Name: Alloy 52
Brand: Kovar

Material Overview

Alloy 52 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

Alloy 52 is a controlled-expansion nickel-iron alloy containing approximately 52% nickel and balance iron. Its thermal expansion is closely matched to a range of soft glasses, allowing reliable glass-to-metal seals during heating, cooling and thermal cycling. The alloy is normally used in the annealed condition because residual cold work can distort the coefficient of thermal expansion. Typical applications include electronic tubes, hermetic headers, fluorescent-lamp components, reed switches, sensors, feedthroughs, ceramic or glass sealing parts and precision electronic packages.

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

Alloy 52 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	Typical Requirement, wt.%	Role in Alloy 52
Nickel	Ni	51.5-52.5	Controls the thermal expansion curve and glass-sealing compatibility.
Iron	Fe	Balance	Forms the iron-nickel matrix and provides the required magnetic and thermal behavior.
Manganese	Mn	0.80 max	Controlled deoxidizing and processing element.
Silicon	Si	0.30 max	Controlled deoxidizing and residual element.
Carbon	C	0.05 max	Restricted to maintain ductility, surface quality and sealing performance.
Phosphorus	P	0.02 max	Restricted impurity.
Sulfur	S	0.02 max	Restricted impurity for forming and sealing quality.

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 / Additional Value	Condition / Notes
Density	8.25-8.30 g/cm3	Approximately 0.298-0.300 lb/in3	Room temperature
Liquidus / Melting Temperature	Approximately 1430-1450 °C	Approximately 2606-2640 °F	Typical range
Inflection Temperature	Approximately 500 °C	Approximately 930 °F	Magnetoelastic expansion transition
Mean Coefficient of Thermal Expansion	10.3 µm/m·°C	20-100 °C	Annealed condition
Mean Coefficient of Thermal Expansion	10.4 / 10.2 µm/m·°C	20-200 / 20-300 °C	Annealed condition
Mean Coefficient of Thermal Expansion	10.3 µm/m·°C	20-400 / 20-500 °C	Annealed condition
Mean Coefficient of Thermal Expansion	10.8 µm/m·°C	20-600 °C	Expansion rises above the inflection region
Thermal Conductivity	16.7-17.0 W/m·°C	Approximately 116-118 Btu·in/ft2·h·°F	Representative room-temperature value
Specific Heat	Approximately 502 J/kg·°C	Approximately 0.120 Btu/lb·°F	Representative value
Electrical Resistivity	0.38-0.43 µΩ·m	38-43 µΩ·cm	Approximately 20 °C

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 / Condition	Tensile Strength	Yield Strength, 0.2%	Elongation	Condition / Notes
Soft annealed wire or strip	Approximately 510-550 MPa	Approximately 276-280 MPa	Approximately 35-40%	Typical annealed values
Soft annealed sheet	Approximately 510-550 MPa	Approximately 276-280 MPa	Approximately 35-40%	Typical values; thickness dependent
Cold-worked strip	Approximately 590 MPa or higher	Condition dependent	Lower than annealed condition	Residual cold work can alter thermal expansion
Hard strip or wire	Approximately 820 MPa or higher	Condition dependent	Condition dependent	Use only when forming and CTE requirements permit cold work
Finished sealing component	Must be evaluated after forming and final annealing		Glass-seal performance is more important than generic tensile strength
Mechanical values are typical and condition-dependent. Alloy 52 is normally specified and used annealed because cold work can change its thermal expansion behavior.

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 Alloy 52 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.

Product Form / Requirement	Common Standard	Scope	Buyer Note
Glass-Sealing Alloy	ASTM F30	Iron-nickel sealing alloys intended primarily for glass-to-metal sealing in electronic applications	Confirm chemistry, surface finish, temper, grain size and expansion requirements.
Nickel-Iron Strip and Sheet	DIN 17745	Controlled-expansion nickel-iron alloy for sealing applications	Specify the required expansion curve and annealed condition.
Nickel-Iron Products	SEW 385	European material reference for controlled-expansion nickel-iron alloys	Verify the applicable product form and current customer specification.
International Designation	W.Nr. 2.4478 / UNS N14052	Material identification for Alloy 52 and Ni 52 products	Designation alone does not define surface finish or thermal-expansion acceptance.
Wire and Fine Wire	ASTM F30 or customer specification	Wire for glass seals, headers and hermetic electronic components	Specify diameter, surface condition, annealing and spool or straight-length supply.
Final Annealing	Project-specific, commonly approximately 850 ±20 °C in hydrogen	Removes residual cold work before sealing and restores the expansion curve	Cycle, atmosphere, cooling rate and cleanliness must be qualified for the glass system.
Glass-to-Metal Seal	Customer glass-seal qualification	Compatibility with soft glass, seal temperature and thermal cycling	Confirm glass composition, wetting, oxidation state and leakage criteria.
Ceramic Sealing	Project-specific ceramic or braze qualification	Special applications involving ceramics or electronic feedthroughs	ASTM F30 is primarily intended for glass seals and does not by itself qualify ceramic seals.

Available Product Forms

Alloy 52 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	Small seamless or welded tubing and custom feedthrough dimensions	Annealed, cleaned and supplied to sealing specification	Hermetic housings, sensor bodies and electronic headers	View Pipe & Tube
Round Bar	Small precision bar and custom machining stock	Annealed or lightly cold worked as specified	Glass-seal pins, headers, bushings and precision components	View Round Bar
Sheet & Plate	Thin sheet through custom plate and blank dimensions	Soft annealed, bright finished or cleaned for sealing	Hermetic lids, electronic packages and glass-seal parts	View Sheet & Plate
Strip & Foil	Precision strip and foil in custom slit widths	Annealed, cold rolled or selectively hard rolled	Lead frames, seals, diaphragms and electronic packaging	View Strip & Foil
Wire	Fine wire through header and pin diameters	Soft annealed, bright, cleaned or precision drawn	Glass-to-metal seals, reed switches, lamps and sensors	View Wire
Fasteners	Small screws, pins, studs and custom electronic hardware	Annealed or lightly cold worked to drawing	Hermetic packages, instruments and precision assemblies	View Fasteners
Fittings	Custom feedthrough fittings and electronic connectors	Machined, cleaned and annealed for sealing	Pressure housings, sensors and instrumentation packages	View Fittings
Flanges	Small precision rings and custom sealing flanges	Machined, annealed and prepared for glass or ceramic joining	Hermetic housings and electronic feedthroughs	View Flanges
Forgings	Small custom forged blanks and rings	Annealed and machined to drawing	Special seal housings and precision electronic components	View Forgings
Welding Wire	Fine wire and custom joining-wire diameters	Annealed, clean and suitable for qualified joining procedures	Repair, header fabrication and dissimilar-metal joining	View Welding Wire

Material Selection Guide

When to consider Alloy 52

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.

Alloy / Material	Selection Strength	Typical Position	Selection Note
Alloy 52	Expansion matched to a wide range of soft glasses	Glass-to-metal seals, headers and hermetic packages	Select when the glass seal requires approximately 10.3 x 10^-6/°C expansion.
Invar 36	Much lower thermal expansion and high dimensional stability	Precision structures, tooling and low-expansion assemblies	Choose Invar 36 when very low expansion is required rather than soft-glass matching.
Kovar	Controlled expansion compatible with selected borosilicate glasses and ceramics	Electronic packages, headers and ceramic seals	Compare glass composition, expansion curve, oxidation behavior and magnetic properties.
Super Invar 32-5	Lower expansion than Alloy 52 over selected temperature ranges	Precision optical and dimensional-control components	Not generally a direct replacement for Alloy 52 soft-glass sealing.
NILO® 42	Intermediate controlled expansion for selected glass and ceramic systems	Electronic seals and lead-frame components	Choose based on the actual glass expansion curve and seal temperature.
Alloy 48	Lower expansion than Alloy 52 with a different sealing match	Soft-glass and ceramic sealing applications	Compare the complete 20-450 °C expansion profile and inflection temperature.

Why Choose Us

Supply and quality support for Alloy 52

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

Alloy 52 questions from buyers

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

Alloy 52 is mainly used for glass-to-metal sealing in electronic tubes, hermetic headers, fluorescent lamps, reed switches, sensors, feedthroughs and specialty electronic packages. It can also be used in selected ceramic sealing systems when separately qualified.

Yes. UNS N14052 is the common UNS designation for Alloy 52, also known as NILO 52, Pernifer 50, Glass Sealing 52 and Ni 52. W.Nr. 2.4478 and DIN 17745 are additional material references.

Residual cold work can distort the coefficient of thermal expansion and reduce the reliability of a glass seal. Alloy 52 is therefore normally supplied, formed and finally annealed so that the expansion curve and surface condition are suitable for the selected glass.

The mean coefficient of expansion is approximately 10.3 µm/m·°C from 20 to 100 °C and remains close to 10.2-10.4 µm/m·°C through approximately 500 °C. The exact curve, inflection temperature and glass compatibility should be verified for the actual product and seal design.

ASTM F30 is the primary U.S. specification for iron-nickel sealing alloys used primarily for glass-to-metal seals. DIN 17745 and SEW 385 are common European references, while UNS N14052 and W.Nr. 2.4478 identify the alloy family.

Alloy 52 can be joined by qualified welding, brazing or glass-sealing processes, but the joining cycle must not introduce excessive residual stress, contamination or unwanted cold work. For hermetic devices, the glass composition, atmosphere, wetting and leak-rate qualification are normally more important than generic weld strength.

We can quote fine wire, strip, foil, sheet, tube, small bar and precision blanks for electronic sealing. Fittings, flanges, fasteners and larger custom parts can be discussed as drawing-based products, subject to the required expansion curve, surface condition and final annealing.

Please send the Alloy 52 or UNS N14052 designation, product form, dimensions, quantity, glass or ceramic composition, sealing temperature, required expansion curve, surface finish, final annealing condition, leak-rate target, inspection requirements and destination.

Alloy 52