Studies on metallurgical and impact toughness behavior of variably sensitized weld metal and heat affected zone of {AISI} 304L welds

By Kumar, Subodh; Shahi, A. S.
Published in Materials & Design NULL 2016

Abstract

Abstract Influence of sensitization on the metallurgical and impact toughness behavior of different gas tungsten arc {AISI} 304L welds has been investigated. Each weld has been characterized individually to understand the role of welding conditions on the carbide precipitation behavior which influences its impact toughness performance. Weld metal subjected to sensitization conditions leads to carbide formation that occurs inter-dendritically along the ?-? interface. Low heat input weld metal possessing lathy ferrite morphology shows relatively a low degree of sensitization (DOS) as compared to the high heat input weld metal possessing vermicular ferrite morphology. Grain coarsening in the heat affected zone (HAZ) of these welds is found to influence the {DOS} significantly. As welding heat input increases, {HAZ} grain coarsening also increases, which results into higher DOS. An increase in the post-weld thermal aging time results into higher DOS, which significantly degrades the impact toughness of the weld metal as well as the {HAZ} of these joints. Charpy V-notch (CVN) testing results under cryogenic testing conditions of (? 196

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