1. 1 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/LCTASept. 14, 2011 International Conference on Hydrogen Safety "Enabling Progress and Opportunities" September 12-14, 2011 San Francisco, California-USA

2. LITEN/DTBH/LCTAICHS 2011Sept. 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. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 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. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 4 Monotonic loading Up to 35 MPa H 2 Tensile test Disk pressure Test (ISO 11114-4 method A) P He / P H2

5. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 5 Cyclic loading Fatigue Crack Growth Fracture mechanics / Dynamic loading Up to 35 MPa H 2 Compact Tensile Monotonic loading Fracture toughness Single Edge Notch Tensile specimen Initial crack

6. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 6 AL Air Inert gas Loading conditions H2H2 30 MPa H 2 Fracture mechanics / Static loading Wedge Opening Load - Static loading (ISO 11114-4 method C)

7. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 7 High-strength steel grade API X80 CMnSiPSFe 0.0751.860.350.015<0.003Bal. Ferrite + pearlite Pearlite alignments  914.4 mm x e12.7 mm w%

8. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 8 Monotonic loading – Main results No influence on  0.2 or UTS  Strain rate   ductility  P (up to ~10 MPa)   ductility Tensile tests Efficient empirical criteria for seamless bottles Not based on an understanding of the HE mechanisms  How to use it for other applications? P He / P H2 ~ 2 Disk pressure tests

9. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 9 Fracture mechanics – Main results Several K Precracking in air or H 2 No crack propagation after 1000 hr 220 kJ/m² (N 2 )  15 kJ/m² (H 2 ) WOL - Static loading – 30 MPa Toughness – Monotonic loading - 30 MPa

10. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 10 Fracture mechanics – Main results Fatigue Crack growth – Cyclic loading - 30 MPa FCG x 10 Significant effect even at low P H 2 - 0.1 Hz air FCG

11. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 11 Some possible HE indices definition 100 % maximum effect Tensile elongation Toughness FCG rate Disk pressure test WOL crack length 0 % no effect And more ……

12. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 12 Damage analysis Tensile test Quasi-cleavage External cracks Same a o Same final COD Toughness test H 2 inlet Quasi-cleavageDuctile Disk pressure test H 2 inlet

13. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 13 Fracture mechanicsContinuum mechanics CyclicMonotonic loading Static loading Embrittlement index  Necessary to provide guidelines to select the appropriate test X80 HS steel

14. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 14 Tensile tests with atmosphere switches Tensile tests under H 2 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 ? HE mechanisms ? High kinetic for HE reversibility HE occurrence

15. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 15 Developing a test facility for full scale pipeline section up to 30 MPa H 2 pressure within the French ANR CATHY-GDF and CESTAR projects Ensure transferability from lab-scale tests to structure Transferability  Numerical simulations + experimental validations CNRS-GDF SUEZ Defects - Fatigue crack propagation - Welds Up to 1 m diameter

16. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 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. LITEN/DTBH/LCTAICHS 2011Sept. 14, 2011 17 Thank you for your attention CEA / LITEN