Nucleation Mechanism of IGF in the HAZs of Ti-Killed HSLA Steel

Abstract:

The weldability of the steel can be improved by formation of intra-granular ferrite (IGF) in heat affected zones (HAZs) on the edge of weld bead. The nucleation mechanism of IGF of Ti-killed high strength low alloyed (HSLA) steel has already been investigated with the aid of transmission electron microscope. Titanium oxides (Ti₂O₃) particles with the diameter of 0.4μm and Si-rich complex inclusions (Ti₃O₅+MnS) with that of 0.5μm can serve as the nuclei of IGF. The nucleation mechanism of IGF is proposed as follows: (1) inclusions are inert substrate. (2) The depletion of the austenite former Mn local to the inclusion increases the thermodynamic driving force of γα for transformation. (3) Lattice matching between inclusion and ferrite reduces the interfacial energy of opposing nucleation.

• Periodical: Advanced Materials Research (Volume 898)
• Pages: 161-163
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.898.161
• Online since: February 2014
• Authors: Dong Ming Duan, Meng Xia Tang, Run Wu*, Yong Bu, Xiao Chen
• Keywords: Heat Affected Zones, Intra-Granular Ferrite, Nucleation Mechanism, Ti-Killed

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