperature range of 650 to 950°C. 13) It was also noted that the WM had a slightly higher hardness in the 700°C/2 h tempered condition (ϳ230 Hv) than in the as-welded condition (ϳ210 Hv). Apparently, the presence of Ni 3 Nb precipitates in the WM could be responsible for such a change.…”