SIST EN ISO 2626:1998

SIST EN ISO 2626:1998 is the Slovenian standard published by SIST for the hydrogen embrittlement test of deoxidized and oxygen-free high-conductivity coppers. It specifies the test principle, the preparation of test pieces, the hydrogen exposure step, and three ways to reveal embrittlement: close bending, reverse bending, or microscopic examination. In practice, it is used to check whether copper has become embrittled by hydrogen during processing or heat treatment.

What does SIST EN ISO 2626:1998 specify?

SIST EN ISO 2626:1998 specifies a test method for hydrogen embrittlement in deoxidized and oxygen-free high-conductivity coppers. The standard focuses on how to prepare the specimen, how to expose it to hydrogen, and how to look for cracking or microstructural signs of embrittlement.

The document is organized into:

• Scope and field of application
• References
• Principle
• Test pieces
• Procedure, including hydrogen exposure and the three examination routes

What are the key requirements of SIST EN ISO 2626:1998?

SIST EN ISO 2626:1998 requires a prepared copper test piece to be heated in hydrogen and then examined for embrittlement. The important point for users is that both the specimen shape and the examination method affect whether cracking can be detected reliably.

Scope and principle

• Clause 1 limits the method to deoxidized and oxygen-free high-conductivity coppers. That tells buyers and laboratories which copper products the method is intended for.
• Clause 3 states the principle: oxygen in the metal can react during heating in hydrogen and cause embrittlement. After cooling out of contact with air, the effect is revealed by bending tests or microscopy.

Test piece preparation

• Clause 4.1 covers the close-bend test piece. It may be full section or reduced, but the thickness or diameter must not exceed 12 mm, and edges must be rounded and smoothed. This matters because sharp edges can distort the bend result.
• Clause 4.2 covers the reverse-bend test piece. Its thickness or diameter must not exceed 2.5 mm, and it also needs rounded, smoothed edges. Reduced sections must include some of the original surface so the tested surface is representative.
• Clause 4.3 covers the test piece for microscopic examination. It must be of convenient size and include an outside surface on at least one face. This lets the examiner inspect the surface layer where embrittlement shows up.

Hydrogen exposure and examination

• Clause 5.1 requires heating in a furnace atmosphere containing not less than 10 % hydrogen at 825 to 875 °C for 30 min, followed by cooling in the furnace atmosphere or quenching in water. In practice, the specimen must not be exposed to air while still hot if the result is to remain meaningful.
• Clause 5.2.1 describes the close-bend test at ambient temperature. The specimen is bent steadily until the ends meet, with the original surface on the outside of the bend, then the stressed surface is checked visually for cracks.
• Clause 5.2.2 directs the reverse-bend test to ISO 2625. The specimen is given 10 reverse bends, then the original surface is inspected with the unaided eye for cracks.
• Clause 5.2.3 defines the microscopic route. The specimen is sectioned across an outside surface, polished, optionally etched, and examined at 200× for gassing or an open grain structure characteristic of embrittlement.

What terms does SIST EN ISO 2626:1998 define?

SIST EN ISO 2626:1998 uses several practical terms that matter during inspection and acceptance.

• Hydrogen embrittlement - loss of ductility caused here by heating copper in hydrogen when oxygen is present in the metal.
• Deoxidized copper - copper intended to have oxygen removed, so it is less likely to suffer the reaction checked by this test.
• Oxygen-free high-conductivity copper - high-purity copper with very low oxygen content, used where conductivity and toughness matter.
• Close-bend test - a bend test where the specimen is bent until the ends come together and cracks are looked for on the stressed surface.
• Reverse-bend test - a repeated bending method used to reveal cracking on the original surface after hydrogen exposure.
• Microscopic examination - inspection of a prepared section under 200× magnification for gassing or open grain structure.

Who uses SIST EN ISO 2626:1998?

SIST EN ISO 2626:1998 is used by laboratories, quality control teams, and copper producers that work with deoxidized or oxygen-free high-conductivity copper. It is also relevant to buyers and inspectors who need a defined test method when checking for hydrogen damage after manufacture, forming, or heat treatment.

Which standards are used with SIST EN ISO 2626:1998?

SIST EN ISO 2626:1998 refers to two companion standards for the bending examinations:

• ISO/R 398 - gives the bend test methods for copper and copper alloys used in the close-bend procedure.
• ISO 2625 - gives the reverse bend testing method for wire used in the reverse-bend procedure.

These references matter because the hydrogen embrittlement test depends on established bend-test methods rather than redefining the bending setup from scratch.

What does the SIST EN ISO 2626:1998 document contain?

SIST EN ISO 2626:1998 contains the test principle, specimen preparation rules, and the exposure conditions in hydrogen. It also includes the detailed close-bend and reverse-bend procedures, plus the microscopy route for detecting embrittlement.

The document includes a figure for the close-bend test and specifies the visual and microscopic checks used after exposure. The detailed conditions support laboratory testing, product qualification, and failure investigation rather than general design work.