Effect of Weld Metal Microstructure on Cold Crack Susceptibility of High Strength Weld

Abstract:

Facing the practical difficulties in reducing the diffusible hydrogen content of fluxcontaining welding consumables like flux-cored arc welding (FCAW) wires, the present study investigated the microstructural aspect to improve the hydrogen-induced cold crack (HICC) resistance of multipass weld metal of 600MPa strength. Two FCA welding wires were prepared by controlling the Ni content to give different weld microstructure, but to have similar levels of hardness and diffusible hydrogen content. HICC susceptibility of those two consumables was evaluated by 'G-BOP test' and also by 'multi-pass weld metal cold cracking test'. As a result of this study, it was demonstrated that microstructural modification with decreased proportion of grain boundary ferrite (GF) improved cold crack resistance of weld metal. The detrimental effect of GF against HICC has also been addressed based on the characteristics of weld metal cold cracking.

• Periodical: Materials Science Forum (Volumes 580-582)
• Pages: 13-16
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.580-582.13
• Online since: June 2008
• Authors: Hee Jin Kim, Jun Seok Seo, Jae Hak Kim, Ka Hee Kim, Jin Hyun Koh, Hoi Soo Ryoo, Moo Young Huh
• Keywords: Acicular Ferrite, Cold Cracking, Diffusible Hydrogen, Grain Boundary Ferrite, Weld Metal

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