Solidification of Tungsten Inert Gas–Welded Austenitic Stainless Steel with 0.17 wt% N

Abstract

In this study, an austenitic CrMnNi–N steel is examined with regard to its solidification behavior of the weld metal. For this purpose, the cooling rate of the weld metal at different welding speeds is determined for tungsten inert gas welding without filler metal. The relationship between secondary dendrite arm spacing () and cooling rate () can be described using . Moreover, the microstructure is characterized by a scanning electron microscope using energy‐dispersive X‐ray spectroscopy (EDS). Based on the EDS measurement, it is possible to describe the microsegregation of Cr, Ni, Mn, Mo, and N. The detected microsegregation behavior is compared with the results obtained from Thermo‐Calc calculations. The microsegregation varies depending on the present phase during solidification and correlate well with microstructure observations. By using the software Thermo‐Calc, the theoretical description of solidification is based on the classical Scheil model with fast diffusion of N. A primary ferritic solidification is calculated, which correlates with the experimental findings.