Delta ferrite in the weld metal of reduced activation ferritic martensitic steel

Shiju Sam, C. R. Das, V. Ramasubbu, S. K. Albert, A. K. Bhaduri, T. Jayakumar, E. Rajendra Kumar

Research output: Contribution to journalJournal articleResearchpeer-review


Formation of delta(δ)-ferrite in the weld metal, during autogenous bead-on-plate welding of Reduced Activation Ferritic Martensitic (RAFM) steel using Gas Tungsten Arc Welding (GTAW) process, has been studied. Composition of the alloy is such that delta-ferrite is not expected in the alloy; but examination of the weld metal revealed presence of delta-ferrite in the weld metal. Volume fraction of delta-ferrite is found to be higher in the weld interface than in the rest of the fusion zone. Decrease in the volume fraction of delta-ferrite, with an increase in preheat temperature or with an increase in heat input, is observed. Results indicate that the cooling rate experienced during welding affects the volume fraction of delta-ferrite retained in the weld metal and variation in the delta-ferrite content with cooling rate is explained with variation in the time that the weld metal spends in various temperature regimes in which delta-ferrite is stable for the alloy during its cooling from the liquid metal to the ambient temperature. This manuscript will discuss the effect of welding parameters on formation of delta-ferrite and its retention in the weld metal of RAFM steel. [All rights reserved Elsevier].
Original languageEnglish
JournalJournal of Nuclear Materials
Issue number1
Pages (from-to)343-348
Publication statusPublished - 2014
Externally publishedYes


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