Optimizing Welding Parameters to Mitigate Hydrogen-Induced Cracking Under Varying Relative Humidity Conditions Using the G-BOP Test

Hydrogen-induced cracking is a critical issue in welding high-strength low-alloy (HSLA) steels, particularly under varying humidity conditions. This study investigates the optimization of welding parameters to mitigate hydrogen-induced cracking in E11018-H4 electrode welds using the G-BOP test and the mercury method. A humidity-controlled chamber was utilized to simulate relative humidity levels of 35%, 65%, and 95%, providing insights into the impact of ambient moisture on diffusible hydrogen content and cold cracking. The Taguchi method, combined with the L18 array, was employed to assess the influence of preheat temperature, welding speed, and current intensity on the incidence of cold cracking. The results show that the amount of diffusible hydrogen in the weld metal goes up with humidity, and the electrode only qualifies as H4 low-hydrogen at 35% relative humidity. Preheating temperatures up to 100°C significantly reduced cold cracking; however, when the preheat temperatures were raised to 125°C and 150°C in high humidity levels of 65% and 95%, cold cracking returned because the extra time and energy allowed more hydrogen to escape from reversible traps. These findings provide new insights for optimizing welding procedures in humid marine environments, where cold cracking in HSLA steel welds poses significant structural risks.