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Title: Oxygen Effects on Solidification Behavior of Gas Tungsten Arc–Welded Laser Powder Bed Fusion–Fabricated 304L Stainless Steel

Abstract

ct The laser – powder bed fusion (L-PBF) process inherently accumulates interstitial gas elements during powder fabrication and laser deposition processes. Such elements can lead to localized variations in the weld pool and affect the solidification behavior (when compared with its wrought equivalent), in addition to chemical micro-segregation within the fabricated material. This study was conducted to characterize the solidification behavior of gas tungsten arc welds made on L-PBF 304L stainless steel. The effect of surface active elements on the local solidification rates was studied. An emphasis was placed on the role local solidification rates and temperature gradients throughout the weld play on the resultant weld solidification structure and micro-segregation. It was determined that gas tungsten arc welds on L-PBF 304L stainless steel exhibited a vermicular ferrite solidification structure compared to a mix of vermicular and lathy ferrite structure in wrought 304L. The varying thermal gradients affected the solidification modes and partitioning of elements leading to fluctuations of micro-segregation in the L-PBF 304L. Macroscopically, such partitioning affected the surface tension within the weld pool, producing asymmetric weld pool geometries. The compositional differences between wrought and L-PBF fabricated 304L stainless steels resulted in irregular solidification behaviors during welding affecting the finalmore » weld microstructure.« less

Authors:
 [1];  [1];  [2]; ORCiD logo [2]; ORCiD logo [2];  [2]; ORCiD logo [2]
  1. Colorado School of Mines, Golden, CO (United States). Dept. of Chemistry and Geochemistry
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1530792
Report Number(s):
LA-UR-18-26056
Journal ID: ISSN 2379-1365; MPCACD
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Materials Performance and Characterization
Additional Journal Information:
Journal Volume: 8; Journal Issue: 4; Journal ID: ISSN 2379-1365
Publisher:
ASTM International
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Gonzales, Devon Scott, Liu, Stephen, Javernick, Daniel Anthony, Pacheco, Robin Montoya, Brand, Michael J., Johnson, Matthew Q., and Tung, David C. Oxygen Effects on Solidification Behavior of Gas Tungsten Arc–Welded Laser Powder Bed Fusion–Fabricated 304L Stainless Steel. United States: N. p., 2019. Web. doi:10.1520/MPC20180115.
Gonzales, Devon Scott, Liu, Stephen, Javernick, Daniel Anthony, Pacheco, Robin Montoya, Brand, Michael J., Johnson, Matthew Q., & Tung, David C. Oxygen Effects on Solidification Behavior of Gas Tungsten Arc–Welded Laser Powder Bed Fusion–Fabricated 304L Stainless Steel. United States. https://doi.org/10.1520/MPC20180115
Gonzales, Devon Scott, Liu, Stephen, Javernick, Daniel Anthony, Pacheco, Robin Montoya, Brand, Michael J., Johnson, Matthew Q., and Tung, David C. 2019. "Oxygen Effects on Solidification Behavior of Gas Tungsten Arc–Welded Laser Powder Bed Fusion–Fabricated 304L Stainless Steel". United States. https://doi.org/10.1520/MPC20180115. https://www.osti.gov/servlets/purl/1530792.
@article{osti_1530792,
title = {Oxygen Effects on Solidification Behavior of Gas Tungsten Arc–Welded Laser Powder Bed Fusion–Fabricated 304L Stainless Steel},
author = {Gonzales, Devon Scott and Liu, Stephen and Javernick, Daniel Anthony and Pacheco, Robin Montoya and Brand, Michael J. and Johnson, Matthew Q. and Tung, David C.},
abstractNote = {ct The laser – powder bed fusion (L-PBF) process inherently accumulates interstitial gas elements during powder fabrication and laser deposition processes. Such elements can lead to localized variations in the weld pool and affect the solidification behavior (when compared with its wrought equivalent), in addition to chemical micro-segregation within the fabricated material. This study was conducted to characterize the solidification behavior of gas tungsten arc welds made on L-PBF 304L stainless steel. The effect of surface active elements on the local solidification rates was studied. An emphasis was placed on the role local solidification rates and temperature gradients throughout the weld play on the resultant weld solidification structure and micro-segregation. It was determined that gas tungsten arc welds on L-PBF 304L stainless steel exhibited a vermicular ferrite solidification structure compared to a mix of vermicular and lathy ferrite structure in wrought 304L. The varying thermal gradients affected the solidification modes and partitioning of elements leading to fluctuations of micro-segregation in the L-PBF 304L. Macroscopically, such partitioning affected the surface tension within the weld pool, producing asymmetric weld pool geometries. The compositional differences between wrought and L-PBF fabricated 304L stainless steels resulted in irregular solidification behaviors during welding affecting the final weld microstructure.},
doi = {10.1520/MPC20180115},
url = {https://www.osti.gov/biblio/1530792}, journal = {Materials Performance and Characterization},
issn = {2379-1365},
number = 4,
volume = 8,
place = {United States},
year = {Mon Apr 01 00:00:00 EDT 2019},
month = {Mon Apr 01 00:00:00 EDT 2019}
}