Effect of Temperature on δ-Ferrite Morphology of Carbon Steel and Austenitic Stainless Steel Welds

Abstract:

δ-ferrite was formed in the weld metal when the melted metal solidified to the room temperature. The δ-ferrite morphology depended on the composition, temperature gradient and growth rate. Research on the influence of heat treatment temperature (400°C, 600°C, 900°C) on the morphology changes and the δ-ferrite content is presented in this paper using optical microscopy, SEM, TEM. The δ-ferrite concentration reduced continuously in increasing temperature (from 23.5% after welding to 11% at 900°C for 10 hours). Besides, the formation of sigma phase and carbides at 600°C were the main cause of increasing hardness values in the fusion zone. However, the heat treatment at a temperature of 900°C eliminated both the sigma phase and brittleness.

• Periodical: Materials Science Forum (Volume 1034)
• Pages: 23-32
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1034.23
• Online since: June 2021
• Authors: Le Thi Nhung, Nguyen Duong Nam, Pham Mai Khanh*
• Keywords: Delta Ferrite, Dissimilar Welds, Heat Treatment, Weld Metal

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