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| Supply Ability | 300 Ton per Month | 
| Delivery Time | 2-30days | 
| Packaging Details | Wooden Crate | 
| Raw Materials | Ni: ≥63%; Cu:28.0-34.0% | 
| Special Use | Compressor disks,machine manufacturing | 
| Applications | Marine and Chemical Processing Industries | 
| Type Of Tube | Straight Tube, U Bend Tube , Coil Tube | 
| Type | Nickel Bar | 
| Alloy | Nickel Copper Alloy | 
| Weldability | Good | 
| Packing | standard export packing | 
| Chemical Position | Ni 63%min; Cu 28-34% | 
| Thickness | 0.3-150mm,(SCH10-XXS) | 
| Tensile Strength | 550-750 MPa | 
| Brand Name | NikTech | 
| Model Number | 4J28 | 
| Certification | ISO 9001:2008 | 
| Place of Origin | China | 
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Product Specification
| Payment Terms | L/C,T/T,Western Union,MoneyGram | Supply Ability | 300 Ton per Month | 
| Delivery Time | 2-30days | Packaging Details | Wooden Crate | 
| Raw Materials | Ni: ≥63%; Cu:28.0-34.0% | Special Use | Compressor disks,machine manufacturing | 
| Applications | Marine and Chemical Processing Industries | Type Of Tube | Straight Tube, U Bend Tube , Coil Tube | 
| Type | Nickel Bar | Alloy | Nickel Copper Alloy | 
| Weldability | Good | Packing | standard export packing | 
| Chemical Position | Ni 63%min; Cu 28-34% | Thickness | 0.3-150mm,(SCH10-XXS) | 
| Tensile Strength | 550-750 MPa | Brand Name | NikTech | 
| Model Number | 4J28 | Certification | ISO 9001:2008 | 
| Place of Origin | China | ||
| High Light | 4J28 expansion alloys ,Corrosion Resistance expansion alloys ,0.3mm nickel copper alloy | ||
Expansion Alloy 4J28 Strips (Alloy 27) are precision-rolled iron-chromium strips formulated to closely match the coefficient of thermal expansion of typical soft sealing glasses, ensuring hermetic, stress-free bonds between metal and ceramic or glass. Between – 50 °C and 400 °C, 4J28 exhibits a mean linear expansion coefficient of approximately 4–8 × 10⁻⁶ /°C, minimizing thermal stresses in glass-to-metal seals. The alloy’s robust chromium-rich matrix (27–29 % Cr) and low carbon, phosphorus, and sulfur (≤ 0.12 % C; ≤ 0.02 % P, S) confer excellent corrosion resistance in mild atmospheres and compatibility with sealing glasses. Standard strip dimensions cover 0.2 – 3.5 mm thickness (cold-rolled) and up to 300 mm width; larger widths and thicknesses via hot-rolling/forging can accommodate broader applications. 4J28 Strips are engineered for reliable sealing in vacuum tubes, hermetic feedthroughs, glass-encapsulated sensors, and precision electronic packages, where dimensional stability and corrosion resistance are paramount. Their formability allows tight-tolerance bending and stamping without springback, while weldability supports complex assembly. For full mechanical property data—tensile, yield, hardness—and thermal-conductivity curves, please consult primary alloy producers like Special Metals (Invar/Glass alloys), Rolled Alloys (precision strip), and Haynes Intl.
| Element | Content (%) | 
|---|---|
| Chromium (Cr) | 27.0 – 29.0 | 
| Carbon (C) | ≤ 0.12 | 
| Phosphorus (P) | ≤ 0.02 | 
| Sulfur (S) | ≤ 0.02 | 
| Manganese (Mn) | ≤ 1.00 | 
| Silicon (Si) | ≤ 0.90 | 
| Nickel (Ni) | ≤ 0.50 | 
| Iron (Fe) | Balance | 
| Property | Value | 
|---|---|
| Tensile Strength | Consult supplier | 
| Yield Strength (0.2 % off.) | Consult supplier | 
| Elongation (4D) | Consult supplier | 
| Hardness (Rockwell B) | Consult supplier | 
| Property | Value | 
|---|---|
| Mean Linear Expansion Coefficient (–50 → 400 °C) | 4–8 × 10⁻⁶ /°C | 
| Density | ~ 7.9 g/cm³ | 
| Melting Range | ~ 1 400 – 1 450 °C | 
| Thermal Conductivity (25 °C) | Consult supplier | 
AMS 4951 – Iron-chromium low-expansion alloy
DIN 17 327 – Nickel-iron sealing alloys
ISO 464 – Glass-to-metal sealing alloys
Vacuum & Electronic Seals – Glass-to-metal feedthroughs, vacuum tubes, hermetic connectors
Precision Instruments – Pressure sensors, gas discharge tubes, photomultiplier bases
Ceramic Package Encapsulation – Sealing of ceramic circuit substrates to metal headers
Thermomechanical Assemblies – Bimetallic thermostats, expansion joints
Medical Devices – Hermetic seals in implantable electronics and sensors
Q1: What makes 4J28 Strips ideal for glass-to-metal seals?
A1: Their thermal expansion closely matches soft glass (4–8 × 10⁻⁶ /°C), eliminating stress and preventing seal cracks during thermal cycling.
Q2: Can 4J28 Strips be welded or brazed to other alloys?
A2: Yes—standard electron-beam and laser welding, plus active brazing alloys, bond 4J28 to Kovar, stainless, and nickel alloys without compromising expansion matching.
Q3: Where can I get certified mechanical data?
A3: For certified tensile, yield, hardness, and thermal conductivity data, consult the technical bulletins from Special Metals (Alloy 27), Rolled Alloys, and Haynes International.
Company Details
Business Type:
Manufacturer 
Year Established:
2002 
Total Annual:
20000000-80000000
Employee Number:
50~500 
Ecer Certification:
Verified Supplier 
Wuxi Nickel New Material Co., Ltd. is a high-tech enterprise integrating the production, manufacturing, and research & development of specialty alloy materials. Located in Wuxi, Jiangsu Province, the company specializes in precision alloys, titanium alloys, high-temperature alloys, corrosion-res... Wuxi Nickel New Material Co., Ltd. is a high-tech enterprise integrating the production, manufacturing, and research & development of specialty alloy materials. Located in Wuxi, Jiangsu Province, the company specializes in precision alloys, titanium alloys, high-temperature alloys, corrosion-res...
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