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Title: Microstructural Study Of Fusion Welds in 304L and 21Cr-6Ni-9Mn Stainless Steels (U)

Abstract

Light-optical and transmission electron microscopy (TEM) have been employed to characterize the microstructures of a series of fusion welds made on 304L and 21-6-9 stainless steels. The materials investigated in this study included high-energy-rate-forged 304L, conventionally forged 21-6-9, and 304L weld critical plate (higher ferrite potential). The weld critical plate contained an electron beam weld (no filler wire) while other specimens were welded with various combinations of 308L, 309L modified (MOD) and 312 MOD stainless steel filler wires to produce samples with a range of delta ferrite contents (4 to 33 percent) in the resulting welds. TEM specimens were prepared from broken arc-shaped, mechanical property test specimens that had been used to measure fracture toughness of the fusion welds. Specimens were prepared from regions of the weld heat-affected zones as well as from areas within the weld metal, including areas close to the fracture surface (plastically deformed regions). The observed microstructures varied according to the amount of ferrite in each weld. At the lowest ferrite levels the microstructure consisted of austenite and skeletal ferrite with austenite being the majority (matrix) phase. At intermediate levels of ferrite, lathy austenite/ferrite was observed and the ferrite became continuous throughout the specimens examined. Inmore » the weld with the most ferrite, many austenite morphologies were observed and ferrite was the matrix phase. Closest to the fracture surface an increase in dislocation density in both the ferrite and austenite were observed in all welds. Deformation twinning was also observed in the austenite. Many of the welds contained a large number of non-metallic inclusions (oxide particles) which most likely originated from impurities in the weld wires.« less

Authors:
Publication Date:
Research Org.:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
840795
Report Number(s):
WSRC-TR-2004-00456
TRN: US200512%%254
DOE Contract Number:  
AC09-96SR18500
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Mar 2005
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 60 APPLIED LIFE SCIENCES; AUSTENITE; DEFORMATION; DISLOCATIONS; ELECTRON BEAMS; FERRITE; FILLERS; FRACTURE PROPERTIES; FRACTURES; HEAT AFFECTED ZONE; IMPURITIES; MICROSTRUCTURE; PLATES; STAINLESS STEELS; TRANSMISSION ELECTRON MICROSCOPY; TWINNING

Citation Formats

MICHAEL, TOSTEN. Microstructural Study Of Fusion Welds in 304L and 21Cr-6Ni-9Mn Stainless Steels (U). United States: N. p., 2005. Web. doi:10.2172/840795.
MICHAEL, TOSTEN. Microstructural Study Of Fusion Welds in 304L and 21Cr-6Ni-9Mn Stainless Steels (U). United States. https://doi.org/10.2172/840795
MICHAEL, TOSTEN. 2005. "Microstructural Study Of Fusion Welds in 304L and 21Cr-6Ni-9Mn Stainless Steels (U)". United States. https://doi.org/10.2172/840795. https://www.osti.gov/servlets/purl/840795.
@article{osti_840795,
title = {Microstructural Study Of Fusion Welds in 304L and 21Cr-6Ni-9Mn Stainless Steels (U)},
author = {MICHAEL, TOSTEN},
abstractNote = {Light-optical and transmission electron microscopy (TEM) have been employed to characterize the microstructures of a series of fusion welds made on 304L and 21-6-9 stainless steels. The materials investigated in this study included high-energy-rate-forged 304L, conventionally forged 21-6-9, and 304L weld critical plate (higher ferrite potential). The weld critical plate contained an electron beam weld (no filler wire) while other specimens were welded with various combinations of 308L, 309L modified (MOD) and 312 MOD stainless steel filler wires to produce samples with a range of delta ferrite contents (4 to 33 percent) in the resulting welds. TEM specimens were prepared from broken arc-shaped, mechanical property test specimens that had been used to measure fracture toughness of the fusion welds. Specimens were prepared from regions of the weld heat-affected zones as well as from areas within the weld metal, including areas close to the fracture surface (plastically deformed regions). The observed microstructures varied according to the amount of ferrite in each weld. At the lowest ferrite levels the microstructure consisted of austenite and skeletal ferrite with austenite being the majority (matrix) phase. At intermediate levels of ferrite, lathy austenite/ferrite was observed and the ferrite became continuous throughout the specimens examined. In the weld with the most ferrite, many austenite morphologies were observed and ferrite was the matrix phase. Closest to the fracture surface an increase in dislocation density in both the ferrite and austenite were observed in all welds. Deformation twinning was also observed in the austenite. Many of the welds contained a large number of non-metallic inclusions (oxide particles) which most likely originated from impurities in the weld wires.},
doi = {10.2172/840795},
url = {https://www.osti.gov/biblio/840795}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Mar 01 00:00:00 EST 2005},
month = {Tue Mar 01 00:00:00 EST 2005}
}