Mechanisms of hydrogen attack in 2 1/4Cr-1Mo reactor steel

Conference · Sat May 01 04:00:00 EDT 1982 · Proc., Am. Pet. Inst., Refin. Dep.; (United States)

OSTI ID:5253169

Erwin, W E

Using laboratory data from 1/4-inch-diameter tensile specimens and 1-inch-thick, stainless-steel-clad hollow rounds, both surface decarburization and methane bubble formation have been shown to be active during hydrogen attack of quenched and tempered 2 1/4Cr-1Mo steel used in hydroprocessing reactor vessels. Test conditions were exposure to hydrogen at about 3000 pounds per square inch at 850-1000 F for times up to 5 1/2 years, with no applied stress on the specimen. Test results indicate essentially no decarburization at 850 F, slight decarburization at 925 F, and at 1000 F a carbon content decrease of 0.02-0.04 percent, which decreased yield and tensile strengths by about 25 percent. For the test conditions above, isolated methane bubbles were observed, primarily along grain boundaries, in all samples exposed to hydrogen. Bubble size and density were characterized and found to increase with both increasing temperature and longer exposure times. At 850 F and 925 F, the rate of bubble growth over time is constant, implying that bubbles are in a stage of isolated growth without coalescence. By extrapolating the rate of bubble growth to longer times, the data without applied stress suggest that at 850 F, after 30 years of hydrogen exposure, bubbles will be too few and widely spaced to coalesce into fissures or affect mechanical properties. The data indicate that stainless cladding has at most a small effect on surface decarburization and no effect on methane bubble formation.

• Research Organization: Standard Oil of California, Richmond, California
• OSTI ID: 5253169
• Report Number(s): CONF-8205233-
• Conference Information: Journal Name: Proc., Am. Pet. Inst., Refin. Dep.; (United States) Journal Volume: 61
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALKANES
ALLOYS
BUBBLE GROWTH
CARBON
CHEMICAL REACTIONS
CHEMICAL REACTORS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-MOLYBDENUM STEELS
CRYSTAL STRUCTURE
DECARBURIZATION
DENSITY
ELEMENTS
EMBRITTLEMENT
GRAIN BOUNDARIES
HEAT TREATMENTS
HYDROCARBONS
HYDROGEN EMBRITTLEMENT
INDUSTRIAL PLANTS
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
METHANE
MICROSTRUCTURE
NONMETALS
ORGANIC COMPOUNDS
PETROLEUM REFINERIES
PHYSICAL PROPERTIES
QUENCHING
SIZE
STEELS
SURFACES
TEMPERATURE DEPENDENCE
TEMPERING
TENSILE PROPERTIES
TESTING
VERY HIGH TEMPERATURE
YIELD STRENGTH