Overview
EN ISO 2626:1995 (ISO 2626:1973) specifies a standard test method for detecting hydrogen embrittlement in deoxidized and oxygen‑free high‑conductivity coppers. The standard defines the principle, required test pieces, heating/exposure procedure in hydrogen and the methods for revealing embrittlement: close‑bend, reverse‑bend and microscopic examination. It is intended for quality control and metallurgical assessment of copper and copper alloys where hydrogen exposure may compromise mechanical performance.
Key Topics and Requirements
- Scope: Applies to deoxidized and oxygen‑free high‑conductivity copper materials.
- Test principle: Heat a prepared test piece in a hydrogen‑containing atmosphere; hydrogen reacts with oxygen in the metal causing embrittlement that is then revealed by mechanical or microscopic inspection.
- Hydrogen exposure:
- Furnace atmosphere must contain not less than 10% hydrogen.
- Temperature range: 825–875 °C.
- Exposure time: 30 minutes.
- Cooling: cool in the furnace atmosphere or quench in water; avoid exposing heated surface to air prior to testing.
- Test pieces:
- Close‑bend test piece: full section or thickness/diameter ≤ 12 mm; original surface must be on at least one face; edges rounded and smoothed.
- Reverse‑bend test piece: thickness/diameter ≤ 2.5 mm; also retain original surface portion.
- Microscopic specimen: section to include outside surface at right angles for metallographic examination.
- Detection methods:
- Close‑bend: bend to prescribed geometry so original surface is outermost; inspect for cracks.
- Reverse‑bend: perform 10 reverse bends (see ISO 2625 for details), inspect visually for cracks.
- Microscopy: polish (and etch if desired), examine at 200× for gassing or open grain structure characteristic of embrittlement.
- Reference methods: ISO/R 398 (bend test) and ISO 2625 (reverse bend testing of wire) are cited for bending procedures.
Applications
- Quality control of high‑conductivity copper products (wire, strip, components) where hydrogen exposure during processing (annealing, brazing, soldering) may occur.
- Incoming inspection, acceptance testing and metallurgical investigations for hydrogen‑related failures.
- Process validation for manufacturers, heat‑treatment shops and metallurgical laboratories monitoring hydrogen embrittlement risk.
Who Should Use This Standard
- Copper producers and fabricators, materials engineers, QA/QC laboratories, failure‑analysis labs, and procurement/specification authors concerned with mechanical integrity of high‑conductivity copper.
Related Standards
- ISO 2625 - Copper and copper alloys: Reverse‑bend testing of wire.
- ISO/R 398 - Bend test for copper and copper alloys.
- EN ISO 2626:1995 is the European adoption of ISO 2626:1973.
Keywords: EN ISO 2626:1995, ISO 2626:1973, copper hydrogen embrittlement test, deoxidized copper, oxygen‑free high‑conductivity copper, close‑bend test, reverse‑bend test, hydrogen embrittlement testing.
