Funded by FCH JU (Grant agreement No ) 1 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 1 Chapter E: Hydrogen embrittlement and permeation Belfast – January 25, 2013 Hervé Barthélémy – Air Liquide

Funded by FCH JU (Grant agreement No ) 2 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 2 1. INTRODUCTION - GENERALITIES 2. REPORTED ACCIDENTS AND INCIDENTS ON HYDROGEN EQUIPMENT 3. TEST METHODS HYDROGEN EMBRITTLMENT AND PERMEATION 4. PERMEATION TESTS

Funded by FCH JU (Grant agreement No ) 3 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 3 6. HYDROGEN EMBRITTLEMENT OF OTHER MATERIALS 8. CONCLUSION - RECOMMENDATION 7. HYDROGEN ATTACK HYDROGEN EMBRITTLMENT AND PERMEATION 5. PARAMETERS AFFECTING HYDROGEN EMBRITTLEMENT OF STEELS - Environment, Design and Material

Funded by FCH JU (Grant agreement No ) 4 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 4  Internal hydrogen embrittlement  External hydrogen embrittlement 1. GENERALITIES

Funded by FCH JU (Grant agreement No ) 5 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE IN METALLIC SOLUTION : Hydrogen attack Gaseous hydrogen embrittlement 1 - COMBINED STATE : 1. GENERALITIES

Funded by FCH JU (Grant agreement No ) 6 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 6 T  200°CHydrogen embrittlement  Important parameter : THE TEMPERATURE T  200°C Hydrogen attack 1. GENERALITIES

Funded by FCH JU (Grant agreement No ) 7 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 7  Reversible phenomena  Transport of H 2 by the dislocations CRITICAL CONCENTRATION AND DECOHESION ENERGY  H 2 traps 1. GENERALITIES

Funded by FCH JU (Grant agreement No ) 8 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 8 FAILURE OF A HYDROGEN TRANSPORT VESSEL IN REPORTED ACCIDENTS AND INCIDENTS

Funded by FCH JU (Grant agreement No ) 9 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 9 FAILURE OF A HYDROGEN TRANSPORT VESSEL IN HYDROGEN CRACK INITIATED ON INTERNAL CORROSION PITS 2. REPORTED ACCIDENTS AND INCIDENTS

Funded by FCH JU (Grant agreement No ) 10 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE REPORTED ACCIDENTS AND INCIDENTS HYDROGEN CYLINDER BURSTS INTERGRANULAR CRACK

Funded by FCH JU (Grant agreement No ) 11 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 11 VIOLENT RUPTURE OF A HYDROGEN STORAGE VESSEL 2. REPORTED ACCIDENTS AND INCIDENTS

Funded by FCH JU (Grant agreement No ) 12 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 12 H2 VESSEL. HYDROGEN CRACK ON STAINLESS STEEL PIPING 2. REPORTED ACCIDENTS AND INCIDENTS

Funded by FCH JU (Grant agreement No ) 13 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 13  Static (delayed rupture test) 3. TEST METHODS Constant strain rate Fatigue  Dynamic

Funded by FCH JU (Grant agreement No ) 14 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 14  Fracture mechanic (CT, WOL, …)  Tensile test  Disk test  Other mechanical test (semi-finished products)  Test methods to evaluate hydrogen permeation and trapping 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 15 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 15 Fracture mechanics test with WOL type specimen 1.Vessel head 2.Specimen 3.O-rings 4.Vessel bottom 5.Gas inlet – Gas outlet 6.Torque shaft 7.Load cell 8.Instrumentation feed through 9.Crack opening displacement gauge 10.Knife 11.Axis 12.Load application 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 16 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 16 Specimens for compact tension test 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 17 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE TEST METHODS Air Liquide/CTE equipment to perform fracture mechanic test under HP hydrogen (up to bar)

Funded by FCH JU (Grant agreement No ) 18 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE Influence of hydrogen pressure (300, 150, 100 and 50 bar) - Crack growth rate versus K curves 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 19 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 19 K, MPa Vm Influence of hydrogen pressure by British Steel X 152 bar 41 bar 1 bar 165 bar H2H2 N2N da dN mm/cycle 3. TEST METHODS N2N2

Funded by FCH JU (Grant agreement No ) 20 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 20 Tensile specimen for hydrogen tests (hollow tensile specimen) (can also be performed with specimens cathodically charged or with tensile spencimens in a high pressure cell) 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 21 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 21  I = (% RA N - % RA H ) / % RA N I = Embrittlement index RA N = Reduction of area without H 2 RA H = Reduction of area with H 2 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 22 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 22 Cell for delayed rupture test with Pseudo Elliptic Specimen Pseudo Elliptic Specimen 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 23 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 23 Tubular specimen for hydrogen assisted fatigue tests Inner notches with elongation measurement strip 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 24 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 24 Disk testing method – Rupture cell for embedded disk-specimen 1.Upper flange 2.Bolt Hole 3.High-strength steel ring 4.Disk 5.O-ring seal 6.Lower flange 7.Gas inlet 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 25 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE TEST METHODS Example of a disk rupture test curve

Funded by FCH JU (Grant agreement No ) 26 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE TEST METHODS I  m (MPa) Hydrogen embrittlement indexes ( I ) of reference materials versus maximum wall stresses (  m) of the corresponding pressure vessels

Funded by FCH JU (Grant agreement No ) 27 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 27 Fatigue test - Principle 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 28 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 28 Fatigue test - Pressure cycle 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 29 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 29 Fatigue tests, versus  P curves nN 2 nH Delta P (MPa) Cr-Mo STEEL Pure H 2 H ppm O 2 F 0.07 Hertz nN 2 nH 2 3. TEST METHODS

Funded by FCH JU (Grant agreement No ) 30 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE TEST METHODS Fatigue test Principle to detect fatigue crack initiation

Funded by FCH JU (Grant agreement No ) 31 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 31 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 testExternalDislocations Cathodic charging testExternalDiffusion TESTS CHARACTERISTICS

Funded by FCH JU (Grant agreement No ) 32 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 32 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 testRelatively small sizeLarge 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 testSmall size and simple Small size and very simple Electrochemical equipment (potentiostat) TESTS CHARACTERISTICS

Funded by FCH JU (Grant agreement No ) 33 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 33 Interpretation of results TESTS TESTS SENSIBILITY POSSIBILITY OF RANKING MATERIALS 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 sensitivityPossible No, but maximum allowable K IH could be defined - K IH - Crack growth rate P.E.S. testPoor sensitivityDifficultNo Tubular specimen test Good sensitivityDifficultNo- K IH Cathodic charging Good sensitivity Possible but difficult in practice No Critical hydrogen concentration TESTS CHARACTERISTICS

Funded by FCH JU (Grant agreement No ) 34 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE PERMEATION TESTS 4.1. Definition 4.2. Important parameter: temperature

Funded by FCH JU (Grant agreement No ) 35 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE Definition Permeability is the result of gas solution and gas diffusion Permeability coefficient is defined as follows : Pe = S × D. Permeation in polymers is a molecular permeation

Funded by FCH JU (Grant agreement No ) 36 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 36 The permeability coefficient is defined as the product of the diffusion and solubility coefficients of the gas for this material. When Henry’s law is satisfied, the flow at steady state, for a given temperature, is given by: J: flow of molecules going through a surface A, at steady state (permeability flow rate) e: thickness of the sample PM: partial pressure of the gas on the upstream side PV: partial pressure of the gas on the downstream side Pe: permeability coefficient of the gas 4.1. Definition A P M P V e J P M P V e J P M P V P M P V e J e 2 <<A

Funded by FCH JU (Grant agreement No ) 37 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 37 According to Arrhenius 4.2. Important parameter: Temperature Permeability investigated mainly for elastomer and plastic materials Hydrogen permeability of metals is several order of magnitude lower than permeability of polymers

Funded by FCH JU (Grant agreement No ) 38 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 38 PERMEATION CELL BY GASEOUS CHARGING 1.Reference electrode (S.C.E.) 2.Argon (inlet) 3.Argon (outlet) 4.Auxiliary electrode (P t ) 5.Teflon cell 6.Disk (working electrode)  58 mm and e = 0,75 mm

Funded by FCH JU (Grant agreement No ) 39 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 39 PERMEATION TEST BY CATHODIC CHARGING - PRINCIPLE 1.Battery 2.Recorder 3.Potentiostat 4.Reference electrodes 5.Solution 6.Auxiliary electrodes (P t ) 7.Membrane 8.Charging solution

Funded by FCH JU (Grant agreement No ) 40 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 40 PERMEATION AND DEGASSING CURVES - PRINCIPLE 1.Hydrogen flow 2.Theorical curve (with D 0 ) 3.2 nd permeation 4.Stop in charging 5.Calculation 6.2 nd permeation 7.Beginning 8.1st permeation 9.Beginning (charging)

Funded by FCH JU (Grant agreement No ) 41 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE PARAMETERS AFFECTING HYDROGEN EMBRITTLEMENT OF STEELS 5.1. Environment 5.2. Material 5.3. Design and surface conditions

Funded by FCH JU (Grant agreement No ) 42 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 42  Hydrogen purity  Hydrogen pressure  Temperature  Stresses and strains  Time of exposure 5.1. Environment or “operating conditions”

Funded by FCH JU (Grant agreement No ) 43 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 43 Influence of oxygen contamination  Hydrogen purity 5.1. Environment or “operating conditions”

Funded by FCH JU (Grant agreement No ) 44 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 44 Influence of H 2 S contamination  Hydrogen purity 5.1. Environment or “operating conditions”

Funded by FCH JU (Grant agreement No ) 45 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 45  Hydrogen pressure 5.1. Environment or “operating conditions” Influence of H 2 S partial pressure for AISI 321 steel

Funded by FCH JU (Grant agreement No ) 46 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 46 Influence of temperature - Principle  Temperature 5.1. Environment or “operating conditions”

Funded by FCH JU (Grant agreement No ) 47 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 47 Influence of temperature for some stainless steels  Temperature 5.1. Environment or “operating conditions”

Funded by FCH JU (Grant agreement No ) 48 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 48  Hydrogen purity  Hydrogen pressure  Temperature  Stresses and strains  Time of exposure 5.1. Environment or “operating conditions”

Funded by FCH JU (Grant agreement No ) 49 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 49  Microstructure  Chemical composition  Heat treatment and mechanical properties  Welding  Cold working  Inclusion 5.2. Material

Funded by FCH JU (Grant agreement No ) 50 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 50  Heat treatment and mechanical properties 5.2. Material

Funded by FCH JU (Grant agreement No ) 51 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 51  Welding 5.2. Material

Funded by FCH JU (Grant agreement No ) 52 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 52  Microstructure  Chemical composition  Heat treatment and mechanical properties  Welding  Cold working  Inclusion 5.2. Material

Funded by FCH JU (Grant agreement No ) 53 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 53  Stress level  Stress concentration  Surface defects 5.3. Design and surface conditions

Funded by FCH JU (Grant agreement No ) 54 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 54 Crack initiation on a geometrical discontinuity  Stress concentration 5.3. Design and surface conditions

Funded by FCH JU (Grant agreement No ) 55 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 55 Crack initiation on a geometrical discontinuity  Stress concentration 5.3. Design and surface conditions

Funded by FCH JU (Grant agreement No ) 56 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 56 FAILURE OF A HYDROGEN TRANSPORT VESSEL IN HYDROGEN CRACK INITIATED ON INTERNAL CORROSION PITS  Surface defects 5.3. Design and surface conditions

Funded by FCH JU (Grant agreement No ) 57 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE HYDROGEN EMBRITTLEMENT OF OTHER MATERIALS 1) All metallic materials present a certain degree of sensitive to HE 2) Materials which can be used  Brass and copper alloys  Aluminium and aluminium alloys  Cu-Be

Funded by FCH JU (Grant agreement No ) 58 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 58 3) Materials known to be very sensitive to HE : 4) Steels : HE sensitivity depend on exact chemical composition, heat or mechanical treatment, microstructure, impurities and strength  Ni and high Ni alloys  Ti and Ti alloys Non compatible material can be used at limited stress level 6. HYDROGEN EMBRITTLEMENT OF OTHER MATERIALS

Funded by FCH JU (Grant agreement No ) 59 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 59 Nelson curves Legend : Surface decarburization Internal decarburization (Hydrogen attack) 7. HYDROGEN ATTACK

Funded by FCH JU (Grant agreement No ) 60 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE HYDROGEN ATTACK  Ti and W have also a beneficial effect  C, Al, Ni and Mn (excess) have a detrimental effect  Heat treatment  Stress level, welding procedure In addition to parameters summarized on the « Nelson curves » (influence of P, T, Cr and Mo): Other parameters :

Funded by FCH JU (Grant agreement No ) 61 © HyFacts Project 2012/13 CONFIDENTIAL – NOT FOR PUBLIC USE 61 1)The influence of the different parameters shall be addressed. 2)To safely use materials in presence of hydrogen, an internal specification shall cover the following : The « scope », i.e. the hydrogen pressure, the temperature and the hydrogen purity The material, i.e. the mechanical properties, chemical composition and heat treatment The stress level of the equipment The surface defects and quality of finishing And the welding procedure, if any 8. CONCLUSION - RECOMMENDATION