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4J32,4J36,4J29
DLX
bright
ISO9001
5kg
Industry
Product Description
Precision Alloy Expansion Alloy Super 4J29 Invar 36 Rod is a controlled-expansion iron-nickel-cobalt alloy renowned for its exceptional thermal expansion compatibility with hard glass and ceramics. 4J29 maintains near-zero dimensional variance across extreme temperature fluctuations, establishing itself as the gold standard for hermetic sealing in critical applications. This alloy bar also exhibits outstanding resistance to thermal stress cracking and corrosion in vacuum environments.
Precision Alloy Expansion Alloy Super 4J29 Invar 36 Rod is particularly valued for its unique thermal expansion synchrony and impermeable sealing capabilities. A defining characteristic is its engineered crystallographic structure that remains geometrically stable from cryogenic to elevated temperatures, enabling the fabrication of precision components requiring micron-level tolerance retention during thermal cycling.
Maintains near-zero differential expansion with hard glass/ceramics across -60°C to +450°C, eliminating interfacial stress-induced sealing failures.
Creates impermeable metal-to-nonmetal joints sustaining helium leak rates <10⁻⁹ Pa·m³/sec under vacuum/high pressure, ensuring lifetime sealing reliability.
Forms a dense, stable chromia (Cr₂O₃) protective layer at high temperatures, resisting oxidation in air or oxygen-containing environments.
Zero outgassing in critical vacuum environments.
Resists weak acids, alkaline vapors, and electronic cleaning agents.
Precisely tuned Fe-Ni-Co atomic ratio stabilizes crystal structure below/above Curie point (~430°C), enabling micron-level dimensional reproducibility during thermal cycling.
Optimized annealed microstructure delivers unified mechanical strength and ductility, supporting complex machining while ensuring thin-wall seal rigidity.
Forms chemical-bonded interfaces with borosilicate glass for hermetic seals.
Compatible with TIG/electron beam welding for hybrid sealing structures.
Specification
| Expansion Alloy 4J29 Invar 36 Rod Chemical Composition | ||
| Elements | 4J29 | 4J36 |
| Carbon (C) | 0.03 | 0.05 |
| Sulfur (S) | 0.02 | 0.02 |
| Phosphorus (P) | 0.02 | 0.02 |
| Manganese (Mn) | ≤0.50 | 0.20-0.60 |
| Silicon (Si) | ≤0.30 | ≤0.30 |
| Nickel (Ni) | 28.5-29.5 | 35.0-37.0 |
| Chromium (Cr) | - | - |
| Cobalt (Co) | 16.8-17.8 | - |
| Iron (Fe) | Rest | Rest |
| Other Elements | - | - |
| Kovar Alloy 4j29 Bar Mechanical Properties | ||
| Alloy Grade | 4J36 Invar Alloy | 4J29 Kovar Alloy |
| Density (g/cm³) | 8.1 | 8.2 |
| Tensile Strength (MPa) | 500-600 | 600-700 |
| Yield Strength (MPa) | 250-350 | 300-400 |
| Hardness (HV) | 150-200 | 200-250 |
Application Field
Leveraging unique thermal expansion properties and hermetic reliability, Expansion Alloy 4J29 Invar 36 Rods are critical in:
Microwave/laser device housings: Glass-to-metal seals for TWTs, magnetrons
Vacuum relays/switches: Ceramic-metal brazed contacts
Optoelectronic sensors: Hermetic packaging for IR detector windows
Satellite sensor modules: Pressure/temperature probes in thermal cycling
Aero-engine igniters: Ceramic-insulated sealing assemblies
Space-grade connectors: Vacuum feedthrough RF connectors
Lithography systems: Thermal-compensation substrates for wafer stages
CVD chambers: Process gas seals at elevated temperatures
Ion implanters: Vacuum feedthroughs for precision electrodes
Fuel cells: Sealing frames for PEM membrane edges
Concentrated solar: Glass-metal transitions for molten salt tubes
Fusion reactors: First-wall diagnostic probe seals
Particle accelerators: UHV beamline sealing flanges
Synchrotrons: Thermal-stress compensators for X-ray windows
Cryogenic systems: Multi-layer insulation seals for LHe dewars
DLX Advantage
CHANGZHOU DLX ALLOY CO, LTD was established in 2002 and has got ISO9001 International Quality Management System Certificate and SGS Certificate. Our factory is professional in researching and producing special alloy material. From melting, drawing, heat treatment, finishing and testing .We offer nickel-based, copper-based, and iron-based alloys, including super alloy, welding materials, anti-corrosion alloy, precision alloy, FeCrAl alloy, NiCr alloy, CuNi alloy, thermocouple and etc, in the form of wire, strip, ribbon, bar, tube, plate.
1.Market Leader - Top 5 in China's nonferrous metal industry
2.Flexible products - Thousands of product specifications,Meet multiple needs of buyers
3.Low MOQ - Can customize samples
4.Short production lead time，fast delivery of whole cabinet
5.Professional inspection equipment - Before delivery, we will use spectrometers, tensile testers and other professional equipment to conduct a comprehensive inspection of the products to ensure that the goods are qualified for acceptance
6.Professional business team - Quickly responds to customer inquiries,24-hour professional quotation online The salesperson will follow the customer's requirements for the use of the product,Professionally recommend more appropriate performance and price products to customers
7.Intact packaging - Packaging according to customer needs.You can customize wooden boxes to ensure that the goods arrive at the destination in good condition
8.Various payment methods - Facilitate customer payment
9.Get good reviews from customers - Old customers have long-term cooperation,The longest is more than 7 years
10.Received various awards - Google is very recognized by us,They give us awards every year
FAQ
Factory Direct Supply with Competitive Wholesale Prices
Custom Sizes & Large Stock Availability
Fast Global Shipping & Reliable Industrial Supply
Guaranteed High Purity for Electronic & Industrial Applications
It depends on the quantity of the order, 10-30 days for small orders. For large orders, it takes 60 days.
Yes! We accept OEM/ODM production. You can send us your samples or drawings.
T/T, L/C, D/A, D/P, Western Union, MoneyGram, Paypal
Yes, you are welcome to visit our factory. We are glad to have the opportunity to get to know each other.
We manufacture our products in Jiangsu, China and ship them from China to your country as soon as possible, which usually depends on your product requirements and quantity.
Yes, we can.
