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Quantifying the hydrogen embrittlement of pipeline steels for safety considerations ( #186)

International Conference on Hydrogen Safety "Enabling Progress and Opportunities" September 12-14, 2011 San Francisco, California-USA. Quantifying the hydrogen embrittlement of pipeline steels for safety considerations ( #186). L. Briottet, I. Moro, P. Lemoine

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Quantifying the hydrogen embrittlement of pipeline steels for safety considerations ( #186)

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  1. International Conference on Hydrogen Safety "Enabling Progress and Opportunities" September 12-14, 2011 San Francisco, California-USA Quantifying the hydrogen embrittlement of pipeline steels for safety considerations(#186) L. Briottet, I. Moro, P. Lemoine CEA,LITEN, DTBH/LCTA, F-38054 Grenoble, France LITEN/DTBH/LCTA Sept. 14, 2011

  2. Scope • Development of a hydrogen pipeline delivery infrastructure •  High initial capital cost • No recognized international methods to choose materials • - specific application • - very different testing conditions • - materials susceptibility to HE • - improving safety coefficients for component design How to quantify Hydrogen Embrittlement under hydrogen gas pressure? French National Research Agency projects – CATHY-GDF, CESTAR

  3. Approach • API grade X80 ferrito-pearlitic steel • Various mechanical tests under hydrogen high pressure • Many ways to quantify hydrogen embrittlement • Comparison of some possible embrittlement indices • Discussion

  4. Monotonic loading Tensile test Up to 35 MPa H2 Disk pressure Test (ISO 11114-4 method A) PHe / PH2

  5. Fracture mechanics / Dynamic loading Compact Tensile Single Edge Notch Tensile specimen Initial crack Monotonic loading Fracture toughness Cyclic loading Fatigue Crack Growth Up to 35 MPa H2

  6. AL Fracture mechanics / Static loading Wedge Opening Load - Static loading (ISO 11114-4 method C) Loading conditions Air Inert gas H2 30 MPa H2

  7. High-strength steel grade API X80 F914.4 mm x e12.7 mm w% Pearlite alignments Ferrite + pearlite

  8. Monotonic loading – Main results Tensile tests • No influence on s0.2 or UTS •  Strain rate   ductility •  P (up to ~10 MPa)   ductility Disk pressure tests • Efficient empirical criteria for seamless bottles • Not based on an understanding of the HE mechanisms •  How to use it for other applications? PHe / PH2~ 2

  9. Fracture mechanics – Main results WOL - Static loading – 30 MPa • Several K • Precracking in air or H2 • No crack propagation after 1000 hr Toughness – Monotonic loading - 30 MPa • 220 kJ/m² (N2)  15 kJ/m² (H2)

  10. H2 - 0.1 Hz air Fracture mechanics – Main results Fatigue Crack growth – Cyclic loading - 30 MPa FCG • FCG x 10 • Significant effect even at low P

  11. Some possible HE indices definition 0 % no effect 100 % maximum effect Tensile elongation Toughness FCG rate Disk pressure test WOL crack length And more ……

  12. Tensile test Quasi-cleavage External cracks Damage analysis Disk pressure test Quasi-cleavage Ductile H2 inlet Toughness test Same ao Same final COD H2 inlet

  13. Embrittlement index X80 HS steel Fracture mechanics Continuum mechanics Static loading Cyclic Monotonic loading • Necessary to provide guidelines to select the appropriate test

  14. High kinetic for • HE reversibility • HE occurrence HE mechanisms ? Tensile tests with atmosphere switches Tensile tests under H2 pressure : HE not due to trapped H in the bulk HE caused by surface / sub surface H populations • Are the same H populations involved depending on the loading conditions ? • Tests on pre-charged specimens or under cathodic charging ?

  15. Ensure transferability from lab-scale tests to structure Transferability  Numerical simulations + experimental validations Developing a test facility for full scale pipeline section up to 30 MPa H2 pressure within the French ANR CATHY-GDF and CESTAR projects Up to 1 m diameter CNRS-GDF SUEZ Defects - Fatigue crack propagation - Welds

  16. Conclusions • Many ways to quantify HE under hydrogen pressure • HE susceptibility measures strongly depend on : • Testing environment (in-situ, P, …) • Presence of defects (crack, weld) • Static / dynamic loading • Monotonic / cyclic loading • Difficult to fit lab-scale tests with in-service conditions • Improve knowledge on HE mechanisms to define the appropriate tests to select materials • Group tests with the same HE features • Propose appropriate methods for a given application  Input for international codes and rules adapted to future hydrogen infrastructures applications

  17. Thank you for your attention CEA / LITEN

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