ASTM A563

The specification for ASTM A563 Nuts covers the chemical and mechanical requirements for eight grades of carbon and alloy steel nuts for general structural and mechanical uses on bolts, studs, and other externally threaded parts. The requirements for any grade of nut may, at the supplier’s option, and with notice to the purchaser, be fulfilled by furnishing nuts of one of the stronger grades specified herein unless such substitution is barred in the inquiry and purchase order.

A563 nuts

Grades

A  Carbon steel, hex or hvy hex
B  Carbon steel, hex or hvy hex
 Carbon steel, quenched and tempered, hvy hex
 Carbon steel, quenched and tempered, hvy hex
DH  Carbon steel, quenched and tempered, hvy hex
C3  Weathering steel, quenched and tempered, hvy hex
DH3         Weathering steel, quenched and tempered, hvy hex

Mechanical Properties

 Grade Style Size, in. Proof Load, ksi  Hardness, HBN         
 Plain   Galvanized 
 A  Hex  1/4 – 1-1/2  90  68   116 – 302
 Heavy  Hex  1/4 – 4  100  75   116 – 302
 B  Heavy  Hex  1/4 – 1  133  100   121 – 302
 Heavy    Hex  1-1/8 – 1-  1/2  116  87   121 – 302
 C / C3  Heavy  Hex  1/4 – 4  144  144   143 – 352
 D  Heavy  Hex  1/4 – 4  150  150   248 – 352
 DH /  DH3  Heavy  Hex  1/4 – 4  175  150   248 – 352
 

Chemical Properties

 Elements  Grades O, A, B, C  D  DH
 Carbon  0.55% max  0.55% max  0.20 – 0.55%
 Manganese, min  0.30%  0.60%
 Phosphorus, max  0.12%  0.04%  0.04%
 Sulfur, max  0.15%*  0.05%  0.05%
  * For grades O, A and B a sulfur content of 0.23% max is acceptable with the purchasers approval
  ** For grades D and DH a sulfur content of 0.05 – 0.15% is acceptable provided the manganese is 1.35% min

Grade Identification Markings

Marking  Specification  Material Type     Nominal Sizes, In. Proof Load Stress, ksi Hardness Rockwell See Note
Min Max
Hex Nut templateNo Marking ASTM A563 Grade O Carbon Steel 1/4 – 1-1/2 69 B55 C32 2,3
ASTM A563 Grade A Carbon Steel 1/4 – 1-1/2 90 B68 C32 2,3
ASTM A563 Grade B Carbon Steel 1/4 – 1 120 B69 C32 2,3
>1 – 1-1/2 105
A563 grade C ASTM A563 Grade C Carbon Steel, may be Quenched and Tempered 1/4 – 4 144 B78 C38 4
A563 grade C3 ASTM A563 Grade C3 Atmospheric Corrosion Resistant Steel, may be Quenched and Tempered 1/4 – 4 144 B78 38 4,6
A563 grade D ASTM A563 Grade D Carbon Steel, may be Quenched and Tempered 1/4 – 4 150 B84 C38 5
A563 grade DH ASTM A563 Grade DH Carbon Steel, Quenched and Tempered 1/4 – 4 175 C24 C38 5
A563 grade DH3 ASTM A563 Grade DH3 Atmospheric Corrosion Resistant Steel, Quenched and Tempered 1/4 – 4 175 C24 C38 4,6

* Nuts made to the requirements of Grades O, A and B are not required to be marked unless individual marking is specified in the inquiry and order. When individual marking is required, the mark shall be the grade letter symbol on one face of the nut*

Thread Dimensions and Overtapping Allowances for Hot Dip Zinc Coated Nuts per Specification A153, C1. C

 Nominal Nut Size, in. and Pitch   Diametral Allowance, in.      Pitch Diameter, in.                                                    
 Minimum  Maximum
 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
 10.437 – 14  0.018  0.4091  0.4152
 0.500 – 13  0.018  0.4680  0.4745
 0.0562 – 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
 4.000 – 4  0.050  3.8876  3.9023

See Also: ASTM A563 Specifications on ASTM.org.