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Heavy Hex Nuts
Steel Grades A, C, 2H, DH, DH3, and 18-8 SST
Steel Heavy Hex Nuts
Mechanical & Physical Properties		 Stainless Heavy Hex Nuts
Mechanical & Physical Properties

Heavy Hex Nuts - ANSI/ASME B18.2.2
Nominal Size
or Basic Major
Thread Diameter		 F G H
Width
Across Flats		 Width
Across Corners		 Thickness
Basic Max Min Max Min Basic Max Min
1/4 .2500 1/2 .500 .488 .577 .556 15/64 .250 .218
5/16 .3125 9/16 .562 .546 .650 .622 19/64 .314 .280
3/8 .3750 11/16 .688 .669 .794 .763 23/64 .377 .341
7/16 .4375 3/4 .750 .728 .866 .830 27/64 .441 .403
1/2 .5000 7/8 .875 .850 1.010 .969 31/64 .504 .464
9/16 .5625 15/16 .938 .909 1.083 1.037 35/64 .568 .526
5/8 .6250 1-1/16 1.062 1.031 1.227 1.175 39/64 .631 .587
3/4 .7500 1-1/4 1.250 1.212 1.443 1.382 47/64 .758 .710
7/8 .8750 1-7/16 1.438 1.394 1.660 1.589 55/64 .885 .833
1 1.0000 1-5/8 1.325 1.575 1.876 1.796 63/64 1.012 .956
1-1/8 1.1250 1-13/16 1.812 1.756 2.093 2.002 1-7/64 1.139 1.079
1-1/4 1.2500 2 2.000 1.938 2.309 2.209 1-7/32 1.251 1.187
1-3/8 1.3750 2-3/16 2.188 2.119 2.526 2.416 1-11/32 1.378 1.310
1-1/2 1.5000 2-3/8 2.375 2.300 2.742 2.622 1-15/32 1.505 1.433
1-5/8 1.6250 2-9/16 2.562 2.481 2.959 2.828 1-19/32 1.632 1.556
1-3/4 1.7500 2-3/4 2.750 2.662 3.175 3.035 1-23/32 1.759 1.679
2 2.0000 3-1/8 3.125 3.025 3.608 3.449 1-31/32 2.013 1.925
2-1/4 2.2500 3-1/2 3.500 3.388 4.041 3.862 2-13/64 2.251 2.155
2-1/2 2.5000 3-7/8 3.875 3.750 4.474 4.275 2-29/64 2.505 2.401
2-3/4 2.7500 4-1/4 4.250 4.112 4.907 4.688 2-45/64 2.759 2.647
3 3.0000 4-5/8 4.625 4.475 5.340 5.102 2-61/64 3.013 2.893
3-1/4 3.2500 5 5.000 4.838 5.774 5.515 3-3/16 3.252 3.124
3-1/2 3.5000 5-3/8 5.375 5.200 6.207 5.928 3-7/16 3.506 3.370
3-3/4 3.7500 5-3/4 5.750 5.562 6.640 6.341 3-11/16 3.670 3.616
4 4.0000 6-1/8 6.125 5.925 7.073 6.755 3-15/16 4.014 3.862


Marking images for steel heavy hex nuts
Steel Grades A, C, 2H, DH, DH3 Heavy Hex Nut Properties
Description A six sided internally threaded fastener which is both thicker and wider than a same-sized finished nut. Nuts size 7/16 and smaller shall be double chamfered. Larger sizes are either double chamfered or chamfered on top with a washer faced bearing surface.
Applications
& Advantages		 The strongest of all comparably graded nuts because of its greater length of thread engegement and greater resistance to dilation (widening or stretching). Grade-A nuts are used with low carbon heavy hex bolts. Grade-C nuts are recommended for use with A-325 structural bolts. Grade-2H nuts are recommended for use with bolts in high-pressure and high-temperature applications. Grade-DH nuts are recommended for use with A-490, Type-1 structural bolts. Grade-DH3 nuts are for use with A-490, Type-3 structural bolts.
Material Nuts are to be made from a steel that conforms to the following chemical composition requirements (heat analysis):
Grades-A and C: Carbon: .55% max   Phosphorus: .12% max   Sulfur: .023% max
Grade-2H: Carbon: .40% min   Manganese: 1.00% max   Phosphorus: .12% max   Sulfur: .05% max   Silicon: .40% max
Grade-DH: Carbon: .20-.55%    Manganese: .60% min   Phosphorus: .04% max   Sulfur: .05% max
Grade-DH3: Carbon: .02-.53%   Manganese: .40% min   Phosphorus: .046% max   Sulfur: .05% max   Copper: .20% min   Chromium: .45% min (Either Nickel: .20% min or Molybdenum: 15% min may be used).
Heat Treatment Grade-2H" Shall be heat treated by quenching in a liquid medium from a temperature above the transformation temperature and tempered at a temperature of at least 850°F.
Grades- C, DH and DH3: Shall be heat treated by quenching in a liquid medium from a temperature above the transformation temperature and tempered at a temperature of at least 800°F.
Core Hardness Grade-A: Rockwell B68 - C32
Grade-C: Rockwell B78 - C38
Grades-2H, DH, and DH3: Rockwell C24 - C38
Proof Load Grade-A: Course: 100,000 psi   Fine: 90,000 psi
Grade-C: 144,000 psi
Grade-2H: 150,000 psi
Grades-DH and DH3: 175,000 psi
Plating See plating page for plating information.
Product standards require all grade-marked nuts 1/4 inch and larger to have a raised or depressed grade-marking and insignia identifying its manufacturer. The X in the images above represent one location where suck marking may appear.


Stainless Steel, 18-8 and 316, Nut Properties
Description A six sided internally threaded fastener which is both thicker and wider than a same-sized finished hex nut, made of 18-8 stainless steel. Nuts size 7/16 and smaller shall be double chamfered. Larger sizes are either double chamfered or chamfered on top with a washer faced bearing surface.
Applications
& Advantages		 The strongest of all the 18-8 nuts because of its greater thread length and greater resistance to dilation (widening or stretching).
Material Nuts shall be made from one of the following austenitic stainless alloys: 303, 302SE, 304 or XM7, all of which are characterized as having a chromium content of 18% and a nickel content of 8%.
Heat Treatment The austenitic alloys develop their strength through work hardening during the manufacturing process, as seen from their hardness properties below. The only hjeat treatment normally available on austenitic stainless steel alloys is annealing, which is done at approximately 1900°F to a dead soft condition and is not normally thermally reversible.
Hardness 1/4 thru 5/8: Rockwell B95 - C32 3/4 thru 1 inch: Rockwell B80 - C32
Proof Load 1/4 thru 5/8: 100,000 psi Fine Thread: 85,000 psi

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Smith Fastener Company, A California Corporation - 3613 East Florence Avenue, Bell, California, 90201 - Phone: ( 323 ) 587-0382 - FAX: ( 323 ) 587-8712 - E-mail: sales@smithfast.com - Copyright © 2000 by Smith Fastener Company - Last updated: May 22nd, 2006 - http://www.smithfast.com/heavyhexnuts.html