Investigation of Iron Aluminide Weld Overlays

Assessment of the effects of heat input on microstructure and mechanical properties in laser beam welded Haynes 188 undermatched joints

“…When k¼1, the segregation of the particular alloying element in the dendrite core regions is negligible, and the composition of the dendrite core region will be close to the nominal composition. However the lower the k value (ko1), the lower the concentration of the particular alloying element in the dendrite core regions [35]. Table 5 lists the calculated values of k from the samples #1 and #9 from this study and others [17] previously reported for Haynes 188.…”

Investigation of the Resistance to Localized Corrosion Associated with Microstructure of Tube-to-Tube Sheet Welds of UNS S32050 Super Austenitic Stainless Steel for Seawater Cooled Condenser

“…2,3) It has been reported that Mo and Cr segregate to the interdendritic regions of austenitic stainless steels (ASSs) arc welds [4][5][6][7][8] whereas they deplete at dendrite cores relative to the base metal. The localized corrosion generates preferentially at the dendrite cores depleted of Mo and Cr.…”

“…[3][4][5][6][9][10][11] In particular, early studies also indicated that the microsegregation of Mo would proceed over a wide range of welding conditions. 8,12,13) However, since it is difficult to locate studies that have quantitatively elucidated the micro-segregation of not only Mo and Cr, but also N and its related corrosion behavior in highly concentrated chloride (Cl À ) environment at hightemperatures, further in-depth study is needed. Moreover, it is necessary to quantitatively verify the difference of the pitting resistance between the interdendritic region and the dendrite core in the weld metal of the UNS S32050 tube-totube sheet welds using a formula of the pitting resistance equivalent number (PREN; mass% Cr + 3.3 mass% Mo + 30 mass% N).…”

An Investigation of the Massive Transformation from Ferrite to Austenite in Laser-Welded Mo-Bearing Stainless Steels

“…However, as current trends continue to increase alloy content (e.g., superaustenitics and superduplexes) to maximize corrosion resistance in aggressive environments, the challenges associated with welding such alloys becomes a major source of concern. It is well known that alloying additions can change the primary solidification mode for a given alloy, and the non-uniform redistribution of critical alloying elements (especially Mo) during primary austenite solidification [13][14][15] results in depletion in localized regions of the fusion zone microstructure, leaving them susceptible to preferential corrosive attack. [16][17][18][19] Furthermore, the concomitant localized buildup of solute in other areas of the microstructure can promote the formation of brittle intermetallics such as sigma.…”