Microstructural Analysis of Inconel 625 Nickel Alloy / UNS S31803 Duplex Stainless-Steel Dissimilar Weldments

Abstract

In this study, Inconel 625 nickel alloy and UNS 31803 duplex stainless steel (DSS) dissimilar pairs were welded with MIG welding process. Weld metal, obtained with ERNiCrMo-3 filler wire, was subjected to mechanical and microstructural investigations. Notch impact test and micro hardness measurements were realized on weld metal in order to evaluate31803 mechanical properties. Microstructural changes in fusion line of the base metals were examined using optical and electron microscopes. Phase precipitations rich of Ti and Mo elements were detected among dendritic austenite arms in the weld metal. It was observed that ERNiCrMo-3 filler metal had sufficient toughness because of high nickel content.

Metallurgical and Mechanical Behaviors of 309L-Si and ERNiCrMo-3 Dissimilar Weld on ASTM A182 F22 Steel

“…The failure surface reveals a rapid fracture, probably came from solidification micro-cracks, propagated during the tensile test in 309/INC625 interface. The micrographic exams before the test could not detect these micro discontinuities throughout the interface due to their small dimensions and the internal location, similar to founded by other researchers [31][32][33] . By Figure 12 it is possible to note that the solidification cracks on the buttery were restrict to the 309L-Si weld metal, and were possibly caused by two main factors.…”

Microstructural evaluation of welded joints of ASTM Mar-M247 superalloy using ERNiCrMo-3 filler alloy

“…The topologically close pack (TCP) phase was found by the intermetallic compound Ni 3 Cr 2 . This crystalline compound represents a detrimental phase due to its ability to deplete the reinforcing elements in the alloy [25,26]. In the welded specimen of ASTM Mar-M247 alloy by the filler alloy AWS ERNiCrMo-3, the X-ray diffraction inspection revealed the predominant phases, including NiCr and NiCrCoMo, as solid solutions, as illustrated in Figure 11.…”

“…They revealed a change in the microstructure from columnar to cellular structure when the parameters of the welding passes changed. KARAHAN et al [26] studied the weldability and microstructure analysis for welding alloys of stainless steel and Inconel 625 by Metal Inert Gas (MIG). The researchers found that precipitations rich in Mo, and Ti elements lie between the dendritic arms.…”