Challenges Associated with the Measurement of Diffusible Hydrogen in Steel Weld Metal Deposits Using the Hot Carrier Gas Extraction Method
Abstract
The Naval Surface Warfare Center, Carderock Division (NSWCCD) Welding, Processing, and Nondestructive Evaluation Branch (Code 611) has undertaken a series of experiments aimed at elucidating the important details and potential challenges associated with the hot carrier gas extraction technique for measuring diffusible hydrogen in deposited weld metal. At the time of this report, the American Welding Society (AWS) was considering revising its specification for diffusible hydrogen testing (AWS A4.3) to include this relatively new method that is invoked by international standards (ISO 3690). However, exploratory work by NSWCCD and others raised questions concerning the technique's robustness, particularly with respect to proper specimen heating and complete hydrogen evolution. To characterize these concerns, two categories of trials were employed: (1) diffusible hydrogen measurements of weld deposits made with electrodes encompassing a wide range of hydrogen contents (3 to 50 mL/100 g) and (2) thermal-only tests using the hot carrier gas extraction apparatus. The results of hydrogen analyses indicate that the time-temperature combinations for hot carrier gas extraction that are specified in the current version of ISO 3690 need to be evaluated for individual combinations of testing apparatus and weld metal hydrogen content to ensure complete hydrogen evolution and correct measurement. Additionally, significant changes to the measured amount of diffusible hydrogen can occur based on interpretation of the hydrogen evolution curve. Finally, the thermal conductivity detector of the Bruker G4 Phoenix was not susceptible to signal saturation during hot carrier gas extraction, even when weld metal deposits that contained extremely large amounts of diffusible hydrogen were analyzed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2022
- Accession Number
- AD1225112
Entities
People
- Daniel H. Bechetti
- Jeffrey D. Farren
- Matthew F. Sinfield
Organizations
- Naval Surface Warfare Center Carderock Division