Macrosegregation in Dissimilar-metal Fusion Welding

Date
2016-03-25
Authors
Pasang, T
Soysal, T
Kou, S
Tat, D
Supervisor
Item type
Journal Article
Degree name
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract

Solute segregation on a macroscopic scale in a weld between two dissimilar metals or alloys has long been recognized, but fundamental understanding of macrosegregation in dissimilar-metal welding is still lacking. Two mechanisms for macrosegregation were proposed based on the liquidus temperature of the bulk weld metal, TLW, relative to the liquidus temperature of metal 1, TL1, and the liquidus temperature of metal 2, TL2. According to the mechanisms, two distinctly different macrosegregation features can form. A “peninsula” of an unmixed metal 1 can form if TLW < TL1. On the other hand, a “beach” of unmixed metal 2 irregular in shape can form if TLW > TL2. To verify the mechanisms, a pure Cu sheet was butt welded to a low carbon steel sheet by gas-tungsten arc welding without a filler metal. Composition measurements were conducted inside and across the weld metal. A peninsula of unmixed steel and an irregular-shaped beach of unmixed Cu were observed, which verified the mechanisms. In addition, the bulk weld metal exhibited a layered structure caused by undercooling of the bulk weld pool into a metastable miscibility gap in the Cu-Fe phase diagram. Macrosegregation in previous studies on laser- and electron-beam welding of Cu to steel or stainless steel was discussed in light of the findings in the present study.

Description
Keywords
Arc welding; Fluid flow; Solute segregation; Cu-to-steel welding; Dissimilar-metal welding
Source
Acta Materialia, 110, 149-160.
Rights statement
Copyright © 2016 Elsevier Ltd. All rights reserved. This is the author’s version of a work that was accepted for publication in (see Citation). Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. The definitive version was published in (see Citation). The original publication is available at (see Publisher's Version).