Overview
ISO 2626:1973 - "Copper - Hydrogen embrittlement test" specifies a standardized procedure for detecting hydrogen embrittlement in deoxidized and oxygen‑free high‑conductivity coppers. The standard defines the principle, required test pieces, exposure in a hydrogen atmosphere, and post‑exposure examination methods. Embrittlement is revealed by close‑bend or reverse‑bend testing, or by microscopic examination for gassing or open grain structure.
Key topics and requirements
- Scope: Applies to deoxidized and oxygen‑free high‑conductivity copper products.
- Principle: Heat test pieces in a hydrogen‑containing atmosphere; if oxygen in the metal reacts to form hydrogen effects, embrittlement becomes detectable after mechanical or microscopic examination.
- Hydrogen exposure: Heat in a furnace atmosphere containing ≥ 10% hydrogen, at 825–875 °C for 30 minutes. Cool in the furnace atmosphere or quench in water.
- Test piece dimensions:
- Close‑bend pieces: convenient length, full section or thickness/diameter up to 12 mm; original surface must be included and become the outside of the bend.
- Reverse‑bend pieces: convenient length, thickness/diameter not exceeding 2.5 mm; original surface must be present.
- Bend tests:
- Close‑bend test: Bend to a V‑shape then bring legs into contact so the original surface is at the outside of the bend; inspect visually for cracks.
- Reverse‑bend test: Performed according to ISO 2625; subject the specimen to 10 reverse bends with the original surface subjected to maximum stress; inspect visually for cracks.
- Microscopic examination: Section to expose an outside surface at right angles, polish (and etch, if desired) and examine at 200× for evidence of gassing or open grain structure.
- Related references: ISO/R 398 (bend test methods) and ISO 2625 (reverse bend testing of wire) are referenced for specific bending procedures.
Applications and users
ISO 2626 is practical for:
- Metallurgical and materials testing laboratories performing hydrogen embrittlement tests on copper.
- Copper producers and quality control departments verifying oxygen‑free high‑conductivity copper integrity.
- Failure‑analysis and R&D groups investigating brittleness or microstructural gas defects.
- Manufacturers of electrical components and conductors where high conductivity copper performance and reliability are critical.
Keywords: ISO 2626:1973, hydrogen embrittlement test, copper, deoxidized copper, oxygen‑free high‑conductivity copper, close‑bend test, reverse‑bend test, microscopic examination.
Related standards
- ISO 2625 - Copper and copper alloys - Reverse bend testing of wire.
- ISO/R 398 - Bend test for copper and copper alloys (methods referenced for close‑bend procedure).
