Patriot Bolt machines ASTM A563 heavy hex nuts, the carbon and alloy steel nut specification used with general and structural bolting such as A354, A449, A307 and F1554. A563 sets nut strength by grade, from Grade A for low-carbon bolts up to quenched and tempered Grade DH for high-strength bolts.
We make A563 nuts alone or with matching studs and bolts. Every order ships with mill test reports traceable to the heat.
A563 Heavy Hex Nuts at a Glance
Choosing the Right A563 Grade
The nut must be at least as strong as the bolt it goes on, so the bolt yields before the nut threads strip. Typical pairings:
- Grade A: A307 bolts and studs, and F1554 Grade 36 anchor rods.
- Grade C: plain-finish A354 BC.
- Grade DH: A354 BD, galvanized A354 BC and A449, and F1554 Grade 105.
A563 allows a stronger grade to be supplied in place of a weaker one unless the order prohibits it. A194 2H nuts are widely used in place of DH, which is hard to find in larger sizes.
A563 Heavy Hex Nut Specifications
A563 sets proof stress and hardness by grade and finish. Values below are for heavy hex nuts with coarse, 8UN and 6UN threads.
| Grade | Size | Proof stress, plain | Proof stress, galvanized | Hardness |
|---|---|---|---|---|
| A | 1/4–4 in | 100 ksi | 75 ksi | 116–302 HBW |
| B | 1/4–1 in | 133 ksi | 100 ksi | 121–302 HBW |
| B | 1-1/8–1-1/2 in | 116 ksi | 87 ksi | 121–302 HBW |
| C / C3 | 1/4–4 in | 144 ksi | 144 ksi | 143–352 HBW |
| D | 1/4–4 in | 150 ksi | 150 ksi | 248–352 HBW |
| DH / DH3 | 1/4–4 in | 175 ksi | 150 ksi | 248–352 HBW |
Galvanized nuts are tapped oversize to fit over the zinc coating, which lowers their proof stress for some grades.
A563 Chemical Composition
| Element | Grades A, B, C | Grade D | Grade DH |
|---|---|---|---|
| Carbon | 0.55 max | 0.55 max | 0.20–0.55 |
| Manganese | — | 0.30 min | 0.60 min |
| Phosphorus | 0.12 max | 0.04 max | 0.04 max |
| Sulfur | 0.15 max | 0.05 max | 0.05 max |
Limits per the current edition of the specification. The mill test report for your heat is the controlling document.
Nut Styles
- Heavy hex nuts to ASME B18.2.2, the standard style for flange and structural studs.
- Heavy hex jam nuts where a thinner nut is needed.
- Threads: UNC through 1 in and 8UN above 1 in, or the thread on your drawing.
Applications and Industries
- Structural and equipment bolting: Nuts for A354, A449 and A307 bolts and studs. See Industrial Manufacturing.
- Anchor rods: Nuts for F1554 foundation anchor bolts.
- Oil and gas: Skid, structure and equipment bolting. See Oil & Gas.
Certification and Traceability
Patriot Bolt is ISO 9001:2015 certified. Each A563 order includes mill test reports traceable to the heat, along with a certificate of conformance to the specification on your purchase order.
Nuts are marked with the grade symbol where the specification requires it, along with our identification.
Compare A563 with other bolting grades in our Fastener Materials Matrix.
A563 Heavy Hex Nuts FAQ
Which A563 grade do I need?
Match the nut to the bolt: Grade A for A307 and F1554 Grade 36, Grade C for plain A354 BC, and Grade DH for A354 BD, galvanized A449 and F1554 Grade 105.
Can A194 2H nuts replace A563 DH?
Yes. 2H nuts are commonly supplied in place of DH because DH is hard to find in larger diameters. Confirm with your project specification.
Why is the proof stress lower for galvanized nuts?
Galvanized nuts are tapped oversize to fit the coated bolt, which reduces thread engagement. A563 lists separate proof values for them.
Do you make the matching bolts and studs?
Yes. We machine A354, A449, A307 and F1554 studs and rods, so the bolt and nuts can come from one source.
Request a Quote
Send us the alloy, nut style, thread size, specification and quantity, or upload your drawing. Our team will confirm the material and lead time. Call (281) 581-0176 or request a quote.
Related: A354 stud bolts · A449 stud bolts · F1554 anchor bolts · All nuts