ASTM 99.9% Pure Copper Earth Rod / Grounding Rod / Copper Rod

I. Raw Materials and Production Process

Raw Materials:  
Made from high-purity electrolytic copper ≥99.95% (Grade 1 cathode copper from Shanghai, Luoyang Copper, or Jinchuan), with total impurities controlled at ≤300 ppm and oxygen content ≤10 ppm.

Smelting:  
Medium-frequency induction furnace + horizontal continuous casting.
Billet grain size ≤0.12 mm, effectively eliminating segregation, porosity, shrinkage cavities, and other defects commonly associated with traditional upward continuous casting methods.

Hot Extrusion:  
3500T–5000T hydraulic extrusion press, extrusion ratio 25–35:1, one-shot forming.
Surface oxide layer ≤0.03 mm, dimensional tolerance stably controlled within ±0.10 mm.

Multi-pass Cold Drawing + Intermediate Annealing:  
Total cold working reduction ≥95%.
Annealing performed in bell-type bright annealing furnace under full nitrogen protection throughout the process, ensuring the finished product is free from oxidation discoloration and internal stress-induced cracking risks.

Finishing:  
Combined drawing-straightening + dual non-destructive testing (eddy current + ultrasonic inspection).
Surface roughness Ra ≤0.8 μm, straightness ≤0.5 mm/m.

II. Quality Control System

Full-process Batch Management:  
From cathode copper plate → cast billet → extruded rod → finished product, physical samples are retained at every process stage, along with spectroscopic, mechanical, and conductivity test reports. Full traceability maintained for ≥5 years.

Testing Capabilities:  
- Direct-reading spectrometer (full analysis of 26 elements, single-element accuracy ±0.0005%)
- Automatic eddy current + ultrasonic flaw detection (100% detection of defects equivalent to ≥Φ0.3 mm)
- Automatic conductivity measurement (MS/m, accuracy ±0.1% IACS)
- Universal material testing machine (yield strength, tensile strength, elongation, repeated bending)

Standard Factory Acceptance Specifications (can be further tightened per contract requirements):
- Diameter tolerance: ±0.10 mm (φ8–φ120 mm range)
- Electrical conductivity: ≥58.0 MS/m (≥101% IACS)
- Elongation A: ≥40% (soft temper)
- Grain size: ≤0.025 mm (soft temper)
- Surface: completely free from mechanical damage, cracks, orange peel, or oxidation discoloration.