Weld metal hydrogen pickup in underwater wet welding is severe due to the presence and dissociation of water surrounding the welding arc. This undesirable behavior can be minimized, however, with the use of oxidizing-type electrodes. The purpose of this investigation has been placed on the fundamental understanding of the effect of hydrogen pickup by the slag on the weld metal diffusible hydrogen content in direct current, shielded metal arc welding (SMAW) for both electrode-positive polarity (DCEP), and electrode-negative polarity (DCEN). To accomplish this purpose, 20 experimental oxidizing electrodes containing systematic ferric oxide (Fe2O3) additions, ranging from 0 to 70 wt. percent, to the flux coating were investigated. The mole fraction ratio of CaO/SiO2 in the fluxes ranged from 0.05 to 0.35, independent of the ferric oxide additions. Underwater, bead-on-plate welds were deposited on ASTM A36 steel coupons at 0.27 m (city) water depth using a gravity feed system. Welding parameters were held constant throughout the experiments. Weld metal diffusible hydrogen content was determined using the mercury displacement method according to current AWS standard. To correlate weld metal hydrogen content with slag chemistry, the slag hydrogen contents were also determined. The measured diffusible hydrogen contents showed that Fe2O3 was effective in reducing weld metal hydrogen content. Higher hydrogen values were always related to lower Fe2O3 contents initially present in the flux, for instance, 71 mL/100g (DCEP − 0 wt. percent Fe2O3) as compared to 31 mL/100g (DCEP − 36 wt. percent Fe2O3). Amazingly, diffusible hydrogen as low as 13 mL/100g was obtained with the use of DCEN polarity along with 53 wt. percent Fe2O3 in the flux coating. X-ray diffraction (XRD) conducted on different slags showed that the lower diffusible hydrogen values were always associated with the presence of fayalite (2FeO·SiO2). Complementing XRD analysis, Mo¨ssbauer spectroscopy analyses carried out on different slags showed that all ferric (Fe3+) oxide initially present in the slags had transformed to ferrous oxide (FeO), free or combined. Chemical analyses showed that weld metal hydrogen pickup was strongly dependent on the solubility of water in the slag systems. The total and diffusible hydrogen content in the weld metal increased monotonically with increasing slag hydrogen content. Finally, variations in weld metal hydrogen as well as slag hydrogen content with both polarity and iron oxide content in the slag were successfully predicted using an electrochemical model that describes the slag/metal interface equilibrium. In this investigation, the slag/metal interface has been identified as responsible in controlling the weld metal hydrogen pickup. The model assumed that hydrogen was present in the slag as (OH)− ions and that FeO displayed ideal solution behavior.
Skip Nav Destination
Article navigation
November 1998
Research Papers
A Predictive Electrochemical Model for Weld Metal Hydrogen Pickup in Underwater Wet Welds
R. C. de Medeiros,
R. C. de Medeiros
Brazilian Foundation of Welding Technology, 28 Rua Capistrano de Abreu, Rio de Janeiro, RJ 22271-000, Brazil
Search for other works by this author on:
S. Liu
S. Liu
Center for Welding, Joining and Coatings Research, Colorado School of Mines, Golden, CO 80401
Search for other works by this author on:
R. C. de Medeiros
Brazilian Foundation of Welding Technology, 28 Rua Capistrano de Abreu, Rio de Janeiro, RJ 22271-000, Brazil
S. Liu
Center for Welding, Joining and Coatings Research, Colorado School of Mines, Golden, CO 80401
J. Offshore Mech. Arct. Eng. Nov 1998, 120(4): 243-248 (6 pages)
Published Online: November 1, 1998
Article history
Received:
January 23, 1998
Revised:
June 11, 1998
Online:
December 17, 2007
Citation
de Medeiros, R. C., and Liu, S. (November 1, 1998). "A Predictive Electrochemical Model for Weld Metal Hydrogen Pickup in Underwater Wet Welds." ASME. J. Offshore Mech. Arct. Eng. November 1998; 120(4): 243–248. https://doi.org/10.1115/1.2829547
Download citation file:
Get Email Alerts
Time-dependent wave motion in a running stream due to initial disturbances in Magnetohydrodynamics
J. Offshore Mech. Arct. Eng
The autonomous urban passenger ferry milliAmpere2: Design and testing
J. Offshore Mech. Arct. Eng
Numerical Analysis of the Effect of Tunnel Hydrofoil—Stern Flap on the Motion Stability of a Double M-Craft in Regular Waves
J. Offshore Mech. Arct. Eng (August 2025)
On the Performance of a Data-Driven Backward Compatible Physics-Informed Neural Network for Prediction of Flow Past a Cylinder
J. Offshore Mech. Arct. Eng (August 2025)
Related Articles
Iron-Containing Yttria-Stabilized Zirconia System For Two-Step Thermochemical Water Splitting
J. Sol. Energy Eng (February,2008)
Effects of Welding Conditions on Molten Drop Geometry in Arc Welding
J. Manuf. Sci. Eng (November,1996)
Weld Metal Chemistry of Mineral Waste Added SiO 2 –CaO–CaF 2 –TiO 2 Electrode Coatings for Offshore Welds
J. Pressure Vessel Technol (June,2020)
Designing Shielded Metal Arc Consumables for Underwater Wet Welding in Offshore Applications
J. Offshore Mech. Arct. Eng (August,1995)
Related Proceedings Papers
Related Chapters
Surface Analysis and Tools
Tribology of Mechanical Systems: A Guide to Present and Future Technologies
Development of New Process and Product Monitoring Technologies for the Manufacturing of High Value Alloy Steels for Use in Critical Applications
Bearing and Transmission Steels Technology
Accurate Detection of Weld Defects Using Chirplet Transform
International Conference on Computer and Automation Engineering, 4th (ICCAE 2012)