Evaluation of temper embrittlement in turbine rotor material

Technical Report · Fri Feb 01 00:00:00 EST 1991

OSTI ID:6174732

Kaplan, A; Pepe, J ^[1]

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1. General Electric Co., Schenectady, NY (USA)

A major requirement for the reliable operation of modern NiCrMoV steel low pressure (LO) rotor forgings is a toughness level high enough to tolerate small flaws. Since LP rotor forgings operate at elevated temperatures for prolonged periods of time, it is important to insure that the rotor's toughness does not degrade due to thermal exposure during its service life. One phenomena which is known to degrade the toughness of NiCrMoV rotor forging material with time is temper embrittlement. Temper embrittlement is of most concern in the temperature range 316--510{degree}C (600--950{degree}F). The major chemical elements responsible for temper embrittlement are known to be P, Si, Sn, Sb and As. This report describes the development of a mathematical model obtained by regression techniques for prediction of the degree of temper embrittlement based on the chemistry, strength, mechanical properties and other characteristics of the rotor. In addition, the effects of temper embrittlement on the fracture toughness as determined by J{sub Ic} samples and on the fatique life were examined. Finally, a model was developed for the prediction of temper embrittlement in CrMoV rotor steels based on some limited available data. 45 refs., 46 figs., 22 tabs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (USA); General Electric Co., Schenectady, NY (USA)
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (USA)
• OSTI ID: 6174732
• Report Number(s): EPRI-GS-7145
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
20 FOSSIL-FUELED POWER PLANTS
EMBRITTLEMENT
MATHEMATICAL MODELS
MOLYBDENUM ALLOYS
NICKEL-CHROMIUM STEELS
ROTORS
MECHANICAL PROPERTIES
VANADIUM ALLOYS
ANTIMONY
ARSENIC
EVALUATION
FATIGUE
FORGING
FRACTURE PROPERTIES
HIGH TEMPERATURE
LEAD
LOW PRESSURE
OPERATION
REGRESSION ANALYSIS
SERVICE LIFE
SILICON
STEAM TURBINES
TIN
ALLOYS
CHROMIUM ALLOYS
ELEMENTS
FABRICATION
IRON ALLOYS
IRON BASE ALLOYS
MACHINERY
MATERIALS WORKING
MATHEMATICS
METALS
NICKEL ALLOYS
NICKEL STEELS
SEMIMETALS
STATISTICS
STEELS
TURBINES
TURBOMACHINERY
360103* - Metals & Alloys- Mechanical Properties
200104 - Fossil-Fueled Power Plants- Components