Our factory
GY Alumina manufactures alumina thermocouple protection tubes, insulators, furnace tubes, crucibles and custom ceramic parts at our factory in Tangshan, Hebei, China. Our Chinese trademark is 鑫国玉™, Xin Guo Yu.
Where we are
Our factory is in Xiaoji Town, Fengnan District, Tangshan, Hebei, China.
Our industrial ceramics serve thermocouple makers, furnace builders, laboratories and equipment manufacturers.
Standard sizes are usually in stock and cut to the ordered length. Small standard orders usually ship in about 3 days; bulk orders in about 7 days. Parts made to drawing usually take 25–30 days, with a usual minimum of 100 pieces. Compare product sizes and configurations or send a drawing for a quotation.
We supplied thermocouple protection tubes for the expansion of China’s solar industry.
Pieces shipped 2024–2026: from our sales records.
Capabilities
How we make it
Milling, forming, firing, finishing and packing all happen in our own factory. Send your drawing and we confirm the route, grade and tolerances at quotation.
We start from calcined alumina powder.
The powder is milled in large drum ball mills.
Tubes and rods are formed on horizontal vacuum extruders and a vertical hydraulic ram extruder; slip casting uses plaster moulds.
Formed pieces dry on multi-tier rack carts and grooved boards before firing.
Tubes hang vertically in the kiln, and our written gas-kiln procedure controls firing with thermocouples and an optical pyrometer.
Tubes are cut to the ordered length, then slotted or drilled where the drawing calls for it.
Outside and inside diameters are measured with vernier calipers.
Tubes are bubble-wrapped or bundled and packed in foam-lined plywood crates.
Continuity
Every product, material and capability we list is in production today. The factory has been running for 42 years, and we have made this product line for at least 15 years. Buyers who qualify a part with us keep ordering it: 100+ of our customers come back to us with repeat orders.
Certified and tested
Quality management
GB/T19001-2016 · certified by CFL Certification Center
The issuer listed this certificate as valid when checked on 6 October 2026. Check the issuer’s record (Chinese).
A copy of the certificate is available on request.
Independent lab test
Alumina tube sample, tested by Chinalco Testing Technology (Zhengzhou) Co., Ltd., 13 May 2026. Report 26-04928.
| Item | % | Method |
|---|---|---|
| Al₂O₃ | 99.61 | GB/T 24487-2022 |
| SiO₂ | 0.15 | GB/T 6609.3-2004 |
| Fe₂O₃ | 0.014 | GB/T 6609.4-2004 |
| Na₂O | 0.054 | GB/T 6609.1-2018 |
| CaO | 0.13 | GB/T 6609.1-2018 |
| Loss on ignition | 0.033 | GB/T 6609.2-2022 |
Tested by the same lab every year
Lab reports are available on request.
Photographs
Request a quote
Tell us the dimensions, grade and quantity. We confirm the grade, dimensions and tolerances in each quotation. Our yearly lab reports are available on request.