Materials for the Hydrogen Economy (2007) Episode 7 potx

Effect of gas pressure on critical stress intensity factor for crack extension in loading, while the carbon steel filled symbols was tested under rising displacement loading... Effect o

1 Iwahara,.H.,.Yajima,.T.,.and.Uchida,.H Solid State Ionics,.70/71,.1994,.267-271.

2 Iwahara,.H Solid State Ionics,.77,.1995,.289-298

3 Guan,.J.,.Dorris,.S E.,.Balachandran,.U.,.and.Liu,.M Solid State Ionics,.100,.1997,.

45-52

4 Guan,.J.,.Dorris,.S E.,.Balachandran,.U.,.and.Liu,.M J Electrochem Soc.,.145,.1998,.

1780-1786

5 Guan,.J.,.Dorris,.S E.,.Balachandran,.U.,.and.Liu,.M Ceram Trans.,.92,.1998,.1-9.

6 Balachandran,.U.,.Lee,.T H.,.and.Dorris,.S E In.Proceedings 16th Annual

Interna-tional Pittsburgh Coal Conf.,.Pittsburgh,.PA,.October.11-15,.1999.

7 Balachandran,.U.,.Lee,.T H.,.Zhang,.G.,.Dorris,.S E.,.Rothenberger,.K S.,.Howard,.

B H.,.Morreale,.B.,.Cugini,.A V.,.Siriwardane,.R V.,.Poston,.J A Jr.,.and.Fisher,.E

P In.Proceedings 26th International Technical Conference on Coal Utilization and

Fuel Systems, Clearwater, FL, March 5-8, 2001 Gaithersburg, MD: Coal Technical.

Gas on Steel Vessels and Pipelines

Brian P Somerday and Chris San Marchi

ConTenTs

7.1 Introduction 158

7.2 Review.of.Hydrogen.Gas.Vessels.and.Pipelines 159

7.2.1 Hydrogen.Gas.Vessels 159

7.2.1.1 Material.Conditions.Affecting.Vessel.Steel.in Hydrogen 159

7.2.1.2 Environmental.Conditions.Affecting.Vessel.Steel.in Hydrogen 160

7.2.1.3 Mechanical.Conditions.Affecting.Vessel.Steel.in Hydrogen 160

7.2.2 Hydrogen.Gas.Pipelines 161

7.2.2.1 Material.Conditions.Affecting.Pipeline.Steel.in Hydrogen 161

7.2.2.2 Environmental.Conditions.Affecting.Pipeline.Steel.in Hydrogen 162

7.2.2.3 Mechanical.Conditions.Affecting.Pipeline.Steel.in Hydrogen 162

7.3 Importance.of.Fracture.Mechanics 162

7.4 Vessels.and.Pipelines.in.Hydrogen.Energy.Applications 164

7.4.1 Effect.of.Gas.Pressure 165

7.4.2 Effect.of.Gas.Impurities 166

7.4.3 Effect.of.Steel.Strength 169

7.4.4 Effect.of.Steel.Composition 171

7.4.5 Effect.of.Welds 173

7.4.6 Effect.of.Mechanical.Loading 174

7.5 Conclusion 176

Acknowledgments 177

References 177

The.objective.of.this.chapter.is.to.provide.guidance.on.the.application.of.car-bon and low-alloy steels for hydrogen gas vessels and pipelines, emphasizing the.

variables that influence hydrogen embrittlement Section 7.2 reviews published

is.anticipated.that.hydrogen.gas.vessels.and.pipelines.will.be.subjected.to.operat-ing conditions that are outside the windows of experience Thus, section 7.4 will

demonstrate trends in hydrogen embrittlement susceptibility for steels as a

func-tion of important material, environmental, and mechanical variables The metric

One of the detrimental mechanical loading conditions for steel hydrogen gas.

vessels is cyclic stress, which drives fatigue crack propagation.4 Pressure cycling

0.90–1.20 0.15–0.25 0.30–0.37 0.50–0.80 0.15–0.35 0.025.max 0.025.max Balance

a The composition limits for 34CrMo4 vary slightly among European countries The specification in.

table.7.1.is.from.Germany 4 The.34CrMo4.steel.composition.is.almost.identical.to.either.AISI.4130.or.

AISI.4135.steel 47

b Limits.for.P.and.S.in.new.hydrogen.gas.vessels.are.0.025.wt%.

Grade.X42 0.22.max 1.30.max 0.025.max 0.015.max 0.15.max Balance

Grade.X52 0.22.max 1.40.max 0.025.max 0.015.max 0.15.max Balance

a Product.Specification.Level.2.composition.for.welded.pipe 49

b

Recommended.maximum.concentrations.of.P.and.S.are.0.015.and.0.01.wt%,.respectively,.for.mod-ern.steels.in.hydrogen.gas.service 5

sources, including welds, corrosion, and third-party damage.5,6 Welds are of

par-ticular concern since steel pipelines can require two different welds: longitudinal

The.stress.intensity.factor.range,.∆K,.is.defined.as.(K max –.K min ),.where.K max and.K min.

are.the.maximum.and.minimum.values.of.K,.respectively,.in.the.load.cycle K max and

hydrogen energy aPPlICaTIons

property equation 7.6 shows that as fugacity (pressure) increases, the quantity.

of atomic hydrogen dissolved in the steel increases; consequently, embrittlement

becomes.more.severe This.trend.is.illustrated.from.K TH ,.K IH ,.and.da/dN

data Fig-ure.7.1 shows data for both low-alloy steels (K TH ) and carbon steels (K IH), where

critical K values decrease as hydrogen gas pressure increases for both types of.

steel.10,29.Data.for.a.low-alloy.steel.in.figure.7.2.demonstrate.that.da/dN.measured.

at.a.fixed.stress.intensity.factor.range,.∆K,.continuously.increases.as.hydrogen.gas.

pressure.increases.30.Finally,.figure.7.3.shows.that.increasing.hydrogen.gas.pressure

also.accelerates.da/dN.in.a.carbon.steel,.but.only.at.lower.∆K.values.31

180Low-Alloy and Carbon Steels

AISI 4130 steel ( uts=820 MPa) AISI 4145 steel ( uts=895 MPa) AISI 4147 steel ( uts=925 MPa) ASTM A516 steel ( uts=530 MPa)

fIgure . Effect of gas pressure on critical stress intensity factor for crack extension in

loading, while the carbon steel (filled symbols) was tested under rising displacement loading

100 ASME SA105 steel uts = 460 MPa frequency = 0.1 Hz load ratio = 0.1

70 MPa H2 gas

7 MPa H2 gas

fIgure .  Effect of hydrogen gas pressure on fatigue crack growth rate (da/dN) vs stress

Hydrogen Gas Pressure (MPa)

helium hydrogen

HY-100 Steeluts = 855 MPa

∆K = 55 MPa m

frequency = 1 Hz

fIgure .  Effect of hydrogen gas pressure on fatigue crack growth rate (da/dN) at

2.25Cr - 1Mo Steel

uts = 555 MPa 1.1 MPa H2 gas

∆K = 24 MPa m

frequency = 5 Hz load ratio = 0.1

CO 0.99% 1.10%SO2 0.03%H2O 0.98%CH4 1.01%CO2 CH1.04%3SH 0.10%H2S

fIgure .  Effect of gas additives on the fatigue crack growth rate (da/dN) at constant

7.4.3 e FFeCt OF S teel S trenGth

Hydrogen embrittlement in steels generally becomes more severe as material

strength.increases This.behavior.arises.because.the.magnitude.of.stress.amplifica-tion.near.defects.is.proportional.to.material.strength These.high.stresses.combined

with.the.resulting.enhanced.hydrogen.dissolution.increase.susceptibility.to.hydrogen

embrittlement The.impact.of.material.strength.on.hydrogen.embrittlement.is.exem-plified.by.the.K TH.data.in.figure.7.5.10.Values.of.K TH.measured.for.low-alloy.steels.in

hydrogen.gas.decrease.as.tensile.strength,.σuts,.increases A.similar.trend.is.expected

120 Low-Alloy and Carbon Steels

41 MPa H 2 gas

AISI 4130 steel AISI 4145 steel AISI 4147 steel

fIgure .   Effect of tensile strength (σuts) on critical stress intensity factor for crack

1000 Low-Alloy Steels frequency = 1 Hz load ratio = 0.007 HY-80 steel

uts = 780 MPa 0.34 MPa H2 gas HY-130 steel

uts = 1020 MPa 0.34 MPa H2 gas

HY- 80 steel air

HY-130 steel air

fIgure .  Fatigue crack propagation rate (da/dN) vs stress intensity factor range (∆K)

relationships measured in low-pressure hydrogen gas for two low-alloy steels with different

and pipelines in the hydrogen energy infrastructure, where high-strength

materi-als may be attractive Increasing the operating pressures of hydrogen gas vessels

B7 Mn=0.007 Si=0.002 P=0.003 S=0.003 Mn=0.02

Si=0.01 P=0.014 S=0.003 Mn=0.09 Si=0.01 P=0.012 S=0.005 Mn=0.02 Si=0.27 P=0.0036 S=0.005

Mn=0.23 Si=0.01 P=0.009 S=0.005

B2 Mn=0.68 Si=0.08 P=0.009 S=0.016

Mn=0.72 Si=0.01 P=0.008 S=0.005

B6 Mn=0.72 Si=0.32 P=0.003 S=0.005

Mn=0.75 Si=0.20 P=0.006 S=0.004

fIgure .   Effect of manganese, silicon, phosphorus, and sulfur content on critical stress

tested in low-pressure hydrogen gas.

sulfur,.and.phosphorus.in.a.low-alloy.steel.40.Figure.7.8.shows.that.K TH.decreases.

as manganese increases from 0.07 to 2.65 wt% Systematic variations in sulfur

and phosphorus concentrations in the range 0.002 to 0.027 wt% did not affect

Mn steels ( uts=1305 MPa)

Co steels ( uts=1415 MPa)

fIgure .   Effect of manganese or cobalt content on critical stress intensity factor for

low-pres-sure hydrogen gas.

7.4.6 e FFeCt OF m eChaniCal l OadinG

Hydrogen embrittlement in steels can be manifested under different modes of

Finally, figure.7.11 shows that fatigue crack growth rates in hydrogen gas do not

depend.on.load.ratio.(i.e.,.K min /K max).for.values.up.to.0.4.46.However,.over.this.range

static-load KIH = 28 to 40 MPa m

fIgure .  Effect of loading rate (dK/dt) on critical stress intensity factor for crack

hydro-gen gas.

fIgure .0  Effect of load cycle frequency on fatigue crack growth rate (da/dN) vs stress

fIgure .   Effect of load ratio (ratio of minimum load to maximum load) on fatigue

crack growth rate (da/dN) at fixed stress intensity factor range (∆K) in hydrogen gas for a

3 .Nelson,.H.G.,.Hydrogen.embrittlement,.in.Treatise on Materials Science and

Technol-ogy: Embrittlement of Engineering Alloys,.Vol 25,.Briant,.C.L and.Banerji,.S.K.,.Eds.,.

related fracture: a review, in Second International Conference on

Corrosion-Defor-mation Interactions, Magnin, T., Ed., The Institute of Materials, London, 1997, pp

Thompson,.A.W and.Bernstein,.I.M.,.The.role.of.metallurgical.variables.in.hydrogen-assisted.environmental.fracture,.in.Advances in Corrosion Science and Technology,.

Vol 7, Fontana, M.G and Staehle, R.W., Eds., Plenum Press, New York, 1980, pp

53–175.

Swisher,.J.H.,.Hydrogen.compatibility.of.structural.materials.for.energy-related.appli-cations,.in.Effect of Hydrogen on Behavior of

Materials,.Thompson,.A.W and.Ber-nstein, I.M., Eds., The Metallurgical Society of AIME, Warrendale, PA, 1976, pp

558–577.

20 .Thompson, A.W., Structural materials use in a hydrogen energy economy,

Interna-tional Journal of Hydrogen Energy,.2,.299–307,.1977.

21

Thompson,.A.W and.Bernstein,.I.M.,.Selection.of.structural.materials.for.hydrogen.pipe-lines.and.storage.vessels,.International Journal of Hydrogen Energy,.2,.163–173,.1977.

22 SanMarchi, C and Somerday, B.P., Technical Reference for Hydrogen

27 Standard Test Method: Laboratory Testing of Metals for Resistance to Sulfide Stress

Cracking and Stress Corrosion Cracking in H 2 S Environments,.Standard.TM0177-96,.

NACE.International,.Houston,.1996.

28 Standard Test Method for Determining Threshold Stress Intensity Factor for

Environ-ment-Assisted Cracking of Metallic Materials, Standard E 1681-03, ASTM

33 Clark,.W.G and.Landes,.J.D.,.An.evaluation.of.rising.load.KIscc.testing,.in.Stress

Cor-rosion: New Approaches,.ASTM.STP.610,.ASTM,.Philadelphia,.1976,.pp 108–127.

crack.growth.in.a.low.alloy.steel,.in.Stress Corrosion Cracking and Hydrogen

Embrit-tlement of Iron Base Alloys,.Staehle,.R.W.,.Hochmann,.J.,.McCright,.R.D.,.and.Slater,.

barrier Coatings

C.H Henager, Jr.

ConTenTs

8.1 Introduction 181

8.2 Background 181

8.3 Historical.Overview 182

8.4 Hydrogen.Barrier.Coatings 182

8.4.1 External.Coatings 183

8.4.2 Grown-On.Oxide.Films 185

8.5 Summary 188

References 188

. InTroduCTIon Gaseous.hydrogen,.H2,.has.many.physical.properties.that.allow.it.to.move.rapidly into.and.through.materials,.which.causes.problems.in.keeping.hydrogen.from.mate-rials that are sensitive to hydrogen-induced degradation Hydrogen molecules are the smallest diatomic molecules, with a molecular radius of about 37 × 10–12 m, and.the.hydrogen.atom.is.smaller.still Since.it.is.small.and.light,.it.is.easily.trans-ported.within.materials.by.diffusion.processes The.process.of.hydrogen.entering and.transporting.through.a.material.is.generally.known.as.permeation,.and.this.sec-tion.reviews.the.development.of.hydrogen.permeation.barriers.and.barrier.coatings for.the.upcoming.hydrogen.economy . baCkground Hydrogen.permeation.is.defined.as.the.transport.of.hydrogen.as.dissociated.hydro-gen.atoms1.and.has.units.of.moles.of.hydrogen.gas.per.square.meter.per.second.(mol m–2.sec–1),.which.is.the.permeation.rate Known.as.Richardson’s.law.this.relation.can be.expressed.as J DK= d (P high1 2 / −P low1 2 / ) (8.1) where J is the permeation rate, D is the diffusion coefficient of hydrogen in the material,.and.K.is.Sievert’s.constant.for.the.material,.which.determines.the.hydrogen. solubility

The.product.of.D.and.K is.referred.to.as.

will.have.a.hydrogen.permeation.rate.of.about.6.×.10–13.moles.of.H2.per.square.meter

of.steel.per.second.(moles-H2.m–2.sec–1).for.a.hydrogen.pressure.of.5,000.psi,.which

hydrogen Permeability of various materials

barrier development has pursued the direct oxidation of suitable alloys and (the.

proven more successful) aluminization of steels with subsequent alumina surface