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Karpenko Physico-Mechanical Institute Bay Zoltan Foundation for Applied Research

Karpenko Physico-Mechanical Institute Bay Zoltan Foundation for Applied Research. H.M. Nykyforchyn, O.Z. Student, G. Lenkey, A.D. Markov STRENGTH OF POWER PLANT INSTALATIONS ELEMENTS AND DURABILITY ANALYSIS BASED ON THE FRACTURE RISK.

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Karpenko Physico-Mechanical Institute Bay Zoltan Foundation for Applied Research

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  1. Karpenko Physico-Mechanical InstituteBay Zoltan Foundation for Applied Research H.M.Nykyforchyn, O.Z. Student, G.Lenkey, A.D.Markov STRENGTH OF POWER PLANT INSTALATIONS ELEMENTS AND DURABILITY ANALYSIS BASED ON THE FRACTURE RISK 2nd Hungarian-Ukrainian Joint Conferenceon SAFETY-REALIABILITY and RISK of ENGINEERING  PLANTS and COMPONENTS 19-21September 2007, Kyiv, Ukraine

  2. Introduction Lifetime of structural element consists in: at ambient temperature Crack initiation stage → Crack propagation stage at elevated temperature Microstructure change (because of diffusion) stage → Crack initiation stage → Crack propagation stage Hydrogen intensifies diffusion and correspondingly accelerates microstructure change stage induced by diffusion processes

  3. 0 hours 48,000 hours 110,000 hours 190,000 hours Microstructure of the 12Kh1MF (0.1C-1.1Cr-0.26Mo-0.17V) steam pipeline steel depending of the service time

  4. Tensile properties of the 12Kh1MF steel The effect of operation time on fracture toughness of the 12Kh1MF steel Effect of the operation time ор (1) on the parameter Kth eff for the 12H1МF steel

  5. Fatigue crack growth rate across pipe wall at constant stress intensity factor range for steel after long term service

  6. The method of high temperature degradation of steels - thermocycling in hydrogen Microstructure of the 12Kh1MF (0.1C-1.1Cr-0.26Mo-0.17V)steam pipeline steel depending of the numbers of thermocycles

  7. Operation Crack growth direction Effect of the operation time ор (1) and number of thermocycles in hydrogen n (2) on the parameter Kth eff for the 12H1МF steel Thermocycling

  8. Hardness of steam pipeline weld joint of exploited 200,000h (on left) and in initial state (on right)

  9. The mechanical properties of weld metal (WM) in virgin state (light bars) and after ~2∙105 h service time (dark bars). Figures indicate a percentage change of properties as a result of exploitation

  10. Comparison of the mechanical parameters of metal state concerning its sensitivity to high temperature degradation of weld metal (a) and base metal (b): l – relative change of the corresponded parameters as a result of service OM OM OM BM OM ← → Hydrogenation allows to reveal even base metal “in-bulk” degradation Ultimate strength (σB) and yield strength (σ0,2) of base metal and weld metal on air (light bars) and after hydrogen charging (dark bars) initial serviceinitial service

  11. The parent A-516 Gr.60 steel was cladded with 410S ferritic stainless steel (flyer)

  12. Peculiarities of hydrogen effect on the creep process in the Cr-Ni steel Fracture of hydrogenated specimen in as received state air Fracture of hydrogenated specimen in degraded state H2

  13. ELECTROCHEMICAL PARAMETERSsteam pipeline 12Kh1MF steel

  14. Risk Based Maintenance and Inspection (RBMI) Approach Allocation of the thermal fatigue cracks around the hole on the internal surface of the collector of water economizer

  15. Risk matrix for the economizer collector after 18∙104 h of service (area 4D) and its predicted state after performing of the recommended works (area 3С)

  16. Conclusions 1. The thermocycling of the material containing dissolved hydrogen is the effective rapid method for testing of high temperature degradation of steels. 2. The parameters of crack growth resistance are especially sensitive to high temperature metal degradation in the service and laboratory conditions. 3. Weld metal of steam pipeline steel is the most disposed to high-temperature degradation. In this case the tensile mechanical properties of strength and plasticity are sensitive enough to “in-bulk” material degradation. The revealed simultaneous reduction of strength and brittle fracture resistance is a phenomenon of in-service degradation. This phenomenon is strengthened by non-typical change of the parameters of plasticity: an elongation increases and reduction of area decreases with the weld metal service. 4. Hydrogen accelerates creep rate in the hydrocracking reactor shell steel. 5. A good correlation between changes of electrochemical and mechanical parameters gives prospects for the development of NDT methods for evaluation of the current state of steels irrespective of the fact that material is exploited or not exploited in corrosion-hydrogenated environments. 6. The example of a usage of Risk Based Maintenance and Inspection (RBMI) Approach is presented concerning the collector of water economizer.

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