Thermal transients and creep effects on theoretical and experimental assessment in operating high temperature steam piping
Transient, creep and relaxation studies of operating high pressure piping in AISI 316 have been developed by the Italian Electrical Board in view of reassessing the structural and mechanical integrity of the line. The influence of the prestressing on the pipe is examined to determine the modifications on stress and strain response in time. Sectional analysis with 3D finite element computer programme, assuming elastic and elastic-plastic deformation of the material, shows the congruence of theoretical approach with the experimental data; also, local strain gauge monitoring of some sections offers a good tool for validating theoretical computations which are in acceptable agreement with the quantities recorded. Many creep-relaxation cycles are introduced to simulate the effect of further long-term exposure to the piping in creep range, up to 50,000 hours, and to understand the cold spring effect on piping stress. The examination of cycles in creep regime allows to describe the behaviour of time dependent stress redistribution along the line, and gives some estimation about the safety margin existing in the structure.
- Research Organization:
- CNEN-DRV, Bologna
- OSTI ID:
- 5611036
- Report Number(s):
- CONF-820601-
- Journal Information:
- Am. Soc. Mech. Eng., Pressure Vessels Piping Div., (Tech. Rep.) PVP; (United States), Vol. PVP-VOL. 66; Conference: ASME pressure vessel and piping conference, Orlando, FL, USA, 27 Jun 1982
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PIPES
CREEP
THERMODYNAMICS
STAINLESS STEEL-316
COMPUTER CALCULATIONS
DEFORMATION
ELASTICITY
HIGH PRESSURE
HIGH TEMPERATURE
PLASTICITY
PROGRAMMING
RELAXATION
SAFETY
STEAM
STRAIN GAGES
STRESSES
TIME DEPENDENCE
TRANSIENTS
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MEASURING INSTRUMENTS
MECHANICAL PROPERTIES
MOLYBDENUM ALLOYS
NICKEL ALLOYS
STAINLESS STEELS
STEELS
TENSILE PROPERTIES
420500* - Engineering- Materials Testing