ASTM F1684 Low-Thermal-Expansion Alloy Products
ASTM F1684 scope and status
ASTM F1684 covered iron-nickel and iron-nickel-cobalt alloys for low-thermal-expansion applications. The scope included UNS K93603 and K93500 in wire, rod, bar, strip, sheet, plate and tubing, and UNS K93050 in bar form. ASTM lists F1684-06(2021) as withdrawn in 2024. When a drawing still cites this standard, state the exact edition and obtain engineering confirmation of the applicable current requirements.
Technical characteristics
This type of precision alloy with specified TKRL contains iron (63-64,5%) and nickel (35-37%) as basic components. has the minimum temperature coefficient of expansion (- 1.5x10-6 1/°С at t° from minus 80 to + 100°C) which determines its use in production of control and measuring instruments parts. The composition is alloyed with silicon, copper, manganese, aluminum, molybdenum, vanadium.
Percentage composition
| Fe | Ni | V | P | Mn | Si | C | Cr | S | Mo | Cu | Al |
|---|---|---|---|---|---|---|---|---|---|---|---|
| basis | 35 - 37 | ≤ 0.1 | ≤ 0.015 | 0.3 - 0.6 | ≤ 0.3 | ≤ 0.05 | ≤ 0.15 | ≤ 0.015 | ≤ 0.1 | ≤ 0.1 | ≤ 0.1 |
| t° | E 10- 5 | a 10 6 | l | r | R 10 9 |
| Degree | MPa | 1/Gradus | W/(m-degree) | kg/m3 | Ohm-m |
| 20 | 1.5 | 8200 | 800 |
E - Modulus of elasticity of the first kind
a - Coefficient of thermal (linear) expansion
l - Coefficient of thermal conductivity (heat capacity of the material)
r - specific weight
R - specific electrical resistance.
Analogues
| England | Germany | Poland | USA | Czech Republic |
| BS | DIN, WNr | PN | CSN | |
| NILO36 | 1.3912 | FeNi36Pr | NILO36 | 17536 |
| Ni36 |
U.S. sourcing overview
Low-expansion alloy requests are specification-sensitive. A useful enquiry identifies the UNS grade, product form, dimensions and the temperature range or dimensional-stability requirement that governs the component.
Product forms and sourcing
Sourcing can be reviewed for sheet, plate, strip, wire, rod, bar, tubing and cut blanks, subject to grade, edition, condition and quantity. State thickness or diameter, width, length, temper or heat treatment, surface condition, tolerances and any thermal-expansion testing.
Evek LLC reviews each requirement against the requested grade, specification, form, dimensions and quantity. Availability, origin, production route, minimum quantity and certification are confirmed during quotation; website text is not a stock or compliance guarantee.
Specification and substitution
Names such as Invar or Kovar are not interchangeable purchase specifications. Nickel and cobalt content, product form, thermal-expansion range, condition and testing may differ. Verify the exact UNS designation and drawing requirements before approving an alternative.
The purchaser remains responsible for material selection, design approval and confirmation that the specified material is suitable for the finished component, manufacturing process and service environment.
Information required for a quote
Provide ASTM F1684 and its required edition, UNS grade, product form, dimensions, condition, quantity, coefficient-of-expansion or other test requirement, material certificate, permitted alternatives and U.S. delivery ZIP code.
Related products and resources
Review Invar 36 products, Kovar products, or contact Evek LLC for assistance with the requirement.
Request a U.S. quote
Evek LLC serves customers throughout the United States. Typical delivery is 2-3 weeks, subject to grade, specification, form, dimensions, quantity, production route and availability.
Contact Evek LLC with the complete requirement and U.S. delivery ZIP code.