ASTM F31-21

Standard Specification for Nickel-Chromium-Iron Sealing Alloys

ABSTRACT
This specification covers iron-nickel-chromium alloy (UNS K94760) used primarily for glass-sealing applications in electronic devices. The chemical composition of the material shall conform to the requirements prescribed. Chemical analysis shall be made, when desired, in accordance with the prescribed requirements. The average linear coefficient of thermal expansion shall be within limits of the requirements specified. The material shall be commercially smooth, uniform in cross section, in composition, and in temper; it shall be free of scale, corrosion, cracks, seams, scratches, slivers, and other defects.
SCOPE
1.1 This specification covers two iron-nickel-chromium alloys (UNS K94760 and UNS K95150) used primarily for glass-sealing applications in electronic devices.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 77.120.40 - Nickel, chromium and their alloys
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:F31 −21
Standard Specification for
1
Nickel-Chromium-Iron Sealing Alloys
ThisstandardisissuedunderthefixeddesignationF31;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope F140Practice for Making Reference Glass-Metal Butt Seals
and Testing for Expansion Characteristics by Polarimetric
1.1 This specification covers two iron-nickel-chromium al-
Methods
loys (UNS K94760 and UNS K95150) used primarily for
F144Practice for Making Reference Glass-Metal Sandwich
glass-sealing applications in electronic devices.
Seal and Testing for Expansion Characteristics by Polari-
1.2 The values stated in SI units are to be regarded as
metric Methods
standard. The values given in parentheses after SI units are
3. Ordering Information
providedforinformationonlyandarenotconsideredstandard.
1.3 This standard does not purport to address all of the 3.1 Ordersformaterialunderthisspecificationshallinclude
the following information:
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1.1 Size,
3.1.2 Temper (Section 6),
priate safety, health, and environmental practices and deter-
3.1.3 Surface finish (Section 8),
mine the applicability of regulatory limitations prior to use.
3.1.4 Marking and packaging (Section 13), and
1.4 This international standard was developed in accor-
3.1.5 Certification if required.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Chemical Composition
Development of International Standards, Guides and Recom-
4.1 The material shall conform to the requirements of Table
mendations issued by the World Trade Organization Technical
1 as to chemical composition.
Barriers to Trade (TBT) Committee.
NOTE 1—The major constituents of this alloy may be adjusted by the
2. Referenced Documents
manufacturer so that the alloy meets the requirement for thermal expan-
2 sion.
2.1 ASTM Standards:
E18Test Methods for Rockwell Hardness of Metallic Ma-
5. Chemical Analysis
terials
5.1 Chemical analysis shall be made, when desired, in
E29Practice for Using Significant Digits in Test Data to
accordance with Test Methods E354.
Determine Conformance with Specifications
E112Test Methods for Determining Average Grain Size 6. Surface Lubricants
E228Test Method for Linear Thermal Expansion of Solid
6.1 Alllubricantsusedduringcold-workingoperationssuch
Materials With a Push-Rod Dilatometer
as drawing, rolling, or spinning, shall be capable of being
E354 Test Methods for Chemical Analysis of High-
removed readily by any of the common organic degreasing
Temperature,Electrical,Magnetic,andOtherSimilarIron,
solvents.
Nickel, and Cobalt Alloys
7. Temper
F14Practice for Making andTesting Reference Glass-Metal
Bead-Seal
7.1 The desired temper of the material shall be specified on
the purchase order. Unless otherwise specified, wire, rod, and
tubing shall be given a final bright anneal by the manufacturer.
1
This specification is under the jurisdiction of ASTM Committee F01 on
Strip and sheet shall be annealed properly to develop drawing
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
properties. For deep drawing, the hardness shall not exceed
Materials, Wire Bonding, and Flip Chip.
HRB 90 when determined in accordance with Test Methods
Current edition approved Nov. 1, 2021. Published December 2021. Originally
approved in 1963 as F31–63T. Last previous edition approved in 2016 as
E18.
F31–16. DOI: 10.1520/F0031-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 8. Grain Size
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
8.1 Strip and sheet for deep drawing applications shall have
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. an average grain size not larger than ASTM No. 5 (Note 2),
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F31−21
TABLE 1 Chemical Composition
10.1.2 Forging,
Element 42Ni-6Cr(UNS K94760) 47Ni-6Cr(UNS K95150)
10.1.3 Centerless grinding (rod),
Composition, % Composition, %
10.1.4 Belt polishing,
Nickel, nominal 42.0 47.0
Chromium, nominal 5.6 6.0
10.1.5 Cold rolling, and drawing, and
Carbon, max 0.07 0.02
10.1.6 Wire drawing.
Manganese, max 0.25 0.30
Phosphorus, max 0.025 0.025
10.2 C
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F31 − 16 F31 − 21
Standard Specification for
1
Nickel-Chromium-Iron Sealing Alloys
This standard is issued under the fixed designation F31; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers two iron-nickel-chromium alloys (UNS K94760 and UNS K95150) used primarily for glass-sealing
applications in electronic devices.
1.2 The values stated in inch-poundSI units are to be regarded as standard. The values given in parentheses are mathematical
conversions to after SI units that are provided for information only and are not considered standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
E18 Test Methods for Rockwell Hardness of Metallic Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E112 Test Methods for Determining Average Grain Size
E228 Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer
E354 Test Methods for Chemical Analysis of High-Temperature, Electrical, Magnetic, and Other Similar Iron, Nickel, and
Cobalt Alloys
F14 Practice for Making and Testing Reference Glass-Metal Bead-Seal
F140 Practice for Making Reference Glass-Metal Butt Seals and Testing for Expansion Characteristics by Polarimetric Methods
F144 Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric
Methods
3. Ordering Information
3.1 Orders for material under this specification shall include the following information:
3.1.1 Size,
1
This specification is under the jurisdiction of ASTM Committee F01 on Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic Materials, Wire
Bonding, and Flip Chip.
Current edition approved May 1, 2016Nov. 1, 2021. Published May 2016December 2021. Originally approved in 1963 as F31 – 63 T. Last previous edition approved in
20122016 as F31 – 12.F31 – 16. DOI: 10.1520/F0031-16.10.1520/F0031-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F31 − 21
3.1.2 Temper (Section 6),
3.1.3 Surface finish (Section 8),
3.1.4 Marking and packaging (Section 13), and
3.1.5 Certification if required.
4. Chemical Composition
4.1 The material shall conform to the requirements of Table 1 as to chemical composition.
TABLE 1 Chemical Composition
Element 42Ni-6Cr(UNS K94760) 47Ni-6Cr(UNS K95150)
Composition, % Composition, %
Nickel, nominal 42.0 47.0
Chromium, nominal 5.6 6.0
Carbon, max 0.07 0.02
Manganese, max 0.25 0.30
Phosphorus, max 0.025 0.025
Sulfur, max 0.025 0.025
Silicon, max 0.30 0.30
Aluminum, max 0.20 -
Iron remainder remainder
NOTE 1—The major constituents of this alloy may be adjusted by the manufacturer so that the alloy meets the requirement for thermal expansion.
5. Chemical Analysis
5.1 Chemical analysis shall be made, when desired, in accordance with Test Methods E354.
6. Surface Lubricants
6.1 All lubricants used during cold-working operations such as drawing, rolling, or spinning, shall be capable of being removed
readily by any of the common organic degreasing solvents.
7. Temper
7.1 The desired temper of the material shall be specified on the purchase order. Unless otherwise specified, wire, rod, and tubing
shall be given a final bright anneal by the manufacturer. Strip and sheet shall be annealed properly to develop
...