F1940 Test Method for Process Control Verification to
Prevent Hydrogen Embrittlement in Plated or Coated
Fasteners
F1941/F1941M Specification for Electrodeposited Coatings
on Mechanical Fasteners, Inch and Metric
F2329/F2329M Specification for Zinc Coating, Hot-Dip,
Requirements for Application to Carbon and Alloy Steel
Bolts, Screws, Washers, Nuts, and Special Threaded
Fasteners
2.2 ASME Standards:
4
B 1.1 Unified Screw Threads
B 1.2 Gages and Gaging for Unified Inch Screw Threads
B 1.13M Metric Screw Threads
B 18.2.2 Square and Hex Nuts
B 18.2.4.6M Metric Heavy Hex Nuts
B18.2.6M Metric Fasteners for Use in Structural Applica-
tions
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 Austenitic Grades—All grades with a prefix of “8” or
“9.”
3.1.2 Ferritic Grades—Grades 1, 2, 2H, 2HM, 3, 6, 6F, 7,
7M, 43, and 16.
3.1.3 Lot—Unless otherwise specified (see Discussion
below), a lot is the quantity of nuts of a single nominal size and
grade produced by the same manufacturing process.
3.1.3.1 Discussion—When Supplementary Requirement S5
is invoked on the purchase order, the following definitions of a
lot shall apply:
3.1.3.2 For Grade 8 Nuts—The quantity of all the nuts of a
single nominal diameter and grade made from the same heat of
steel and made by the same manufacturing process.
3.1.3.3 For All Other Grade Nuts—(see 8.2 and
8.1.2.1)—All the nuts of a single nominal diameter and grade
made from the same heat number and heat treated in the same
batch if batch-type heat treating equipment is used or heat
treated in the same continuous run of not more than 8 h under
the same conditions if continuous-type heat treating equipment
is used.
3.1.4 Type:
3.1.4.1 For Grade 8 Nuts—Variations within the grade
designated by a letter and differentiated by chemistry and by
manufacturing process.
3.1.4.2 For Grade 6 Nuts—Variations within the grade
designated by the letter F as differentiated by chemical addi-
tions made for machineability.
3.1.5 Series—The dimensional relationship and geometry of
the nuts as described in ASME B 18.2.2 for inch nuts, ASME
B 18.2.6M or ASME B 18.2.4.6M for metric nuts.
4. Ordering Information
4.1 The inquiry and order for bolting material and bolting
components under this specification shall include the following
as required to describe the items adequately:
4.1.1 Specification designation, year date, and grade, issue
date and revision letter,
4.1.2 Quantity, number of pieces,
4.1.3 Dimensions (see Section 9),
4.1.4 Options in accordance with 8.2.2.1,9.1,9.2,10.3, and
12, and
4.1.5 Supplementary Requirements, if any.
4.2 Coatings—Coatings are prohibited unless specified by
the purchaser (see Supplementary Requirements S7 and S8).
When coated nuts are ordered, the purchaser should take
special care to ensure that Appendix X2 is thoroughly under-
stood.
4.3 See Supplementary Requirement S3 for nuts to be used
in low temperature applications (Specification A320/A320M).
4.4 Proof Load Testing—See Supplementary Requirement
S9 for proof load testing of nuts manufactured to dimensions
and configurations other than those covered in Tables 3 and 4.
5. Common Requirements
5.1 Bolting material and bolting components supplied to
this specification shall conform to the requirements of Speci-
fication A962/A962M, of which nuts are considered bolting
components, as are bolts, studs, screws, and washers intended
for use in special service applications. These requirements
include test methods, finish, thread dimensions, marking,
certification, optional supplementary requirements, and others.
Failure to comply with the requirements of Specification
A962/A962M constitutes nonconformance with this specifica-
tion. In case of conflict between the requirements of this
specification and Specification A962/A962M, this specification
shall prevail.
6. Manufacture (Process)
6.1 Stainless steels for all types of Grade 6 and 8 nuts shall
be made by one of the following processes:
6.1.1 Electric-furnace (with separate degassing and refining
optional),
6.1.2 Vacuum induction furnace, or
6.1.3 Either of the above followed by electroslag remelting,
or consumable-arc remelting.
6.2 The steel producer shall exercise adequate control to
eliminate excessive unhomogeneity, nonmetallics, pipe,
porosity, and other defects.
6.3 Grades 1 and 2 nuts shall be hot or cold forged, or shall
be machined from hot-forged, hot-rolled, or cold-drawn bars.
6.3.1 All Grade 1 and 2 nuts shall be stress-relieved at a
temperature of at least 1000 °F [538 °C] after forming or
machining from bar with the following exceptions:
6.3.1.1 Nuts made by hot forging.
6.3.1.2 Nuts machined from hot-forged or hot-rolled bar.
6.3.1.3 Nuts machined from hot-forged/hot-rolled and cold-
finished (max 10 % reduction in area) bar.
4
Available from American Society of Mechanical Engineers (ASME), ASME
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
A194/A194M − 24
2