Evaluation of temper embrittlement in turbine rotor material

Technical Report · Fri Feb 01 04:00:00 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

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