Mechanisms of fatigue in AISI 304 and 316 stainless steels under viscous oil environments, including a coal-process solvent
The fatigue behavior of smooth and pre-cracked specimens of 304 and 316 stainless steels was investigated at 300 K in four environments, namely ambient air, silicone oil, silicon oil + 5 vol.% naphthenic acid, and a coal process solvent. The fatigue life of smooth specimens was enhanced by the three oils in the low cycle regime (<10/sup 5/ cycles) and by the silicone-oil-based environments further in the high cycle regime (>10/sup 5/ cycles), but degraded by the coal process solvent in the high cycle regime. The increased fatigue life in the oils was attributed to an increase in the initiation lifetime for Stage II macrocrack growth. This in turn was related to the smaller slip line spacing in the oils compared to air. The decreased high cycle fatigue life in the coal process solvent was attributed to the formation of coarse slip bands, leading to the crack initiation, which did not occur in air. This is turn was considered to be related to the corrosive attack of aggressive constituents in the coal process solvent. The effect of the oil environments on fatigue crack growth rate (FCGR) of pre-cracked specimens depended on the magnitude of the stress intensity range ..delta..K. For low ..delta..K values the FCGR was relatively little influenced by the three oil environments compared to air. For high ..delta..K values the FCGR was significantly less in the oils than that in air. The shielding from moisture-induced chemical interactions was considered to be a principal factor for retarding the FCGR in the oil at low ..delta..K values. Additional contributions are considered to stem from the greater crack tortuosity, slip reversibility, and the crack tip geometry change.
- Research Organization:
- North Carolina State Univ., Raleigh (USA)
- OSTI ID:
- 6915783
- Country of Publication:
- United States
- Language:
- English
Similar Records
Influence of anodization on the fatigue life of WE43A-T6 magnesium
Fatigue strength of smooth and notched specimens of ASME SA 106-B steel in PWR (pressurized water reactor) environments
Related Subjects
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
02 PETROLEUM
020400 -- Petroleum-- Processing
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
AIR
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
COAL LIQUIDS
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
CRACK PROPAGATION
ENERGY SOURCES
FATIGUE
FLUIDS
FOSSIL FUELS
FRACTURE MECHANICS
FUELS
GASES
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
LIQUIDS
MATERIALS
MECHANICAL PROPERTIES
MECHANICS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
OILS
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
OTHER ORGANIC COMPOUNDS
PETROLEUM
PETROLEUM FRACTIONS
POLYMERS
SILICONES
SILOXANES
STAINLESS STEEL-304
STAINLESS STEEL-316
STAINLESS STEELS
STEELS
STRESS INTENSITY FACTORS