SOFT ZONE FORMATION IN DISSIMILAR WELDS BETWEEN 2 CR-MO STEELS

Citation
Sk. Albert et al., SOFT ZONE FORMATION IN DISSIMILAR WELDS BETWEEN 2 CR-MO STEELS, Welding journal, 76(3), 1997, pp. 135-142
Citations number
23
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Metallurgy & Metallurigical Engineering
Journal title
ISSN journal
0043-2296
Volume
76
Issue
3
Year of publication
1997
Pages
135 - 142
Database
ISI
SICI code
0043-2296(1997)76:3<135:SZFIDW>2.0.ZU;2-4
Abstract
Two dissimilar weldments between 9Cr-1Mo and 2.25Cr-1Mo ferritic steel s have been characterized for their microstructural stability during v arious postweld heat treatments (PWHTs). The samples for the investiga tion were extracted from bead-on-plate weldments made by depositing 2. 25Cr-1Mo weld metal on 9Cr-1Mo base plate and vice versa. Subsequent a pplication of PWHT resulted in the formation of a soft zone in the low Cr ferritic steel weld or base plate. A carbide-rich hard zone, adjoi ning the soft zone, was also detected in the high Cr side of the weldm ent. Unmixed zones in the weld metal provided additional soft and hard zones in the weld metals. The migration of carbon from low-Cr steel t o high-Cr steel, driven by the carbon activity gradient, has been show n to be responsible for the formation of soft and hard zones. A carbon activity diagram for 2.25Cr-1Mo/9Cr-1Mo weldments has been proposed t o aid in the selection of welding consumables for reducing or preventi ng the soft zone formation.