TiO2-Assisted Microstructural Variations in the Weld Metal of EH36 Shipbuilding Steel Subject to High Heat Input Submerged Arc Welding

Two simple yet comparable fluxes, CaF2 and CaF2-40 wt pct TiO2, have been employed to engineer shipbuilding steels under high heat input submerged arc welding, aiming to clarify the unique functions demonstrated by incurring TiO2 addition. Compared with pure CaF2, TiO2-containing flux could increase columnar austenite width from 119.2 +/- 18.1 to 201.5 +/- 32.2 mu m. Furthermore, TiO2 could significantly enhance acicular ferrite fraction, which has been primarily enabled by the formation of Ti-bearing inclusions.

Automated summary

Two comparable fluxes, pure CaF2 and CaF2-40 wt pct TiO2, were used to modify shipbuilding steels under high heat input submerged arc welding to investigate the unique functions of TiO2 addition. Compared with pure CaF2, TiO2-containing flux could increase the width of columnar austenite from 119.2 +/- 18.1 to 201.5 +/- 32.2 μm. Furthermore, TiO2 could significantly enhance the fraction of acicular ferrite, primarily through the formation of Ti-bearing inclusions.