HPIS
Standard Test Method for Humid Gas Stress Corrosion Cracking ofAluminium Alloys for Compressed Hydrogen Containers

HPIS E 103:2018

High Pressure Institute of JapanAll rights reserved especially (also in extracts) for translation, reprinting, reproduction by copying or other technical means.

ContentsPageIntrocution ········································································································· 1
1Scope ·········································································································· 12Normative references ······················································································ 1

3Terms and definition ······················································································· 14Principle ······································································································ 25Specimens ···································································································· 25.1 Specimen geometries ······················································································ 25.2 Materials ····································································································· 35.3 Specimen orientation ······················································································ 36Fatigure pre-cracking ······················································································ 37Test method ·································································································· 47.1Loading ······································································································ 47.2 Test environment and period ············································································ 57.3 Measurement of load ······················································································ 57.4 Fatigue post-cracking and breaking ···································································· 67.5 Measurement of crack length ············································································ 67.6 Validity of test ······························································································ 68Qualification of materials ················································································· 7

Annex A (normative)

The compact specimen ····························································· 9Annex B (normative)

The single-edge bend specimen (SE specimen) ·······························12Bibliography ······································································································14
List of Members of the HG-SCC committee································································15(1)All rights reserved especially (also in extracts) for translation, reprinting, reproduction by copying or other technical means.

HPIS E 103:2018

Standard Test Method for Humid Gas Stress Corrosion Cracking ofAluminium Alloys for Compressed Hydrogen Containers
Introduction
This standard is established at the request of automotive industry in order to evaluate the humid gas
stress corrosion cracking (HG-SCC) susceptibility of aluminium alloys used in compressed hydrogencontainers.

1

Scope
This standard specifies the test method for humid gas stress corrosion cracking (HG-SCC) and thequalification criteria of aluminium alloys for compressed hydrogen containers for automotive use.

2

Normative references
The following referenced documents are indispensable for the application of this document. For

dated document, only the edition cited applies. For undated references, the latest edition of thereferenced document (including any amendments) applies.
ISO 6892-1, Metallic materials – Tensile testing – Part1: Method of test at room temperature
ISO 7539-6:2011, Corrosion of metals and alloys – Part 6: Preparation and use of precracked
specimens for tests under constant load or constant displacement
ISO 7866:2012, Gas cylinders – Refillable seamless aluminium alloy gas cylinders – Design,
construction and testing
ASTM E399-12e2, Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness KIc ofMetallic Materials

3Terms and definitions
For the purpose of this document, the terms and definitions given in ISO 7539-6:2011 and thefollowing apply.
3.1
HG-SCC (Humid Gas Stress Corrosion Cracking)stress corrosion cracking in a humid gas environment
3.2
KI1
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HPIS E 103:2018

stress intensity factor of a crack subjected to opening mode displacements (mode I)
3.3
KIAPP
stress intensity factor of a crack when a load was applied to the specimen at the beginning of the HGSCC test
3.4
σ0.2
average of the 0.2% proof stress of two specimens measured at room temperature in accordance withthe procedures given in ISO 6892-1
3.5
small scale yielding condition
condition in which the plastic zone at the crack tip is so small in comparison to the dimensions of thespecimen that the plastic zone does not significantly affect the stress distribution in the surrounding
elastic zone, thus enabling the description of the field of stress at the crack tip in terms of stress intensity
factor K
3.6
plane strain condition
condition in which the dimensions of the plastic zone at the crack tip are so small in comparison to
the length of the crack and to the thickness of the specimen that plastic deformation along the thickness
direction inside the plastic zone is restricted by elastic deformation in the surrounding elastic zone (dueto difference in the Poisson’s ratios), thus generating a tensile stress in the thickness direction andattaining a tri-axial tensile stress state

4Principle

A fatigue pre-cracked specimen is loaded by a constant-load or constant-displacement method to aKIAPP equal to a defined value. Then, the specimen is maintained in the loaded state at prescribed
environment for a prescribed duration. After the test duration, the specimen is examined as to whetheror not the cracking has extended from the initial fatigue pre-crack. If the crack extension length does
not exceed a prescribed value, the material of the specimen is considered suitable for compressedhydrogen containers as far as the required resistance to crack extension under loading is concerned.

5Specimens

5.1

Specimen geometries

The geometries of the HG-SCC specimen shall be as follows.
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