Prediction of creep life exhaustion in high energy piping system girth welds

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:176094

Cohn, M J ^[1]

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1. APTECH Engineering Services, Inc., Sunnyvale, CA (United States)

Conventional United States designs of high energy fossil power piping systems use the American Society of Mechanical Engineers (ASME) B31.1 Power Piping Code. Analytical methodology in the Code is based on thin shell linear elastic beam theory. The Code is developed to be used as a piping system design tool. It is inadequate as a tool to evaluate some in-service problems in high energy piping systems. Main steam and hot reheat piping system materials are usually subject to creep during normal operation. The process of time dependent material creep damage leads to accelerated rates of creep cavitation and life consumption. This effect results in the redistribution of high thermal stresses and material property degradation in service. There are no guidelines in the Code to address life consumption or in-service degradation issues. A methodology is presented which considers an approach to evaluate the time dependent life consumption in high energy piping systems. This approach is applied in a case study to reconcile stresses which significantly exceed the Code stress allowable. The paper also includes an approach to select highest creep damage locations for nondestructive examination (NDE).

• OSTI ID: 176094
• Report Number(s): CONF-950740--; ISBN 0-7918-1346-0
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
42 ENGINEERING
CREEP
ELASTICITY
FORECASTING
FOSSIL-FUEL POWER PLANTS
NONDESTRUCTIVE TESTING
SAFETY STANDARDS
SERVICE LIFE
STEAM LINES
STEAM TURBINES
STEEL-CR2MO
STRESS ANALYSIS
STRESS RELAXATION
THERMAL STRESSES
WELDED JOINTS