ASTM F3043-15

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: F3043 − 14 F3043 − 15
Standard Specification for
“Twist Off” Type Tension Control Structural Bolt/Nut/Washer
Assemblies, Alloy Steel, Heat Treated, 200 ksi Minimum
1,2
Tensile Strength
This standard is issued under the fixed designation F3043; 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.
ε NOTE—Section 1.7 and the title of Annex A1 were editorially corrected in February 2015.
1. Scope
1.1 This specification covers one style of heat treated, alloy steel, tension control bolt-nut-washer assemblies, also referred to
as “sets,” having a tensile strength of 200 to 215 ksi. These assemblies are capable of developing a minimum predetermined tension
when installed by applying torque to the nut, while at the same time applying a counter torque to separate the spline end from the
body of the bolt using an appropriate spline drive installation tool.
1.2 An assembly consists of a tension control bolt with spline end, nut and washer covered by this specification.
1.3 The assemblies are available with round heads described in Section 10, in sizes 1 in. to 1 ⁄4 in. inclusive.
1.4 The fastener assemblies are intended for use in structural connections in the following environmental conditions:
1.4.1 Interiors, normally dry, including interiors where structural steel is embedded in concrete, encased in masonry or protected
by membrane or noncorrosive contact type fireproofing.
1.4.2 Interiors and exteriors, normally dry, under roof, where the installed assemblies are soundly protected by a shop-applied
or field-applied coating to the structural steel system.
1.5 The fastener assemblies are not intended for use in structural connections in the following environments, with or without
protection by a shop-applied or field-applied coating to the structural steel system:
1.5.1 Exteriors not under roof.
1.5.2 Chemical environments in which strong concentrations of highly corrosive gases, fumes, or chemicals, either in solution
or as concentrated liquids or solids, contact the fasteners or their protective coating.
1.5.3 Heavy industrial environments severe enough to be classified as a chemical environment as described in 1.5.2.
1.5.4 Condensation and high humidity environments maintaining almost continuous condensation, including submerged in
water and soil.
1.5.5 Cathodically protected environments, in which current is applied to the structural steel system by the sacrificial anode
method or the DC power method.
1.6 Units—The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included
in this standard.
1.7 The following precautionary statement pertains only to the test method portions, Section 13, Section 14 and Annex A2 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.
This specification is under the jurisdiction of ASTM Committee F16 on Fasteners and is the direct responsibility of Subcommittee F16.02 on Steel Bolts, Nuts, Rivets
and Washers.
Current edition approved Oct. 1, 2014Nov. 15, 2015. Published December 2014February 2016. Originally approved in 2014. last previous edition approved in 2014 as
ɛ1
F3043–14 . DOI: 10.1520/F3043-14E01.10.1520/F3043-15.
The "Twist Off" Type Tension Control Structural Bolt/Nut/Washer Assemblies, Alloy Steel, Heat Treated, 200 ksi Minimum Tensile Strength of Grade 2 is covered by
US patent number 7 070 664, July 4, 2006. Interested parties are invited to submit information regarding the identification of an alternative(s) to this patented item to the
ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3043 − 15
2. Referenced Documents
2.1 ASTM Standards:
A751 Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
E709 Guide for Magnetic Particle Testing
E1444E1444/E1444M Practice for Magnetic Particle Testing
F606F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners,
Washers, and Rivets (Metric) F0606_F0606M Direct Tension Indicators, and Rivets
F788/F788MF788 Specification for Surface Discontinuities of Bolts, Screws, and Studs, Inch and Metric Series
F812/F812MF812 Specification for Surface Discontinuities of Nuts, Inch and Metric Series
F1470 Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
F1789 Terminology for F16 Mechanical Fasteners
F2328 Test Method for Determining Decarburization and Carburization in Hardened and Tempered Threaded Steel Bolts,
Screws, Studs, and Nuts
2.2 ASME Standards:
B1.3 Screw Thread Gaging Systems for Acceptability: Inch and Metric Screw Threads (UN, UNR, UNJ, M, and MJ)
B1.15 Unified Inch Screw Threads (UNJ Thread Form)
B18.2.6 Fasteners for Use in Structural Applications
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 The definition of terms used in this specification shall be as specified in Terminology F1789, unless otherwise defined
herein.
3.1.2 component lot, n—component lot, for the purpose of assigning an identification number and from which test samples shall
be selected, shall consist of all tension control bolts, all nuts or all washers processed essentially together through all operations
to the shipping container, of which each component has the following common characteristics: heat number (mill heat); nominal
dimensions (size), grade, and heat treatment lot.
3.1.3 manufacturer, n—entity that assembles, lubricates, tests, and certifies compliance with this specification.
4. Ordering Information
4.1 Orders for assemblies shall include the items of information below. Optional items not on the purchase order shall be
considered as not being required (see Note 1):
4.1.1 Quantity of assemblies,
4.1.2 Size, including nominal tension control bolt diameter, bolt length (without the spline end), and thread pitch,
4.1.3 Grade, that is, Grade 1 or Grade 2,
4.1.4 Name of product, that is, twist off type tension control bolt/nut/washer assemblies ,
4.1.5 ASTM designation and year of publication, and
4.1.6 Special requirements, if required.
NOTE 1—A typical order description follows: 1000 assemblies, 1 ⁄4 diameter by 4 in. long with 7 threads per in., Grade 2, Tension Control
Bolt/Nut/Washer Assemblies, Round Heads, ASTM F3043.
5. Materials and Manufacture
5.1 Tension Control Bolt/Nut/Washer Assemblies:
5.1.1 The assemblies shall be of the round head style.
5.1.2 The assemblies shall consist of one tension control bolt, with one nut and one washer assembled on the bolt and the nut
threaded on the bolt a minimum of one turn.
5.1.3 All nuts shall be heavy hex.
5.1.4 All washers used in the assembly shall be circular and through hardened.
5.1.5 Protective Coatings—The bolts, nuts and washers shall not be coated by hot dip zinc coating, mechanical deposition,
electroplating, dip-spin, dip-drain, or spray methods with zinc or other metallic coatings.
NOTE 2—Protective coatings may be shop-applied or field-applied to installed assemblies.
5.1.6 Lubrication:
5.1.6.1 The assemblies shall be lubricated by the manufacturer to meet the Assembly Lot Tension requirements in Section 9.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. 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://
www.asme.org.
F3043 − 15
5.1.6.2 Lubrication other than that applied by the manufacturer shall not be permitted, as the type and amount of lubrication
is critical to meeting the minimum clamping forces specified.
5.1.7 Secondary Processing—Secondary processing shall not be permitted to an assembly lot.
5.2 Tension Control Bolts:
5.2.1 Heat Treatment:
5.2.1.1 If phosphate coating has been applied to the raw material, the residual phosphate shall be removed prior to heat
treatment, and a record of the application of this processing step shall be maintained by the processor.
5.2.1.2 Tension control bolts shall be heat treated by quenching in oil from the austenitizing temperature and then tempering
by reheating to a temperature not less than 1000°F.
5.2.2 Thread—The threads of tension control bolts shall be rolled.
5.3 Nuts:
5.3.1 Nuts shall be made by hot forming.
5.3.2 Nuts shall be heat treated by quenching in a liquid medium from a temperature above the transformation temperature and
tempering at a temperature of at least 850°F.
5.3.3 Threads shall be formed by tapping.
5.4 Washers:
5.4.1 Washers shall be through hardened.
6. Chemical Composition
6.1 Tension Control Bolts:
6.1.1 Steel for tension control bolts shall be made by the basic oxygen process.
6.1.2 Bolts shall be alloy steel conforming to the chemical composition in Table 1.
6.1.3 Product analysis may be made by the purchaser on finished bolts representing each lot. The chemical composition shall
conform to the requirements in Table 1, Product Analysis.
6.1.4 Heats of steel to which bismuth, selenium, tellurium, lead or boron has been intentionally added shall not be permitted.
6.1.5 Compliance with 6.1.4 shall be based on certification that heats of steel having any of the listed elements intentionally
added were not used to produce the bolts.
6.1.6 Chemical analysis shall be performed in accordance with Test Methods, Practices, and Terminology A751.
6.2 Nuts:
6.2.1 Steel for nuts shall be made by the basic oxygen or electric-furnace process.
6.2.2 Nuts shall conform to the chemical composition in Table 2.
6.2.3 Product analysis may be made by the purchaser on finished nuts representing each lot. The chemical composition shall
conform to the requirements in Table 2, Product Analysis.
6.2.4 Chemical analysis shall be performed in accordance with Test Methods, Practices, and Terminology A751.
6.3 Washers:
6.3.1 Steel used in the manufacture of washers shall be produced by the basic-oxygen or electric-furnace process.
6.3.2 Washers shall conform to the chemical composition specified in Table 3.
6.3.3 Product analysis may be made by the purchaser on finished washers representing each lot. The chemical composition shall
conform to the requirements in Table 3, Product Analysis.
6.3.4 Chemical analysis shall be performed in accordance with Test Methods, Practices, and Terminology A751.
A
TABLE 1 Chemical Requirements for Tension Control Bolts
Composition, %
Element Heat Analysis, % Product Analysis, %
min max min max
Carbon 0.38 0.42 0.36 0.44
Manganese 0.40 0.60 0.37 0.63
Phosphorus . . . 0.01 . . . 0.015
Sulfur . . . 0.01 . . . 0.015
Silicon . . . 0.10 . . . 0.12
Chromium 1.20 1.40 1.15 1.45
Molybdenum 0.60 0.80 0.57 0.83
Vanadium 0.30 0.40 0.27 0.43
A
Aluminum, cobalt, niobium / columbium, nickel, titanium, tungsten, zirconium, or
any other alloying elements may be added to obtain the desired alloying effect.
F3043 − 15
TABLE 2 Chemical Requirements for Nuts
Composition, %
Element Heat Analysis, % Product Analysis, %
min max min max
Carbon 0.30 0.48 0.28 0.50
Manganese 0.60 0.90 0.57 0.93
Silicon 0.15 0.35 0.13 0.37
Phosphorus . . . 0.050 . . . 0.055
Sulfur . . . 0.050 . . . 0.055
TABLE 3 Chemical Requirements for Washers
Composition, %
Element Heat Analysis, % Product Analysis, %
min max min max
Carbon 0.42 0.48 0.40 0.50
Manganese 0.60 0.90 0.57 0.93
Silicon 0.15 0.35 0.13 0.37
Phosphorus . . . 0.030 . . . 0.035
Sulfur . . . 0.030 . . . 0.035
7. Mechanical Property Requirements for Tension Control Bolts, Nuts and Washers
7.1 Tension Control Bolts:
7.1.1 Hardness—Bolts shall conform to the hardness specified in Table 4.
7.1.2 Tensile Properties:
7.1.2.1 Bolts shall be wedge tested full size and shall conform to the minimum and maximum wedge tensile load, and proof
load or alternative proof load specified in Table 5. The load achieved during proof load testing shall be equal to or greater than
the specified proof load.
7.1.2.2 When the length of the bolt makes full size testing impractical, machined specimens shall be tested and shall conform
to the requirements specified in Table 6. When bolts are tested by both full size and machined specimen methods, the full size test
shall take precedence.
7.1.2.3 For bolts on which both hardness and tension tests are performed, acceptance based on tensile requirements shall take
precedence in the event of low hardness readings.
7.1.2.4 Sample bolts shall be used to verify that the alloy steel material and heat treatment provides resistance to Environmental
Hydrogen Embrittlement (EHE), in accordance with the requirements of Annex A2.
7.2 Nuts:
7.2.1 Nuts shall conform to the surface hardness specified in Table 7.
7.2.2 Nuts shall withstand the proof load stress specified in Table 8.
7.3 Washers:
7.3.1 Washers shall conform to the core hardness specified in Table 9.
8. Assembly Lot Tension Test
8.1 Purpose—The assembly lot tension test shall be performed on fastener assemblies to determine the ability of the assembly
to provide the required minimum tension.
8.2 Requirement—Full size completed assemblies tested in accordance with 14.4 shall develop a bolt tension when the spline
end is separated from the bolt conforming to the requirements in Table 10, Column 1.
9. Carburization/Decarburization of Bolts
9.1 This test is intended to evaluate the presence or absence of carburization and decarburization as determined by the difference
in microhardness near the surface and core.
9.2 Requirements:
9.2.1 Carburization—The assemblies shall show no evidence of a carburized surface when evaluated in accordance with 14.1.4.
TABLE 4 Hardness Requirements for Tension Control Bolts
Rockwell C
Bolt Size, in. Bolt Length, in.
min max
1 to 1 ⁄4, incl all 38 45
F3043 − 15
TABLE 5 Tensile Requirements for Full Size Tension Control
Bolts
C
Tensile Load, lbf
Bolt Size, Stress Area,
2 A,B
Threads per in. in.
min max
Column 1 Column 2 Column 3 Column 4
Grade 1
1 in. - 8 0.615 123 100 132 300
1 ⁄8 in. - 7 0.776 155 200 166 800
1 ⁄4 in. - 7 0.983 196 700 211 400
Grade 2
1 in. - 8 0.640 128 000 137 700
1 ⁄8 in. - 7 0.808 161 600 173 600
1 ⁄4 in. - 7 1.019 203 800 219 100
A
The stress area for Grade 1 is calculated as:
A = 0.7854 [0.5 (d + d )]
s 3 max 2 max
B
The stress area for Grade 2 is calculated in accordance with Annex A1.
C
Loads tabulated are based on the following:
Bolt Size, in. Column 3 Column 4
1 to 1 ⁄4 200 000 psi 215 000 psi
TABLE 6 Tensile Strength Requirements for Specimens
Machined from Bolts
Yield
Nominal Elongation
Tensile Strength, ksi
Strength Reduction
Bolt in 2 in. or
(0.2 % of Area,
Diameter, 50 mm,
offset), min, %
min max
in. min, %
min, ksi
1 to 1 ⁄4, 200 215 180 14 40
incl
TABLE 7 Hardness Requirements for Nuts
Surface Hardness, Rockwell C
Bolt Size, in.
min max
1 to 1 ⁄4, incl 30 40
TABLE 8 Proof Load Requirements for Nuts
Nominal Size - Stress Area, A , Proof Load Nut Proof Load,
s
2 A,B C
Threads per in. in. Stress, ksi lbf
Grade 1
1 in. - 8 0.615 200 123 100
1 ⁄8 in. - 7 0.776 200 155 200
1 ⁄4 in. - 7 0.983 200 196 700
Grade 2
1 in. - 8 0.640 200 128 000
1 ⁄8 in. - 7 0.808 200 161 600
1 ⁄4 in. - 7 1.019 200 203 800
A
The stress area for Grade 1 is calculated as:
A = 0.7854 [0.5 (d + d )]
s 3 max 2 max
B
The stress area for Grade 2 is calculated in accordance with Annex A1.
C
To determine nut proof load in pounds, multiply the appropriate nut proof load
stress by the tensile stress area of the thread.
TABLE 9 Core Hardness Requirements for Washers
Rockwell C
Min 40 Max 45
9.2.2 Decarburization—Hardness value differences shall not exceed the requirements set forth for decarburization in Test
Method F2328 for class ⁄4 H materials when evaluated in accordance with 14.1.4.
10. Dimensions of Tension Control Bolts, Nuts, and Washers
10.1 Tension Control Bolts:
10.1.1 Tension control bolts shall be furnished with round heads.
F3043 − 15
TABLE 10 Assembly Lot Tension Test Requirements
Grade 1 Grade 2
Manufacturers Manufacturers
Tension Tension
Acceptance Acceptance
Bolt Size, lbs, min (for lbs, min (for
Test Test
in. information information
Tension, Tension,
B B
only) only)
A A
lbs, min lbs, min
Column 1 Column 2 Column 1 Column 2
1 90 000 86 000 94 000 90 000
1 ⁄8 114 000 109 000 119 000 113 000
1 ⁄4 145 000 138 000 150 000 143 000
A
The manufacturer’s acceptance test tension values are 5 % higher than the
tension in Column 2 and are rounded to the nearest 1000 lbs (kip).
B
The values in Column 2 are equal to 70 % of the specified minimum tensile
strength for tests of full size F3043 bolts tested in axial tension and are rounded to
the nearest 1000 lbs (kip).
10.1.2 The head, body and spline dimensions shall conform to the dimensional requirements in Table 11, and ASME B18.2.6
section 6.5 for straightness, 6.6 for true position of head, and 6.11 for incomplete thread diameter.
10.1.3 Threads:
10.1.3.1 The thread length shall be as specified in Table 11.
10.1.3.2 Threads for Grade 1 shall have the coarse series, class 2A UNJ thread as specified in ASME B1.15.
10.1.3.3 Threads for Grade 2 shall be as specified in Annex A1, and shall have Class 2A tolerances as calculated in section 4.3.3
of ASME B1.15.
10.1.3.4 The gauging limit for bolts shall be verified during manufacture. In case of purchaser/supplier controversy over thread
compliance, System 21 of ASME B1.3 shall be used for referee purposes.
10.2 Nuts:
10.2.1 The dimensions for nuts shall conform to the dimensional requirements in Table 12, and ASME B18.2.6, sections 3.1.4,
3.1.5 and 3.1.6.
10.2.2 Threads for nuts for Grade 1 shall be coarse series, class 2B UNJ thread as specified in ASME B1.15.
10.2.3 Threads for nuts for Grade 2 shall be as specified in Annex A1, with UNJ thread and without root radius, and and shall
have Class 2B tolerances as calculated in section 4.3.4 of ASME B1.15.
10.3 Washers:
10.3.1 All circular washers shall conform to the dimensions shown in Table 13.
10.3.2 The deviation from flatness shall not exceed 0.010 in. per inch as the maximum deviation from a straight edge placed
on the cut side.
10.3.3 Circular runout of the outside diameter with respect to the hole shall not exceed 0.030 FIM.
10.3.4 Burrs shall not project above the immediately adjacent washer surface more than 0.010 in.
11. Workmanship, Finish, and Appearance
11.1 For tension control bolts, the allowable limits, inspection, and evaluation of the surface discontinuities, quench cracks,
forging cracks, head bursts, shear bursts, seams, folds, thread laps, voids, tool marks, nicks, and gouges shall be in accordance with
Specification F788/F788MF788.except that threads shall have no laps at the root or on the flanks located below the pitch line, when
inspected in accordance with Specification F788, S1.2.
11.2 For the nut component, the allowable limits, inspection, and evaluation of surface discontinuities, quench cracks, forging
cracks, inclusion cracks, bursts, shear bursts, seams, voids, tool marks, nicks and gouges shall be in accordance with Specification
F812/F812MF812.
11.3 Washers shall be free of excess mill scale and foreign material on bearing surfaces.
12. Magnetic Particle Inspection for Tension Control Bolt Longitudinal Discontinuities and Transverse Cracks
12.1 Requirements:
12.1.1 Each sample representative of the bolt lot shall be magnetic particle inspected for longitudinal discontinuities and
transverse cracks.
12.1.2 The lot, as represented by the sample, shall be free from nonconforming bolts, as defined in Specification
F788/F788MF788, when inspected in accordance with Section 12.2.
12.2 Inspection Procedure:
12.2.1 The inspection sample shall be selected at random from each bolt lot in accordance with 13.4.2.4 and examined for
longitudinal discontinuities and transverse cracks in the threads, body, fillet, and underside of the head.
F3043 − 15
TABLE 11 Tension Control Bolts
NOTE 1—The bolt length L shall be the distance measured parallel to the axis of the bolt from the bearing surface of the head to the center point of
the groove through which shear will occur. Bolts are normally supplied in ⁄4 in. length increments.
NOTE 2—For bolts 1 in. diameter with length up to 6 in., inclusive, length tolerance is ⁄16 in. underlength. For longer 1 in. diameter bolts and other
diameters, length tolerance is ⁄4 in. underlength.
1 1
Nominal Size 1 1 ⁄8 1 ⁄4
A
Basic Diameter, E, in. 1.000 1.125 1.250
Full-Size Body Diameter E, in. max 1.022 1.149 1.277
min 0.976 1.098 1.223
B
Head Height, H, in. nom 39/64 11/16 25/32
max 0.643 0.738 0.824
min 0.607 0.678 0.759
C
1 3 1
Head Diameter, D, in. nom 2 ⁄8 2 ⁄8 2 ⁄2
max 2.158 2.375 2.589
D
1 1
Bearing Diameter, C, in. nom 2 2 ⁄4 2 ⁄2
min 1.771 1.991 2.224
3 3 7
Radius of Fillet, R, in. nom ⁄32 ⁄32 ⁄64
max 0.110 0.110 0.138
min 0.087 0.087 0.098
1 5
Transition Body Diameter, E , in. nom 59/64 1 ⁄32 1 ⁄32
R
max 0.933 1.046 1.171
min 0.917 1.030 1.155
Body Transition Length, Y , in. nom 0.305 0.354 0.354
max 0.394 0.450 0.450
min 0.207 0.244 0.244
1 9 9
Reduced Body Length, L , in. nom ⁄2 ⁄16 ⁄16
R
max 0.625 0.715 0.715
min 0.375 0.429 0.429
E
Transition Thread Length Y , in. Ref 0.31 0.34 0.34
F
Thread Length, L , in. Ref 2.049 2.322 2.322
T
G
Maximum center of groove to First Fully Formed Thread, U, in. Max 0.455 0.500 0.500
H
Spline Length, L , in. Ref 0.80 0.90 0.984
s
H
Spline Width Across Flats, S, in. Ref 0.700 0.787 0.897
A
Where specifying nominal size in decimals, zeros preceding the decimal shall be used and the fourth decimal place shall be omitted.
B
The head height shall be that overall distance measured parallel to the axis of the product from the top of the head to the bearing surface and shall include the thickness
of the washer face. Raised grade and manufacturer’s identification are excluded from head height.
C
The circumference may be irregular with a rounded or flat edge.
D
The bearing surface shall be flat and perpendicular to the body within the FIM limits specified for total runout. Measurement of FIM shall extend as close to the periphery
of the bearing surface as possible while the bolt is being held in a collet or other gripping device at a distance of one bolt diameter from the underside of the head. A die
seam across the bearing surface is not permissible.
E
Transition thread length, Y , is a reference dimension, intended for calculation purposes only, that represents the length of incomplete threads and tolerance on grip
gaging length.
F
See ASME B18.2.6, section 6.10.
G
Unless otherwise specified, bolts need not be pointed. The distance, U, is from the center of the groove to the first fully formed thread crest. This shall be determined
by measuring how far the point enters into a cylindrical NOT GO major diameter ring gage.
H
The spline dimensions and groove dimensions are reference dimensions and shall be at the discretion of the manufacturer. Users should consult with the supplier to
assure wrenchability.
12.2.2 Magnetic particle inspection shall be conducted in accordance with Guide E709 or Practice E1444E1444/E1444M.
Guide E709 shall be used for referee purposes. If any nonconforming bolt is found during the manufacturers examination of the
lot selected in 12.2.1, the lot shall be 100 % magnetic particle tested and all nonconforming bolts shall be removed and scrapped
or destroyed.
12.2.3 Eddy current or liquid penetrant inspection may be substituted for the 100 % magnetic particle inspection when
nonconforming bolts are found and 100 % inspection is required. On completion of the eddy current or liquid penetrant inspection,
F3043 − 15
TABLE 12 Nut Dimensions
NOTE 1—The tops of washer faced nuts shall be flat and the diameter of chamfer circle shall be equal to the maximum width across flats within a
tolerance of -15%. The length of chamfer at hex comers shall be 5% to 15% of the basic thread diameter. The surface of chamfer may be slightly convex
or rounded.
NOTE 2—Bearing surfaces shall be flat and perpendicular to the axis of the threaded hole within the total runout (FIM) tabulated for the respective nut
size.
NOTE 3—FIM = Full Indicator Movement
A
1 1
Nominal Size 1 1 ⁄8 1 ⁄4
1.000 1.125 1.250
B
5 13
Width Across Flats, F nom 1 ⁄8 1 ⁄16 2
max 1.625 1.812 2.000
min 1.575 1.756 1.938
C
Width Across Corners, G max 1.876 2.093 2.309
min 1.796 2.002 2.209
D
3 11 15
Thickness, H nom 1 ⁄16 1 ⁄32 1 ⁄32
max 1.214 1.367 1.501
min 1.147 1.295 1.424
1 1 1
Washer Face Height nom ⁄64 ⁄64 ⁄64
E
Total Runout of Bearing Face FIM 0.024 0.027 0.030
A
Where specifying nominal size in decimals, zeros preceding the decimal shall be used and the fourth decimal place shall be omitted.
B
The width across flats of heavy hex nuts shall be the overall distance measured, perpendicular to the axis of the nut, between two opposite sides of the nut. No transverse
section through the nut between 25% and 75% of the actual nut thickness, as measured from the bearing surface, shall be less than the minimum width across flats.
C
A rounding or lack of fill at junction of hex comers with chamfer shall be permissible, provided the width across comers is within specified limits at and beyond a distance
equal to 17.5% of the basic thread diameter from the chamfered faces.
D
The nut thickness shall be the overall distance measured parallel to the axis of the nut, from the top of the nut to the bearing surface, and shall include the thickness
of the washer face where provided.
E
Nuts shall have a washer faced bearing surface and chamfered top. The diameter of washer face shall be within the limits of the maximum width across flats and 95%
of the minimum width across flats.
a random sample selected from each bolt lot in accordance with Guide F1470, shall be reexamined by the magnetic particle
method. In case of controversy, the magnetic particle test shall take precedence.
12.2.4 Magnetic particle indications of themselves shall not be cause for rejection. If in the opinion of the quality assurance
representative the indications may be cause for rejection, a sample taken in accordance with Guide F1470 shall be examined by
microscopic examination or removal by surface grinding to determine if the indicated discontinuities are within Specification
F788/F788MF788 limits.
13. Testing
13.1 Testing Responsibility:
13.1.1 Each component lot and assembly lot shall be tested by the manufacturer prior to shipment in accordance with the lot
identification control quality assurance plan in 13.4.
13.1.2 When components or assemblies are furnished by a source other than the manufacturer, the responsible party as defined
in Section 18 shall be responsible for assuring all tests have been performed and the components and assemblies comply with the
requirements of this specification.
13.2 Purpose of Lot Inspection—The purpose of a lot inspection program is to ensure that each lot conforms to the requirements
of this specification. For such a plan to be fully effective, it is essential that distributors and purchasers maintain the identification
and integrity of each lot until the assemblies are installed.
13.3 Lot Control—All components shall be manufactured, processed, and tested in accordance with a lot control plan that
provides lot purity and lot identification. The manufacturer and distributors shall identify and maintain the integrity of each lot of
F3043 − 15
TABLE 13 Hardened Circular Washers Dimensions
1 1
Nominal Size 1 1 ⁄8 1 ⁄4
1 3 3
Inside Diameter (ID), in. nom 1 ⁄16 1 ⁄16 1 ⁄8
max 1.085 1.251 1.438
min 1.063 1.188 1.375
1 1
Outside Diameter (OD), in. nom 2 2 ⁄4 2 ⁄2
max 2.063 2.313 2.563
min 1.937 2.187 2.437
1 1 5
Thickness (T), in. nom ⁄4 ⁄4 ⁄16
max 0.264 0.264 0.343
min 0.209 0.209 0.287
components and finished assemblies from raw material selection through all processing operations and treatments to final packing
and shipment. Each component lot shall be assigned its own component lot number and each assembly lot its own assembly lot
number.
13.4 Number of Tests:
13.4.1 Sampling of Assemblies:
13.4.1.1 Assembly lot tension test sample size shall be in accordance with Guide F1470, Sample Level C, Table 3, with a
minimum of two assemblies.
13.4.1.2 When tested in accordance with the required sampling plan, a component lot shall be rejected if any of the test
specimens fail to meet the applicable requirements.
13.4.2 Sampling of Tension Control Bolts:
13.4.2.1 Tensile strength, proof load, product hardness and carburization/decarburization sampling shall be in accordance with
Guide F1470.
13.4.2.2 Chemical composition sampling shall be one test per heat conducted by the steel producer.
13.4.2.3 Sampling for dimensional and thread fit compliance shall be in accordance with the quality assurance provisions of
ASME B18.2.6.
13.4.2.4 Sampling for workmanship, surface discontinuities, including head bursts, and magnetic particle inspection shall be in
accordance with Guide F1470.
13.4.2.5 Sampling for resistance to Environmental Hydrogen Embrittlement shall be in accordance with Annex A2.
13.4.3 Sampling of Nuts:
13.4.3.1 Proof load, cone proof load and product hardness sampling shall be in accordance with Guide F1470.
13.4.3.2 Chemical composition sampling shall be one test per heat conducted by the steel producer.
13.4.3.3 Sampling for dimensional and thread fit compliance shall be in accordance with the quality assurance provisions of
ASME B18.2.6.
13.4.4 Sampling of Washers:
13.4.
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