Present status of investigations of attacks by hydrogen upon non-loaded test pieces, as affected by hydrogen pressure, the duration of the experiment, and the hardening state of the material

Technical Report · Tue Apr 04 04:00:00 EDT 1944

OSTI ID:6889747

Tests run before 1940 on resistance of steels to hydrogen attack seemed to indicate that steels containing at least 3% chromium (with or without molybdenum, vanadium, and tungsten) were resistant to attack up to 600/sup 0/C and 700 atm pressure for up to 1000 hours of testing. Hydrogen attack was evaluated by change (reduction) in the value of contraction of the steel. Thus it seemed then that steels such as N6, N8, N9, and N10 could be used in preheater hairpins with no problems. Since ruptures of the steels did occur after all, additional tests were run to take greater measure of the effects of length of exposure of the steels to hydrogen and of hardening procedures used in producing the steel. Those tests showed that hydrogen attack was present, but that it proceeded much more slowly than previously supposed and by unexpected mechanisms, so that even 1000 hours of testing was sometimes not a sufficient testing time. Tests showed that steels should be air-quenched instead of oil-quenched, that they should be annealed at some temperature outside the range 700/sup 0/C to 750/sup 0/C, and that they should have as little as possible of carbides in grain boundaries and carbon dissolved in ferrites. The mechanism of hydrogen attack was reevaluated. Instead of direct attack on carbide within crystalline grains, the mechanism was probably one of attack on carbides at grain boundaries, producing a slow migration of carbon out of the grains to the boundaries (concentration-gradient effect) and leaving a lower carbon concentration in the grains to be compensated for by breakup of carbides in the grains. 4 diagrams.

• Research Organization: I.G. Farbenindustrie, A.G., Merseburg (Germany)
• OSTI ID: 6889747
• Report Number(s): TOM-237-768-774
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
36 MATERIALS SCIENCE
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
ANNEALING
CARBIDES
CARBON
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHROMIUM
COAL
COAL LIQUEFACTION PLANTS
CONTAINERS
CORROSION FATIGUE
CORROSIVE EFFECTS
CRYOGENIC FLUIDS
CRYSTALLIZATION
DIAGRAMS
DIFFUSION
ELEMENTS
ENERGY SOURCES
EQUILIBRIUM
FAILURE MODE ANALYSIS
FAILURES
FATIGUE
FLUIDS
FOSSIL FUELS
FUELS
HARDENING
HEAT TREATMENTS
HIGH PRESSURE
HIGH TEMPERATURE
HYDRIDATION
HYDROGEN
HYDROGENATION
INDUSTRIAL PLANTS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS TESTING
MECHANICAL PROPERTIES
METALS
MOLYBDENUM
NONMETALS
PHASE TRANSFORMATIONS
PRESSURE VESSELS
QUENCH HARDENING
REFRACTORY METALS
RUPTURES
STEELS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
TEMPERATURE EFFECTS
TENSILE PROPERTIES
TESTING
TRANSITION ELEMENTS
TUBES
TUNGSTEN
VANADIUM