1. Raw Materials

UHP graphite electrodes are made from high-quality raw materials to ensure high density, low resistivity, and excellent thermal shock resistance. Key components include:

Needle Coke (Core Material)

Petroleum-based Needle Coke (Low sulfur/ash, high crystallinity)

Coal-based Needle Coke (Lower cost, slightly inferior performance)

Coal Tar Pitch (Binder, ~20–30% of mix)

Requires high carbon yield (>50%) to ensure post-graphitization strength.

Additives (Optional)

Examples: Boron compounds (improve oxidation resistance), silicon powder (enhance high-temperature stability).

2. Manufacturing Process

The production of UHP graphite electrodes involves complex steps:

Stage	Key Process	Description
1. Raw Material Prep	Calcination (1200–1400°C)	Removes volatiles, increases density.
2. Crushing & Sizing	Particle Size Distribution	Optimized mix (e.g., 4:3:3 coarse/medium/fine).
3. Kneading	Pitch Impregnation (160–200°C)	Forms moldable paste.
4. Forming	Extrusion (rods) / Molding (shapes)	Shapes the green electrode.
5. Baking	Slow heating (800–1200°C, 15–30 days)	Carbonizes pitch for initial strength.
6. Impregnation (Opt.)	Secondary Pitch Treatment	Enhances density (1–2 repeats for premium grades).
7. Graphitization	High-Temp Treatment (2500–3000°C)	Converts amorphous carbon to crystalline graphite.
8. Machining	Threading (NPT/ISO) & End-Facing	Ensures precise joint connections.
9. Quality Control	Resistivity, Flexural Strength, Density Tests	UHP standards (e.g., ≤6.5 μΩ·m, ≥1.68 g/cm³).

3. Applications

UHP electrodes are designed for ultra-high power, high-temperature, and high-current-density industrial processes:

Industry	Applications	Key Requirements
Steelmaking	Large EAFs (≥100 tons)	High current (>20,000A), low consumption.
Special Alloys	Stainless steel, Ni-based alloys	Thermal shock resistance (>1800°C).
Silicon Metal	Polysilicon, metallurgical Si	Anti-oxidation coatings (e.g., Al).
CaC₂ & P₄	Calcium carbide, phosphorus furnaces	Chemical corrosion resistance, low ash (<0.5%).
Others	Graphitization furnaces, vacuum melting	Ultra-high purity (ash <0.1%).

UHP vs. Regular Electrodes: Key Advantages

Property	UHP Electrodes	Regular HP Electrodes
Current Density	25–35 A/cm²	15–25 A/cm²
Resistivity	≤6.5 μΩ·m	7–10 μΩ·m
Flexural Strength	≥12 MPa	8–10 MPa
Furnace Compatibility	Large EAFs, ladle furnaces	Medium/small furnaces

Usage Notes:

Avoid rapid cooling/heating to prevent thermal cracking.

Store in dry conditions to prevent joint arcing.

Follow torque specs (e.g., 300–400 N·m) to avoid thread damage.

For detailed parameters (e.g., current capacity by diameter), provide specific requirements for further analysis.

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Products Parameters

Item		Unit	RP		HP		UHP
			≤∅400	≥∅450	≤∅400	≥∅450	≤∅400	≥∅450
Electric Resistivity	Electrode	μΩ*m	≤8.5	≤9.0	≤6.0	≤6.5	≤5.0	≤5.5
	Nipple		≤6.5	≤6.5	≤5.5	≤5.5	≤4.5	≤4.5
Transverse Strength	Electrode	MPa	≥8.0	≥7.0	≥10.5	≥10.5	≥15.0	≥15.0
	Nipple		≥16.0	≥16.0	≥20.0	≥20.0	≥22.0	≥22.0
Young's Modulus	Electrode	Gpa	≤9.3		≤12.0		≤14.0
	Nipple		≤14.0		≤16.0		≤18.0
Bulk Density	Electrode	g/cm³	≥1.54		≥1.65		≥1.68
	Nipple		≥1.69		≥1.73		≥1.76
Coefficient of Termal Expansion (100℃﹣600℃)	Electrode	100^-6/℃	≤2.5		≤2.0		≤1.5
	Nipple		≤2.0		≤1.6		≤1.2
Ash		%	≤0.3		≤0.2		≤0.2

UHP Electrodes

1. Raw Materials

2. Manufacturing Process

3. Applications

Products Parameters