Hydrogen diffusion and trapping in X70 pipeline steel. (13th January 2020)

• Record Type: Journal Article
• Authors: Thomas, Alen; Szpunar, Jerzy A.
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 3(2020)
• Page Start: 2390
• Page End: 2404
• Publication Date: 2020-01-13
• Subjects: Hydrogen permeation -- Hydrogen microprint technique -- Hydrogen traps -- Diffusion path -- Grain boundary -- Triple junctions; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.11.096
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In this investigation, the hydrogen permeation experiment was used to determine the parameters for diffusion, and the hydrogen microprint technique was used to visualize the diffusion path in X70 pipeline steels. The samples in mid-layer at the segregation zone and top-layer of the steel were used in this study. The diffusion parameters from the hydrogen permeation experiment enabled us to determine that the calculated density of total, reversible, and irreversible hydrogen trapping sites in the top layer of the steel decreases for larger grains. However, the irreversible and total trapping sites of the mid-layer showed an initial growth and subsequent decay with grain growth due to the inclusions in mid-layer. The observations from the hydrogen microprint experiment allowed us to conclude that the preferential hydrogen diffusion increases in the order of grains, grain boundaries, triple junctions and cementites with cementites being the easiest path for hydrogen diffusion. Highlights: Dual-polarized hydrogen permeation testing in different layers of pipeline steel. The rise in hydrogen diffusion by reduced trapping for larger grains. Improvement in hydrogen microprint technique to identify reversible hydrogen traps. Visualization of hydrogen diffusion path in degenerate pearlite microstructure. Comparison of preferential hydrogen diffusion in steel microstructure.