Silicon Carbide Thermocouple Tube
Silicon carbide ceramic tube sheathing thermocouples in high-temperature furnaces up to 1600°C. HTS 6903.90.00 covers such refractory tubes and sheaths for industrial thermal protection. Composed of fired nonmetallic carbides per Chapter 69 definition.
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More Specific Codes
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If aluminosilicate composition
Aluminosilicate refractories specifically in 6902.20; pure carbide ceramics are 6903 'other'
If used solely as electrical insulators
Chapter 69 excludes electrical insulators (note f); functional refractory tubes remain ceramic
If unglazed tiles >3.2cm thick for flooring
US note excludes thick tiles from refractory definitions; tubes don't meet tile criteria
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Import Tips & Compliance
• Include thermal conductivity specs proving refractory function; avoid electrical insulator classification by showing non-insulating use
• Pitfall: thin tubes mistaken for Chapter 70 glass tubing
Related Products under HTS 6903.90.00
Alumina Crucible
High-purity alumina ceramic crucible used for melting and holding metals or chemicals at high temperatures in laboratories and foundries. Classified under HTS 6903.90.00 as a refractory ceramic good designed to withstand extreme heat without deforming, distinct from building materials in 6901-6902. Fired after shaping from inorganic nonmetallic materials like alumina oxide.
Zirconia Nozzle for Continuous Casting
Refractory zirconia ceramic nozzle used in steel mills for controlling molten metal flow during continuous casting. Falls under HTS 6903.90.00 as 'other refractory ceramic goods' like nozzles, engineered for extreme thermal shock resistance. Fired ceramic body meets Chapter 69 firing requirements.
Magnesia Slide Gate Plate
Magnesia-carbon ceramic slide gate plate for controlling molten steel flow in ladle casting. Specifically named in HTS 6903.90.00 as refractory slide gates for steelmaking. High-fired refractory withstands 1700°C+ temperatures.
Graphite Crucible with Clay Bond
Clay-bonded graphite crucible for non-ferrous metal melting in jewelry and investment casting. HTS 6903.90.00 as refractory crucible of fired ceramic materials including graphite-carbon composites. Meets Chapter 69 firing and composition requirements.
Refractory Ceramic Furnace Muffle
High-alumina ceramic muffle protecting furnace heating elements from process atmosphere. Named example in HTS 6903.90.00 for refractory muffles used in industrial heat treatment. Fired ceramic construction per Chapter 69 standards.
Ceramic Ladle Plunger
Zirconia-graphite ceramic plunger for stirring molten steel in secondary refining ladles. Refractory 'other goods' under HTS 6903.90.00 for steelmaking immersion devices. High-fired for extreme corrosion resistance.