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ASTM A563 Nuts Specification

Carbon Steel & Alloy Steel Imperial Nuts for general structural and mechanical uses on bolts, studs, and other externally threaded parts

ASTM A563 Hex Nut, Heavy hex Nut, Square Nuts, Hexagon High Nuts, Slotted Nuts

ASTM A563 specification covers imperial 1/4 inch to 4 inch Carbon Steel & Alloy Steel Imperial Nuts for general structural and mechanical uses on bolts, studs, and other externally threaded parts. rades C3 and DH3 nuts have atmospheric corrosion resistance and weathering characteristics comparable to that of the steels covered in Specifications A242/A242M, A588/A588M, and A709/A709M. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition. When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications. Steel for nuts shall be made by the open-hearth, basic-oxygen, or electric-furnace process except that steel for Grades O, A, and B nuts may be made by the acid-bessemer process. Nuts may be made cold or hot by forming, pressing, or punching or may be machined from bar stock. Threads shall be formed by tapping or machining.

Related Specifications of ASTM A563 Bolting

A563M A194 A307 A325 A394 A449 F3148 F3125 F2437 A490 A242/A242M A588/A588M A606/A606M A687 A709/A709M

ASTM A563 Nut and Bolt Suitability Guide

Grade of BoltD Surface FinishE Nominal Size, in. Grade and ANSI Nut StyleA
RecommendedB SuitableC
Hex Heavy Hex Square Hex Heavy Hex Hex Thick
A307 Grade A non-zinc-coated and zinc-coated 1/4 to 11/2 A ... A B, D, DH A, B, C, D, DH, Dh4 A, B, D, DH
>11/2 to 2 ... A ... AF C, D, DH, Dh4 ...
>2 to 4 ... A ... ... C, D, DH, Dh4 ...
A307 Grade B non-zinc-coated and zinc-coated 1/4 to 11/2 ... A A B, D, DH B, C, D, DH, Dh4 A, B, D, DH
>11/2 to 2 ... A ... AF C, D, DH, Dh4 ...
>2 to 4 ... A ... ... C, D, DH, Dh4 ...
A325 Type 1 non-zinc-coated 1/2 to 11/2 ... C ... ... C3, D, DH, Dh4 ...
zinc-coated 1/2 to 11/2 ... DH ... ... ... ...
A325 Type 3 non-zinc-coated 1/2 to 11/2 ... C3 ... ... Dh4 ...
A354 Grade BC non-zinc-coated 1/4 to 11/2 ... C ... D, DH C3, D, DH, Dh4 D, DH
>11/2 to 4 ... C ... ... C3, D, DH, Dh4 ...
zinc-coated 1/4 to 11/2 ... DH ... ... ... DH
>11/2 to 4 ... DH ... ... ... ...
A354 Grade BD non-zinc-coated 1/4 to 11/2 ... DH ... DH D, DH, Dh4 D, DH
>11/2 to 4 ... DH ... ... Dh4 ...
A394 Type 0 zinc-coated 1/2 to 1 A ... ... B, D ... ...
A394 Types 1 and 2 zinc-coated 1/2 to 1 DH ... ... D ... ...
A394 Type 3 non-zinc-coated 1/2 to 1 Dh4 ... ... ... C3 ...
A449 Types 1 and 2 non-zinc-coated 1/4 to 11/2 B ... ... D, DH B, C, C3, D, DH, Dh4 B, D, DH
>11/2 to 3 ... A ... ... C, C3, D, DH, Dh4 ...
zinc-coated 1/4 to 11/2 ... DH ... D, DH D D, DH
>11/2 to 3 ... DH ... ... D ...
A490 Types 1 and 2 non-zinc-coated 1/2 to 11/2 ... DH ... ... Dh4 ...
A490 Type 3 non-zinc-coated 1/2 to 11/2 ... Dh4 ... ... ... ...
A687 non-zinc-coated 11/4 to 3 ... D ... ... DH, Dh4 ...
zinc-coated 11/4 to 3 ... DH ... ... ... ...
  • (A) The availability of DH nuts in nominal sizes 3/4 in. and larger is very limited and generally available only on special orders for 50 000 pieces or more. For smaller quantities A194 Gr. 2H nuts should be considered.
  • (B) "Recommended" denotes a commercially available nut having the most suitable mechanical properties and dimensional configuration (style) that will make it possible to torque the bolt to the required load when used in combination with the nut.
  • (C) "Suitable" denotes nuts having mechanical properties that will make it possible to torque the bolt to the required load when used in combination with the nut; but, which require consideration of dimensional configuration (style) suitability and availability. Others are not suitable.
  • (D) The term "bolt" includes all externally threaded types of fasteners.
  • (E) Non-zinc-coated nuts are nuts intended for use with externally threaded fasteners, which have a plain (nonplated or noncoated) finish or a have a plating or coating of insufficient thickness to necessitate overtapping the nut thread to provide assembiability. Zinc-coated nuts are nuts intended for use with externally threaded fasteners which are not hot-dip zinc-coated, mechanically zinc-coated, or have a plating or coating of sufficient thickness to necessitate overtapping the nut thread to provide assembiability.
  • (F) Hex nuts in nominal sizes over 11/2 to 2 in. inclusive are not covered in the tables of tabulated sizes in ANSI B18.2.2 but are commercially available. Such nuts are suitable. See 7.2 for dimensions.

ASTM A563 Chemical Requirements

ASTM A563 Chemical Requirements for Grades O, A, B, C, D, and DH Nuts

Grade of Nut Analysis C Mn, min P, max S, max
ASTM A563 Grade O, A, B, C heat 0.55 max ... 0.12  0.15A
 product 0.58 max ... 0.13B  ...
ASTM A563 Grade DC  heat 0.55 max 0.30 0.04  0.05
 product 0.58 max 0.27 0.048  0.058
ASTM A563 Grade DHC  heat 0.20-0.55 0.60 0.04  0.05
  • (A) For Grades O, A, and B a sulfur content of 0.23 % max is acceptable with the purchasers approval.
  • (B) Acid bessemer steel only.
  • (C) For Grades D and DH a sulfur content of 0.05 - 0.15 % is acceptable provided the manganese is 1.35 % min.

ASTM A563 Chemical Requirements for Grades C3 and DH3 Nuts

Element Analysis Classes for ASTM A563 Grade C3 Nuts A ASTM A563 Grade Dh 3  Nuts
N A B C D E F
C Heat analysis . . . 0.33-0.40 0.38-0.48 0.15-0.25 0.15-0.25 0.20-0.25 0.20-0.25 0.20-0.53
Product analysis . . . 0.31-0.42 0.36-0.50 0.14-0.26 0.14-0.26 0.18-0.27 0.19-0.26 0.19-0.55
Mn Heat analysis . . . 0.90-1.20 0.70-0.90 0.80-1.35 0.40-1.20 0.60-1.00 0.90-1.20 0.40 min
Product analysis . . . 0.86-1.24 0.67-0.93 0.76-1.39 0.36-1.24 0.56-1.04 0.86-1.24 0.37 min
P Heat analysis 0.07-0.15 0.040 max 0.06-0.12 0.035 max 0.040 max 0.040 max 0.040 max 0.046 max
Product analysis 0.07-0.155 0.045 max 0.06-0.125 0.040 max 0.045 max 0.045 max 0.045 max 0.052 max
S Heat analysis 0.050 max 0.050 max 0.050 max 0.040 max 0.050 max 0.040 max 0.040 max 0.050 max
Product analysis 0.055 max 0.055 max 0.055 max 0.045 max 0.055 max 0.045 max 0.045 max 0.055 max
Si Heat analysis 0.20-0.90 0.15-0.35 0.30-0.50 0.15-0.35 0.25-0.50 0.15-0.35 0.15-0.35 . . .
Product analysis 0.15-0.95 0.13-0.37 0.25-0.55 0.13-0.37 0.20-0.55 0.13-0.37 0.13-0.37 . . .
Cu Heat analysis 0.25-0.55 0.25-0.45 0.20-0.40 0.20-0.50 0.30-0.50 0.30-0.60 0.20-0.40 0.20 min
Product analysis 0.22-0.58 0.22-0.48 0.17-0.43 0.17-0.53 0.27-0.53 0.27-0.63 0.17-0.43 0.17 min
Ni Heat analysis 1.00 max 0.25-0.45 0.50-0.80 0.25-0.50 0.50-0.80 0.30-0.60 0.20-0.40 0.20 minB
Product analysis 1.03 max 0.22-0.48 0.47-0.83 0.22-0.53 0.47-0.83 0.27-0.63 0.17-0.43 0.17 min
Cr Heat analysis 0.30-1.25 0.45-0.65 0.50-0.75 0.30-0.50 0.50-1.00 0.60-0.90 0.45-0.65 0.30 min
Product analysis 0.25-1.30 0.42-0.68 0.47-0.83 0.27-0.53 0.45-1.05 0.55-0.95 0.42-0.68 0.25 min
V Heat analysis . . . . . . . . . 0.020 min . . . . . . . . . . . .
Product analysis . . . . . . . . . 0.010 min . . . . . . . . . . . .
Mo Heat analysis . . . . . . 0.06 max . . . 0.10 max . . . . . . 0.15 minB
Product analysis . . . . . . 0.07 max . . . 0.11 max . . . . . . 0.14 min
Ti Heat analysis . . . . . . . . . . . . 0.05 max . . . . . . . . .
Product analysis . . . . . . . . . . . . . . . . . . . . . . . .
  • (A) C3 nuts may be made of any of the above listed material classes. Selection of the class shall be at the option of the manufacturer.
  • (B) Nickel or molybdenum may be used.

ASTM A563 Mechanical Requirements

ASTM A563 Mechanical Requirements Nuts with UNC, 8 UN, 6 UN and Coarser Pitch Threads

Grade of Nut Nominal Nut Size, in. Style of Nut Proof Load Stress, ksiA Hardness
Non-Zinc-Coated NutsB Zinc-Coated NutsB Brinell Rockwell
min max min max
ASTM A563 Grade O 1/4 to 11/2 square 69 52 103 302 B55 C32
ASTM A563 Grade A 1/4 to 11/2 square 90 68 116 302 B68 C32
ASTM A563 Grade O 1/4 to 11/2 hex 69 52 103 302 B55 C32
ASTM A563 Grade A 1/4 to 11/2 hex 90 68 116 302 B68 C32
ASTM A563 Grade B 1/4 to 1 hex 120 90 121 302 B69 C32
ASTM A563 Grade B 11/8 to 11/2 hex 105 79 121 302 B69 C32
ASTM A563 Grade CE 1/4 to 11/2 hex 130 130 143 352 B78 C38
ASTM A563 Grade DC 1/4 to 11/2 hex 135 135 159 352 B84 C38
ASTM A563 Grade DHD 1/4 to 11/2 hex 150 150 248 352 C24 C38
ASTM A563 Grade Dh4 1/2 to 1 hex 150 150 248 352 C24 C38
ASTM A563 Grade A 1/4 to 4 heavy hex 100 75 116 302 B68 C32
ASTM A563 Grade B 1/4 to 1 heavy hex 133 100 121 302 B69 C32
ASTM A563 Grade B 11/8 to 11/2 heavy hex 116 87 121 302 B69 C32
ASTM A563 Grade CC 1/4 to 4 heavy hex 144 144 143 352 B78 C38
ASTM A563 Grade C3 1/4 to 4 heavy hex 144 144 143 352 B78 C38
ASTM A563 Grade DC 1/4 to 4 heavy hex 150 150 159 352 B84 C38
ASTM A563 Grade DHD 1/4 to 4 heavy hex 175 150 248 352 C24 C38
ASTM A563 Grade Dh4 1/4 to 4 heavy hex 175 150 248 352 C24 C38
ASTM A563 Grade A 1/4 to 11/2 hex thick 100 75 116 302 B68 C32
ASTM A563 Grade B 1/4 to 1 hex thick 133 100 121 302 B69 C32
ASTM A563 Grade B 11/8 to 11/2 hex thick 116 87 121 302 B69 C32
ASTM A563 Grade DC 1/4 to 11/2 hex thick 150 150 159 352 B84 C38
ASTM A563 Grade DHD 1/4 to 11/2 hex thick 175 175 248 352 C24 C38

ASTM A563 Mechanical Requirements Nuts with UNC12 UN, and Finer Pitch Threads

Grade of Nut Nominal Nut Size, in. Style of Nut Proof Load Stress, ksiA Hardness
Non-Zinc-Coated NutsB Zinc-Coated NutsB Brinell Rockwell
min max min max
ASTM A563 Grade O 1/4 to 11/2 hex 65 49 103 302 B55 C32
ASTM A563 Grade A 1/4 to 11/2 hex 80 60 116 302 B68 C32
ASTM A563 Grade B 1/4 to 1 hex 109 82 121 302 B69 C32
ASTM A563 Grade B 11/8 to 11/2 hex 94 70 121 302 B69 C32
ASTM A563 Grade DC 1/4 to 11/2 hex 135 135 159 352 B84 C38
ASTM A563 Grade DHD 1/4 to 11/2 hex 150 150 248 352 C24 C38
ASTM A563 Grade A 1/4 to 4 heavy hex 90 68 116 302 B68 C32
ASTM A563 Grade B 1/4 to 1 heavy hex 120 90 121 302 B69 C32
ASTM A563 Grade B 11/8 to 11/2 heavy hex 105 79 121 302 B69 C32
ASTM A563 Grade DC 1/4 to 4 heavy hex 150 150 159 352 B84 C38
ASTM A563 Grade DHD 1/4 to 4 heavy hex 175 150 248 352 C24 C38
ASTM A563 Grade A 1/4 to 11/2 hex thick 90 68 116 302 B68 C32
ASTM A563 Grade B 1/4 to 1 hex thick 120 90 121 302 B69 C32
ASTM A563 Grade B 11/8 to 11/2 hex thick 105 79 121 302 B69 C32
ASTM A563 Grade DC 1/4 to 11/2 hex thick 150 150 159 352 B84 C38
ASTM A563 Grade DHD 1/4 to 11/2 hex thick 175 175 248 352 C24 C38
  • (A) To determine nut proof load in pounds, multiply the appropriate nut proof load stress by the tensile stress area of the thread. Stress areas for UNC, UNF, and 8 UN thread series are given in Table 4.
  • (B) Non-zinc-coated nuts are nuts intended for use with externally threaded fasteners which have a plain (nonplated or noncoated) finish or have a plating or coating of insufficient thickness to necessitate overtapping the nut thread to provide assemblability. Zinc-coated nuts are nuts intended for use with externally threaded fasteners which are hot-dip zinc-coated, mechanically zinc-coated, or have a plating or coating of sufficient thickness to necessitate overtapping the nut thread to provide assemblability.
  • (C) Nuts made in accordance to the requirements of Specification A194/A194M, Grade 2 or Grade 2H, and marked with their grade symbol are acceptable equivalents for Grades C heavy hex and hex and D nuts. When A194 zinc-coated inch series nuts are supplied, the zinc coating, overtapping, lubrication and rotational capacity testing shall be in accordance with Specification A563.
  • (D) Nuts made in accordance with the requirements of Specification A194/A194M, Grade 2H, and marked with its grade symbol are an acceptable equivalent for Grade DH nuts. When A194 zinc-coated inch series nuts are supplied, the zinc coating, overtapping, lubrication and rotational capacity testing shall be in accordance with Specification A563.
  • (E) ASTM A194 Grades 2 or 2H shall not be supplied for Grade C hex nuts unless approved by purchaser.

ASTM A563 Tensile Stress Areas

Nominal Size- Threads per Inch UNC Nominal Size- Threads per Inch UNF Nominal Size- Threads per Inch 8 UN
Tensile Stress Area,AAs in.2 Tensile Stress AreaAAs in.2 Tensile Stress Area,AAs in.2
1/4 -20 0.0318  1/4 -28 0.0364 ...  ...
5/16 -18 0.0524 5/16 -24 0.0580 ... ...
3/8 -16 0.0775 3/8 -24 0.0878 ... ...
7/16 -14 0.1063 7/16 -20 0.1187 ... ...
1/2 -13 0.1419 1/2 -20 0.1599 ... ...
9/16 -12 0.182 9/16 -18 0.203 ... ...
5/8 -11 0.226 5/8 -18 0.256 ... ...
3/4 -10 0.334 3/4 -16 0.373 ... ...
7/8 -9 0.462 7/8 -14 0.509 ... ...
1-8 0.606 1-12 0.663 1-8 0.606
11/8 -7 0.763 11/8 -12 0.856 11/8 -8 0.790
11/4 -7 0.969 11/4 -12 1.073 11/4 -8 1.000
13/8 -6 1.155 13/8 -12 1.315 13/8 -8 1.233
11/2 -6 1.405 11/2 -12 1.581 11/2 -8 1.492
13/4 -5 1.90 ... ... 13/4 -8 2.08
2-41/2 2.50 ... ... 2-8 2.77
21/4 -41/2 3.25 ... ... 21/4 -8 3.56
21/2 -4 4.00 ... ... 21/2 -8 4.44
23/4 -4 4.93 ... ... 23/4 -8 5.43
3-4 5.97 ... ... 3-8 6.51
31/4 -4 7.10 ... ... 31/4 -8 7.69
31/2 -4 8.33 ... ... 31/2 -8 8.96
33/4 -4 9.66 ... ... 33/4 -8 10.34
4-4 11.08 ... ... 4-8 11.81
  • (A) As The stress area is calculated as follows:

ASTM A563 Thread Dimensions and Overtapping Allowances for Nuts Hot Dip Zinc Coated per Specification F2329

Nominal Nut Size, in. and Pitch Diametral Allowance, in.A Pitch Diameter, in.
min max
0.250-20 0.016 0.2335 0.2384
0.312-18 0.017 0.2934 0.2987
0.375-16 0.017 0.3514 0.3571
0.437-14 0.018 0.4091 0.4152
0.500-13 0.018 0.4680 0.4745
0.562-12 0.020 0.5284 0.5352
0.625-11 0.020 0.5860 0.5932
0.750-10 0.020 0.7050 0.7127
0.875-9 0.022 0.8248 0.8330
1.000-8 0.024 0.9428 0.9516
1.125-8 0.024 1.0678 1.0768
1.125-7 0.024 1.0562 1.0656
1.250-8 0.024 1.1928 1.2020
1.250-7 0.024 1.1812 1.1908
1.375-8 0.027 1.3208 1.3301
1.375-6 0.027 1.2937 1.3041
1.500-8 0.027 1.4458 1.4553
1.500-6 0.027 1.4187 1.4292
1.750-5 0.050 1.6701 1.6817
2.000-4.5 0.050 1.9057 1.9181
2.250-4.5 0.050 2.1557 2.1683
2.500-4 0.050 2.3876 2.4011
2.750-4 0.050 2.6376 2.6513
3.000-4 0.050 2.8876 2.9015
3.250-4 0.050 3.1376 3.1517
3.500-4 0.050 3.3876 3.4019
3.750-4 0.050 3.6376 3.6521
3.750-4 0.050 3.6376 3.6521
4.000-4 0.050 3.8876 3.9023
  • (A) These allowances also apply to the minimum and maximum major and minor diameters.

ASTM A563 Bolting Surface Treatment Specifications

ASTM A563 Bolting Components Marking

Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

ASME Dimensional Standards

B18.2.2 Imperial Square, Hex, Heavy Hex, Lock, Heavy Hex Lock Nuts

ASTM A563 Bolting Certifications

  • EN 10204 3.1
  • EN 10204 3.2
  • PED 2014/68/EC
  • MERKBLATT AD 2000 W2/W7/W10
  • API 20 E BSL 1/ BSL 2
  • NACE MR 0175
  • NACE MR 0103

ASTM A563 Testing Standards

E18 Test Methods for Rockwell Hardness of Metallic Materials
E21 Test Methods for Elevated Temperature Tension Tests of Metallic Materials
E709 Guide for Magnetic Particle Testing
A962/A962M Specification for Common Requirements for Bolting Intended for Use at Any Temperature from Cryogenic to the Creep Range
A788/A788M Specification for Steel Forgings, General Requirements

ASME Threading Specifications

ASME B1.1 Unified Inch Screw Threads (UN and UNR Thread Form)
ASME B1.3 Screw Thread Gaging System for Dimensional Acceptability - Inch Screw Threads (IN, UNR, and UNJ)

ASTM A563 Supplementary Requirements

S1 Supplementary Lubricant Requirements for Nuts
S2 Lubricant Dye
S3 Lubricant Placement