![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
4J29 Capillary Tubes: Precision Engineering for Critical Applications
4J29 capillary tubes, made from the iron-nickel-cobalt alloy (also known as Kovar), are engineered for ultra-fine, high-performance components. With a composition of 29% nickel, 17% cobalt, and trace elements, these tubes offer a controlled coefficient of thermal expansion (CTE) that matches borosilicate glass and alumina ceramics. This ensures dimensional stability and eliminates mechanical stress during temperature changes, making them ideal for vacuum seals, optical systems, and electronic packaging.
Our manufacturing process achieves inner diameters as small as 0.1 mm with tolerances of ±0.005 mm and a surface finish of Ra ≤ 0.4 μm. Advanced annealing optimizes ductility while preserving thermal properties, enabling complex forming for medical devices and aerospace sensors.
| Grades | Chemical Composition(wt)% |
| | C | Cr | Ni | Ti | Fe | Co | Mn | Si | Mo | Cu | W | P | S | Al | Nb | V | B | Zr | O+N | H |
| 4J29 | | 0.03 | - | 29.5 | - | rest | 17.8 | 0.5 | 0.3 | - | 0.2 | - | 0.02 | 0.02 | - | - | - | - | - | - | - |
| | - | - | 28.5 | - | - | 16.8 | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
Jiangsu Zhongxing Nickel Alloy Co., Ltd. is a leading manufacturer specializing in the research, development, and production of seamless pipes and capillary coils. With a factory spanning 16,000 square meters, we offer a diverse range of products, including nickel alloys, high-temperature alloys, nickel-copper alloys, nickel-titanium alloys, Invar alloys, soft magnetic alloys, and other alloy materials.
Our technical team has achieved world-leading levels through years of technological improvement and innovation, developing domestically produced technologies that are high-performance, high-quality, and high-yield.
Our company is certified under ISO 9001, EU PED, and China TS for pressure pipeline systems, ensuring our commitment meeting and going beyond what international industry standards' required. Each product undergoes rigorous quality control and performance testing, and has accumulated rich OEM/ODM production experience for international market supply.
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
![Kovar-Matched 4j29 Alloy Capillary Tubes for Glass-to-Metal Seals]()
Q1:Are you a factory or trade company?
A1: A Factory and A subsidiary international trade company for export.
Q2:Where is your factory?
A2:Our company is located in Huaian city, China, which is well equipped with kinds of machines.
Q3: How do you control quality?
A3: Inspection & Guarantee Certificate is supplied with shipment, and the Third Party Inspection is available.
Q4: What are the advantages of your company?
A4: We have many professional and technical personnel, more competitive prices and better after-sales service than other companies.
Q5: Can you arrange the shipment?
A5: Sure, we can help you with the shipment. We have forwarders who have cooperated with us for many years.
Q6: How about the delivery time?
A6: It is based on the order, normally within 30 days after receiving your advance payment.
Q7: Can you provide sample?
A7: Small samples in store can be provided for free.
Please contact us for more information today!
