ASTM B691-18(2024)

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: B691 − 18 (Reapproved 2024)
Standard Specification for
Iron-Nickel-Chromium-Molybdenum Alloy (UNS N08367)
Rod, Bar, and Wire
This standard is issued under the fixed designation B691; 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 E8/E8M Test Methods for Tension Testing of Metallic Ma-
terials
1.1 This specification covers iron-nickel-chromium-
2 E29 Practice for Using Significant Digits in Test Data to
molybdenum alloy (UNS N08367) in the form of hot-finished
Determine Conformance with Specifications
and cold-finished rounds, squares, hexagons, octagons, and
E1473 Test Methods for Chemical Analysis of Nickel,
rectangles.
Cobalt, and High-Temperature Alloys
1.2 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
3. Terminology
conversions to SI units that are provided for information only
3.1 Definitions of Terms Specific to This Standard:
and are not considered standard.
3.1.1 The terms rod, bar, and wire, as used in this
1.3 The following safety hazards caveat pertains only to the
specification, are described as follows:
test methods portion, Section 12, of this specification: This
3.1.2 bar, n—hot-finished or cold-finished material of
standard does not purport to address all of the safety concerns,
round, square, hexagon, octagon, or rectangular solid section in
if any, associated with its use. It is the responsibility of the user
straight lengths.
of this standard to become familiar with all hazards including
3.1.3 rod, n—hot-finished material of round, square,
those identified in the appropriate Safety Data Sheet (SDS) for
hexagon, octagon, or rectangular solid section furnished in
this product/material as provided by the manufacturer, to
coils for subsequent cold drawing into finished products.
establish appropriate safety, health, and environmental
practices, and determine the applicability of regulatory limi-
3.1.4 wire, n—cold-finished material of round, square,
tations prior to use.
hexagon, octagon, or rectangle solid section furnished in coils.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Ordering Information
ization established in the Decision on Principles for the
4.1 It is the responsibility of the purchaser to specify all
Development of International Standards, Guides and Recom-
requirements that are necessary for material ordered to this
mendations issued by the World Trade Organization Technical
specification. Examples of such requirements include, but are
Barriers to Trade (TBT) Committee.
not limited to, the following:
2. Referenced Documents 4.1.1 Quantity (feet, meters, or number of pieces),
4.1.2 Form (rod, bar, wire),
2.1 ASTM Standards:
4.1.3 Name of material or UNS number,
B880 Specification for General Requirements for Chemical
4.1.4 Finish (see 8.2),
Check Analysis Limits for Nickel, Nickel Alloys and
4.1.5 Dimensions, including length,
Cobalt Alloys
4.1.6 Purchaser’s inspection, if required (Section 13),
4.1.7 ASTM designation and year of issue, and
This specification is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee 4.1.8 Samples for product analysis, if required.
B02.07 on Refined Nickel and Cobalt and Their Alloys.
Current edition approved April 1, 2024. Published May 2024. Originally
5. Chemical Composition
approved in 1981. Last previous edition approved in 2018 as B691 – 18. DOI:
10.1520/B0691-24.
5.1 The material shall conform to the composition limits
Designation established in accordance with ASTM E527 and SAE J1086,
specified in Table 1.
Practice for Numbering Metals and Alloys.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.2 If a product (check) analysis is made by the purchaser,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
the material shall conform to the permissible variations for
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. product (check) analysis in Specification B880.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B691 − 18 (2024)
TABLE 1 Chemical Requirements TABLE 3 Permissible Variations in Diameter Cold-Finished
Round Bars and Wire
Composition Limits, %
Element
A,B,C
Diameter tolerance, in. (mm)
N08367
Specified Diameter, in. (mm)
Plus and Minus
Carbon 0.030 max
Manganese 2.00 max
0.0030 (0.076) to 0.0048 (0.122), excl 0.0001 (0.003)
Silicon 1.00 max
0.0048 (0.122) to 0.0080 (0.203), excl 0.0002 (0.005)
Phosphorus 0.040 max
0.0080 (0.203) to 0.0120 (0.305), excl 0.0003 (0.008)
Sulfur 0.030 max
0.0120 (0.305) to 0.0240 (0.610), excl 0.0004 (0.010)
Chromium 20.00 to 22.00
0.0240 (0.610) to 0.0330 (0.838), excl 0.0005 (0.013)
Nickel 23.50 to 25.50
0.0330 (0.838) to 0.0440 (1.118), excl 0.0008 (0.020)
Molybdenum 6.00 to 7.00
0.0440 (1.118) to 0.3125 (7.938), excl 0.001 (0.03)
Nitrogen 0.18 to 0.25
0.3125 (7.938) to 0.5000 (12.700), excl 0.0015 (0.038)
A
Iron remainder
0.5000 (12.700) to 1.000 (25.4), excl 0.002 (0.05)
Copper 0.75 max 1.000 (25.40) to 1.500 (38.10), excl 0.0025 (0.06)
1.500 (38.10) to 4.000 (101.6), incl 0.003 (0.08)
A
Iron shall be determined arithmetically by difference.
A
Diameter tolerances are over and under as shown in the above table. Also,
rounds can be produced to tolerances all over and nothing under, or all under and
nothing over, or any combination of over and under, if the total spread in diameter
tolerance for a specified diameter is not less than the total spread shown in the
table.
6. Mechanical Properties and Other Requirements
B
The maximum out-of-round tolerance for round wire is one-half of the total size
tolerance shown in the above table.
6.1 The material shall conform to the mechanical property
C
When it is necessary to heat treat or heat treat and pickle after cold finishing, size
requirements specified in Table 2.
tolerances are double those shown in the table for sizes 0.0240 in. (0.610 mm) and
over.
7. Dimensions and Permissible Variations
7.1 Size:
7.1.1 Rounds—The permissible variations in size of cold-
7.4 Machining Allowances—When the surfaces of hot-
finished round shall be as given in Table 3. For hot-finished
finished material are to be machined, the allowances given in
round bars and rod, they shall be as given in Table 4.
Table 10 are recommended for normal machining operations.
7.1.2 Squares—The permissible variations in size of cold-
finished square bars shall be as given in Table 5. For hot-
7.5 Length:
finished square bars and rods, they shall be as given in Table 4.
7.5.1 Unless multiple, nominal, or cut lengths are specified,
7.1.3 Hexagons and Octagons—The permissible variations
random mill lengths shall be furnished.
in size of cold-finished hexagons and octagons shall be as
7.5.2 When bars are ordered in multiple lengths, ⁄4 in. (6.4
given in Table 5. For hot-finished bar and rod hexagons and
mm) will be allowed for each multiple cut, unless otherwise
octagons they shall be as given in Table 6.
specified.
7.1.4 Flats (Rectangles)—The permissible variations in
7.5.3 The permissible variations in length of hot or cold-
width and thickness of cold-finished flats shall be as given in
finished bars shall be as specified in Table 11 or Table 12
Table 7 for bars and for wire in Table 8. For hot-finished flat
depending upon whether or not the material is specified to be
bars and rods, the tolerances for width and thickness shall be as
machine-cut after straightening.
given in Table 9.
7.6 Ends:
7.2 Out-of-Round—Hot-finished rounds and cold-finished
7.6.1 Bars ordered to random or nominal lengths will be
rounds (except forging quality), all sizes, in straight lengths,
furnished with either cropped or saw-cut ends.
shall not be out-of-round by more than shown in Table 4 and
7.6.2 Bars ordered to cut lengths will be furnished with
Table 3.
square saw-cut or machine cut ends.
7.3 Corners—Cold-finished squares, rectangles, hexagons
7.7 Straightness:
and octagons will have equal angles and sharp corners.
7.7.1 The permissible variations in straightness of cold-
finished bars shall be as specified in Table 13.
7.7.2 The permissible variations in straightness of hot-
finished bars shall be as specified in Table 13.
TABLE 2 Mechanical Properties
Cold-Finished-
8. Workmanship, Finish, and Appearance
Annealed and
Forging Quality
Hot-Finished-
(All Sizes)
8.1 The material shall be uniform in quality and condition,
Annealed
(All Sizes) smooth, commercially straight or flat, and free of injurious
N08367 N08367 imperfections.
A
Tensile strength, min, 95 (655)
8.2 Finishes available include hot-rolled, hot rolled-
ksi (MPa)
A
annealed-descaled, cold-drawn, ground, turned, and machined.
Yield strength, 0.2 % 45 (310)
offset, min, ksi (MPa)
A
Elongation in 2 in. or 50 30
9. Sampling
mm, or 4D, min, %
A 9.1 Lot Definition:
No tensile properties are required on forging quality.
9.1.1 A lot for chemical analysis shall consist of one heat.
B691 − 18 (2024)
TABLE 4 Permissible Variations in Size of Hot-Finished Round and Square Bars and Rods
A
Permissible Variations from Specified Size, Out-of-Round or
B
Out-of-Square, in.
in. (mm)
Specified size, in. (mm)
(mm)
Plus Minus
1 5
⁄4 (6.4) to ⁄16 (7.9), incl 0.005 (0.13) 0.005 (0.13) 0.008 (0.20)
5 7
Over ⁄16 (7.9) to ⁄16 (11.1), incl 0.006 (0.15) 0.006 (0.15) 0.009 (0.23)
7 5
Over ⁄16 (11.1) to ⁄8 (15.9), incl 0.007 (0.18) 0.007 (0.18) 0.010 (0.25)
5 7
Over ⁄8 (15.9) to ⁄8 (22.2), incl 0.008 (0.20) 0.008 (0.20) 0.012 (0.30)
Over ⁄8 (22.2) to 1 (25.4), incl 0.009 (0.23) 0.009 (0.23) 0.013 (0.33)
Over 1 (25.4) to 1 ⁄8 (28.6), incl 0.010 (0.25) 0.010 (0.25) 0.015 (0.38)
1 1
Over 1 ⁄8 (28.6) to 1 ⁄4 (31.8), incl 0.011 (0.28) 0.011 (0.28) 0.016 (0.41)
1 3
Over 1 ⁄4 (31.8) to 1 ⁄8 (34.9), incl 0.012 (0.30) 0.012 (0.30) 0.018 (0.46)
3 1
Over 1 ⁄8 (34.9) to 1 ⁄2 (38.1), incl 0.014 (0.36) 0.014 (0.36) 0.021 (0.53)
1 1 1
Over 1 ⁄2 (38.1) to 2 (50.8), incl ⁄64 (0.4) ⁄64 (0.4) 0.023 (0.58)
1 1
Over 2 (50.8) to 2 ⁄2 (63.5), incl ⁄32 (0.8) 0 0.023 (0.58)
1 1 3
Over 2 ⁄2 (63.5) to 3 ⁄2 (88.9), incl ⁄64 (1.2) 0 0.035 (0.89)
1 1 1
Over 3 ⁄2 (88.9) to 4 ⁄2 (114.3), incl ⁄16 (1.6) 0 0.046 (1.17)
1 1 5
Over 4 ⁄2 (114.3) to 5 ⁄2 (139.7), incl ⁄64 (2.0) 0 0.058 (1.47)
1 1 1
Over 5 ⁄2 (139.7) to 6 ⁄2 (165.1), incl ⁄8 (3.2) 0 0.070 (1.78)
1 5
Over 6 ⁄2 (165.1) to 8 (203.2), incl ⁄32 (4.0) 0 0.085 (2.16)
A
Out-of-round is the difference between the maximum and minimum diameters of the bar, measured at the same cross section.
B
Out-of-square section is the difference in the two dimensions at the same cross section of a square bar, each dimension being the distance between opposite faces.
TABLE 5 Permissible Variations in Distance Between Parallel
Surfaces of Cold Finished Hexagonal, Octagonal, and Square
Bars and Wire
Permissible Variations from Specified
Size, in.
Specified Size, in. (mm) A
(mm)
Plus Minus
0.125 (3.18) to 0.3125 (7.938), excl 0 0.002 (0.05)
0.3125 (7.938) to 0.500 (12.70), excl 0 0.003 (0.08)
0.500 (12.70) to 1.000 (25.40), incl 0 0.004 (0.10)
Over 1 (25.40) to 2 (50.80), incl 0 0.006 (0.15)
Over 2 (50.80) to 3 (76.20), incl 0 0.008 (0.20)
Over 3 (76.20) 0 0.010 (0.25)
A
When it is necessary to heat treat or heat treat and pickle after cold finishing, size
tolerances are double those shown in the table.
TABLE 6 Permissible Variations in Size of Hot-Finished Hexagonal and Octagonal Bars and Rods
Permissible Variations from Specified Size, Maximum Difference,
Specified Sizes Measured Between Opposite in. (mm) in. (mm), 3 Measure-
Sides, in. (mm) ments for Hexagons
Plus Minus
Only
1 1
⁄4 to ⁄2 (6.4 to 12.7), incl 0.007 (0.18) 0.007 (0.18) 0.011 (0.28)
Over ⁄2 to 1 (12.7) to (25.4), incl 0.010 (0.25) 0.010 (0.25) 0.015 (0.38)
Over 1 (25.4) to 1 ⁄2 (38.1), incl 0.021 (0.53) 0.021 (0.53) 0.025 (0.64)
1 1 1 1
Over 1 ⁄2 (38.1) to 2 (50.8), incl ⁄32 (0.8) ⁄32 (0.8) ⁄32 (0.8)
1 3 3 3
Over 2 (50.8) to 2 ⁄2 (63.5), incl ⁄64 (1.2) ⁄64 (1.2) ⁄64 (1.2)
1 1 1 1 1
Over 2 ⁄2 (63.5) to 3 ⁄2 (88.9), incl ⁄16 (1.6) ⁄16 (1.6) ⁄16 (1.6)
9.1.2 Lots for mechanical testing shall consist of the mate- 9.2.2 Sampling for Mechanical Testing—Samples of the
rial from one heat, in the same condition (temper), and of the material to provide test specimens for mechanical testing shall
same specified size (
...