A novel liquid-shielded welding solution for diffusible hydrogen content restriction and metal transfer controlling in underwater FCAW condition. (5th February 2022)

• Record Type: Journal Article
• Authors: Zhang, Xin; Guo, Ning; Luo, Wenxue; Xu, Changsheng; Tan, Yanbo; Fu, Yunlong; Cheng, Qi; Chen, Hao; He, Jinlong
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 11(2022)
• Page Start: 7362
• Page End: 7367
• Publication Date: 2022-02-05
• Subjects: Liquid shielded welding -- Diffusible hydrogen -- Underwater welding -- Glycerol -- X-ray imaging method -- Flux-cored welding; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.12.052
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Hydrogen produced by water decomposition caused high diffusible hydrogen content in deposited metal, but also produced numerous spatter and unstable fragments which were considered as the main reason that deteriorated the weld formation during underwater wet flux cored welding (FCAW). Drawn inspiration from onshore gas shielded welding, in this paper, a liquid shielded welding method was invented. As a by-product of biodiesel, glycerol was chosen as liquid protectant. The results suggested that the diffusible hydrogen content in deposited metal was reduced by 62.4% with glycerol shielded due to its higher decomposition threshold and less hydrogen in decomposition products. Arc bubbles were attached to the molten pool surface and their expansion rate and rising velocity were slowed down resulted in more stable droplet transfer process and less spatter owing to high viscosity glycerol protectant. Almost porosity-free joints were obtained and the mechanical properties of the welded joints were also improved. Highlights: A novel liquid shielded welding method with glycerol as protectant was developed for underwater welding. The generation and movement of hydrogen arc bubbles were under stable control. The proportion of unstable droplet transfer ratio decreased from 14.74% to 6.71%. The weld morphology was smoother and the porosity disappears. The diffused hydrogen content decreased from 8.56 to 3.22 ml/100 g by 35.7%.