Change in the crack resistance of steam pipes of steel 12Kh1MF as a result of long service

Journal Article · Thu May 01 00:00:00 EDT 1986 · Sov. Mater. Sci. (Engl. Transl.); (United States)

DOI:https://doi.org/10.1007/BF00722248· OSTI ID:7141721

Blanter, M E; Dzioba, I R; Islamov, A A; Simin'kovich, V N

Steam pipes in electric power plants are subjected in service to the long-term action of mechanical loads and high temperatures. Since emergencies can arise due to slow crack growth and subsequent sudden fracture of a structural element, the optimum design and reliable use of power plants require data on the crack resistance of the structural materials used. The goal of the present study is to evaluate the change in the resistance of the metal of steam lines in heat and electric power plants to brittle fracture in relation to structural changes in service. Microstructural analysis showed the initial ferrite-pearlite structure is transformed during service into a ferritecarbide structure. It is found that the structural and phase transformations which occur in the metal of steam pipes during service cause a significant reduction in resistance to brittle fracture. There is a simultaneous deterioration in the strength properties of the steel. The study results show a need to allow for the embrittlement of steam-pipe metal during service when performing periodic cold hydraulic pressing. This pressure-testing may, according to the authors, cause the nucleation and growth of brittle cracks capable of leading to pipe fracture.

• Research Organization: G.V. Karpenko Physicomechanical Institute, Academy of Sciences of the Ukrainian SSR, Lvov
• OSTI ID: 7141721
• Journal Information: Sov. Mater. Sci. (Engl. Transl.); (United States), Vol. 21:6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
STEAM LINES
FRACTURE PROPERTIES
THERMAL DEGRADATION
STEEL-12KH1MF
THERMAL POWER PLANTS
CRACK PROPAGATION
CRYSTAL-PHASE TRANSFORMATIONS
DUCTILE-BRITTLE TRANSITIONS
FERRITE
MICROSTRUCTURE
PEARLITE
PIPES
SERVICE LIFE
TEMPERATURE EFFECTS
THERMAL CYCLING
ALLOYS
CARBON ADDITIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CRYSTAL STRUCTURE
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ADDITIONS
MANGANESE ALLOYS
MECHANICAL PROPERTIES
MOLYBDENUM ADDITIONS
MOLYBDENUM ALLOYS
PHASE TRANSFORMATIONS
POWER PLANTS
SILICON ADDITIONS
SILICON ALLOYS
STEELS
VANADIUM ADDITIONS
VANADIUM ALLOYS
360103* - Metals & Alloys- Mechanical Properties