Product Description
Kovar (also known as 4J29) is a nickel-iron alloy that exhibits a unique combination of low thermal expansion and good mechanical properties. It is widely used in applications where a close match of thermal expansion characteristics with materials like glass or ceramics is required. Kovar has a coefficient of thermal expansion (CTE) that is similar to that of borosilicate glass, making it ideal for sealing metal-to-glass components, such as in electronic and vacuum tube industries.
Key Features
- Low Thermal Expansion: Excellent dimensional stability across temperature changes, especially when used with glass and ceramics.
- Strong and Tough: Good mechanical strength and toughness at both ambient and elevated temperatures.
- Good Weldability: Allows for easy joining with other materials, especially in electronic components.
- Magnetic Properties: Magnetic behavior makes it suitable for specific applications in electronics.
Chemical Composition
| Element |
Percentage (%) |
| Nickel (Ni) |
29.0 - 35.0 |
| Iron (Fe) |
Balance |
| Cobalt (Co) |
0.30 max |
| Manganese (Mn) |
0.50 max |
| Silicon (Si) |
0.30 max |
| Carbon (C) |
0.02 max |
| Phosphorus (P) |
0.015 max |
| Sulfur (S) |
0.015 max |
Specifications
- UNS Number: K94610
- Available Forms: Plate, Sheet, Coil, Strip, Wire, Rod, Tube
- Standards:
- ASTM F15
- ASTM A333
- MIL-DTL-3922
Applications
- Glass-to-Metal Seals: Used for manufacturing hermetically sealed electronic components, such as vacuum tubes and semiconductors.
- Electronics: Essential for packaging in devices like transistors, diodes, and integrated circuits.
- Aerospace: Often used in specialized sealing applications.
- Medical: Sealing of components in medical devices requiring stable thermal properties.
Mechanical Properties
| Property |
Value |
| Tensile Strength |
500 MPa (min) |
| Yield Strength |
350 MPa (min) |
| Elongation |
25% (min) |
| Hardness |
180 HBW (max) |
Fabrication and Machining
- Weldability: Kovar can be welded with methods such as TIG, MIG, and laser welding. It requires careful control of heat to avoid material distortion.
- Machining: Can be machined using conventional tools. Its strength allows for precision machining, particularly in high-tolerance applications.
- Forming: Suitable for cold and hot forming, but care should be taken to avoid work hardening.
Advantages
- Thermal Expansion Match: Exceptional for use in metal-to-glass seals, ensuring that components do not crack or break when exposed to temperature changes.
- Durability and Strength: Excellent resistance to wear, making it ideal for high-stress applications.
- Versatile: Used in numerous industries, including electronics, aerospace, and medical devices, for its unique combination of properties.
Detailed Photos
Company Profile
Shandong Titanium Nickel Special Steel Co., Ltd., registered funds (one thousand yuan for 10,000 yuan), the company is mainly committed to high -tech enterprises that are integrated with special alloy materials, specializing in the research and sales of special alloys such as nickel -based and iron -based. Products include corrosion-resistant alloys, superalloys, precision alloys, Hastelloy, Monel, INCONEL, INCOLOY, copper-nickel alloys, titanium and titanium alloys, zirconium and zirconium alloys, nickel and nickel-based alloys, nickel-cobalt-based heat-resistant alloys , Hafnium alloy, etc., more than 60 kinds of alloy materials such as special stainless steel. On the basis of stabilizing the quality of the original products, according to the market demand, it solves the quality problems existing in the traditional metallurgical process, and ensures the low miscellaneous and low deflection of the alloy material products, which has won an excellent reputation in the industry.
Factory workshop
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Packaging & Shipping
FAQ
1. What is Kovar alloy?
Kovar is a nickel-iron alloy, primarily composed of 29% nickel and 17% cobalt, with iron as the balance. It is known for its low coefficient of thermal expansion (CTE), which makes it an ideal material for metal-to-glass seals. Kovar is highly valued in industries requiring high dimensional stability and compatibility with glass.
2. What are the key properties of Kovar alloy?
- Low Coefficient of Thermal Expansion (CTE): Kovar has a thermal expansion rate similar to that of glass, making it perfect for glass sealing applications.
- High Strength: Kovar has good mechanical strength and can withstand various stresses, making it durable for industrial applications.
- Magnetic Properties: Kovar retains ferromagnetic properties, which can be beneficial in certain applications like electronics.
- Corrosion Resistance: Kovar offers moderate resistance to corrosion but can be prone to attack in highly aggressive environments.
- Formability: Kovar can be welded, brazed, and formed easily using standard metalworking techniques.
3. What are the common applications of Kovar alloy?
- Glass-to-Metal Seals: Kovar is widely used for metal-to-glass seals, especially in electronic components like vacuum tubes, semiconductor packages, and optical components.
- Electronic Components: Kovar is often used in the electronics industry for manufacturing relays, transformers, and vacuum-sealed devices.
- Precision Instrumentation: Used in applications that require precise measurement and control, such as micrometers and optical instruments.
- Aerospace: Kovar is used for various components that require low thermal expansion and high durability, like satellite parts and aerospace seals.
- Medical Devices: Often used in medical electronic equipment where glass sealing is needed, such as implants or scanners.
4. What is the composition of Kovar alloy?
Kovar generally consists of:
- Nickel (Ni): 29%
- Cobalt (Co): 17%
- Iron (Fe): Balance
- Other Elements: Small amounts of elements like manganese and silicon can be present.
5. What are the mechanical properties of Kovar alloy?
| Property |
Value |
| Tensile Strength |
550-750 MPa |
| Yield Strength |
250-500 MPa |
| Elongation |
15-20% |
| Hardness |
150-250 HBW |
6. What are the advantages of using Kovar alloy?
- Dimensional Stability: Kovar's low CTE makes it an ideal choice for applications requiring precise, stable dimensions, particularly in glass sealing.
- Strong and Durable: It has good mechanical strength and toughness, making it suitable for a wide range of applications.
- Magnetic Compatibility: Kovar's ferromagnetic properties are beneficial for electronic components.
- Weldability and Machinability: It can be easily welded, brazed, and machined, facilitating its use in complex manufacturing processes.
7. What are the disadvantages of using Kovar alloy?
- Corrosion Resistance: While Kovar has moderate resistance to corrosion, it is not suitable for extremely corrosive environments.
- Cost: Due to its specialized properties, Kovar can be more expensive than general-purpose alloys.
- Limited High-Temperature Resistance: Kovar's performance can degrade at extremely high temperatures, limiting its use in some high-temperature applications.
8. Can Kovar alloy be welded or machined?
Yes, Kovar alloy can be welded using TIG or laser welding methods. It is also machinable with conventional equipment, although it is somewhat harder than other common alloys, so cutting tools may wear out faster. Proper cooling and tool management are important when machining Kovar.
9. What industries use Kovar alloy?
- Electronics Industry: For packaging of electronic devices, especially for vacuum tubes and semiconductors.
- Aerospace and Defense: For applications requiring precise glass-to-metal sealing and parts that need dimensional stability in various environments.
- Medical Devices: In implants, medical scanning devices, and other applications requiring hermetic sealing.
- Optics: Used in optical components where glass sealing is critical.
10. What are the most common grades of Kovar alloy?
- Kovar 29: This is the standard grade of Kovar, composed of 29% nickel and 17% cobalt. It is the most widely used and offers excellent sealing properties with glass.
- Kovar 4J29: A variation of Kovar with slightly different alloy composition, specifically designed for specific applications requiring lower expansion rates.
11. What is the price range for Kovar alloy?
The price of Kovar alloy can vary depending on factors such as the form (plate, sheet, rod, or coil), size, and quantity. As Kovar is a specialty alloy, its price is typically higher than standard iron or steel materials. It is advisable to contact a reliable supplier for an accurate quote based on your specific needs.
12. How do I order Kovar alloy?
You can contact a supplier that specializes in nickel-iron alloys and specify your requirements, such as dimensions, quantity, and any certifications you need. Make sure to clarify whether you require Kovar in sheet, plate, rod, or coil form.
13. Is Kovar alloy magnetically active?
Yes, Kovar is a ferromagnetic material. It retains its magnetic properties, which can be useful in applications such as magnetic sensors, relays, or magnetic field shielding.
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