ASTM G148-97 (2018) PDF

Full title and description

ASTM G148-97(2018) — Standard Practice for Evaluation of Hydrogen Uptake, Permeation, and Transport in Metals by an Electrochemical Technique. This practice describes the Devanathan–Stachurski electrochemical permeation method and associated procedures for measuring hydrogen uptake, steady-state hydrogen flux, effective hydrogen diffusivity, and distinguishing reversible versus irreversible trapping in metals and alloys.

Abstract

This practice provides laboratory procedures, specimen preparation guidance, cell and electrode arrangements, test controls, and data-analysis methods for evaluating hydrogen charging, permeation, and transport in metals using an electrochemical technique. It is intended to quantify hydrogen flux through a membrane, determine effective diffusivity, assess trapping behavior, and rank the aggressivity of environments with respect to hydrogen uptake. Results can be combined with mechanical or cracking tests to address hydrogen embrittlement risks.

General information

• Status: Active (reapproved).
• Publication date: January 5, 2018 (designation shown as G148-97(2018)).
• Publisher: ASTM International (Committee G01 — Corrosion of Metals; Subcommittee G01.11).
• ICS / categories: 77.040.01 (Testing of metals in general) — corrosion and hydrogen testing related categories.
• Edition / version: G148-97, reapproved 2018 (commonly cited as G148-97(2018)).
• Number of pages: Approximately 10 pages (ASTM published format).

Scope

The practice gives a procedure for evaluation of hydrogen uptake, permeation, and transport in metals using an electrochemical technique developed by Devanathan and Stachurski. It describes calculation of effective hydrogen diffusivity, methods to distinguish reversible and irreversible traps, measurement of steady-state hydrogen flux as an index of uptake, and guidance for specimen preparation, environmental control, and analysis. The method is applicable in principle to metals and alloys for which hydrogen permeation is measurable and may be adapted for laboratory or field/plant situations with appropriate modifications.

Key topics and requirements

• Devanathan–Stachurski electrochemical permeation cell configuration (charging and oxidation compartments).
• Specimen preparation and mounting to ensure defined exposed areas and minimal edge effects.
• Electrochemical charging procedures (galvanostatic or potentiostatic charging) and control of charging conditions.
• Detection (oxidation) side control, reference/counter electrode selection, and potential control to measure oxidation current from permeated hydrogen.
• Measurement and interpretation of permeation transients, steady-state flux, and decay currents.
• Methods for calculating effective hydrogen diffusivity and for identifying reversible vs. irreversible trapping.
• Recommendations for solution compositions, temperature control, and precautions to avoid contamination or parasitic currents.
• Data analysis and combination of permeation results with mechanical or cracking tests to assess embrittlement thresholds.

Typical use and users

Used by corrosion and materials laboratories, research groups, and engineering teams assessing hydrogen charging and embrittlement risks. Typical users include materials scientists, corrosion engineers, failure analysts, quality/control laboratories, and R&D groups in sectors such as oil & gas (pipelines, fittings), hydrogen energy and fuel systems, aerospace, automotive, and any industry where hydrogen-induced cracking or hydrogen transport in metals is a concern.

Related standards

Commonly referenced and complementary documents include ISO 17081 (electrochemical measurement of hydrogen permeation and transport), ASTM G1 (preparation of corrosion test specimens), ASTM G142 and other hydrogen embrittlement test methods, and various ASTM and ISO guides and test methods for environmentally assisted cracking, slow strain rate testing, and specimen handling. Users should consult ISO 17081:2014 and pertinent ASTM G-series test methods for complete program design.

Keywords

hydrogen permeation, hydrogen uptake, Devanathan–Stachurski, electrochemical technique, hydrogen diffusivity, trapping, hydrogen flux, hydrogen embrittlement, corrosion testing, permeation cell.

FAQ

Q: What is this standard?

A: ASTM G148-97(2018) is a practice that specifies an electrochemical laboratory technique for evaluating hydrogen uptake, permeation, and transport in metals using the Devanathan–Stachurski cell and related procedures.

Q: What does it cover?

A: It covers specimen preparation, cell and electrode arrangements, charging and detection procedures, environmental control, measurement of permeation transients and steady-state flux, calculation of effective hydrogen diffusivity, and approaches to distinguish reversible and irreversible trapping.

Q: Who typically uses it?

A: Materials and corrosion laboratories, researchers, failure analysts, and engineers in industries concerned with hydrogen exposure or hydrogen-induced damage—such as oil & gas, hydrogen fuels, aerospace, and automotive—use this practice.

Q: Is it current or superseded?

A: The designation indicates original adoption in 1997 with reapproval in 2018 (G148-97(2018)). As of the 2018 reapproval it is listed as an active ASTM practice. Users should confirm the current status with ASTM if they require the absolute latest revision status.

Q: Is it part of a series?

A: Yes — it is part of the ASTM G-series on corrosion of metals (under Committee G01) and is complementary to other hydrogen- and embrittlement-related standards and international standards (for example ISO 17081) addressing hydrogen permeation and embrittlement assessment.

Q: What are the key keywords?

A: Hydrogen permeation, hydrogen uptake, Devanathan–Stachurski cell, diffusivity, trapping, steady-state flux, electrochemical measurement, hydrogen embrittlement.