Precision engineering demands materials that maintain dimensional accuracy despite temperature fluctuations. Expansion Alloy 36 for Precision Engineering stands out as the industry's top choice because it delivers ultra-low thermal expansion (approximately 1.0 × 10-6/°C) and exceptional dimensional stability from cryogenic temperatures up to ~500°F. This nickel-iron alloy containing ~36% nickel maintains nearly constant dimensions across normal atmospheric temperatures, making it indispensable for applications where even micrometer-level deviations can cause failure.
As discussed in our article on Key Advantages of Expansion Alloy in Engineering, the unique properties of these materials make them invaluable across multiple sectors.
Understanding Expansion Alloy 36: The Low-Expansion Supermetal
Low Expansion Alloy 36 (also known as Invar 36, NILO 36, UNS K93600, DIN 1.3912) is a binary nickel-iron alloy engineered specifically for minimal thermal expansion—about one-tenth that of carbon steel. Its unique composition of approximately 36% nickel and balance iron produces this extraordinary property, enabling precision components to withstand thermal stress without dimensional change.
Expansion Alloy 36 Material Properties: Technical Specifications
| Property | Value | Significance |
|---|---|---|
| Coefficient of Thermal Expansion | ~1.0 × 10-6/°C (20–100°C) | Ultra-low expansion ensures dimensional stability |
| Density | 8.0–8.1 g/cm³ | Balanced weight-strength ratio |
| Thermal Conductivity | 10–12 W/m·K | Moderate conductivity maintains stability |
| Yield Strength | 240–260 MPa minimum | Good mechanical strength |
| Tensile Strength | 490–630 MPa | High strength for precision components |
| Elongation | 30–42% minimum | Excellent ductility for machining |
| Melting Point | ~1430°C (2605°F) | High temperature resistance |
| Magnetic Properties | Ferromagnetic at room temperature | Considered for magnetic stability applications |
Critical Expansion Alloy 36 Applications Across Industries
Expansion Alloy 36 Applications span multiple high-tech industries where dimensional stability is non-negotiable:
- Aerospace & Defense – Satellite and missile electronic control unit frames operating below -200°C; CRP (composite) component tempering molds for aircraft where low expansion provides better tolerance control; Mounting and support structures for satellite-based optics and precision sensors
- Optical Instruments & Metrology – Metal-to-glass seals for telescopes, microscopes, and laser systems; Optical benches, optical metering components, and support structures; High-precision watches, precision scales, optical telescopes, radar systems; Length standards, tape measures, gauges, and measuring devices
- Cryogenic Engineering – Liquefied natural gas (LNG) piping and tanks; Cryogenic instruments and structural supports maintaining stability at cryogenic temperatures; Production, storage, and transportation of liquefied gases
- Electronics & Precision Tools – Thermostat rods and bimetallic components in electrical industries; Precision springs, washers, and electronic components requiring flexibility with low expansion; Mobile-phone network filters and tank membranes
Learn more about how this alloy compares to other grades in our detailed comparison: Expansion Alloy 49 vs Conventional Alloys.
Why Plus Metals Leads Global High-Performance Metal Supply
Plus Metals has built a reputation for excellence over more than two decades of service in the specialty metals and alloys industry, serving clients from Fortune 500 companies to individual engineers and researchers worldwide. Based in Mumbai, India, Plus Metals operates as a trusted global metal alloy supplier exporting high-performance alloys to the Middle East, Europe, Southeast Asia, and beyond.
For more on our expansion alloy product range, visit our product page.
Plus Metals' Expansion Alloy 36 Offerings
Plus Metals supplies high-quality Expansion Alloy 36 in multiple forms with mill test certifications:
| Form | Available Sizes | Applications |
|---|---|---|
| Sheets | Thickness: 0.010" to 0.500"; custom widths/lengths | Precision machining, structural components |
| Plates | Thickness: 0.500" and up; custom sizes | Aerospace parts, scientific instruments |
| Rods/Bars | Diameter: 0.250" to several inches; length up to 36"+ | Shafts, spindles, fittings |
| Strips/Coils | Thin, flexible sections | Springs, washers, electronics |
| Tubes/Pipes | Diameter: 0.5" to several inches; custom wall thickness | LNG piping, cryogenic systems |
| Wire | Diameter: 0.010" to 0.250"; supplied in coils | Precision electronics |
Quality Commitment
- International quality standards (ASTM/ASME compliance)
- Mill Test Certificates & full traceability
- Strict quality inspections
- Secure export packaging
- On-time global logistics
Contact Plus Metals for Expansion Alloy 36
For Expansion Alloy 36 for Precision Engineering requirements globally, partner with Plus Metals—the trusted source for high-performance materials:
Email: sales@plusmetals.in
Call / WhatsApp: +91 91673 47029
Website: www.plusmetals.in
Address: "X" lane, C. P. Tank, Mumbai, India
Message them today to discuss your requirements. They understand international standards and project timelines, delivering trust, quality, and long-term performance.
Frequently Asked Questions (FAQs)
Q1: What is Expansion Alloy 36 and why is it called "Invar"?
Expansion Alloy 36 is a nickel-iron alloy with ~36% nickel known for extremely low thermal expansion. It's called "Invar" (from "invariant") because its dimensions remain virtually invariant despite temperature changes.
Q2: What are the primary Expansion Alloy 36 Applications in aerospace?
In aerospace, Alloy 36 is used for satellite electronic control frames operating below -200°C, composite component tempering molds, and mounting structures for satellite optics and precision sensors.
Q3: How does Low Expansion Alloy 36 compare to carbon steel?
Alloy 36 has thermal expansion approximately one-tenth that of carbon steel (~1.0 × 10⁻⁶/°C vs. ~10 × 10⁻⁶/°C), making it far superior for precision applications.
Q4: What are the key Expansion Alloy 36 Material Properties for cryogenic use?
Alloy 36 retains good strength and toughness at cryogenic temperatures, with low expansion from cryogenic conditions up to ~500°F, making it ideal for LNG systems and cryogenic engineering.
Q5: Why is Precision Engineering Alloy 36 preferred for optical instruments?
Its ultra-low thermal expansion enables metal-to-glass seals in telescopes, microscopes, and laser systems that maintain dimensional stability over wide temperature ranges, preventing optical misalignment.
