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How to choose crucible for melting metal? Graphite crucible or quartz crucible?

Crucible has good thermal conductivity and high temperature resistance, and is widely used in metallurgy, casting, machinery, chemical industry and other industrial sectors, especially in metal smelting industry, mainly used for melting metal materials. Commonly used melting metal crucibles are graphite crucibles and quartz crucibles. What is the difference between these two crucibles, we can compare their appearance, heat resistance, way of heating materials and use.

4graphite crucible (1)graphite crucible (4)Graphite mold for continuous casting (3)

  • Quartz crucibles and graphite crucibles have different colors. The quartz crucible is in the shape of a white cup, and the graphite crucible is in the shape of a black cup, which is easy to distinguish.
  • Quartz crucibles are more resistant to high temperatures than graphite crucibles. The maximum temperature of the intermediate frequency melting furnace is 2600°C, with a quartz crucible; the maximum temperature of the high frequency melting furnace is 1600°C, with a graphite crucible.
  • The heating methods of the two crucibles are different. Quartz has no resistance. When the intermediate frequency current passes, the metal material in the quartz crucible will be heated by induction, and the quartz crucible will not be heated. It is suitable for smelting iron, aluminum, stainless steel, platinum, gold, palladium, etc. ; There is resistance in graphite. When the high-frequency current passes, the graphite crucible can heat the metal material by its own induction to melt gold, silver, copper, alloy K gold, etc.
  • Quartz crucibles can be used alone, but graphite crucibles should be used with a quartz jacket because graphite will oxidize. The quality of graphite crucible is related to its material and density. A good graphite crucible oxidizes evenly, it is not easy to eat gold, and the production loss is low; bad graphite oxidizes unevenly, it will eat materials, and cause high losses. Graphite oxidation is easy to become thinner or even cracked, so a quartz crucible coat must be worn when using a graphite crucible to protect the quartz coat.

Knowing the difference between graphite crucible and quartz crucible, we can choose crucible better and more accurately when melting metal.


Post time: Jan-07-2023