Do you CNC-machine custom parts?

Yes. We machine graphite and carbon-graphite parts from drawings or samples, with typical tolerances down to ±0.02 in depending on geometry and grade.

Which graphite is used for crucibles and ingot molds?

Depending on metal, temperature, and thermal cycle we recommend vibro-molded, molded, or isostatic grades. We supply crucibles, ingot molds, sintering molds, and pouring spouts as catalog or custom parts.

Do you manufacture build-to-print?

Yes. From drawing or sample we make graphite/carbon parts: bushings, electrodes, crucibles, seals, molds, and special components, with dimensional control and traceability.

Why does a graphite crucible resist thermal shock?

Because it conducts heat quickly and expands little, so the temperature difference between the inner and outer face stays low when charged cold. That combination — high conductivity and low expansion — is what prevents cracking, more than the mechanical strength of the material.

Which metals can be melted in a graphite crucible?

It is commonly used with aluminium, copper, brass, bronze, zinc, and precious metals, where the metal does not wet graphite. With ferrous alloys, carbon can dissolve into the bath, so the exact alloy must be reviewed before recommending a grade.

What shortens crucible life?

Oxidation of the outer face when it is exposed to hot air, erosion from metal flow, and poorly distributed cold charging. Covering the crucible between casts and avoiding point loading often matter as much as the grade chosen.

Are crucibles made to size?

Yes, machined from rod or block to drawing or sample. That is the route when the size is not in the catalogue or when the furnace imposes a particular seating or pouring geometry.

Graphite crucibles of various sizes with pouring spouts

Metallurgical applications

Foundry crucibles

Graphite crucibles for containing and melting metals in foundry and laboratory use.

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Melting and holding vessel

Also known as: Graphite crucibles · Carbon-graphite crucibles · Metal melting crucibles · Graphite laboratory crucibles

[ Technical summary ]

A graphite crucible holds the metal while it melts and stays liquid. It works under two simultaneous demands: withstanding the thermal shock of a cold charge against a hot crucible, and not reacting with the bath. Graphite answers both because it conducts heat quickly — reducing the gradient that cracks the material — and is not wetted by most non-ferrous metals. It is used in melting aluminium, copper, their alloys, and precious metals.

Graphite crucibles for containing and melting metals in foundry and laboratory use.

Grade selection depends on the metal or alloy, operating temperature, atmosphere and how aggressively the crucible is cycled. The wrong grade shortens life through thermal shock, erosion or contamination risk.

ESGRAF supplies commercial shapes when stocked and custom crucibles machined from drawing. Share metal, temperature, geometry and quantity for a technical recommendation.

[ Problem it solves ]

Contain molten metal without the vessel cracking when charged cold or giving up elements to the bath, in a service where the crucible heats and cools on every melting cycle.

Operating conditions

Melting
Holding liquid metal
Pouring

When it is suitable

Non-ferrous or precious metals are being melted
The charge is introduced cold and causes thermal shock
The bath must stay free of oxides from the vessel
A crucible geometry other than the standard sizes is needed

When it may not be suitable

The contacting metal readily dissolves carbon and the alloy cannot tolerate it
The part sits in air at high temperature between casts without protection
The crucible takes blows from the charge or from the tapping tool

Process challenges

Thermal shock
Erosion
Metal contamination
Short life of unsuitable crucibles

Advantages

Excellent thermal shock resistance
High thermal conductivity
Stock and custom options

Limitations

Wear from erosion and thermal shock
Possible metal contamination if the grade is unsuitable
Service life depends on cycles and metal flow

[ Critical selection variables ]

These variables define the grade and the geometry. Actual values are confirmed against the grade datasheet.

Molten metal or alloy in contactDecisive
Operating temperatureDecisive
Thermal shock severityDecisive
Geometry and tolerancesDecisive
Required purity and allowable contaminationRelevant
Thermal and duty cyclingRelevant
Bath or flux chemistryRelevant

[ Required material properties ]

Properties that guide selection. Numerical values come from each grade's datasheet.

Critical properties

Thermal shock resistance
Non-wetting by molten metal
Thermal conductivity
Chemical resistance

Secondary properties

Bulk density
Ash content
Machinability

[ Related ]

[ Frequently asked questions ]

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Technical content reviewed by ESGRAF — Last reviewed: September 8, 2026

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