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FP7-FCH-JU-2011-1 -303422

MATHRYCE

Material Testing and Recommendations for Hydrogen Components under fatigue

Deliverable D2.2

Nature Report

Dissemination CO - Confidential

Existing codes and standards

Foreseen submission date Project Month 7 – April, 30, 2013

Actual submission date Project Month 10 – August 07, 2013

Author(s)

Randy Dey – CCS

Jader Furtado – AL

Paolo Bortot - Tenaris

Version number for EC V1

Doc ID Code

MATHRYCE_ D2.2_2013-08-07_V1

Contract Start Date 2012-10-01

Duration 36 months

Project Applicant CEA - LITEN

FCH Joint Undertaking Collaborative Project

Project funded by the European Commission

D2.2 Existing codes and standards

MATHRYCE

Grant agreement n° 303422

NATURE

REDACTEUR VERIFICATEUR APPROBATEUR

NOM

FONCTION

SIGNATURE

Material Testing and Design Recommendations for

Components exposed to HYdrogen enhanCed fatiguE


EXECUTIVE SUMMARY

Project Number FP7- FCH JU – 2011 – 1 - 303422

Project Acronym MATHRYCE

Title Material Testing and Recommendations for Hydrogen Components under fatigue

Deliverable N° D2.2

Due Date Project Month 7

Delivery Date Project Month 10 – August 07, 2013

SHORT DESCRIPTION as per the DoW:

Report and updates on existing codes and standards for pressure vessels design in presence of hydrogen.

Document Control

Title: D2.2 Existing codes and standards

Project: MATHRYCE

Type: Report Dissemination: Confidential

The information contained in this report is subject to change without notice and should not be construed as a commitment by any members of the MATHRYCE Consortium. The MATHRYCE Consortium assumes no responsibility for the use or inability to use any procedure, protocol, which might be described in this report. The information is provided without any warranty of any kind and the MATHRYCE Consortium expressly disclaims all implied warranties, including but not limited to the implied warranties of merchantability and fitness for a particular use.

Authors Randy Dey – CCS / Jader Furtado – AL / Paolo Bortot - Tenaris

Doc ID MATHRYCE_ D2.2_2013-08-07_V1

Amendment History

Version Date Author Description/Comments

V1 August 07, 2013 Randy Dey – CCS

Jader Furtado – AL

Paolo Bortot - Tenaris

Further details and improvements


Abstract

Deliverable D2.2 - Existing Codes and Standards. Collect list of existing RCS standards relevant to the project and analyze the limits of these standards.


Table of contents

1 REMINDER OF THE PROJECT MAIN OBJECTIVES ......................................................................... 6

2 DELIVERABLE’S CONTEXT ................................................................................................................ 7

3 REVIEW OF EXISTING CODES AND STANDARDS ON H2 VESSEL DESIGN ................................ 9

3.1 INTRODUCTION ........................................................................................................................... 9

4 EARLY FINDINGS OF TASK 2.2 .......................................................................................................... 9

4.1 STANDARDS FOR TRANSPORTATION AND AUTOMOTIVE STORAGE ................................ 10 4.1.1 ISO 9809 – 1/2 [2, 3] and ISO 11120 [4]: ................................................................................ 10 4.1.2 DOT 3AA and 3AAX [6]: .......................................................................................................... 10 4.1.3 ISO/TS 15869 [7]:.................................................................................................................... 11 4.1.4 ASME Section VIII, Div.3, Art. KD-10 [1]: ............................................................................... 11

4.2 STANDARDS FOR STATIONARY STORAGE ........................................................................... 13 4.2.1 EN 13445 [11]: ........................................................................................................................ 13 4.2.2 AD2000-Merkblatt [12]: ........................................................................................................... 13 4.2.3 ASME Section VIII, Div. 1-2 [13, 14]: ...................................................................................... 13 4.2.4 ASME Section VIII, Div.3, Art. KD-10 [1]: ............................................................................... 14 4.2.5 CODAP [17, 18]....................................................................................................................... 14 4.2.6 Japanese standards for the design of high pressure vessels [19 – 21] .................................. 16

5 COMMENTS & REMARKS ................................................................................................................. 20

6 CONCLUSION ..................................................................................................................................... 21


1 REMINDER OF THE PROJECT MAIN OBJECTIVES

The main objectives of the MATHRYCE project are centered on the development and dissemination for standardization of a methodology for the design of hydrogen high pressure metallic vessels and for their lifetime assessment that takes into account hydrogen-enhanced fatigue. This needs to be achieved without requiring full scale component testing under hydrogen as this is not practicable considering the expected cycle lives and equipment size. The project therefore targets the justification of an approach where lifetime assessment results from combining the hydraulic cycling performance of the component with the appropriate knowledge of the performance of the metallic material in hydrogen under cyclic loading.

This will be validated by comparing the lifetime prediction of a component calculated from the lab-scale tests to that obtained from large scale component tests. The analysis of the results, based on numerical simulations as well as on the scientific knowledge of the possible hydrogen embrittlement mechanisms, will allow to assess or to modify the proposed design methodology.

Once the testing method as well as the associated design methodology is validated, specific recommendations will be proposed for implementations in international standards.

To summarize, the main outcomes of the MATHRYCE project will be:

- The development of a reliable testing method to characterize materials exposed to hydrogen-enhanced fatigue,

- The experimental implementation of this testing approach, generating extensive characterization (microstructural and mechanical) of metallic materials for hydrogen service,

- The definition of a methodology for the design of metallic components exposed to hydrogen enhanced fatigue and for the assessment of their service lifetime; this methodology being liable to be recognized for pressure equipment regulation,

- The dissemination of this methodology, as a proposed approach for standardization,

- The dissemination of prioritized recommendations for implementations in international standards.


2 DELIVERABLE’S CONTEXT

Due delivery This Deliverable D2.2 mainly results from the work done in Task 2.2 Review of existing codes and standards on H2 vessel design. It is the second of the six deliverables of work package 2 which main role in the MATHRYCE project is reminded below in reference to the DoW. The last version (v1) of this deliverable has been submitted successfully for quality assurance and has been accepted by the Consortium Committee according to the Consortium Agreement.

Work package number 2 Start date or starting event: Month1

Work package title From End User specifications to experimental approach

Activity Type RTD

Participant number 1 2 3 4 5 6 7

Participant short name CEA AL VTT JRC CCS CSM Tenaris

Person-months per participant

4 5 - - 3 2 3

Objective

The objective of WP2 is to characterize service life conditions for selected components (e.g. pressure vessel for refueling station buffer), in order to define tests to be conducted in the following work packages (WP3 and WP4). The other goal of WP2 consists in a review of existing scientific data and codes and standards for hydrogen pressure vessels design, in particular to design components to be used for WP4 tests.

Description of work

Task 2.1: Component selection and operation specifications (M1-M3) Participants: AL (task leader), Tenaris One or several components undergoing hydrogen pressure cycles, and exposed to high pressure hydrogen (400-1000 bar) in the hydrogen energy applications will be selected for the project. Thus, operational data (e.g. pressure ranges, pressure cycles, temperature) describing the solicitations on the component(s) will be gathered, and compared to model solicitations already considered in similar projects. AL will provide data on the operation mode of hydrogen refueling station (e.g., for buffer tank, time under pressure, number and amplitude of cycles…). Tenaris will add its comments and observations based on AL input data.

Task 2.2: Review of existing codes and standards on H2 vessel design (M1-M34) Participants: CCS (task leader), AL, Tenaris A review of existing codes and standards for hydrogen pressure vessels design will be made, in order to gather information on the different possible approaches. In particular, the limits of each code or standard will be highlighted, and particular attention will be paid to high pressures and to fatigue-based design. CCS will collect existing RCS information relevant to the project. AL contributing to many activities in the RCS field with hydrogen technologies will analyze the limits of existing standards. Tenaris will present its point of view, including comments on the approaches used for fatigue design and qualification of gas cylinders, based on the experience gained during participation to different ISO committees.

Task 2.3: In service stress analysis (M2-M4) Participants: CEA (task leader)


Data collected in Task 2.1 will be transformed into data useful to define tests carried out in WP3. In particular, stress analysis will be based on component design and conditions of use (e.g. pressure), to define loads applied during the tests. CEA will provide finite element calculations using a model of hydrogen diffusion which couples mechanical stress and plastic strain to hydrogen diffusion. Thus, stress analysis as well as hydrogen concentration and localization in pressure vessels for conditions of use will be investigated in order to define experimental conditions (hydrogen pressure...) and global specimen geometry to use for in service representative lab mechanical tests.

Task 2.4: Defect design for component testing (M9-M12) Participants: CEA (task leader), CSM, AL, Tenaris Based on the scientific data review for the selected grade of steel, and on microstructural analysis performed in WP3, defects (either microstructural such as inclusions or precipitates, or cracks) will be introduced in Task 2.3 stress analysis, to obtain new conditions of tests for WP3. Indeed, it is well known that microstructural defects can play the role of stress concentrators, and initiate cracks in the presence of H2. In addition, stress analysis will be performed on components to be tested in WP4, with several sizes of defects. As in Task 2.3, CEA will provide finite element calculations to analyze stress and hydrogen distribution in pressure vessels including defects (microstructural...). The size of the defects will be defined using the microstructural characterization performed by CSM in the task 3.2. Thus, specimen geometries and experimental conditions for representative lab-scale mechanical tests will be defined. Two sizes of components will be tested, a small one (10 to 30 l) and a full scale one. The small size components will have to be representative of damages (initiation and crack growth) occurring in real size component while it allows to test in parallel numerous pressure vessels. CEA will also design a new specimen geometry for disk pressure tests including notches designed upon data collected in WT2.3. The purpose is to obtain a stress field at the notch tip close to that existing ahead of a crack in a pressure vessel during service. Finite element calculations will be used to realize such a design. If this goal is achieved, this should provide a quite simple mechanical test for studying hydrogen enhanced fatigue with a hydrogen cyclic charging. Such test would have the advantage to test the material under cycling hydrogen pressure whereas the other tests are carried out at a constant pressure. AL will also follow the designing of this new specimen for disk pressure test to make sure that it is easy enough to implement for industrial purpose. CSM will contribute to the stress analysis, by FEA, of components including defects. In particular the activity will have a twofold aim. On the one hand the stress analysis will aim to define stress concentration factors deriving from the presence of defects as inclusions or microstructural defects. The results of the microstructural characterization performed in WP3 will supply the input information on possible defects shape and dimensions to be considered in the activity. On the other hand a devoted stress analysis will be performed in order to define suitable dimensions for defect to be manufactured on components for full scale hydraulic tests planned in WP4. Tenaris will give its feedback on possible imperfections and/or microstructural heterogeneities which can be found in a pressure vessel below the typical NDT detection limit.

Deliverables (month of delivery, Leader, Nature, Dissemination level)

D2.1 Operational data AL, R, CO, M3 D2.2 Existing codes and standards CCS, R, PU, M7 D2.3 Stress analysis CEA, R, CO, M4 D2.4 Defect design CEA, R, CO, M12 D2.5 Existing codes and standards – first update CEA, R, PU, M21 D2.6 Existing codes and standards – final update CEA, R, PU, M34


3 REVIEW OF EXISTING CODES AND STANDARDS ON H2 VESSEL DESIGN

3.1 INTRODUCTION

There exist few, if any, international standards that properly address fitness for service of pressure vessels subject to hydrogen-enhanced fatigue. The main idea of the MATHRYCE project is to develop an easy to implement methodology based on lab-scale experimental tests under hydrogen gas to assess the service life of a real scale component taking into account fatigue loading under hydrogen gas.

The aim of task 2.2 is to review existing codes and standards for pressure vessels, mainly type 1 cylinder in the presence of hydrogen. Type 2, 3, 4 cylinders will also be covered since all have a metallic component in contact with hydrogen. Standards will be analyzed for their limits and attention will be paid to high pressures and fatigue-based design.

Specifically, the task has focused on:

Collecting existing standards

Analyzing the limits of these standards

Reviewing the different approaches used for fatigue design and qualification of gas cylinders

Indeed, this project will provide data and methodology aimed to improve European and International standards on high-pressure components exposed to hydrogen-enhanced fatigue.

4 EARLY FINDINGS OF TASK 2.2

We have looked at the contribution to the state of the art on normative standards for design of seamless type 1 cylinders used for storage and transportation of compressed gases, with a particular attention on requirements for H2 gas.

The present document contains information from an initial list of standards for design of high pressure seamless steel type 1 gas cylinders used for storage and transportation of compressed gas, including H2. It is by no means an exhaustive compendium. See an initial list below of recognized standards for compressed gas including gaseous H2 for:

- Transportation/automotive

- Stationary Storage

The focus is on seamless steel gas cylinders and fatigue loading, even though welded cylinders are admitted in particular cases (see for example rules in [1].

In general, standards for transportation, except ASME KD-10 [1] do not specify cylinder service life in terms of years and/or maximum number of filling cycles, while a specified life is generally defined through standards for storage applications. This may be due to a lake of reliable data accounting for the


effect of hydrogen embrittlement phenomena on the degradation of mechanical properties of metals and alloys under specific loading conditions.

4.1 STANDARDS FOR TRANSPORTATION AND AUTOMOTIVE STORAGE

Table 1 provides a summary of the identified standards with the main design requirements with a particular focus on gaseous hydrogen.

4.1.1 ISO 9809 – 1/2 [2, 3] and ISO 11120 [4]:

WT design: carried out according to an equation which depends on proof pressure (greater than 1,5 times the working pressure), material properties and cylinder dimensions with safety factors incorporated.

Service life: not specified.

Experimental fatigue verification: for ISO 9809 – 1/2 [2], fatigue design is verified through an experimental full scale test performed at 1.5 times the working pressure and for minimum N=12,000 cycles in a non-corrosive fluid (e.g. oil). No such requirement exists for large tubes where ISO 11120 [4] applies.

HE: all the standards impose a maximum UTS equal to 950 MPa. Moreover, in case of large cylinders, where ISO 11120 applies, a higher safety factor is also employed when calculating the minimum WT. Use of steel with strength higher than 950 MPa is admitted provided the material can pass one of the compatibility tests reported in ISO 11114-4 [5]. All these tests are static and do not evaluate fatigue performances in H2 gas.

NDT: mandatory with ultrasonic technique with a maximum allowable defect depth not greater than 5% of the minimum WT.

4.1.2 DOT 3AA and 3AAX [6]:

WT design: carried out according to an equation which gives the expected wall stress in the vessel depending on proof pressure (greater than 1.67 times the working pressure) and cylinder dimensions. The minimum wall thickness shall be such that the calculated wall stress is either maximum 67% of the minimum Rm, or a maximum value of 70,000 psi (482 MPa).

Service life: not specified.

Experimental fatigue verification: not required.

HE: No clear indications given.

NDT: required only for detection of quenching cracks after cylinder heat treatment and only when the cooling rate during quenching exceeds 80% of the cooling rate of water. Indications are given in case cracks are detected.


4.1.3 ISO/TS 15869 [7]:

Wall thickness (WT) design: The standard specifies minimum burst ratios. Also, several performance tests are required for the cylinder qualification. However, for type 1 cylinders (the standard also covers types 2, 3 and 4) reference is made to ISO 9809-1/2, therefore the same design requirements apply.

Service life: a minimum service life of either N=5,500 cycles or N=11,250 cycles is required.

Experimental fatigue verification: for type 1 rules of ISO 9809-1/2 are applied.

HE: for type 1 rules of ISO 9809-1/2 are applied. In case of use of steels with Rm exceeding 950 MPa two options are available: to carry out one of the test methods reported in ISO 11114-4 followed by a full scale test in H2 gas for an unspecified number of cycles, or a full scale test in H2 gas for the specified service life.

NDT: for type 1 and metal liners rules of ISO 9809-1/2 are applied.

4.1.4 ASME Section VIII, Div.3, Art. KD-10 [1]:

WT design: carried out according to a fracture mechanics approach in accordance with rules of article KD-4, Div.3 modified to take H2 effect into account. Fracture mechanics calculations are based on the assumption that cracks exist at the most stressed locations in a pressure vessel and allow to calculate the number of cycles to propagate these cracks from the initial depth to the critical crack depth using a Paris law type as determined by ASTM E647 standard [8]. The critical crack depth is defined through the failure assessment diagram (FAD) reported in API 579-1/ASME FFS [9], based on material properties, applied stress, and the maximum allowable crack depth. The allowable crack depth is defined based on the calculated number of cycles, both calculated using the FAD in API 579-1/ASME FFS-1. An analysis of leak before break (LBB) should also be considered.

Service life: the calculated number of design cycles is the number of cycles required to propagate the crack from its initial depth to the allowable crack depth. The initial crack size is based on the non-destructive examination used. The number of design cycles is defined as the lesser of:

a) The number of cycles corresponding to one-half of the number of cycles required to propagate a crack from the initial assumed flaw size to the critical crack depth;

b) The number of cycles required to propagate a crack from the initial assumed flaw size to an allowable crack depth lesser than 25% of the section thickness or 25% of the critical crack depth.


HE: considered when determining fatigue crack growth rate and threshold stress intensity factor. These data need to be experimentally obtained according to respectively ASTM E 647 [8] and ASTM E 1681 [10] in H2 gas at a pressure not less than the design pressure of the vessel. For fatigue crack growth rate tests stress ratio shall not be less than the one used in the vessel design and frequency shall not exceed 0.1 Hz.

NDT: used as input for initial crack size determination.


Table 1. Standards for Transportation and Automotive storage applications: overview of design requirements against fatigue in gaseous hydrogen

Transport applications

Standard (Country)

Volume Minimum Pressure [MPa]

Maximum Pressure [MPa]

Material Design Rule Service life (number of cycles)

Requirements for H2 gas

ISO 9809-1/2 (International) [2, 3]

From 0,5 l up to 150 l

- - Low alloy Cr-Mo steel Prescriptive formula for minimum wall thickness

Not defined Yes

ISO 11120 (International) [4]

From 150 l up to 3000 l

- - Low alloy Cr-Mo steel Prescriptive formula for minimum wall thickness

Not defined Yes

DOT 3AA (USA) [6]

<= 450 l 1.0 - Low alloy Cr-Mo steel Prescriptive formula for minimum wall thickness

Not defined Yes

DOT 3AAX [6] (USA)

> 450 l 3.5 - Low alloy Cr-Mo steel Prescriptive formula for minimum wall thickness

Not defined No

ISO/TS 15869 (International) [7]

- - - Low alloy Cr-Mo steel Not specified. For type I ISO 9809 can be applied.

N=11,250 or N=5,500

Yes

ASME Section VIII, Div.3 – Art. KD-10 (USA) [1]

- - 100 Low and high alloy Cr-Mo steel, Al alloy

Fracture Mechanics Approach

Yes, depending on fracture mechanics calculations

Yes

13


4.2 STANDARDS FOR STATIONARY STORAGE

Table 2 gives an overview of the main international recognized standards for compressed gas storage applications including gaseous H2, highlighting the main design requirements with a particular focus on H2 gas.

4.2.1 EN 13445 [11]:

WT design: carried out according to an equation which depends on material and maximum pressure and vessel diameter.

Service life: maximum number of cycles is calculated based on an S-N approach. S-N curves are given in the standard and are valid for ferritic steels up to 1000 MPa of ultimate tensile strength. The user can however derive its own S-N data based on fatigue tests. Recommendations are given on how to carry out tests and analyze results.


HE: not quantitatively considered, however cylinder manufacturer is responsible to ensure compatibility between gas and vessel.

NDT: not specified.

4.2.2 AD2000-Merkblatt [12]:

WT design: carried out according to an equation which depends on material and maximum pressure and vessel diameter.

Service life: maximum number of cycles is calculated based on an S-N approach. S-N curves are given in the standard and are valid for ferritic steels up to 1000 MPa of ultimate tensile strength. The user can however derive its own S-N data based on fatigue tests. Recommendations are given on how to carry out tests and analyze results. Experimental fatigue verification: not required.

HE: quantitatively considered by a reduction factor of 10 on the calculated number of cycles.

NDT: not clearly specified.

4.2.3 ASME Section VIII, Div. 1-2 [13, 14]:

WT design: carried out according to an equation which depends on material and maximum pressure and vessel diameter. Div.2 allows lower safety margin, therefore obtaining lighter cylinders.

Service life: maximum number of cycles is calculated based on an S-N approach. S-N data are given in the standard with a list of materials authorized, for which these fatigue data are valid.


HE: not quantitatively considered, however cylinder manufacturer is responsible to verify that the material is suitable for the intended service conditions.

14


NDT: for SA 372 steel (similar to AISI 4130) magnetic inspection is required in accordance to Test Method A 275 [15]. This test method specifies how to carry out magnetic particle inspection which is a non-destructive test technique. In case of doubt about the obtained results liquid penetrant shall also be applied under Div. 1 rules. For other materials specifications and designs, according to Div. 2 rules, further investigation may be required. In case of integrally forged vessels made of SA372 Grade J, after Q&T heat treatment, ultrasonic examination shall be carried out in accordance to ASTM A388 [16].

4.2.4 ASME Section VIII, Div.3, Art. KD-10 [1]:

WT design: carried out according to a fracture mechanics approach in accordance with rules of article KD-4, Div.3 modified to take H2 effect into account. Fracture mechanics calculations are based on the assumption that cracks exist at the most stressed locations in a pressure vessel and allow to calculate the number of cycles to propagate these cracks from the initial depth to the critical crack depth and the maximum allowable crack depth, both calculated using the FAD in API 579-1/ASME FFS-1 [9]. An analysis of leak before break (LBB) should also be considered.

Service life: the calculated number of design cycles is the number of cycles required to propagate the crack from its initial depth to the allowable crack depth.

4.2.5 CODAP [17, 18]

CODAP is developed by SNCT (Syndicat National de la Chaudronnerie, Tuyauterie et Maintenance Industrielle), and is in accordance to the harmonized standard EN 13445, following the European Directive 97/23/CE which defines the risk category associated with the type of fluid contained by the pressure vessel and the product of pressure by volume (PV), i.e. the energy available to burst the vessel in case of explosion. A synopsis of major design requirements is provided in Table 2 [16, 17, 21].

WT design: carried out according to an equation that depends on the type of application domain. For instance, in order to determine the minimum thickness required for a cylindrical envelope under internal pressure, the average diameter of the envelope must be equal or greater than 5 times the thickness, based on shell theory. For thick vessels the Lamé formulae is used instead.

Service life: Fatigue analysis is carried out for the critical points (where there is stress concentration) which are more prone to fatigue. All possible loads are considered, including residual stress and thermal fluctuations. They are superimposed to the actual fatigue loading cycle expected for the service life of the equipment. The fatigue life is then referred to the

applicable S-N curve and the linear damage summation law (Miner’s law: 11

i

i

i

N

n) is used in

order to take into account the effect of different cycles on the expected total fatigue life of the vessel. In this case, the predict life cycle is decomposed in specific block cycles. All superimposed loads are considered based on S-N curves provided by the code for each critical point. They are provided also for welded parts. There are no rules to account for fatigue crack propagation.

Experimental fatigue verification: If needed to set the values of stresses for alternative rules. No detailed procedure is available.

15


HE: CODAP design rules don’t consider the effect of environments that are susceptible of reducing the fatigue lifetime. However, the annex « MA3-Comportament des aciers en presence d’hydrogène sous pression » gives some recommendations regarding the possibility of hydrogen damage and the requirements in terms of mechanical properties to avoid or minimize the hydrogen effect. It considers not only hydrogen embrittlement, but also hydrogen attack, internal hydrogen cracking and hydrogen delayed cracking, which are not considered in the present revision. The annex refers to carbon and low-alloy steels subject to hydrogen embrittlement (HE) at almost environment temperature. HE is localized in regions of higher stress concentrations. Material recommendations depend on the type of pressure equipment, if welded or not. As an example, low-alloy steels to be used for hydrogen containment shall have the Rm≤ 950 MPa, and for the chemical composition contents limits are imposed for sulfur and phosphorus to ≤ 0.015% in weight. The accepted heat treatment is quenched and tempered.

Materials allowed for construction: CODAP allow the use of various classes of alloys for gas containment in general, including C-Mn steel, low alloyed steels, alloyed steels, austenitic stainless steels, austenitic-ferritic stainless steels; martensitic stainless steels, ferritic stainless steels, Ni and Nickel alloys, Al and Aluminum alloys, Ti and Titanium alloys, and Cu and Cu alloys. For gaseous hydrogen storage the Cr-Mo steels with Rm ≤ 950 MPa is the material recommended.

16


4.2.6 Japanese standards for the design of high pressure vessels [19 – 21]

The design of pressure vessels in Japan follows a hierarchy as given in Figure 1. The first level is mandatory and it is enacted by METI (Ministry of Economy, Trade and Industry) and regulates pressure vessels and related equipments used in pressurized gas plants such as in the chemical and petrochemical industries [18]. The Ordinance Notices issued by METI are equivalent to the Pressure Equipment Directive (PED) in Europe or USA.

KHK (High Pressure Gas Safety Institute of Japan) develops and issues technical standards to ensure and maintain high pressure gas safety activities. KHK also submits proposals to METI on technical matters concerning high pressure gas safety. Another activity of KHK is to inspect and evaluate high pressure-gas related equipments, vessels, etc. as an impartial and neutral organization.

KHK S0220 Design standards for equipments containing ultra-high pressure gas (see Table 2) is applied in Japan to pressure gas equipment operating over 100 MPa, and hydrogen in particular for all ranges of pressure. In the case of hydrogen only two classes of materials are allowed for the containment of high pressure gaseous hydrogen: Cr-Mo steels for pressures up to 40 MPa and the austenitic stainless steels 316 and 316L for pressures higher than 40 MPa.

Figure 1. Hierarchy of pressure vessel standards in Japan [19 – 21].

The KHK S0220 standard establishes the requirements needed for the design of high pressure devices and equipment with design pressures beyond 100 MPa, and for gaseous hydrogen installations such as hydrogen refueling station reservoirs at any pressure. The basic flowchart of KHK S0220 is given in Figure 2. It starts with material selection taking into consideration that the yield ratio will be between 0.5 and

0.936. This ratio is given by the relationship ys/Rm. The calculation of thickness is calculated according to section 4.3.1, and the calculation of design life is performed by fatigue analysis in accordance to Section 4.4 and 4.5.1.

Regarding the fracture analysis, the leak-before-break (LBB) criteria must be carried out in accordance to section 4.7. Two possibilities may arise from this analysis: in the first one LBB is fulfilled, and in this case design life is defined by fatigue analysis. The second possibility is that the LBB criterion is not fulfilled, and for this case calculation of design life must be performed by crack growth analysis (Section 4.8) and by fatigue analysis (S-N curves). The smaller value of designed life calculated is then considered.

17


Figure 2. KHK S0220 standard for the design of hydrogen refueling station reservoirs [19 – 21].

Similarly to ISO, European and American standards used for the design and quality control requirements of gas pressure reservoirs, some Japanese standards listed in Table 2 are also used for. No details are given but references are made to ISO and ASME codes they have been derived from (see Table 2).

18


Table 2: Overview of the standards for stationary storage applications

Storage applications

Standard (Country)

Volume Minimum Pressure [MPa]

Maximum Pressure [MPa]

Material Design Rule Service life (number of cycles)

Requirements for H2 gas

EN 13445 (European Community) [11]

- - - Several steels, including low alloy Cr-Mo steel

Prescriptive formula for minimum wall thickness

Fatigue design based on S-N approach

Not quantitatevely considered

AD 2000-Merkblatt (Germany) [12]




Considered through a safety factor of 10 on the number of cycles

ASME Section VIII, Div.1/2 (USA) [13]





ASME Section VIII, Div.3 – Art. KD-10 (USA) [14]

- - 100 Low and high alloy Cr-Mo steel, Al alloy

Fracture Mechanics Approach


Yes

ISO DIS 15399 (International) [27]

Up to 10,000 l

15 110 Low alloy Cr-Mo steel Not specified. For type I ISO 9809 or ISO 11120 can be applied.

To be specified by the manufacturer, 15 years minimum


CODAP (France) [17]

No limitations.

No rules for high pressure equipment

No rules for high pressure equipment

Low alloy Cr-Mo steel

(Rm≤950 MPa) for

seamless reservoirs

1. Prescriptive formula for minimum wall thickness. 2. Design by formula 3. Design by analysis

Fatigue analysis: Rules of exemption; Simplified rules; Alternative rules

Only recommendations, such as the limit of allowed UTS for low alloys-steels set to ≤950 MPa

JIS B8265 (Japan) [22]

<30 Steel, non-ferrous metal

Design by formula (Refers to ASME Sec. VIII Div. 1 (1987); Similar to ISO 16528).

Not defined

19


Design coefficient: 4.0


<100 Steel, non-ferrous metal

Design by analysis (Refers to ASME Sec. VIII Div. 2 (2004); Similar to ISO 16528) Design coefficient:3.0

Not defined


<30 Steel, non-ferrous metal Refers to ASME Sec. VIII Div. 1 (2004) Design coefficient:3.5

Not defined

JIS B8230 (seamless gas cylinders) (Japan) [25]

0.1 – 1.0 Steel, Cr-Mo steel, non-ferrous metal, stainless steel

Not specified.

Not defined

JIS B8241 (seamless gas cylinders) (Japan) [26]

1 – 700 Steel, Cr-Mo steel, non-ferrous metal, stainless steel

Not specified. Similar to ISO 4705

Not defined

KHK (The High Pressure Gas Safety Institute of Japan) [19]

-/>100 MPa

Cr-Mo steel, Ni-Cr-Mo steels

1. Design by formula 2. Fracture Mechanics Approach


Yes

20


5 Comments & Remarks

Several standards exist at national or regional levels for the design and qualification of high pressure cylinders for H2 storage; however an international worldwide recognized standard does not yet exist.

In Europe, the harmonized European code EN 13445 is used by the European Community member countries, but local codes such as the German code AD2000 and the French code CODAP are also applied to the design of unfired pressure vessels. The ASME Section VIII, Div. 1-2-3 is used in USA, and KHK codes together with some related JIS standards are applied in Japan. Most of the evaluated standards consider the possibility of hydrogen embrittlement and hydrogen enhanced fatigue for steels at different levels and some of them require specific design depending on the hydrogen pressure.

The standard AD2000 applies a reduction factor of 10 on the calculated number of cycles in a non embrittling environment, regardless of the H2 pressure.

ASME Section VIII, Div. 3 requires a mandatory fracture mechanics approach, therefore considering only fatigue crack propagation phase, when dealing with hydrogen pressures above 41 MPa and similar requirements are established by the Japanese KHK code.

The new international standard ISO-CD 15399, “Gaseous hydrogen - Cylinders and tubes for stationary storage” [27], at the present time being developed by the ISO TC197/WG15, refers to the well-developed standards for transportable as a way to address the storage of H2 gas by adding requirements which are needed to take into account the different number of cycles and different operational conditions seen by the buffer storage cylinders with respect to transportable cylinders.

In case of type I steel cylinders the reference standards are ISO 9809-1 and ISO 11120 and the hydrogen embrittlement occurrence is addressed in a traditional way, meaning by the limitation of the steel mechanical properties.

None of the above mentioned standards require verification of expected cylinder service life through the use of full scale tests in H2 gas and this is also the approach that will be taken in the MATHRYCE project.

The expected outcome of the MATHRYCE project is the definition of a new methodology for the design of high hydrogen steel pressure vessels and for their lifetime assessment taking into account hydrogen-enhanced fatigue, but without the requirement of full scale tests to be carried out under hydrogen gas for the cylinder qualification.

This new methodology will consider the effect of hydrogen on the initiation as well as on the propagation phase of a possible imperfection, through the use of specific coefficients, determined by means of laboratory tests and later transferred to full scale tests.

This new approach will mainly consist of two steps:

Determination of the factor by which cycle life, consisting of both initiation and crack propagation, is reduced due to the effect of hydrogen in the projected worst case service conditions. This will be obtained by means of laboratory tests in gaseous hydrogen environment. This factor will be named as “H2 Sensitivity Factor”.

Verification of cylinder fatigue life through full scale tests in hydraulic to ensure that the component has a cycle life exceeding the expected cycle life in the projected worst case service conditions, multiplied by the H2 sensitivity factor. This will avoid the requirement to carry out full scale tests in H2 gas.

The outputs of the MATHRYCE project will be collected into guidelines and recommendations for the development of a new international standard for the design and manufacturing of high pressure gas cylinders, where hydrogen embrittlement and hydrogen enhanced fatigue will be clearly addressed.

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6 CONCLUSION

During the design of gaseous hydrogen reservoirs under fatigue loading conditions the effect of H2 is often not considered or not evaluated by design codes. Only recently, the ASME Section VIII-Division III code through the KD-10 code case and the Japanese KHK code through the S0220 standard started addressing the effect of hydrogen by providing specific requirements based on the fracture mechanics crack growth analysis methodology which are added to the existing S-N curves (or fatigue analysis) approach.

Considering that the fatigue of H2 reservoirs of HRS (hydrogen refueling stations) will spend most of its service life to initiate a crack and that fatigue crack propagation is fast when compared to propagation in air or inert environment [28], another design methodology is required, which is the main focus of the MATHRYCE project.

As a follow-up of this first revision on codes and standards focused on hydrogen enhanced fatigue a second report will be provided as deliverable D2.5 with a quantitative comparison of a H2 pressure vessel design according to the codes ASME Section VIII Division 3, EN13445 and KHK S0220 [28 - 30]

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REFERENCES

[1] ASME Boiler and Pressure Vessel Code, Section VIII, Div.3, Alternative rules for construction of high pressure vessels. Article KD4 - Fracture Mechanics Evaluation, Article KD-10 – Special Requirements for vessels in high pressure gaseous hydrogen transport and storage service, 2010.

[2] ISO 9809-1, ISO 9809-1, Gas Cylinders – Refillable seamless steel gas cylinders – Design, construction and testing – Part 1: Quenched and tempered steel cylinders with tensile strength less than 1110 MPa, 2010.

[3] ISO 9809-2, Gas Cylinders – Refillable seamless steel gas cylinders – Design, construction and testing - Part 2: Quenched and tempered steel cylinders with tensile strength greater than or equal to 1110 MPa, 2010.

[4] ISO 11120, Gas Cylinders - Refillable seamless steel tubes for compressed gas transport of water capacity between 150 l and 3000 l - Design, construction and testing, 1999.

[5] NF EN ISO 11114-4: 2006. Compatibilité des matériaux des bouteilles et des robinets avec les contenus gazeux - Part4 : Méthodes d’essai pour le choix des matériaux métalliques résistants à la fragilisation par l’hydrogène, AFNOR, Paris.

[6] § 178.37 Specification 3AA and 3AAX seamless steel cylinders.

[7] ISO/TS 15869, Gaseous hydrogen and hydrogen blends – Land vehicle fuel tanks, 2009.

[8] ASTM E647, Measurement of Fatigue Crack Growth Rates.

[9] API 579-1/ASME FFS-1, 2007.

[10] ASTM E1681, Determining Threshold Stress Intensity Factor for Environment-Assisted Cracking of Metallic Materials.

[11] EN 13445 Unfired Pressure Vessels.

[12] AD 2000 Codes of Practice on Pressure Vessels.

[13] ASME Boiler and Pressure Vessel Code, Section VIII, Div.1, Rules for construction of pressure vessels.

[14] ASME Boiler and Pressure Vessel Code, Section VIII, Div.2, Alternative rules for construction of pressure vessels.

[15] ASTM A275/A275M - 08 Standard Practices for Magnetic Particle Examination of Steel Forgings.

[16] ASTM A388 - Standard Practice for Ultrasonic Examination of Steel Forgings.

[17] CODAP-Code de construction des appareils à pression non soumis à l’action de la flame, SNCT – Syndicat National de la Chaudronnerie, Tuyauterie et Maintenance Industrielle, Paris, France.

[18] Di Rienzo A. SNCT – Syndicat National de la Chaudronnerie, Tuyauterie et Maintenance Industrielle, Paris, France, Private communication, May 2013.

[19] KHK S 0220: 2010 - Design standards for equipment containing ultra high pressure gas. The High Pressure Gas Safety Institute of Japan (KHK), Tokyo.

[20] Manabe T. Air Liquide Japan, Personal communication, April 2013.

[21]Matsumoto T., Air Liquide Laboratories, Japan, Personal communication, June 2013.

[22] JIS B8265: 2010 – Construction of pressure vessel – General principles. Japanese Standards Association, Tokyo, Japan.

[23] JIS B8266 : 2003 – Alternative standard for construction of pressure vessels. Japanese Standards Association, Tokyo, Japan.

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[24] JIS B8267 : 2008 – Construction of pressure vessel. Japanese Standards Association, Tokyo, Japan.

[25] JIS B8230: 1989 – Small type seamless steel gas cylinder. Japanese Standards Association, Tokyo, Japan.

[26] JIS B8241: 1989 - Seamless steel gas cylinder. Japanese Standards Association, Tokyo, Japan.

[27] ISO/DIS 15399 Gaseous hydrogen— Cylinders and tubes for stationary storage.

[28] Tanno Y, Naruse T, Arai S, Kurita S. Strength evaluation for pressure-containing parts of ultra-high pressure compressor by using standards for ultra-high pressure gas equipment. PVP2011-57149. ASME Pressure Vessels and Piping Conference, Baltimore, Maryland, July 17-21, 2011.

[29] European Commission, DG Enterprise, Contract N° FIF.20030114. Comparative Study on Pressure Equipment Standards, July 2004.

[30] ASME STP-PT-007: Comparison of Pressure Vessel Codes ASME Section VIII and EN13445: Technical, Commercial, and Usage Comparison, Design Fatigue Life Comparison, ASME Standards Technology, LLC, New York, December 2006.

ANNEXES:

List of active RCS

List of published RCS

List of active standards

List of published standards

NOMENCLATURE H2 - Hydrogen gas UTS or Rm- Ultimate tensile strength

YS - Yield stress WT - Wall thickness FAD - Failure assessment diagram HE - Hydrogen embrittlement NDT – Non-destructive test N - Number of cycles Q&T - Quenched and tempered

mathryce material testing and recommendations for … · material testing and recommendations for...

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