Elevated-temperature fracture toughness and fatigue testing of steels for geothermal applications. Annual progress report
Conventional drill bit steels exhibit increased wear and decreased toughness when run at elevated temperatures in geothermal wells. Bits are therefore run at lower speeds and lighter loads, resulting in lower penetration rates for geothermal wells than for conventional rock drilling. Carpenter EX-00053, Timken CBS 600, Timken CBS 1000M and Vasco X-2M, steels with improved hot hardness (improved wear resistance), were tested in conjunction with the steels used for cones (AISI 4820 and 9315) and lugs (AISI 8620 and 9315) in conventional roller cone rock bits. Shortrod fracture toughness measurements were made on each of these steels between room temperature and 400/sup 0/C. Fatigue crack resistance was determined at 300/sup 0/C for high-temperature steels and at room temperature for conventional steels. Scanning electron microscopy analyses of the fractured short-rod specimens were correlated with observed crack behavior from the test records. Test results are discussed, recommendations made for further testing and preliminary steel selections made for improved geothermal bits.
- Research Organization:
- Terra Tek, Inc., Salt Lake City, UT (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6121884
- Report Number(s):
- DOE/CH/00016-T2; ON: DE83013874
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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DRILL BITS
MATERIALS TESTING
GEOTHERMAL WELLS
STEELS
FRACTURE PROPERTIES
WEAR RESISTANCE
CRACKS
FATIGUE
WELL DRILLING
ALLOYS
DRILLING
DRILLING EQUIPMENT
EQUIPMENT
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
TESTING
WELLS
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