Penetration-Dependent Microstructures in TiO2-Induced Weld Metal of EH36 Shipbuilding Steel

Microstructural characteristics has been investigated along the weld metal penetration of EH36 shipbuilding steel processed by CaF2–30 wt. pct TiO2 flux under 60 kJ·cm−1 submerged arc welding. It is demonstrated that microstructures have been significantly refined from equiaxed to columnar grain zone, where acicular ferrite morphology varies from plate to lath. Concurrently, the fraction of acicular ferrites is enhanced while that of polygonal ferrites shrinks, enabling a bimodal misorientation distribution towards auspicious properties.