Remaining-life estimation of boiler pressure parts

Technical Report · Fri Feb 01 04:00:00 EST 1991

OSTI ID:6077988

Borden, M P; Ellis, F V ^[1]; Miller, D A; Gladwin, D ^[2]

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1. ABB Combustion Engineering Systems, Chattanooga, TN (USA)
2. National Power, Leatherhead (UK)

One of the objectives of this project was to determine the effect of prior creep damage on the remaining life of base material and HAZ material subjected to pure fatigue and creep fatigue loading. Life assessment techniques for cyclic loading conditions are required due to the need to two shifts (two shifts on, one shift off) or load-follow for conventional fossil power plant as new nuclear units become available. Described herein are the results of work undertaken at ABB Combustion Engineering Systems in the US and South Western Regional Scientific Services Department and Central Electricity Research Laboratories of the Central Electricity Generating Board in the UK. An interrupted creep testing program was conducted on a single heat of 1Cr--1/2Mo steel to produce creep damaged or pre-crept material for the pure fatigue and creep-fatigue test programs. Metallographic examination of the pre-crept material revealed the primary creep damage mechanism was thermal softening for the base material and creep cavitation for the HAZ material. Creep rupture properties were measured for the virgin, aged, and pre-crept materials at the creep-fatigue test temperature of 535{degree}C to aid in interpretation of the effect of prior creep on creep-fatigue life. Creep-fatigue life prediction was performed using the linear life fraction rule, stress based and strain-based life fraction approaches. The remanent creep-fatigue of the HAZ material can be predicted by conducting a linear summation of creep life fraction and creep-fatigue life fraction. This approach is not applicable for base material. The life fraction method of predicting the as-received creep-fatigue endurance data based on a ductility exhaustion approach gave better prediction than a stress based approach. The implications of the current project results are discussed in terms of developing an assessment procedure for determining the creep-fatigue life of elevated temperature components. 21 refs., 54 figs., 15 tabs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (USA); ABB Combustion Engineering Systems, Chattanooga, TN (USA); National Power, Leatherhead (UK); Central Electricity Generating Board, Bristol (UK). Scientific Services Dept.
• Sponsoring Organization: EPRI; Electric Power Research Inst., Palo Alto, CA (USA)
• OSTI ID: 6077988
• Report Number(s): EPRI-CS-5588-Vol.5
• 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
BOILERS
CHROMIUM-MOLYBDENUM STEELS
CREEP
DAMAGE
EQUATIONS
FAILURE MODE ANALYSIS
FATIGUE
FOSSIL-FUEL POWER PLANTS
FRACTURE PROPERTIES
HIGH TEMPERATURE
MECHANICAL PROPERTIES
POWER PLANTS
PREDICTION EQUATIONS
RELAXATION
SERVICE LIFE
STRAINS
STRESS RELAXATION
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
TENSILE PROPERTIES
TESTING
THERMAL POWER PLANTS