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Title: Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels

Abstract

Highlights: • The microstructure and mechanical properties of FSSW of ultra high strength DP and CP steels are compared. • The stir zone (SZ) of CP steel mainly consists of bainite and martensite; no bainite is identified in the SZ of DP steel. • The cooling was not fast enough for the CP steel to suppress the effect of chemical composition on phase transformation. - Abstract: The microstructure and mechanical properties of friction stir spot welding of ultrahigh strength dual phase (DP) and complex phase (DP) steels are compared based on the experimental results. For both DP and CP steels, FSSW joints are successfully fabricated using the same process parameter set. While the microstructure of joints are characterized in detail using scanning electron microscopy, electron back scattered diffraction, and transmission electron microscopy, the mechanical property of joints are evaluated by shear tensile tests. The result of the microstructural analysis shows that the stir zone (SZ) of CP steel mainly consists of bainite and martensite, while no bainite is identified in the SZ of DP steel. The existence of bainite in the SZ of CP steel suggests that the cooling rate, which is nearly identical for both CP and DP steels,more » was not fast enough to suppress the effect of the alloying composition, particularly that of Mn, on the phase transformation. The result of the present study contributes to the development of solid state joining process of the ultrahigh strength steels.« less

Authors:
; ;  [1];  [2];  [2]
  1. School of Mechanical Engineering, University of Ulsan, Ulsan (Korea, Republic of)
  2. Environment Materials and Components Center, Korea Institute of Industrial Technology (Korea, Republic of)
Publication Date:
OSTI Identifier:
22804992
Resource Type:
Journal Article
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 139; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-5803
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BACKSCATTERING; COMPARATIVE EVALUATIONS; ELECTRON DIFFRACTION; MICROSTRUCTURE; PHASE TRANSFORMATIONS; SCANNING ELECTRON MICROSCOPY; STEELS; TRANSMISSION ELECTRON MICROSCOPY; WELDED JOINTS

Citation Formats

Das, Hrishikesh, Mondal, Mounarik, Hong, Sung-Tae, Lim, Yeongseok, Mechanical Design Engineering, Chonbuk National University, and Lee, Kwang-Jin. Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels. United States: N. p., 2018. Web. doi:10.1016/J.MATCHAR.2018.03.022.
Das, Hrishikesh, Mondal, Mounarik, Hong, Sung-Tae, Lim, Yeongseok, Mechanical Design Engineering, Chonbuk National University, & Lee, Kwang-Jin. Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels. United States. https://doi.org/10.1016/J.MATCHAR.2018.03.022
Das, Hrishikesh, Mondal, Mounarik, Hong, Sung-Tae, Lim, Yeongseok, Mechanical Design Engineering, Chonbuk National University, and Lee, Kwang-Jin. 2018. "Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels". United States. https://doi.org/10.1016/J.MATCHAR.2018.03.022.
@article{osti_22804992,
title = {Comparison of microstructural and mechanical properties of friction stir spot welded ultra-high strength dual phase and complex phase steels},
author = {Das, Hrishikesh and Mondal, Mounarik and Hong, Sung-Tae and Lim, Yeongseok and Mechanical Design Engineering, Chonbuk National University and Lee, Kwang-Jin},
abstractNote = {Highlights: • The microstructure and mechanical properties of FSSW of ultra high strength DP and CP steels are compared. • The stir zone (SZ) of CP steel mainly consists of bainite and martensite; no bainite is identified in the SZ of DP steel. • The cooling was not fast enough for the CP steel to suppress the effect of chemical composition on phase transformation. - Abstract: The microstructure and mechanical properties of friction stir spot welding of ultrahigh strength dual phase (DP) and complex phase (DP) steels are compared based on the experimental results. For both DP and CP steels, FSSW joints are successfully fabricated using the same process parameter set. While the microstructure of joints are characterized in detail using scanning electron microscopy, electron back scattered diffraction, and transmission electron microscopy, the mechanical property of joints are evaluated by shear tensile tests. The result of the microstructural analysis shows that the stir zone (SZ) of CP steel mainly consists of bainite and martensite, while no bainite is identified in the SZ of DP steel. The existence of bainite in the SZ of CP steel suggests that the cooling rate, which is nearly identical for both CP and DP steels, was not fast enough to suppress the effect of the alloying composition, particularly that of Mn, on the phase transformation. The result of the present study contributes to the development of solid state joining process of the ultrahigh strength steels.},
doi = {10.1016/J.MATCHAR.2018.03.022},
url = {https://www.osti.gov/biblio/22804992}, journal = {Materials Characterization},
issn = {1044-5803},
number = ,
volume = 139,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2018},
month = {Tue May 15 00:00:00 EDT 2018}
}