Mechanisms of hydrogen attack

Journal Article · Sun Jan 01 04:00:00 EST 1978 · Scr. Metall.; (United States)

DOI:https://doi.org/10.1016/0036-9748(78)90121-7· OSTI ID:6783284

Saguees, A A; Hall, B O; Wiedersich, H

A highly sensitive dilatometer was designed for the use of studying the rate of hydrogen attack on carbon steels, measured by the swelling rate, for specimens exposed to various hydrogen pressures and temperatures. The size and distribution of cavities were determined after exposures using standard metallographic techniques. An analytical cavity-growth model which semiquantitatively describes the observed dependence of swelling rate on hydrogen pressure and temperature has been developed. Ferrovac 1020 specimens were exposed to hydrogen pressure of 900 psi at 475/sup 0/C until the substance attained a volume change (..delta..V/V) between 10/sup -3/ and 10/sup -2/. An incubation time, arbitrarily defined as the time required to attain a ..delta..V/V = 10/sup -4/ (usually 40h), and a set of swelling rates were obtained from measured versus time curves. Transverse and longitudinal sections of samples cooled in circulating helium were polished mechanically or electrolytically and examined in either unetched or etched condition by optical or scanning-electron microscopy. The measurements of the rate of hydrogen attack and the methane cavity growth model prove that expansion by creep and surface-reaction rates for methane formation are the primary processes which determine the rate of attack after incubation. A complete quantitative description requires additional study.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 6783284
• Journal Information: Scr. Metall.; (United States), Journal Name: Scr. Metall.; (United States) Vol. 12; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALKANES
ALLOYS
BUBBLES
CARBON STEELS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
DILATOMETRY
ELECTRON SCANNING
ELECTRONIC EQUIPMENT
ELEMENTS
EQUIPMENT
FLUIDS
HIGH TEMPERATURE
HYDRIDATION
HYDROCARBONS
HYDROGEN
IRON ALLOYS
IRON BASE ALLOYS
MEDIUM PRESSURE
METALLURGICAL EFFECTS
METHANE
NONMETALS
OPTICAL EQUIPMENT
OPTICAL SCANNERS
ORGANIC COMPOUNDS
PRESSURE DEPENDENCE
STEELS
TEMPERATURE DEPENDENCE
THERMAL ANALYSIS
TIME DEPENDENCE
YIELDS