1. INTERNATIONAL CONFERENCE ON HYDROGEN SAFETY September 8-10, 2005 – PISE - ITALY 230003_Barthélémy, H. and Allidières, L., Gaseous hydrogen Refuelling Stations : Selection of Materials for Hydrogen High Pressure Fuelling Connectors

2. The world leader in industrial and medical gases 2 EXAMPLE OF FUELLING STATION FOR HYDROGEN VEHICLES

3. The world leader in industrial and medical gases 3 HYDROGEN EMBRITTLEMENT  Internal  External

4. The world leader in industrial and medical gases 4 1 - COMBINED STATE : Hydrogen attack 2 - IN METALLIC SOLUTION : Gaseous hydrogen embrittlement HYDROGEN EMBRITTLEMENT

5. The world leader in industrial and medical gases 5 T  200°CHydrogen embrittlement T  200°C Hydrogen attack  Important parameter : THE TEMPERATURE HYDROGEN EMBRITTLEMENT

6. The world leader in industrial and medical gases 6 GASEOUS HYDROGEN EMBRITTLEMENT (G H E)  Reversible phenomena  Transport of H 2 by the dislocations H 2 TRAPS – CRITICAL CONCENTRATION AND DECOHESION ENERGY

7. The world leader in industrial and medical gases 7 (GHE) – DIFFERENT TYPES OF TEST METHODS (1)  Static (delayed rupture test)  Dynamic Constant strain rate Fatigue

8. The world leader in industrial and medical gases 8 (GHE) – DIFFERENT TYPES OF TEST METHODS (2)  Fracture mechanic (CT, WOL, …)  Tensile test  Disk test  Other mechanical test (semi-finished products)  Test methods to evaluate hydrogen permeation and trapping

9. The world leader in industrial and medical gases 9 Specimens for compact tension test (GHE) – DIFFERENT TYPES OF TEST METHODS (3)

10. The world leader in industrial and medical gases 10  Can also be performed with specimens cathodically charged and with tensile specimens in a high pressure cell (GHE) – DIFFERENT TYPES OF TEST METHODS (4) Tensile specimens for hydrogen tests (hollow tensile specimen)

11. The world leader in industrial and medical gases 11  I = (% RA N - % RA H ) / % RA N  I = Embrittlement index  RA N = Reduction of area without H 2  RA H = Reduction of area without H 2 (GHE) – DIFFERENT TYPES OF TEST METHODS (5)

12. The world leader in industrial and medical gases 12 Disk testing method – Rupture cell for embedded disk-specimen (GHE) – DIFFERENT TYPES OF TEST METHODS (6) 1.Upper flange 2.Bolt Hole 3.High-strength steel ring 4.Disk 5.O-ring 6.Lower flange 7.Gas inlet

13. The world leader in industrial and medical gases 13 EXAMPLE OF A DISK RUPTURE TEST CURVE

14. The world leader in industrial and medical gases 14 DISK TEST – EMBRITTLEMENT INDEX

15. The world leader in industrial and medical gases 15 Hydrogen embrittlement indexes ( I ) of reference materials versus maximum wall stresses (  m) of the corresponding pressure vessels  m (MPa) I Thin wall cylinders Thick wall cylinders (Good H 2 behaviour) (Bad H 2 behaviour) DISK TEST – EMBRITTLEMENT INDEX

16. The world leader in industrial and medical gases 16 Fatigue test - Principle DISK TEST – EMBRITTLEMENT INDEX

17. The world leader in industrial and medical gases 17 Fatigue test - Pressure cycle DISK TEST – EMBRITTLEMENT INDEX

18. The world leader in industrial and medical gases 18 0 1 2 3 4 5 6 45678910111213 Delta P (MPa) Cr-Mo STEEL Pure H 2 H 2 + 300 ppm O 2 F 0,07 Hertz FATIGUE TESTS, VERSUS  P CURVES nN 2 nH 2

19. The world leader in industrial and medical gases 19 Fatigue test Principle to detect fatigue crack initiation

20. The world leader in industrial and medical gases 20 TESTS CHARACTERISTICS Type of hydrogen embrittlement and transport mode TESTS LOCATION OF HYDROGEN TRANSPORT MODE Disk rupture testExternalDislocations F % testExternal + InternalDiffusion + Dislocation Hollow tensile specimen test ExternalDislocations Fracture mechanics tests ExternalDislocations P.E.S. testExternalDislocations Tubular specimen test ExternalDislocations Cathodic charging test ExternalDiffusion

21. The world leader in industrial and medical gases 21 TESTS CHARACTERISTICS Practical point of view TESTS SPECIMEN (Size-complexity) CELL (Size-complexity) COMPLEMENTARY EQUIPMENT NEEDED Disk rupture test Small size and very simple Hydrogen compressor and high pressure vessel Tensile test Relatively small size Large sizeTensile machine Fracture mechanics test Relatively large size and complex Very large size and complex Fatigue tensile machine for fatigue test only P.E.S. test Average size and very easy to take from a pipeline Average size-- Tubular specimen test Large size and complex No cell necessary Large hydrogen source at high pressure Cathodic charging test Small size and simple Small size and very simple Electrochemical equipment (potentiostat)

22. The world leader in industrial and medical gases 22 TESTS CHARACTERISTICS Type of hydrogen embrittlement and transport mode TESTS TESTS SENSIBILITY HYDROGEN BEHAVIOR OF MATERIALS – POSSIBILITY OF CLASSIFICATION SELECTION OF MATERIALS – EXISTING CRITERIA PRACTICAL DATA TO PREDICT IN SERVICE PERFORMANCE Disk ruptureHigh sensitivityPossible Yes P H e/P H2 Fatigue life Tensile test Good/Poor sensitivity Possible/DifficultYes/NoTreshold stress Fracture mechanics Good sensitivity Possible No, but maximum allowable K IH could be defined - K IH - Crack growth rate P.E.S. testPoor sensitivityDifficultNo Tubular specimen test Good sensitivity DifficultNo- K IH Cathodic charging Good sensitivity Possible but difficult in practice No Critical hydrogen concentration

23. The world leader in industrial and medical gases 23 MAIN CHARACTERISTICS AND EMBRITTLEMENT INDEXES (E.I.) N° AISI GRADE E.I.  D* (%) Ni.eq. (%) MS (°C) y.s. (MPa) u.t.s. (MPa) 1 2 3 4 5 6 7 9 13 14 16 17 18 321 304 304 L 316 Ti 204 LN 304 316 L 321 301 LN 316 LN 321 304 L 3.9 2.6 1.25 1.3 4.94 2.13 1.29 3.77 5.18 4.55 1.36 2.2 1.2 - 1.8 - 2.2 - 1 + 1.5 - 4 - 1 + 1.1 - 1.9 - 2.2 - 4.2 + 0.6 - 0.4 + 0.05 12 37 60 > 100 5 30 > 100 10 2 14 > 100 30 10.25 9.545 10.025 13.25 8.195 10.97 12.88 10.395 9.725 8.11 12.585 12.11 12.055 - 135 - 168 - 150 - 258 - 232 - 189 - 286 94 - 129 - 224 - 395 - 173 - 248 280 301 258 299 585 343 278 254 273 361 368 264 680 698 618 956 931 666 610 640 708 794 703 620 583 *D : Deformation necessary at 20°C to initiate 1 % of martensite formation TEST RESULTS

24. The world leader in industrial and medical gases 24 EFFECT OF STEEL STABILITY (  ) ON THE EMBRITTLEMENT INDEX (E.I.)

25. The world leader in industrial and medical gases 25 EFFECT OF MARTENSITE FORMED AT LOW TEMPERATURE AND CHEMICAL COMPOSITION EFFECT OF MARTENSITE FORMED AT LOW TEMPERATURE STEEL No AISI GRADEE.I.E.I. (20 % M s )* 3 7 18 304 316 L 304 L 1.25 1.29 1.2 3.83 1.71 3.5 * Embrittlement index after cold working at – 196°C so as to form 20 % martensite in the austenitic structure

26. The world leader in industrial and medical gases 26 TEST RESULTS FOR A 1.4057 (x 7 CrNi 16-2) STEEL (HV ~ 500 HV)

27. The world leader in industrial and medical gases 27 SELECTION OF MATERIALS FOR FUELLING CONNECTORS  Hydrogen compatible materials for parts exposed to high pressure hydrogen  Non hydrogen compatible materials only for :  Material not exposed to hydrogen  Material used at a low enough stress  If a risk analysis shows that the failure has no consequence on the safe use  If the connector is only used for a short period (to be checked by fatigue test)

28. The world leader in industrial and medical gases 28 CONCLUSION The fuelling connector is a critical part for the dispensing line This equipment is exposed during service to very severe conditions We have indicated how to select the right materials (test methods and design considerations)