Factors affecting the impact toughness of ultra low carbon steel weld metal
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Authors
Gwin, Mary Elizabeth
Subjects
HSLA-100
Gas Metal Arc Welding
Ultra Low Carbon Steel
Non-Metallic Inclusions
Gas Metal Arc Welding
Ultra Low Carbon Steel
Non-Metallic Inclusions
Advisors
Fox, A.G.
Date of Issue
1996-09
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
The fundamental factors affecting the impact toughness of four gas metal arc welds (GMAW) made on HSLA-100 base plate using a newly developed steel weld wire were studied. The weld metal analysis included chemistry, mechanical testing (hardness, CVN/FATT), as well as optical, scanning and transmission electron microscopy. Studies of inclusion composition using energy dispersive x-ray (EDX), and electron energy loss spectroscopy (EELS) in the transmission electron microscope were also performed. It was found that increasing oxygen content of the weld metal (due to increased oxygen in the shielding gas) led to increased non-metallic inclusion size and volume fraction; which in turn, led to both decreasing strength and toughness. The strength was lowered because increasing oxygen in the shielding gas led to increased 'consumption' of strengthening alloys such as carbon, manganese and silicon. The toughness was compromised by the increasing size and number of oxide inclusions as these provide sites for void formation and subsequent fracture
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
91 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.