Ultra-fine grain isostatic graphite is an engineered carbon material produced through cold isostatic pressing and high-temperature graphitization. Unlike conventional extruded or vibration-molded alternatives, this isotropic manufacturing route ensures a homogeneous internal structure with uniform physical properties in all directions.
Engineered for precision, fine-detail machining, and reliable performance under severe thermal and mechanical loads, this material is supplied in two flexible formats: raw material blocks/rods and custom-machined components built precisely to engineering drawings.
Technical Specifications
|
Property |
Unit |
Typical Range / Specification |
|
Average Grain Size |
um |
2 - 10 (custom options available) |
|
Bulk Density |
g/cm3 |
1.75 - 1.88 |
|
Flexural Strength |
MPa |
40 - 75 |
|
Compressive Strength |
MPa |
80 - 140 |
|
Electrical Resistivity |
uOmega*m |
10 - 15 |
|
Coefficient of Thermal Expansion (CTE) |
10^-6/K |
4.0 - 5.5 (20 deg C - 400 deg C) |
|
Ash Content |
ppm |
< 50 (Standard) down to < 5 (Purified) |
|
Available Stock Forms |
-- |
Sawn blocks, round rods, tailored blanks, or finished parts |
Key Material Characteristics
Homogeneous Microstructure: Fine and uniform grain distribution supports high-precision CNC machining, sharp edge retention, and smooth surface finishes on complex geometries.
Isotropic Physical Behavior: Isostatic pressing minimizes directional variance in thermal and mechanical properties, reducing the risk of localized stress failure.
Mechanical Strength: High flexural and compressive strength deliver structural integrity for load-bearing industrial furnace components, dies, and fixtures.
Thermal & Electrical Stability: Controlled thermal expansion (CTE), optimal thermal conductivity, and predictable electrical resistivity ensure stable operation in high-temperature heating zones.
Purity Options: Available in standard commercial grades or high-purity specifications (controlled ash content) designed for contamination-sensitive processes.
Typical Industrial Applications
Precision Molds & Tooling: Powder metallurgy dies, sintering molds, EDM electrodes, and continuous casting components requiring high surface integrity.
Vacuum & High-Temperature Furnaces: Heating elements, thermal insulation shields, structural supports, and hot-zone fixtures (governed by operating temperatures and atmosphere).
Semiconductor & Crystal-Growth Equipment: Components requiring rigorous control over micro-impurities, thermal gradients, and outgassing in specialized crystal pulling environments.
Custom Engineering Parts: Finished components machined from raw isostatic blocks according to client CAD files or 2D technical drawings.
How to Select the Right Grade
Selecting an isostatic graphite grade requires evaluating the exact operating environment rather than relying on grain size alone:
Mechanical Load
Verify compressive and flexural strength if the component acts as a structural support or undergoes physical pressing.
Thermal Environment
Assess maximum working temperature, thermal shock frequency, and furnace atmosphere (preventing oxidation in oxygen-bearing air above 400 deg C).
Electrical Demands
Check electrical resistivity if the component functions as a heating element or current conductor.
Purity Requirements
Determine whether standard commercial ash content is sufficient or if high-purity chemical treatment is mandatory to avoid process contamination.
Quality Control & Inspection Standards
To ensure zero-defect delivery for critical industrial applications, strict quality control protocols are applied:
Dimensional Inspection: Verified using calibrated CMM (Coordinate Measuring Machines) against critical drawing tolerances.
Physical Property Verification: Batch testing of density, hardness, and flexural strength.
Visual & Surface Checks: Edge integrity, micro-defect screening, and surface finish verification.
Traceability & Documentation: Material Test Reports (MTR) and certificate of conformance (CoC) provided upon request per order agreement.
Packaging & Global Logistics Protection
Fine-grain graphite and precision-machined components are fragile and vulnerable to moisture and impact during international transit. Industrial export packaging standards include:
Moisture Protection: Individual wrapping with anti-corrosion barrier films and moisture-absorbent packets.
Physical Cushioning: High-density EPE foam padding to prevent edge chipping and surface scratching.
Secure Export Crating: Fumigation-free wooden boxes or reinforced heavy-duty cartons designed for safe maritime and air freight.
FAQ
Q: What is the difference between isostatic graphite and extruded graphite?
A: Isostatic graphite is formed under uniform hydraulic pressure in all directions, yielding isotropic properties and a fine grain structure. Extruded graphite is formed by pushing material through a die, creating directional (anisotropic) properties and coarser grains. Isostatic grades are ideal for multi-directional loading and complex machining.
Q: Can ultra-fine grain isostatic graphite withstand high temperatures?
A: Yes, up to over 2000 deg C in vacuum or protective inert gas atmospheres. However, it will oxidize rapidly in oxygen-containing air at temperatures above approximately 400 deg C. Verify the operating atmosphere before deployment.
Q: Does smaller grain size guarantee higher mechanical strength?
A: Not necessarily. While finer grains improve machinability and surface finish, overall strength and density depend heavily on raw material formulation, binder quality, and graphitization parameters.
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