Comprehensive Quality Control System for Graphite Electrodes

Comprehensive Quality Control System for Graphite Electrodes

--From Premium Raw Materials to Precision Inspection

I. Stringent Raw Material Selection Standards

Global Needle Coke Supply Chain

Imported Coke: Phillips 66 (USA), Mizushima (Japan), Mitsubishi Chemical (Japan)

Key specs: CTE ≤1.0×10⁻⁶/℃ (800℃), sulfur content <0.3%

Domestic Coke: Daqing/Fushun petroleum coke

Low sulfur control: S≤0.5%, ash content≤0.3%

Binder Optimization

Bengang/Anshan modified pitch

Softening point: 88-95℃, quinoline insolubles <8%

Coking value ≥54% (ensures baking yield)

Quality Control Points:

Batch-wise XRF sulfur analysis + polarized light microscopy anisotropy testing

Proprietary 5:2 blend ratio of needle coke/petroleum coke

II. Critical Process Control Points

III. World-Class Inspection System

Microstructure Analysis

Universal optical microscope (1000X):

Detects coke particle fragmentation from tool wear (integrity >90%)

Analyzes pitch-coke interface bonding

Dimensional Accuracy

JIS standard ring gauges (Japan): Diameter tolerance ±0.05mm

DIN standard ring gauges (Germany): Thread concentricity ≤0.02mm

Destructive Testing

Three-point bending test (ASTM C651)

Elastic modulus measurement (ultrasonic pulse method)

IV. Typical Quality Issue Resolution Cases

V. Traceability System

Blockchain Tracking:

Unique electrode ID (raw material batch → process parameters → test data)

SPC Monitoring:

Critical process CPK consistently >1.67

VI. Industry Benchmarking

Technical Discussion:
How to optimize the blending ratio of Phillips 66 needle coke (high cost) with domestic coke to maintain CTE performance while reducing material costs by 5%? Industry experts are welcome to share insights!

(Note: All inspection equipment is CNAS-certified)