Dissimilar-welded failure analysis and development: Volume 6, Weld condition and remaining life assessment manual: Final report
Step-by-step guidelines contained in a new engineering manual explain how to evaluate dissimilar metal weld loadings, assess the current state of damage, and predict remaining weld life. Suggested plant and operational modifications will help utility personnel identify root causes and avoid additional failures in a given boiler. Failure of dissimilar metal welds (DMWs) between the austenitic and ferritic steel tubing used in superheaters and reheaters constitutes a major cause of forced outages in fossil boilers. EPRI has undertaken a study of DMWs, reported in volumes 1-6 of this nine-volume series, to provide utilities with a systematic approach for identifying root causes, remedying identified problems, and estimating remaining DMW useful life. This manual follows the three-phase approach outlined in the EPRI guidelines for life extension (report CS-4778). The investigators subjected the samples to detailed metallurgical examination and established correlations among operating conditions, system stresses, and the extent of observed DMW cracking. These correlations were quantified in the PODIS computer code (prediction of damage in service code; EPRI report CS-4252, volume 7). The investigators documented this information in a manual explaining how to carry out life assessment of DMWs. These guidelines describe an analytic procedure that computes the current level of DMW damage based on operating temperature, the number and nature of cycles, and system stresses. They explain a procedure for supplementary destructive examinations to verify the analytic predictions. 10 refs., 20 figs., 2 tabs.
- Research Organization:
- Electric Power Research Inst., Palo Alto, CA (USA); Materials Properties Council, Inc., New York (USA)
- OSTI ID:
- 7128164
- Report Number(s):
- EPRI-CS-5252-Vol.6; ON: TI88016218
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
20 FOSSIL-FUELED POWER PLANTS
AUSTENITIC STEELS
WELDED JOINTS
FERRITIC STEELS
SERVICE LIFE
FORECASTING
FAILURE MODE ANALYSIS
STRESS ANALYSIS
BOILERS
CREEP
FATIGUE
FOSSIL-FUEL POWER PLANTS
HEAT AFFECTED ZONE
MANUALS
METALLOGRAPHY
NONDESTRUCTIVE TESTING
OUTAGES
P CODES
PROGRESS REPORT
STAINLESS STEELS
STEELS
SUPERHEATERS
THERMAL EXPANSION
ALLOYS
CHROMIUM ALLOYS
COMPUTER CODES
CORROSION RESISTANT ALLOYS
DOCUMENT TYPES
EXPANSION
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
MATERIALS TESTING
MECHANICAL PROPERTIES
POWER PLANTS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
TESTING
THERMAL POWER PLANTS
ZONES
360103* - Metals & Alloys- Mechanical Properties
200101 - Fossil-Fueled Power Plants- Cooling & Heat Transfer Equipment & Systems