ASTM F256-05e1

Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium

ABSTRACT
This specification covers two chromium-iron alloys, one is UNS K91800 with nominally 18% chromium, balance iron, and the other is UNS K92801 with nominally 28% chromium, both in strip, bar, wire, and rod forms intended primarily for sealing to glass in electronic applications. The alloys are classified by nominal chemical composition, specifically by chromium content, in two types: Type I (UNS K91800) and Type II (UNS K92801). The materials shall show no evidence of transformation to martensite. For Type I alloy, the austenite formed during heat treating will transform to martensite at or above room temperature. The presence of austenite, as may be noted in Type II alloy, is acceptable if the thermal expansion requirement is met. Different tests shall be performed in order to determine the following properties of the alloys: thermal expansion, Rockwell hardness, and tensile strength.
SCOPE
1.1 This specification covers two chromium-iron alloys, the former, (UNS K91800), nominally 18 % chromium, balance iron, the latter, (UNS K92801), nominally 28 % chromium, in strip, bar, wire, and rod forms intended primarily for sealing to glass in electronic applications.
Note 1—UNS K92801 should only be considered for use at service temperatures below 300°C. The alloy is prone to sigma phase formation at temperatures close to 620°C, and exhibits brittle mechanical behavior after prolonged exposures at temperatures close to 475°C.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 The following hazard caveat pertains only to the test method portion, Sections 16 and 17, of this specification. 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Dec-2004
• ICS: 21.140 - Seals, glands
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaces: ASTM F256-05 - Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium
• Effective Date: 01-Jan-2005
• Replaced By: ASTM F256-05(2010) - Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium
• Effective Date: 01-Oct-2010
• Referred By: ASTM F144-80(2019) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Jan-2005
• Referred By: ASTM F140-98(2020) - Standard Practice for Making Reference Glass-Metal Butt Seals and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Jan-2005
• Referred By: ASTM F14-80(2019) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-Jan-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation: F256 – 05
Standard Specification for
Chromium-Iron Sealing Alloys with 18 or 28 Percent
1
Chromium
ThisstandardisissuedunderthefixeddesignationF256;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1
´ NOTE—Note 1 and 16.1.2 were updated editorially in August 2005.
1. Scope E38 Methods for Chemical Analysis of Nickel-Chromium
and Nickel-Chromium-Iron Alloys
1.1 This specification covers two chromium-iron alloys, the
E228 Test Method for Linear Thermal Expansion of Solid
former, (UNS K91800), nominally 18 % chromium, balance
Materials With a Push-Rod Dilatometer
iron, the latter, (UNS K92801), nominally 28 % chromium, in
F14 PracticeforMakingandTestingReferenceGlass-Metal
strip, bar, wire, and rod forms intended primarily for sealing to
Bead-Seal
glass in electronic applications.
F140 PracticeforMakingReferenceGlass-MetalButtSeals
NOTE 1—UNS K92801 should only be considered for use at service
and Testing for Expansion Characteristics by Polarimetric
temperatures below 300°C.The alloy is prone to sigma phase formation at
Methods
temperatures close to 620°C, and exhibits brittle mechanical behavior
F144 Practice for Making Reference Glass-Metal Sandwich
after prolonged exposures at temperatures close to 475°C.
Seal and Testing for Expansion Characteristics by Polari-
1.2 The values stated in inch-pound units are to be regarded
metric Methods
as the standard. The values given in parentheses are for
information only.
3. Terminology
1.3 The following hazard caveat pertains only to the test
3.1 Definitions of Terms Specific to This Standard:
method portion, Sections 16 and 17, of this specification. This
3.1.1 bar:
standard does not purport to address all of the safety concerns,
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3.1.1.1 hot-finished rounds, squares, and hexagons, ⁄4 in.
if any, associated with its use. It is the responsibility of the user
(6.4 mm) and over in diameter or size.
of this standard to establish appropriate safety and health
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3.1.1.2 hot-finished flats, ⁄4 in. to 10 in. (6.4 to 254 mm),
practices and determine the applicability of regulatory limita-
1
inclusive, in width and ⁄8 in. (3.2 mm) and over in thickness.
tions prior to use.
3.1.1.3 cold-finished rounds, squares, octagons, hexagons
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and shapes, over ⁄2 in. (12.7 mm) in diameter or size.
2. Referenced Documents
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3.1.1.4 cold-finished flats, ⁄8 in. (9.5 mm) and over in width
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2.1 ASTM Standards:
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and ⁄8 in. (3.2 mm) and over in thickness (see Discussions).
A370 Test Methods and Definitions for Mechanical Testing
3
Discussion—Widths less than ⁄8 in. (9.5 mm) and thick-
of Steel Products
3
nesses less than ⁄16 in. (4.8 mm) are generally described as flat
E3 Guide for Preparation of Metallographic Specimens
wire.
E18 Test Methods for Rockwell Hardness of Metallic Ma-
1 3
Discussion—Thicknesses of ⁄8 in. (3.2 mm) to under ⁄16 in.
terials
(4.8 mm) can also be described as cold-rolled strip or, if in cut
E29 Practice for Using Significant Digits in Test Data to
lengths, bar.
Determine Conformance with Specifications
3.1.2 rod—hot-rolled, or hot-rolled, annealed, and pickled,
rounds, squares, octagons, hexagons and shapes, in coils, for
1 3
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subsequent cold drawing or cold rolling, ⁄4 in. or ⁄4 in. (6.4 or
This specification is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
19.0 mm) in diameter or size.
Materials.
3.1.3 strip—cold-finished coils or cut lengths, under 24 in.
Current edition approved Jan. 1, 2005. Published January 2005. Originally
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(610mm)downtoandincluding ⁄16in.(4.8mm)inwidth,and
approved in 1951 as F256 – 51 T. Last previous edition approved in 1999 as
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F256 – 94 (1999) . Consolidated with F257 in 1972. DOI: 10.1520/F0256-05E01. under ⁄16 in. down to and including 0.005 in. (0.13 mm) in
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
thickness.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.1.4 No. 1 edge—a rolled edge either round or square as
Standards volume information, refer to the standard’s Document Summary page on
specified.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F256 – 05
3.1.5 No. 3 edge—an edge produced by slitting. 7.1.2 Annealed for deep drawing (strip),
3.1.6 No. 5 edge—an approximately square edge produced 7.1.3 Cold rolled or cold drawn to a specified mechanical
by rolling or filing after slitting. property level, or
Discussion—Cold-finished product 0.005 in. (0
...