Abstract: A study was conducted on the welding process for 9Ni steel used in Type B fuel tanks of Dual-Fuel Container Ships. During procedure qualification tests according to the IGF Code and Classification Society Rules, bend tests of submerged arc welding (SAW) joints exhibited cracking, leading to non-compliance. The issue was resolved by implementing measures such as increasing the width of back gouging and adjusting welding heat input. Microstructural analysis via metallographic examination and fractography of the bend test specimens using scanning electron microscopy (SEM) were performed to investigate the root cause of the cracking. The results indicate that the primary cause of bending failure was a mismatch in strength between the base metal and the weld metal. Furthermore, an excessively acute angle at the junction between the face and root weld beads created a significant stress concentration. The implemented corrective measure involved increasing the width of the back gouging during root preparation. This enlargement increased the overall width at the fusion boundaries of the face and root welds, thereby obtunding the angle at their junction. The modification successfully mitigated the stress concentration, eliminating the bending cracks and ensuring compliance with the required standards.