Invar® 36
Alloy Materials for Low Thermal Expansion
INVAR® 36 (UNS K93600) is a 36% nickel and 64% iron alloy with a very low thermal expansion. It is available in wire, rod, strip, or sheet.
A popular material having the lowest coefficient of expansion of any known iron alloy in the temperature range of -20°C to 300°C and approximately one-tenth that of carbon steel at temperatures up to 400°F, INVAR® is often thought of as the material of choice for low expansion nickel alloy applications.
The ability to maintain strength at very low temperatures also makes it the optimum exotic metal choice for containing some liquid gasses.
What you need to know about buying INVAR® 36 materials:
- INVAR® 36 is typically produced per ASTM F1684 for these standard forms.
- It is important to provide the “temper” that is required, as the sheet/strip can be provided in the annealed, ½ hard, or hard tempers with rod/bar products being provided in the annealed, cold worked, or unannealed conditions.
- Please provide information if the material will be used for deep drawing requirements.
- INVAR® 36 alloys are soft alloys like type 304/316 stainless and can be machined using similar techniques.
Product Selection and Purchasing Options
Beyond INVAR®, Leading Edge offers a wide range of products in multiple shapes and sizes, even in small quantities. Many are available for immediate shipment from our warehouse. If we don’t have the specialty material you need, there’s a good chance we can find it. With our flexible purchasing options, you can ensure materials are available when they’re needed. Purchasing options include blanket orders, just-in-time delivery, and consignment materials.
Industry Standards and Requirements
Industries constantly evolve, driven by a growing demand for scientific and technological advancement. Successful experimentation must ensure material integrity, safety, performance, and compliance with strict environmental and operational regulations.
These standards typically focus on aspects like purity, quality, and durability to guarantee that refractory metals meet the demanding conditions of high-stakes research applications. Because they serve multiple industries and extreme environments, this list includes more than average standards and requirements.
Standards and Requirements:
- ASTM International (American Society of Mechanical Engineers): Standards for materials used in energy applications.
- SAE Aerospace Material Specifications (AMS, formerly known as the Society of Automotive Engineers or SAE)
- ASME BPVC (Boiler and Pressure Vessel Code): Guidelines for materials used in pressure vessels and reactors.
- Department of Defense (DoD) Military Standards or Military Specifications (MIL) on the Defense Logistics Agency (DLA) ASSIST Database
We adhere to quality compliance certification standards and statutory regulations that pertain to our exotic materials, processes, custom machining services, traceability, and other aspects of our in-house expertise. Our materials specialists provide expert counsel on metal selection and inspection to ensure you receive materials that meet or exceed your expectations.
Leading Edge Metals & Alloys Certifications include:
- ISO9001:2015 and AS9100D Registered
- ITAR Registered
- NIST SP 800-171 and CMMC Complian
Our deep understanding of this industry stems from our extensive experience, skilled metallurgy professionals, and a history of successful partnerships with leading national research labs.
FAQs About INVAR
Customers should share the operating temperature range, tolerance sensitivity, fabrication method, part geometry, and compliance requirements. These details allow Leading Edge Metals & Alloys to recommend the optimal form and condition.
Yes. LEMA supplies machined INVAR 36 components, near-net shapes, and precision blanks for tooling, instrumentation, and aerospace and research applications.
Yes. INVAR 36 can be cold-worked, formed, and deep-drawn depending on thickness and temper. Deep-drawing or forming requirements should be specified at the time of inquiry to ensure the correct condition is supplied.
Yes. INVAR 36 can be welded using appropriate techniques. Welding parameters and post-weld stress relief should be considered for applications requiring high dimensional accuracy.
Both alloys control thermal expansion, but they serve different purposes. INVAR® 36 is optimized for minimal expansion, while KOVAR® is engineered to match the expansion of glass and ceramics for hermetic sealing. Selection depends on whether dimensional stability or seal compatibility is the priority.
INVAR 36 exhibits minimal thermal expansion from approximately -20°C to 300°C (-4°F to 572°F), with especially stable behavior near room temperature. Performance outside this range should be evaluated based on application requirements.
INVAR 36 is typically produced to ASTM F1684, which defines chemical composition, mechanical properties, and dimensional requirements for standard product forms used in precision applications.
Customers should specify ASTM F1684 compliance, product form, dimensions, temper or condition, and whether the application requires high dimensional stability or precision machining. Providing end-use context helps LEMA recommend the correct condition.
INVAR 36 machines similarly to austenitic stainless steels but tends to work-harden during machining. Proper tooling, controlled cutting parameters, and attention to stress relief are important to maintain dimensional accuracy in finished parts.
Leading Edge Metals & Alloys supplies INVAR 36 in sheet, strip, plate, rod, bar, and wire, along with cut-to-size blanks and machined components. Availability depends on thickness, temper, and dimensional requirements.
Precision systems rely on stable geometry. INVAR 36 minimizes thermal distortion, helping ensure repeatable measurements, optical alignment, and tight tolerances in environments subject to temperature fluctuation.
INVAR 36 is widely used in precision instruments, aerospace tooling, optical systems, electronics fixtures, scientific equipment, and metrology components. These applications depend on dimensional accuracy under temperature variation.
INVAR 36 is known for its exceptionally low coefficient of thermal expansion, combined with good strength, toughness, and machinability. This allows components to maintain precise dimensions across a wide temperature range where other metals would shift measurably.
INVAR® 36 (UNS K93600 or K9360) is used instead of conventional steels or aluminum alloys when dimensional stability across temperature changes is critical. Conventional metals expand and contract significantly with temperature, while INVAR® 36 is engineered to exhibit extremely low thermal expansion, reducing distortion and loss of precision.
