Designation: A31 − 14
Standard Speciﬁcation for
Steel Rivets and Bars for Rivets, Pressure Vessels
This standard is issued under the ﬁxed designation A31; 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.
1.1 This speciﬁcation
covers steel rivets for use in boilers
and pressure vessels and steel bars for use in the manufacture
1.2 Two grades are covered:
1.2.1 Grade A—Bars having a yield point of 23 000 psi
(160 MPa) minimum with carbon 0.18% maximum.
1.2.2 Grade B—Bars having a yield point of 29 000 psi
(200 MPa) minimum with carbon 0.28 % maximum.
1.2.3 Rivets are manufactured from the applicable bar
1.3 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.
2. Referenced Documents
2.1 ASTM Standards:
A29/A29M Speciﬁcation for General Requirements for Steel
Bars, Carbon and Alloy, Hot-Wrought
A370 Test Methods and Deﬁnitions for Mechanical Testing
of Steel Products
A751 Test Methods, Practices, and Terminology for Chemi-
cal Analysis of Steel Products
F1470 Practice for Fastener Sampling for Speciﬁed Me-
chanical Properties and Performance Inspection
B18.1.1 Small Solid Rivets
Inch Nominal Diameter and
B18.1.2 Large Rivets
Inch Nominal Diameter and Larger
B18.24 Part Identifying Number (PIN) Code System Stan-
dard for B18 Fastener Products
3. Ordering Information
Orders for rivets and bars under this speciﬁcation shall
3.1.1 Speciﬁcation designation and date of issue,
3.1.2 Quantity—Number of pieces for rivets and weight for
3.1.3 Name of product and grade (A or B),
3.1.4 Size (diameter and length),
3.1.5 Rivet head type,
3.1.6 If inspection at point of manufacture is required,
3.1.7 Certiﬁcation, if required (Section 14), and
Additional testing or special requirements, if required.
3.1.9 For establishment of a part identifying system, see
NOTE 1—A typical ordering description is: ASTM A31 – 82, 10 000
pieces, steel rivets Grade A,
by 2 in., button head, test reports required.
4. Materials and Manufacture
4.1 The steel shall be made by any of the following
processes: open-hearth, electric-furnace, or basic-oxygen.
4.2 Rivets shall be manufactured from rivet bars conform-
ing to the applicable grade ordered.
4.3 Rivets shall be manufactured by hot- or cold-heading.
4.4 Bars shall be furnished as rolled and not pickled, blast
cleaned, or oiled. At producer’s option, bars may be cleaned for
inspection or cold drawn.
5. Chemical Composition
5.1 The steel shall conform to chemical composition pre-
scribed in Table 1.
Analysis—An analysis of each heat of steel shall be
made by the bar manufacturer to determine for Grades A and B
the percentages of carbon, manganese, phosphorus, and sulfur.
This analysis shall be made from a test ingot taken during the
pouring of the heat. The chemical composition thus determined
shall be reported to the purchaser or his representative and shall
conform to the requirements for heat analysis in accordance
with Table 1.
This speciﬁcation is under the jurisdiction of ASTM Committee F16 on
Fasteners and is the direct responsibility of Subcommittee F16.02 on Steel Bolts,
Rivets and Washers.
Current edition approved April 1, 2014. Published April 2014. Originally
approved in 1976. Last previous edition approved in 2009 as A31 – 04(2009). DOI:
For ASME Boiler and Pressure Vessel Code applications see related Speciﬁ-
cation SA-31 in Section II of that Code.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at email@example.com. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available from American Society of Mechanical Engineers (ASME), ASME
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
*A Summary of Changes section appears at the end of this standard
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5.3 Product Analysis—An analysis may be made by the
purchaser from ﬁnished materials representing each heat. The
chemical composition thus determined shall conform to the
requirements for product analysis prescribed in
5.4 Application of heats of steel to which bismuth,
selenium, tellurium, or lead has been intentionally added shall
not be permitted.
5.5 Chemical analyses shall be performed in accordance
with Test Methods, Practices, and Terminology
6. Mechanical Properties
6.1 Rivet Bend Tests:
6.1.1 The rivet shank of Grade A steel shall stand being bent
cold through 180° ﬂat on itself, as shown in
Fig. 1, without
cracking on the outside of the bent portion.
6.1.2 The rivet shank of Grade B steel shall stand being bent
cold through 180° without cracking on the outside of the bent
portion in accordance with
6.2 Rivet Flattening Tests—The rivet head shall stand being
ﬂattened, while hot, to a diameter 2
times the diameter of the
shank, as shown in Fig. 2, without cracking at the edges.
6.3 Bar Tensile Properties—Bars shall conform to the ten-
sile requirements in accordance with
6.4 Bar Bend Tests:
6.4.1 The test specimen for Grade A steel bars shall stand
being bent cold through 180° ﬂat on itself without cracking on
the outside of the bent portion.
6.4.2 The test specimen for Grade B steel bars shall stand
being bent cold through 180° without cracking on the outside
of the bent portion to an inside diameter which shall have a
relation to the diameter of the specimen in accordance with
7. Dimensions, Mass, and Permissible Variations
7.1.1 The dimensions of rivets shall conform to B18.1.2 for
nominal diameters in. and larger and B18.1.1 for nominal
in. and less.
7.1.2 Snap gage measurement shall be made at the point of
minimum diameter, but it is not required that the rivet shall turn
completely in the gage. Measurements of the maximum toler-
ance shall be made with a ring gage, all rivets to slip full to the
head in the gage of the required size for the various diameters.
7.2 Bars—The diameter of hot-ﬁnished rivet bars shall not
vary from the size speciﬁed by more than the amounts in
8. Workmanship, Finish, and Appearance
8.1 Rivets—The ﬁnished rivets shall be true to form,
concentric, and free of injurious defects.
8.2.1 Bars shall be free of visible pipe, undue segregation,
and injurious surface imperfections.
8.2.2 Surface Finish—The bars shall have a commercial
hot-wrought ﬁnish obtained by conventional hot rolling. See
4.4 for producer’s descaling option.
TABLE 1 Chemical Requirements
Grade A Grade B
Carbon, max, % 0.18 0.18 0.28 0.31
Manganese, % 0.30–0.60 0.27–0.63 0.30–0.80 0.27–0.83
Phosphorus, max, % 0.040 0.048 0.040 0.048
Sulfur, max, % 0.050 0.058 0.050 0.058
FIG. 1 Bend Test of Rivet
TABLE 2 Bend Requirements, Rivets
Rivet Shank, in.
Ratio of Bend Diameter to Diameter of
Grade A Grade B
FIG. 2 Flattening Test of Rivet
TABLE 3 Tensile Requirements, Bars
Grade A Grade B
Tensile strength, psi (MPa) 45 000–58 000
58 000–68 000
Yield point, min, psi (MPA) 23 000 (160) 29 000 (200)
Elongation in 8 in. or 200
mm, min, %
Elongation in 2 in. or 50
mm, min, %
TABLE 4 Bend Requirements, Bars
Specimen Diameter, in.
Ratio of Bend Diameter to Diameter of
Grade A Grade B
9. Number of Tests and Retests
9.1 Rivets—Sampling for rivet bend and rivet ﬂattening tests
shall be in accordance with Guide
F1470, detection process.
9.2.1 Two tension tests shall be made from each heat, unless
the ﬁnished material from a heat is less than 50 tons (45 Mg),
when one tension test will be sufficient. However, for material
2 in. (51 mm) and under in thickness, when the material from
one heat differs
in. (9.5 mm) or more in thickness, one
tension test shall be made from both the thickest and the
thinnest material rolled regardless of the weight represented.
Each test shall conform to the speciﬁed requirements.
9.2.2 Retests on bars may be made in accordance with
10. Specimen Preparation
10.1 Rivets—Rivets shall be tested in their full-size ﬁnished
10.2.1 Test specimen selection and preparation shall be in
accordance with Speciﬁcation
A29/A29M and Test Methods
and Deﬁnitions A370.
10.2.2 Tension and bend test specimens for rivet bars which
have been cold drawn shall be normalized before testing.
11. Test Methods
11.1 Rivets—Rivet bend and ﬂattening tests shall be in
accordance with the manufacturers standard test procedures.
11.2 Bars—Tension and bend tests shall be conducted in
accordance with Test Methods and Deﬁnitions
especially Supplement I thereof, on steel bar products.
12.1 If the testing described in Section
9 is required by the
purchaser, it shall be speciﬁed in the inquiry and contract or
12.2 The inspector representing the purchaser shall have
free entry at all times, while work on the contract of the
purchaser is being performed, to all parts of the manufacturer’s
works that concern the manufacture of the material ordered.
The manufacturer shall afford the inspector all reasonable
facilities, without charge, to satisfy him that the material is
being furnished in accordance with this speciﬁcation. All tests
(except product analysis) and inspection shall be made at the
place of manufacture prior to shipment, unless otherwise
speciﬁed, and shall be so conducted as not to interfere
unnecessarily with the operation of the works.
13. Rejection and Rehearing
13.1 Rivets—Rivets that fail to conform to the requirements
of this speciﬁcation may be rejected. Rejection should be
reported to the producer or supplier promptly and in writing. In
case of dissatisfaction with the results of the test, the producer
or supplier may make claim for a rehearing.
13.2 Bars—Rejection and rehearing shall be in accordance
14.1 When speciﬁed on the purchase order, the manufac-
turer shall furnish certiﬁcation that the material was manufac-
tured and tested in accordance with this speciﬁcation together
with a report of the heat analysis (
5.2) and mechanical property
test results (Section 6) as applicable to the product ordered. The
report shall include the manufacturer’s name, ASTM
designation, grade, heat number (bars only), and authorized
15.1 The party responsible for the fastener shall be the
organization that supplies the fastener to the purchaser.
16. Packaging and Package Marking
16.1 Rivets—Rivets shall be properly packed and marked to
prevent damage and loss during shipment.
16.2 Bars—Bars shall be packed and marked in accordance
17.1 bars; carbon steel; pressure vessel rivets; rivets; steel
TABLE 5 Permissible Variations in the Size of Hot-Rolled Rounds
Speciﬁed Size, in.
Variations, from Size, in.
and under 0.005 0.005 0.008
, incl 0.006 0.006 0.009
, incl 0.007 0.007 0.010
, incl 0.008 0.008 0.012
to 1, incl 0.009 0.009 0.013
Over 1 to 1
, incl 0.010 0.010 0.015
, incl 0.011 0.011 0.016
, incl 0.012 0.012 0.018
, incl 0.014 0.014 0.021
Out-of-round is the difference between the maximum and minimum diameters of
the bar, measured at the same cross section.
S1.1 The certiﬁcation requirements in
14.1 are mandatory.
SUMMARY OF CHANGES
Committee F16 has identiﬁed the location of selected changes to this standard since the last issue
(A31 –04(2009)) that may impact the use of this standard.
(1) Revised Sections
1.2.1, and 3.1.1, and Table 1 and Table 3. (2) Added Supplementary Requirement S1.
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