The effect of varying the MnO content of the flux used for the submerged arc welding of Navy HY-100 steel
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Authors
Clark, Allen L.
Subjects
Advisors
Fox, A.G.
Date of Issue
1995-12
Date
December 1995
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Weld metal strength and toughness are determined by its microstructure, which is in turn determined by the concentration of various alloying elements and impurities as well as the welding thermal cycle. This study investigated the effects of systematically varying the manganese oxide content in the flux used for HY-l00 submerged arc welds. A trial addition of cerium oxide was also performed. Specimens were compared using mechanical properties, weld metal chemistry, inclusion chemistry, and microstructural analysis. It was found that cerium oxide addition and the correct amount of manganese oxide resulted in improved toughness. These improved properties were determined to arise from a low proportion of bainite in the fully reaustenitized region of the weld metal HAZ in these multipass welds. In the MnO series welds, the bainite is replaced by a fine low carbon martensite due to the increased weld metal hardenability. In the CeO2 weld it is replaced by acicular ferrite due to the lowering of the austenite grain boundary energy by the cerium. The production of a series of welds with different manganese contents also resulted in the extension of existing theories of weld metal deoxidation. p3.
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Identifiers
NPS Report Number
Sponsors
Funder
NA
Format
146 p.
Citation
Distribution Statement
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.