Name: Super Invar 32-5
Brand: Invar

Material Overview

Super Invar 32-5 material profile

A concise grade introduction for buyers who need to confirm composition, properties, standards, available forms and suitable applications before sending an inquiry.

Engineering profile

Super Invar 32-5 is an iron-nickel-cobalt controlled-expansion alloy developed for exceptionally low dimensional change around room temperature. Identified as UNS K93500, it provides lower thermal expansion than Invar 36 over approximately -55 to 95 °C while retaining a stable austenitic structure to at least -55 °C. The alloy is used for optical and laser systems, ring laser gyroscopes, semiconductor components, metrology instruments, waveguide tubes, telescope structures, precision positioning systems and assemblies matched to low-expansion glass or quartz.

Technical data on this page is for material selection reference. Final acceptance values should be confirmed by the purchase standard, heat treatment condition, product form, size and material test certificate.

Chemical Composition

Super Invar 32-5 composition range

The following table shows common limiting composition values for Alloy 625 / UNS N06625. Actual product chemistry is reported by heat on the material test certificate.

Element	Symbol	Nominal Content (%)	Role in Super Invar 32-5
Iron	Fe	Balance	Forms the base matrix of the controlled-expansion alloy.
Nickel	Ni	32.00	Controls the low-expansion behavior and stabilizes the austenitic structure.
Cobalt	Co	5.50	Further reduces thermal expansion around room temperature.
Manganese	Mn	0.40	Supports melting practice and controls metallurgical behavior.
Silicon	Si	0.25	Controlled as a minor deoxidizing and alloying element.
Carbon	C	0.02	Kept low to support dimensional stability and workability.

Physical Properties

Key physical and thermal data

These values help customers compare density, thermal behavior, magnetic response and conductivity during early material selection.

Property	Metric Value	Imperial / Notes	Condition
Density	Approx. 8.14 g/cm3	Approx. 0.294 lb/in3	Room temperature
Melting Point	Approx. 1427 °C	Approx. 2600 °F	Typical value
Curie Temperature	Approx. 260 °C	Approx. 500 °F	Typical value
Thermal Conductivity	Approx. 10 W/m·K	Approx. 69 Btu·in/ft2·h·°F	Room temperature
Specific Heat	Approx. 500 J/kg·°C	Approx. 0.119 Btu/lb·°F	Room temperature
Electrical Resistivity	Approx. 0.80 µΩ·m	Approx. 80 µΩ·cm	Room temperature
Modulus of Elasticity	Approx. 159 GPa	Approx. 23.1 x 10³ ksi	Annealed, room temperature
Mean CTE, 30-100 °C	Approx. 0.84 µm/m·°C	Approx. 0.47 µin/in·°F	Representative anneal at 871 °C for 1 hour, furnace cooled
Mean CTE, 30-200 °C	Approx. 1.72 µm/m·°C	Approx. 0.96 µin/in·°F	Representative anneal at 871 °C for 1 hour, furnace cooled
Mean CTE, 30-300 °C	Approx. 4.16 µm/m·°C	Approx. 2.31 µin/in·°F	Representative anneal at 871 °C for 1 hour, furnace cooled
Mean CTE, 30-400 °C	Approx. 7.03 µm/m·°C	Approx. 3.91 µin/in·°F	Representative anneal at 871 °C for 1 hour, furnace cooled

Mechanical Properties

Room-temperature mechanical properties

Mechanical properties vary with product form, size, processing route and heat treatment. The table below summarizes commonly referenced nominal values for material selection.

Product Form / Condition	Tensile Strength	Yield Strength, 0.2%	Elongation	Hardness
Representative wrought product – annealed	Approx. 483 MPa / 70 ksi	Approx. 276 MPa / 40 ksi	Approx. 40%	Approx. 75 HRB
Cold-worked product	Product and reduction dependent	Product and reduction dependent	Lower than annealed condition	Processing dependent
Finished precision component	By drawing or purchase specification	By drawing or purchase specification	By specification	By specification

For pressure equipment, aerospace parts or project-specific acceptance, use the minimum requirements in the specified ASTM, ASME, AMS, EN or customer drawing rather than nominal values.

Standards & Specifications

Common Super Invar 32-5 standards by product form

YSN128 can quote Alloy 625 products according to ASTM, ASME, AMS, EN, DIN, ISO or customer drawing requirements. Certificate scope can be matched to the purchase order.

Scope	Common Standard / Requirement	Application	Buyer Note
Controlled-Expansion Material	ASTM F1684-06(2021), withdrawn 2024	Legacy specification covering UNS K93500 wire, rod, bar, strip, sheet and tubing	Use only when accepted by the purchaser or referenced by an established project specification.
Thermal Expansion Testing	ASTM E228-22	Linear thermal expansion testing by push-rod dilatometer	Specify the temperature interval, specimen orientation, thermal history and acceptance limits.
Tensile Testing	ASTM E8/E8M-25	Room-temperature tensile strength, yield strength and elongation testing	Results depend on product form, specimen direction and delivery condition.
Custom Precision Products	Customer drawing, OEM specification or approved material control plan	Machined parts, optical structures, waveguide tubes, rings, flanges and fittings	Drawing requirements normally govern dimensions, heat treatment, CTE and dimensional stability.
Inspection Documents	EN 10204 3.1 or agreed mill certificate	Chemical analysis, heat treatment, mechanical testing and traceability	Confirm required tests and certificate format before ordering.

Available Product Forms

Super Invar 32-5 supply range

Review available product forms, size ranges, standards and delivery options for this alloy.

Form	Common Size Range	Delivery Condition	Typical Applications	Page Link
Pipe & Tube	Precision small-bore to large drawing-based dimensions	Annealed, cold drawn, welded or seamless as agreed	Waveguides, optical supports and dimensionally stable tubular assemblies	View Pipe & Tube
Round Bar	Diameter 3-300 mm, larger custom forgings available	Hot rolled, forged, annealed, peeled or ground	Optical mounts, metrology parts, rings and precision-machined components	View Round Bar
Sheet & Plate	Thickness 0.5-100 mm, custom widths and lengths	Annealed, cold rolled, hot rolled or precision flattened	Telescope structures, instrument frames and semiconductor equipment	View Sheet & Plate
Strip & Foil	Thickness 0.02-3 mm, slit widths to specification	Cold rolled, annealed, bright finished or tension leveled	Precision spacers, flexible elements and low-expansion laminations	View Strip & Foil
Wire	Diameter 0.1-12 mm, coil, spool or straight length	Cold drawn, annealed or processing-specific condition	Instrument components, glass assemblies and precision wire parts	View Wire
Fasteners	Standard-style and custom drawing dimensions	Machined or thread rolled, annealed or stress relieved	Low-expansion optical, metrology and positioning assemblies	View Fasteners
Fittings	Drawing-based elbows, tees, reducers and special connectors	Machined, formed, welded and heat treated as specified	Precision tubular systems and controlled-expansion assemblies	View Fittings
Flanges	Custom diameters, thicknesses and drilling patterns	Forged or plate-cut, machined and dimensionally stabilized	Optical chambers, instrument interfaces and vacuum assemblies	View Flanges
Forgings	Rings, discs, blocks and drawing-based components	Forged, annealed, rough machined or finish machined	Gyroscopes, telescope structures and precision support components	View Forgings
Welding Wire	Diameter 0.8-4.0 mm or project-specific dimensions	Clean bright finish with controlled Fe-Ni-Co chemistry	Qualified joining and repair of Super Invar assemblies	View Welding Wire

Material Selection Guide

When to consider Super Invar 32-5

This guide helps buyers connect service conditions with the typical advantage of Alloy 625. Final selection should consider medium concentration, temperature, pressure, fabrication, availability and budget.

Service Requirement	Recommended Alloy	Reason for Selection	Buyer Note
Minimum expansion around room temperature	Super Invar 32-5	Provides exceptionally low expansion over approximately -55 to 95 °C when correctly processed.	Specify the complete operating temperature interval and maximum permitted CTE.
Low expansion over a broader moderate-temperature range	Invar 36	Offers established low-expansion performance with wider commercial availability.	Compare the full expansion curves rather than one room-temperature value.
Expansion matching selected glass or ceramic	Kovar or another sealing alloy	Its expansion behavior is designed for compatible hermetic glass-to-metal or ceramic seals.	Select according to the exact glass or ceramic composition and sealing cycle.
Expansion matching soft glass or electronic components	Invar 42	Its higher nickel content provides an expansion curve suited to selected electronic and glass applications.	Confirm the required expansion interval and sealing material.
Critical optical or metrology structure	Super Invar 32-5 with stabilization treatment	Low CTE can be combined with stress relief and dimensional stabilization for precision service.	Define rough machining, stress relief, finish machining and thermal cycling requirements.
General corrosion-resistant or high-temperature structural service	Select another nickel alloy	Super Invar 32-5 is optimized for dimensional control, not broad corrosion resistance or high-temperature strength.	Provide the atmosphere, chemicals, loads and operating temperature for material selection.

Why Choose Us

Supply and quality support for Super Invar 32-5

For ranking traffic, buyers need more than a data sheet. This section gives clear trust signals for procurement, engineering and quality teams.

STASTM / ASME / AMS / EN

Quotation can be matched to project standards and product form specifications.

MTEN10204 3.1 MTC

Heat number, chemistry, mechanical properties and inspection records can be supplied.

QCPMI & Inspection

PMI, UT, dimensional inspection, visual inspection and packing check are available.

CSCustom Size

Cutting, machining allowance, rough machining and drawing-based supply can be arranged.

EPExport Packing

Wooden case, bundle, waterproof protection and international shipping documents.

RFFast Technical Reply

Send grade, size, standard, quantity and destination for a practical quotation route.

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FAQ

Super Invar 32-5 questions from buyers

Find practical answers about procurement, standards, fabrication and industrial applications.

Super Invar 32-5 is used for optical and laser systems, ring laser gyroscopes, semiconductor components, metrology instruments, waveguide tubes, telescope structures, positioning systems and assemblies matched to low-expansion glass or quartz.

Yes. UNS K93500 is the standardized UNS designation associated with the iron-nickel-cobalt alloy commonly known as Super Invar 32-5.

Super Invar 32-5 contains approximately 32% nickel and 5.5% cobalt, while Invar 36 contains approximately 36% nickel without the same cobalt addition. Super Invar 32-5 can provide lower expansion around room temperature, but its performance is more sensitive to chemistry, processing and thermal history.

The alloy is designed for minimum expansion around room temperature and typically provides lower expansion than Invar 36 over approximately -55 to 95 °C. The exceptionally low CTE does not remain near zero across broad high-temperature intervals.

YSN128 can quote plate, sheet, strip, round bar, rod, wire, precision tube, forgings and drawing-based fasteners, fittings and flanges. Availability and minimum quantity depend on the required dimensions and delivery condition.

ASTM F1684 historically covered UNS K93500 but was withdrawn in 2024. ASTM E228 may be specified for thermal expansion testing and ASTM E8/E8M for tensile testing. Current orders should be controlled by an agreed purchase specification, customer drawing or OEM material requirement.

Super Invar 32-5 can be welded using a qualified process and compatible project-approved filler chemistry. Welding stresses and heat input can change dimensional stability, so critical assemblies may require stress relief, re-annealing, thermal cycling and final CTE verification.

Please send the UNS or alloy grade, product form, dimensions, quantity, operating temperature range, required CTE, delivery condition, heat treatment, dimensional tolerances, inspection requirements and certificate type. Drawings should be supplied for precision-machined or custom products.

Super Invar 32-5