ASTM F256-05(2020)

Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium (Withdrawn 2023)

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 standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
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, 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.
WITHDRAWN RATIONALE
This specification covered 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.
Formerly under the jurisdiction of F01 on Electronics, this specification was withdrawn in November 2023. This standard is being withdrawn without replacement because Committee F01 was disbanded.

General Information

• Status: Withdrawn
• Publication Date: 30-Apr-2020
• Withdrawal Date: 28-Nov-2023
• 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(2015) - Standard Specification for Chromium-Iron Sealing Alloys with 18 or 28 Percent Chromium
• Effective Date: 01-May-2020
• Refers: ASTM F14-80(2019) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-Nov-2019
• Refers: ASTM F144-80(2019) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-Nov-2019
• Refers: ASTM A370-19 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jul-2019
• Refers: ASTM E18-18 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2018
• Refers: ASTM A370-17a - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2017
• Refers: ASTM E18-17 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Jul-2017
• Refers: ASTM A370-17 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Jan-2017
• Refers: ASTM E228-11(2016) - Standard Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer
• Effective Date: 01-Sep-2016
• Refers: ASTM A370-15 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Nov-2015
• Refers: ASTM F14-80(2015) - Standard Practice for Making and Testing Reference Glass-Metal Bead-Seal
• Effective Date: 01-May-2015
• Refers: ASTM F144-80(2015) - Standard Practice for Making Reference Glass-Metal Sandwich Seal and Testing for Expansion Characteristics by Polarimetric Methods
• Effective Date: 01-May-2015
• Refers: ASTM A370-14 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-May-2014
• Refers: ASTM A370-13 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Nov-2013
• Refers: ASTM E18-12 - Standard Test Methods for Rockwell Hardness of Metallic Materials
• Effective Date: 01-Dec-2012

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:F256 −05 (Reapproved 2020)
Standard Specification for
Chromium-Iron Sealing Alloys with 18 or 28 Percent
Chromium
ThisstandardisissuedunderthefixeddesignationF256;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope A370Test Methods and Definitions for Mechanical Testing
of Steel Products
1.1 This specification covers two chromium-iron alloys, the
E3Guide for Preparation of Metallographic Specimens
former, (UNS K91800), nominally 18% chromium, balance
E18Test Methods for Rockwell Hardness of Metallic Ma-
iron, the latter, (UNS K92801), nominally 28% chromium, in
terials
strip, bar, wire, and rod forms intended primarily for sealing to
E29Practice for Using Significant Digits in Test Data to
glass in electronic applications.
Determine Conformance with Specifications
NOTE 1—UNS K92801 should only be considered for use at service
E38Methods for Chemical Analysis of Nickel-Chromium
temperaturesbelow300°C.Thealloyispronetosigmaphaseformationat
and Nickel-Chromium-Iron Alloys
temperatures close to 620°C, and exhibits brittle mechanical behavior
E228Test Method for Linear Thermal Expansion of Solid
after prolonged exposures at temperatures close to 475°C.
Materials With a Push-Rod Dilatometer
1.2 The values stated in inch-pound units are to be regarded
F14Practice for Making andTesting Reference Glass-Metal
as standard. The values given in parentheses are mathematical
Bead-Seal
conversions to SI units that are provided for information only
F140Practice for Making Reference Glass-Metal Butt Seals
and are not considered standard.
and Testing for Expansion Characteristics by Polarimetric
1.3 The following hazard caveat pertains only to the test
Methods
method portion, Sections 16 and 17, of this specification. This
F144Practice for Making Reference Glass-Metal Sandwich
standard does not purport to address all of the safety concerns,
Seal and Testing for Expansion Characteristics by Polari-
if any, associated with its use. It is the responsibility of the user
metric Methods
of this standard to establish appropriate safety, health, and
environmental practices and determine the applicability of
3. Terminology
regulatory limitations prior to use.
3.1 Definitions of Terms Specific to This Standard:
1.4 This international standard was developed in accor-
3.1.1 bar:
dance with internationally recognized principles on standard-
3.1.1.1 hot-finished rounds, squares, and hexagons, ⁄4 in.
ization established in the Decision on Principles for the
(6.4 mm) and over in diameter or size.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 3.1.1.2 hot-finished flats, ⁄4 in. to 10 in. (6.4 to 254 mm),
Barriers to Trade (TBT) Committee. inclusive, in width and ⁄8 in. (3.2 mm) and over in thickness.
3.1.1.3 cold-finished rounds, squares, octagons, hexagons
2. Referenced Documents
and shapes, over ⁄2 in. (12.7 mm) in diameter or size.
2.1 ASTM Standards: 3
3.1.1.4 cold-finishedflats, ⁄8in.(9.5mm)andoverinwidth
and ⁄8 in. (3.2 mm) and over in thickness (see Discussions).
Discussion—Widths less than ⁄8 in. (9.5 mm) and thick-
This specification is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
nesseslessthan ⁄16in.(4.8mm)aregenerallydescribedasflat
Materials, Wire Bonding, and Flip Chip.
wire.
Current edition approved May 1, 2020. Published June 2020. Originally
1 3
Discussion—Thicknesses of ⁄8 in. (3.2 mm) to under ⁄16 in.
approved in 1951 as F256–51T. Last previous edition approved in 2015 as
F256–94(2015). Consolidated with F257 in 1972. DOI: 10.1520/F0256-05R20. (4.8 mm) can also be described as cold-rolled strip or, if in cut
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
lengths, bar.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.1.2 rod—hot-rolled, or hot-rolled, annealed, and pickled,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. rounds, squares, octagons, hexagons and shapes, in coils, for
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F256−05 (2020)
1 3
subsequent cold drawing or cold rolling, ⁄4 in. or ⁄4 in. (6.4 or 6. Process
19.0 mm) in diameter or size.
6.1 The purchaser shall specify that the alloy be made by
3.1.3 strip—cold-finished coils or cut lengths, under 24 in.
one or more of the following processes: electric-arc, electric-
(610mm)downtoandincluding ⁄16in.(4.8mm)inwidth,and
induction, or other process approved by the purchaser.
under ⁄16 in. down to and including 0.005 in. (0.13 mm) in
7. Temper and Finish
thickness.
3.1.4 No. 1 edge—a rolled edge either round or square as 7.1 The desired temper of the material shall be specified on
specified. the purchase order as follows:
7.1.1 Annealed for forming (strip),
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. (0.13 mm) in
7.1.4 As hot rolled.
thickness and under 24 in. (609.6 mm) in width is sometimes
7.2 The desired surface of the material shall be specified on
identified as foil.
the purchase order as follows:
3.1.7 wire:
7.2.1 Pickled,
3.1.7.1 coldfinishedonly,roundorsquare, ⁄2in.(12.7mm)
7.2.2 Cold drawn (wire and bar),
and under in diameter or size.
7.2.3 Centerless ground (wire and bar), or
3.1.7.2 cold finished only, flat wire of ⁄16 in. (1.6 mm) to
7.2.4 Cold rolled (strip).
under ⁄8 in. (9.5 mm) in width and 0.010 in. (0.25 mm) to
under ⁄16 in. (4.8 mm) in thickness.
8. Chemical Composition
8.1 The material shall conform to the chemical composition
4. Classification
specified in Table 1.
4.1 Thealloyscoveredbythisspecificationareclassifiedby
nominal chemical composition, specifically by chromium
content, in two types:
TABLE 1 Chemical Requirements
4.1.1 Type I—18% chromium (UNS K91800) and
NOTE 1—Round observed or calculated values to the nearest unit in the
4.1.2 Type II—28% chromium (UNS K92801).
last right-hand place of figures used in expressing the limiting value, in
accordance with the rounding-off method of Practice E29.
5. Ordering Information
Composition, %
Element
5.1 Ordersformaterialunderthisspecificationshallinclude
Type I Type II
the following information:
Carbon, max 0.08 0.12
Manganese, max 1.00 1.00
5.1.1 Quantity (weight (Note 2) or number of pieces),
Silicon, max 0.75 0.75
5.1.2 Name of material (chromium-iron alloy),
Phosphorus, max 0.040 0.040
5.1.3 Type (Section 4),
Sulfur, max 0.030 0.030
Chromium, nominal 18.0 28.0
5.1.4 Form (Section 3),
Nickel, max 0.50 0.50
5.1.5 Temper and finish (Section 7),
Nitrogen, max . 0.20
A
Titanium .
5.1.6 Permissible variations in dimensions for rod (Section
Iron remainder remainder
13),
A
Five times the carbon content, minimum, and 0.60, max.
5.1.7 Certification if required (Section 21),
5.1.8 Packaging required (Section 22),
5.1.9 Dimensions (width, thickness, diameter, etc.),
5.1.10 ASTM designation: F256, and
8.2 Ladle Analysis—A ladle analysis of each heat of steel
5.1.11 Exceptions to the specification or special require-
shall be made by the manufacturer to determine the percent-
ments.
ages of the elements specified in Table 1.The analysis shall be
NOTE 2—The term “weight” is temporarily used in this standard
made from test castings made during the pouring of the heat.
becauseofestablishedtradeusage.Thewordisusedtomeanboth“force”
The chemical composition thus determined shall conform to
and“ mass,” and care must be taken to determine which is meant in each
the requirements specified in Table 1.
case (SI unit for force = newton and for mass = kilogram).
8.3 Check Analysis—If check analysis is made by the
5.2 If possible, the intended end use of the item should be
purchaser, the chemical composition thus determined shall
givenonthepurchaseorderespeciallywhentheitemisordered
conform to the requirements specified in Table 1 subject to the
for a specific end use or uses. Such information will enable the
permissible tolerances of Table 2.
manufacturer to produce a material more satisfactory for the
purchaser’s process and product.
9. Chemical Analysis
NOTE 3—A typical ordering description is as follows: 2000 kg,
9.1 Chemical analysis shall be made in accordance with
chromium-iron alloy. Type II, wire, annealed, cold drawn, commercial
packaging, ⁄4 in. (6.4 mm) round by coil, ASTM F256, end use-redraw. Method E38 or equivalent methods.
F256−05 (2020)
TABLE 2 Check Analysis Tolerances TABLE 5 Permissible Variations in Size of Cold-Finished Round
Bars
Tolerances over maxi-
Element mum or under minimum
Permissible Variations from Specified
Specified Size, in.
A,B
limits, percentage points
Size, in. (mm)
(mm)
Carbon 0.01
Over Under
Manganese 0.03
Over ⁄2 (12.7) to 1 0.002 (0.05) 0.002 (0.05)
Phosphorus 0.005 (25.4), excl
Sulfur 0.005
1 (25.4) to 1 ⁄2 (38.1), 0.0025 (0.064) 0.0025 (0.064)
Silicon 0.05 excl
Nickel 0.03
1 ⁄2 (38.1) to 4 (101.6), 0.003 (0.08) 0.003 (0.08)
C
Nitrogen 0.01 incl
Titanium 0.05
A
Unless otherwise specified, size tolerances are over and under as shown in the
above table. When required, however, they may be specified all over and nothing
under, or all under and nothing over, or any combination of over and under, if the
total spread in size tolerance for a specified size is not less than the total spread
10. Thermal Expansion Requirements shown in the table.
B
When it is necessary to heat treat or heat treat and pickle after cold finishing, size
10.1 The material shall conform to the thermal expansion
tolerances are double those shown in the table.
C
Cold-finished bars over 4 in. (101.6 mm) in diameter are produced; size
requirements prescribed in Table 3.
tolerances for such bars have not been evolved.
A,B
TABLE 3 Thermal Expansion Requirements
TABLE 6 Permissible Variations in Length of Hot-Finished or
Mean Coefficient of Linear Thermal
Temperature A
Cold-Finished Bars
Expansion, µm/m ·°C
Range,° C
UNS K91800 UNS K92801
Permissible Variations in Length, in.
30 to 530 11.3 to 11.7 10.8 to 11.4
Specified Size of
(mm)
Rounds, Squares,
A
Typical thermal expansion data for the alloys covered by this specification are
For Lengths over
Hexagons, Octagons, For Lengths up to
given for information only in the Appendix.
12 ft (3.7 m), to 25 ft
and Widths of Flats, 12 ft (3.7 m), incl
B
These requirements apply to specimens heat treated prior to test in accordance
(7.6 m), incl
B
in. (mm)
with Section 16.
Over Under Over Under
1 3
To 2 (50.8), incl ⁄2 (12.7) 0 ⁄4 (19.0) 0
Over 2 (50.8) to 4 (101.6), incl ⁄4 (19.0) 0 1 (25) 0
Over 4 (101.6) to 6 (152.4), incl 1 (25) 0 1 ⁄4 (32) 0
11. Mechanical Property Requirements 1 1
Over 6 (152.4) to 9 (228.6), incl 1 ⁄4 (32) 0 1 ⁄2 (38) 0
Over 9 (228.6) to 12 (304.8), incl 1 ⁄2 (38) 0 2 (51) 0
11.1 The material shall conform to the mechanical property
A
The order should specify random lengths or specific lengths. When random
requirementsprescribedinTable4.Rockwellhardnessshallbe
lengths are ordered, the length tolerance is not less than 2 ft (609.6 mm). When
specific lengths are ordered, Table 8 or Table 9 shall apply.
B
The maximum width of bar flats is 10 in. (254.0 mm).
A
TABLE 4 Mechanical Property Requirements
Rockwell Tensile Strength,
Hardness (or max.
Thickness, in. (mm)
equivalent)
14. Workmanship, Finish, and Appearance
(max) ksi MPa
Under 0.015 (0.38) . 85 590
14.1 The material shall be commercially smooth and uni-
0.015 (0.38) to 1 (25.4), incl B85 . .
form in cross section, composition, and temper; it shall be free
Over 1 (25.4) B88 . .
ofscalecorrosion,cracks,seams,scratches,slivers,processing
A
Applicable to strip in the annealed condition only. All other mechanical properties
lubricants, and other defects as best commercial practice will
as agreed upon between purchaser and manufacturer.
permit.
15. Number of Tests and Retests
determined in accordance with Test Method E18.
15.1 Test specimens for thermal expansion and phase-
transformation requirements shall be selected on the basis of a
12. Transformation Requirements
minimum of one specimen per heat.
12.1 The material shall show no evidence of transformation
15.2 Test specimens for mechanical properties shall be
to martensite. For Type I alloy, the austenite formed during
selected on the basis of a minimum of one specimen per size,
heat treating will transform to martensite at or above room
eachheat,eachlotannealedorotherwiseheattreatedunderthe
temperature. The presence of austenite, as may be noted in
same conditions, and each lot with like processing.
Type II alloy, is acceptable if the thermal expansion require-
ment is met.
15.3 If any test specimen shows defective machining or
develops flaws, it may be discarded and another specimen
13. Permissible Variations in Dimensions
substituted.
13.1 Material furnished under this specification, except rod,
15.4 Iftheresultsofanytestlotarenotinconformancewith
shall conform to the dimensional requirements of Tables 5-15.
the requirements of this specification, such lots may be
13.2 Permissible variations in dimensions for rod for re- retreated at the option of the manufacturer. The material shall
drawingorrerollingshallbeasagreeduponbetweenpurchaser beacceptableiftheresultsoftestsontheretreatedmaterialare
and manufacturer. within the requirements of this specification.
F256−05 (2020)
TABLE 7 Permissible Variations in Straightness of Machine-Straightened Hot-Finished or Cold-Finished Bars
Measure the length of the maximum gap between the bar and a straightedge of appropriate length when the straightedge is laid along the length of the bar on its
concave side. Unless otherwise specified, hot-finished or cold-finished bars for machining purposes are furnished machine straightened to the following tolerances
(maximum gap length), in in. (mm):
Hot-Finished
1 1
⁄8 in. (3.2 mm) in any 5 ft (1.5 m), but may not exceed ⁄8 in. (3.2 mm)×
Cold-Finished
1 1 length in ft (m)
⁄16 in. (1.6 mm) in any 5 ft (1.5 mm), but may not exceed ⁄16 in. (1.6 mm)× ⁄5 ft (1.5 mm)
TABLE 8 Diame
...

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
Designation: F256 − 05 (Reapproved 2020)
Standard Specification for
Chromium-Iron Sealing Alloys with 18 or 28 Percent
Chromium
This standard is issued under the fixed designation F256; 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 A370 Test Methods and Definitions for Mechanical Testing
of Steel Products
1.1 This specification covers two chromium-iron alloys, the
E3 Guide for Preparation of Metallographic Specimens
former, (UNS K91800), nominally 18 % chromium, balance
E18 Test Methods for Rockwell Hardness of Metallic Ma-
iron, the latter, (UNS K92801), nominally 28 % chromium, in
terials
strip, bar, wire, and rod forms intended primarily for sealing to
E29 Practice for Using Significant Digits in Test Data to
glass in electronic applications.
Determine Conformance with Specifications
NOTE 1—UNS K92801 should only be considered for use at service
E38 Methods for Chemical Analysis of Nickel-Chromium
temperatures below 300°C. The alloy is prone to sigma phase formation at
and Nickel-Chromium-Iron Alloys
temperatures close to 620°C, and exhibits brittle mechanical behavior
E228 Test Method for Linear Thermal Expansion of Solid
after prolonged exposures at temperatures close to 475°C.
Materials With a Push-Rod Dilatometer
1.2 The values stated in inch-pound units are to be regarded
F14 Practice for Making and Testing Reference Glass-Metal
as standard. The values given in parentheses are mathematical
Bead-Seal
conversions to SI units that are provided for information only
F140 Practice for Making Reference Glass-Metal Butt Seals
and are not considered standard.
and Testing for Expansion Characteristics by Polarimetric
1.3 The following hazard caveat pertains only to the test
Methods
method portion, Sections 16 and 17, of this specification. This
F144 Practice for Making Reference Glass-Metal Sandwich
standard does not purport to address all of the safety concerns,
Seal and Testing for Expansion Characteristics by Polari-
if any, associated with its use. It is the responsibility of the user
metric Methods
of this standard to establish appropriate safety, health, and
environmental practices and determine the applicability of
3. Terminology
regulatory limitations prior to use.
3.1 Definitions of Terms Specific to This Standard:
1.4 This international standard was developed in accor-
3.1.1 bar:
dance with internationally recognized principles on standard-
3.1.1.1 hot-finished rounds, squares, and hexagons, ⁄4 in.
ization established in the Decision on Principles for the
(6.4 mm) and over in diameter or size.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 3.1.1.2 hot-finished flats, ⁄4 in. to 10 in. (6.4 to 254 mm),
Barriers to Trade (TBT) Committee. inclusive, in width and ⁄8 in. (3.2 mm) and over in thickness.
3.1.1.3 cold-finished rounds, squares, octagons, hexagons
2. Referenced Documents
and shapes, over ⁄2 in. (12.7 mm) in diameter or size.
2.1 ASTM Standards: 3
3.1.1.4 cold-finished flats, ⁄8 in. (9.5 mm) and over in width
and ⁄8 in. (3.2 mm) and over in thickness (see Discussions).
Discussion—Widths less than ⁄8 in. (9.5 mm) and thick-
This specification is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
nesses less than ⁄16 in. (4.8 mm) are generally described as flat
Materials, Wire Bonding, and Flip Chip.
wire.
Current edition approved May 1, 2020. Published June 2020. Originally
1 3
Discussion—Thicknesses of ⁄8 in. (3.2 mm) to under ⁄16 in.
approved in 1951 as F256 – 51 T. Last previous edition approved in 2015 as
(4.8 mm) can also be described as cold-rolled strip or, if in cut
F256 – 94 (2015). Consolidated with F257 in 1972. DOI: 10.1520/F0256-05R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
lengths, bar.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.1.2 rod—hot-rolled, or hot-rolled, annealed, and pickled,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. rounds, squares, octagons, hexagons and shapes, in coils, for
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F256 − 05 (2020)
1 3
subsequent cold drawing or cold rolling, ⁄4 in. or ⁄4 in. (6.4 or 6. Process
19.0 mm) in diameter or size.
6.1 The purchaser shall specify that the alloy be made by
3.1.3 strip—cold-finished coils or cut lengths, under 24 in.
one or more of the following processes: electric-arc, electric-
(610 mm) down to and including ⁄16 in. (4.8 mm) in width, and
induction, or other process approved by the purchaser.
under ⁄16 in. down to and including 0.005 in. (0.13 mm) in
thickness. 7. Temper and Finish
3.1.4 No. 1 edge—a rolled edge either round or square as 7.1 The desired temper of the material shall be specified on
specified. the purchase order as follows:
7.1.1 Annealed for forming (strip),
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. (0.13 mm) in
7.1.4 As hot rolled.
thickness and under 24 in. (609.6 mm) in width is sometimes
7.2 The desired surface of the material shall be specified on
identified as foil.
the purchase order as follows:
3.1.7 wire:
7.2.1 Pickled,
3.1.7.1 cold finished only, round or square, ⁄2 in. (12.7 mm)
7.2.2 Cold drawn (wire and bar),
and under in diameter or size.
7.2.3 Centerless ground (wire and bar), or
3.1.7.2 cold finished only, flat wire of ⁄16 in. (1.6 mm) to
7.2.4 Cold rolled (strip).
under ⁄8 in. (9.5 mm) in width and 0.010 in. (0.25 mm) to
under ⁄16 in. (4.8 mm) in thickness.
8. Chemical Composition
8.1 The material shall conform to the chemical composition
4. Classification
specified in Table 1.
4.1 The alloys covered by this specification are classified by
nominal chemical composition, specifically by chromium
content, in two types:
TABLE 1 Chemical Requirements
4.1.1 Type I—18 % chromium (UNS K91800) and
NOTE 1—Round observed or calculated values to the nearest unit in the
4.1.2 Type II—28 % chromium (UNS K92801).
last right-hand place of figures used in expressing the limiting value, in
accordance with the rounding-off method of Practice E29.
5. Ordering Information
Composition, %
Element
5.1 Orders for material under this specification shall include Type I Type II
the following information:
Carbon, max 0.08 0.12
Manganese, max 1.00 1.00
5.1.1 Quantity (weight (Note 2) or number of pieces),
Silicon, max 0.75 0.75
5.1.2 Name of material (chromium-iron alloy),
Phosphorus, max 0.040 0.040
5.1.3 Type (Section 4), Sulfur, max 0.030 0.030
Chromium, nominal 18.0 28.0
5.1.4 Form (Section 3),
Nickel, max 0.50 0.50
5.1.5 Temper and finish (Section 7),
Nitrogen, max . 0.20
A
5.1.6 Permissible variations in dimensions for rod (Section Titanium .
Iron remainder remainder
13),
A
Five times the carbon content, minimum, and 0.60, max.
5.1.7 Certification if required (Section 21),
5.1.8 Packaging required (Section 22),
5.1.9 Dimensions (width, thickness, diameter, etc.),
5.1.10 ASTM designation: F256, and
8.2 Ladle Analysis—A ladle analysis of each heat of steel
5.1.11 Exceptions to the specification or special require-
shall be made by the manufacturer to determine the percent-
ments.
ages of the elements specified in Table 1. The analysis shall be
NOTE 2—The term “weight” is temporarily used in this standard
made from test castings made during the pouring of the heat.
because of established trade usage. The word is used to mean both “force”
The chemical composition thus determined shall conform to
and“ mass,” and care must be taken to determine which is meant in each
the requirements specified in Table 1.
case (SI unit for force = newton and for mass = kilogram).
8.3 Check Analysis—If check analysis is made by the
5.2 If possible, the intended end use of the item should be
purchaser, the chemical composition thus determined shall
given on the purchase order especially when the item is ordered
conform to the requirements specified in Table 1 subject to the
for a specific end use or uses. Such information will enable the
permissible tolerances of Table 2.
manufacturer to produce a material more satisfactory for the
purchaser’s process and product.
9. Chemical Analysis
NOTE 3—A typical ordering description is as follows: 2000 kg,
9.1 Chemical analysis shall be made in accordance with
chromium-iron alloy. Type II, wire, annealed, cold drawn, commercial
packaging, ⁄4 in. (6.4 mm) round by coil, ASTM F256, end use-redraw. Method E38 or equivalent methods.
F256 − 05 (2020)
TABLE 2 Check Analysis Tolerances TABLE 5 Permissible Variations in Size of Cold-Finished Round
Bars
Tolerances over maxi-
Element mum or under minimum
Permissible Variations from Specified
Specified Size, in.
A,B
limits, percentage points
Size, in. (mm)
(mm)
Carbon 0.01
Over Under
Manganese 0.03 Over ⁄2 (12.7) to 1 0.002 (0.05) 0.002 (0.05)
Phosphorus 0.005
(25.4), excl
Sulfur 0.005 1 (25.4) to 1 ⁄2 (38.1), 0.0025 (0.064) 0.0025 (0.064)
Silicon 0.05
excl
Nickel 0.03 1 ⁄2 (38.1) to 4 (101.6), 0.003 (0.08) 0.003 (0.08)
C
Nitrogen 0.01
incl
Titanium 0.05
A
Unless otherwise specified, size tolerances are over and under as shown in the
above table. When required, however, they may be specified all over and nothing
under, or all under and nothing over, or any combination of over and under, if the
total spread in size tolerance for a specified size is not less than the total spread
10. Thermal Expansion Requirements shown in the table.
B
When it is necessary to heat treat or heat treat and pickle after cold finishing, size
10.1 The material shall conform to the thermal expansion
tolerances are double those shown in the table.
C
Cold-finished bars over 4 in. (101.6 mm) in diameter are produced; size
requirements prescribed in Table 3.
tolerances for such bars have not been evolved.
A,B
TABLE 3 Thermal Expansion Requirements
TABLE 6 Permissible Variations in Length of Hot-Finished or
Mean Coefficient of Linear Thermal
Temperature A
Cold-Finished Bars
Expansion, µm/m ·°C
Range,° C
UNS K91800 UNS K92801
Permissible Variations in Length, in.
30 to 530 11.3 to 11.7 10.8 to 11.4 Specified Size of
(mm)
Rounds, Squares,
A
Typical thermal expansion data for the alloys covered by this specification are
For Lengths over
Hexagons, Octagons, For Lengths up to
given for information only in the Appendix.
12 ft (3.7 m), to 25 ft
and Widths of Flats, 12 ft (3.7 m), incl
B
These requirements apply to specimens heat treated prior to test in accordance
(7.6 m), incl
B
in. (mm)
with Section 16.
Over Under Over Under
1 3
To 2 (50.8), incl ⁄2 (12.7) 0 ⁄4 (19.0) 0
Over 2 (50.8) to 4 (101.6), incl ⁄4 (19.0) 0 1 (25) 0
Over 4 (101.6) to 6 (152.4), incl 1 (25) 0 1 ⁄4 (32) 0
11. Mechanical Property Requirements 1 1
Over 6 (152.4) to 9 (228.6), incl 1 ⁄4 (32) 0 1 ⁄2 (38) 0
Over 9 (228.6) to 12 (304.8), incl 1 ⁄2 (38) 0 2 (51) 0
11.1 The material shall conform to the mechanical property
A
The order should specify random lengths or specific lengths. When random
requirements prescribed in Table 4. Rockwell hardness shall be
lengths are ordered, the length tolerance is not less than 2 ft (609.6 mm). When
specific lengths are ordered, Table 8 or Table 9 shall apply.
B
The maximum width of bar flats is 10 in. (254.0 mm).
A
TABLE 4 Mechanical Property Requirements
Rockwell Tensile Strength,
Hardness (or max.
Thickness, in. (mm)
equivalent)
14. Workmanship, Finish, and Appearance
(max) ksi MPa
Under 0.015 (0.38) . 85 590
14.1 The material shall be commercially smooth and uni-
0.015 (0.38) to 1 (25.4), incl B85 . .
form in cross section, composition, and temper; it shall be free
Over 1 (25.4) B88 . .
of scale corrosion, cracks, seams, scratches, slivers, processing
A
Applicable to strip in the annealed condition only. All other mechanical properties
lubricants, and other defects as best commercial practice will
as agreed upon between purchaser and manufacturer.
permit.
15. Number of Tests and Retests
determined in accordance with Test Method E18.
15.1 Test specimens for thermal expansion and phase-
transformation requirements shall be selected on the basis of a
12. Transformation Requirements
minimum of one specimen per heat.
12.1 The material shall show no evidence of transformation
15.2 Test specimens for mechanical properties shall be
to martensite. For Type I alloy, the austenite formed during
selected on the basis of a minimum of one specimen per size,
heat treating will transform to martensite at or above room
each heat, each lot annealed or otherwise heat treated under the
temperature. The presence of austenite, as may be noted in
same conditions, and each lot with like processing.
Type II alloy, is acceptable if the thermal expansion require-
ment is met.
15.3 If any test specimen shows defective machining or
develops flaws, it may be discarded and another specimen
13. Permissible Variations in Dimensions
substituted.
13.1 Material furnished under this specification, except rod,
15.4 If the results of any test lot are not in conformance with
shall conform to the dimensional requirements of Tables 5-15.
the requirements of this specification, such lots may be
13.2 Permissible variations in dimensions for rod for re- retreated at the option of the manufacturer. The material shall
drawing or rerolling shall be as agreed upon between purchaser be acceptable if the results of tests on the retreated material are
and manufacturer. within the requirements of this specification.
F256 − 05 (2020)
TABLE 7 Permissible Variations in Straightness of Machine-Straightened Hot-Finished or Cold-Finished Bars
Measure the length of the maximum gap between the bar and a straightedge of appropriate length when the straightedge is laid along the length of the bar on its
concave side. Unless otherwise specified, hot-finished or cold-finished bars for machining purposes are furnished machine straightened to the following tolerances
(maximum gap length), in in. (mm):
Hot-Finished
1 1
⁄8 in. (3.2 mm) in any 5 ft (1.5 m), but may not exceed ⁄8 in. (3.2 mm)×
Cold-Finished
1 1 len
...