Jade Alloys is a specialized manufacturer, supplier and exporter of ASTM A563 Nuts from Mumbai, India, serving procurement teams across the USA, Canada, UAE, Saudi Arabia, Kuwait, Qatar, Germany, UK, Singapore, Malaysia, South Korea and Australia. Our A563 nuts are manufactured in strict compliance with ASTM standards and are available in all grades, types, sizes and surface finishes with full material certifications, dual ASME/ASTM certification and mill test reports. Our full range of carbon steel nuts and carbon steel fasteners, bolts, nuts, and washers is available from stock for immediate despatch.
What is the ASTM A563 Standard?
ASTM A563 covers carbon steel and alloy steel nuts for general structural and mechanical applications specifically those intended for use with externally threaded fasteners such as bolts, stud bolts, and anchor rods. The specification replaces the need to specify nuts by material alone by instead defining eight grades (O, A, B, C, D, DH, C3, DH3), each with progressively higher strength and hardness requirements. Full details of the governing ASTM fastener standards are available in our ASTM fastener standards, A563, A194, A193 overview.
The standard also addresses oversize tapping allowances critical for hot-dip galvanized assemblies, where the zinc coating adds measurable material thickness to the thread profile. This dimensional provision is what distinguishes A563 from other nut specifications and why galvanizing engineers specify it explicitly.
Key technical points engineers should note:
- Grade A nuts are the most commonly specified for general structural work with A307, A325, and similar bolt grades.
- Grade C and Grade DH nuts provide substantially higher proof loads, required for high-strength bolt assemblies per AISC and RCSC specifications.
- Grade DH is interchangeable with ASTM A194 Grade 2H in most structural applications — both are widely specified for high-strength bolted connections in steel construction.
- C3 and DH3 grades use weathering (atmospheric corrosion-resistant) steel, suited for unpainted exposed structures such as bridges.
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Nuts Weight Chart
ASTM A563 Grades — Complete Guide
ASTM A563 defines eight grades, each identified by a specific marking and intended for different bolt-nut pairings and environments. Selecting the wrong grade is a code violation in structural steel connections — here is what each grade means:
| O |  |
Carbon steel, hex or heavy hex |
| A |  |
Carbon steel, hex or heavy hex |
| B |  |
Carbon steel, hex or heavy hex |
| C |  |
Carbon steel, hex or heavy hex |
| D |  |
Carbon steel, hex or heavy hex |
| DH |  |
Carbon steel, hex or heavy hex |
| C3 |  |
Carbon steel, hex or heavy hex |
| DH3 |  |
Carbon steel, hex or heavy hex |
ASTM A563 Grade Identification Markings
Grade identification is critical for quality assurance and code compliance. ASTM A563 requires that nuts 1/4 inch and larger carry specific markings on the bearing face or wrench flats. The following marks are required:
| Grade | Required Marking | Notes |
|---|---|---|
| O | No marking required | Unmarked or manufacturer’s mark only |
| A | No marking required for Grade A | Manufacturer may add identification |
| B | Grade B mark or ‘B’ | Must be on bearing face or flat |
| C | Circle (O) or ‘C’ | Dot or letter mark on bearing face |
| D | ‘D’ | On wrench flat or bearing face |
| DH | Three equally-spaced dots (or ‘DH’) | Most common structural grade marking |
| C3 | Three lines (or ‘C3’) | Identifies weathering steel grade |
| DH3 | Three lines + three dots (or ‘DH3’) | Q&T weathering steel — high strength |
ASTM A563 Nut-Bolt Compatibility Guide
Structural codes (AISC, RCSC) specify which A563 grade must be used with each bolt grade. Mismatching nuts and bolts is a structural failure risk. Use this guide for correct specification:
| Bolt Grade | Bolt Type | Plain — Acceptable A563 Grades | Galvanized — Acceptable A563 Grades |
|---|---|---|---|
| ASTM A307 Gr. A/B | Low carbon hex bolt | A, B, C, D, DH | A, C, DH |
| ASTM A325 Type 1/3 | High-strength hex bolt | C, D, DH (1/4″–1″) | DH |
| ASTM A490 Type 1/3 | Ultra high-strength bolt | DH, D | DH only |
| ASTM A193 B7 | Alloy stud bolt | C, D, DH | DH |
| ASTM A193 B8/B8M | Stainless stud bolt | Use F594 nuts | N/A |
| ASTM F3125 Gr. A325M | Metric high-strength | DH (metric) | DH |
ASTM A563 Nut Specification
| Parameter | Specification Detail |
|---|---|
| Standard Designation | ASTM A563 / A563M |
| Applicable Nut Styles | Hex, Heavy Hex, Jam, Square, Coupling, Cap, Lock, Wing |
| Thread System | UNC (Unified National Coarse), 8-UN, 6-UN series; Metric coarse (ASME B1.13M 6H) |
| Dimension Standards | ASME B18.2.2 (hex and heavy hex); ASME B18.3 (socket types) |
| Certifications | Dual certified per ASME & ASTM codes; Mill Test Reports (MTR) available |
| Surface Coatings | Plain (uncoated), Hot-Dip Galvanized (HDG), Black Oxide, Zinc Plated, Xylan, Teflon, Cadmium, Mechanically Galvanized |
| Country of Origin | Made in India (Mumbai) |
| Raw Material Origin | South America, East Europe, Japan, South Korea |
| Marking | Grade-specific markings per ASTM A563 Clause 9 |
| Supplemental Requirements | Oversize tapping allowed for HDG per F2329; proof load testing per ASTM F606 |
Chemical Composition of ASTM A563 Nuts
| Element | Grades O, A, B, C | Grade D | Grade DH / DH3 |
|---|---|---|---|
| Carbon (max) | 0.55% | 0.55% | 0.20 – 0.55% |
| Manganese (min) | Not specified | 0.30% | 0.60% |
| Phosphorus (max) | 0.12% | 0.04% | 0.04% |
| Sulfur (max) | 0.15%* | 0.05% | 0.05% |
*For Grade O and A, a sulfur content of 0.33% max is acceptable with purchaser approval. For grades C, D, DH, a sulfur content of 0.05–0.13% max is acceptable if manganese ≥ 1.35%.
ASTM A563 Mechanical Properties
| Grade | Style | Size Range | Proof Load — Plain (ksi) | Proof Load — Galv. (ksi) | Hardness (HBN) |
|---|---|---|---|---|---|
| A | Hex | 1/4″ – 1-1/2″ | 90 | 68 | 116 – 302 |
| A | Heavy Hex | 1/4″ – 4″ | 100 | 75 | 116 – 302 |
| B | Heavy Hex | 1/4″ – 1″ | 133 | 100 | 121 – 302 |
| B | 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 |
All proof loads are for UNC, 8UN, 6UN, and coarse-pitch threads. For fine-thread nuts, refer to ASTM A563 Table 3.
ASTM A563 vs ASTM A194 — Key Differences
Engineers frequently ask when to specify A563 versus A194. Here is a concise comparison:
| Criteria | ASTM A563 | ASTM A194 |
|---|---|---|
| Primary Use | General structural & mechanical | High-temperature & pressure service |
| Grade System | O, A, B, C, D, DH, C3, DH3 | 1, 2, 2H, 2HM, 4, 7, 8, 8M, 8C, 8T, 8S |
| Nut Styles | Hex, Heavy Hex, and others | Primarily Heavy Hex |
| Weathering Steel | Yes (C3, DH3 grades) | No |
| Galvanizing Provisions | Explicit oversize tapping allowance | Limited coverage |
| Structural Code Use | AISC, RCSC (preferred for A325/A490) | Often used in ASME code work |
| Interchangeability | A563 DH = A194 2H (most cases) | A194 2H cannot replace all A563 grades |
| Temperature Rating | Ambient / structural | Up to 1200°F with appropriate grade |
ASTM A563 Hex Nut Dimensions (Metric)
| Nom. Size | Body D Max | Body D Min | Height H Max | Height H Min | Flats F Max | Flats F Min | Corners C Max | Corners C Min |
|---|---|---|---|---|---|---|---|---|
| M10 | 10.00 | 9.78 | 6.63 | 6.17 | 17.00 | 15.73 | 18.48 | 17.77 |
| M12 | 12.00 | 11.73 | 7.76 | 4.24 | 19.00 | 17.73 | 20.78 | 20.03 |
| M14 | 14.00 | 13.73 | 9.09 | 8.51 | 22.00 | 20.67 | 24.25 | 23.35 |
| M16 | 16.00 | 15.73 | 10.32 | 9.68 | 24.00 | 23.67 | 27.71 | 26.75 |
| M20 | 20.00 | 19.67 | 12.88 | 12.12 | 30.00 | 29.16 | 34.64 | 32.95 |
| M24 | 24.00 | 23.67 | 15.44 | 14.56 | 36.00 | 35.00 | 41.57 | 39.55 |
| M30 | 30.00 | 29.67 | 19.48 | 17.92 | 46.00 | 45.00 | 53.12 | 50.85 |
| M36 | 36.00 | 35.61 | 23.38 | 21.63 | 55.00 | 53.80 | 63.51 | 60.79 |
| M42 | 42.00 | 41.38 | 26.97 | 25.03 | 65.00 | 62.90 | 75.06 | 71.71 |
| M48 | 48.00 | 47.38 | 31.07 | 28.93 | 75.00 | 72.60 | 86.60 | 82.76 |
| M56 | 56.00 | 55.26 | 36.20 | 33.80 | 85.00 | 82.20 | 98.15 | 93.71 |
| M64 | 64.00 | 63.26 | 41.32 | 38.68 | 95.00 | 91.80 | 109.70 | 104.65 |
| M72 | 72.00 | 71.26 | 46.45 | 43.55 | 105.00 | 101.40 | 121.24 | 115.60 |
| M80 | 80.00 | 79.26 | 51.58 | 48.42 | 115.00 | 111.00 | 132.72 | 126.54 |
| M90 | 90.00 | 89.13 | 57.74 | 54.26 | 130.00 | 125.50 | 150.11 | 143.07 |
| M100 | 100.00 | 99.13 | 63.90 | 60.10 | 145.00 | 140.00 | 167.43 | 159.60 |
ASTM A563 Heavy Hex Nut Dimensions (Inch)
| Dia (in) | Body Max | Body Min | Flats Max | Flats Min | Corners Max | Corners Min | Height Max | Height Min |
|---|---|---|---|---|---|---|---|---|
| 1/2 | 0.515 | 0.482 | 0.875 | 0.850 | 1.010 | 0.969 | 0.364 | 0.302 |
| 5/8 | 0.642 | 0.605 | 1.062 | 1.031 | 1.227 | 1.175 | 0.444 | 0.378 |
| 3/4 | 0.768 | 0.729 | 1.250 | 1.212 | 1.443 | 1.383 | 0.524 | 0.455 |
| 7/8 | 0.895 | 0.852 | 1.438 | 1.394 | 1.660 | 1.589 | 0.604 | 0.531 |
| 1 | 1.022 | 0.976 | 1.625 | 1.575 | 1.876 | 1.796 | 0.700 | 0.591 |
| 1-1/8 | 1.149 | 1.098 | 1.812 | 1.756 | 2.093 | 2.002 | 0.780 | 0.658 |
| 1-1/4 | 1.277 | 1.223 | 2.000 | 1.938 | 2.309 | 2.209 | 0.876 | 0.749 |
| 1-3/8 | 1.404 | 1.345 | 2.188 | 2.119 | 2.526 | 2.416 | 0.940 | 0.810 |
| 1-1/2 | 1.531 | 1.470 | 2.375 | 2.300 | 2.742 | 2.622 | 1.036 | 0.902 |
| 1-3/4 | 1.785 | 1.716 | 2.750 | 2.662 | 3.175 | 3.035 | 1.196 | 1.054 |
| 2 | 2.039 | 1.964 | 3.125 | 3.025 | 3.608 | 3.449 | 1.388 | 1.175 |
| 2-1/4 | 2.305 | 2.214 | 3.500 | 3.388 | 4.041 | 3.862 | 1.548 | 1.327 |
| 2-1/2 | 2.559 | 2.461 | 3.875 | 3.750 | 4.474 | 4.275 | 1.708 | 1.479 |
| 2-3/4 | 2.827 | 2.711 | 4.250 | 4.112 | 4.907 | 4.688 | 1.869 | 1.632 |
| 3 | 3.081 | 2.961 | 4.625 | 4.475 | 5.340 | 5.102 | 2.060 | 1.815 |
Calculate the weight of your ASTM A563 nut order using our Nuts Weight Chart Calculator →
Oversize Tapping Allowances for Hot-Dip Galvanized Nuts
One of the most practical provisions of ASTM A563 is the allowance for oversize tapping of hot-dip galvanized nuts. Zinc coating increases the thread root diameter, and without oversize tapping, galvanized nuts will not engage the bolt thread correctly. ASTM A563 specifies the following oversize tapping allowances (Diametral Allowance, in inches):
| Nut Size & Thread Pitch | Diametral Allowance (in) | Pitch Diameter Min | Pitch Diameter Max |
|---|---|---|---|
| 1/4-20 | 0.016 | 0.2050 | 0.2284 |
| 5/16-18 | 0.017 | 0.2614 | 0.2871 |
| 3/8-16 | 0.018 | 0.3143 | 0.3426 |
| 1/2-13 | 0.019 | 0.4229 | 0.4542 |
| 5/8-11 | 0.020 | 0.5342 | 0.5688 |
| 3/4-10 | 0.020 | 0.6418 | 0.6751 |
| 7/8-9 | 0.020 | 0.7473 | 0.7823 |
| 1-8 | 0.022 | 0.8480 | 0.8858 |
| 1-1/8-7 | 0.022 | 0.9506 | 0.9966 |
| 1-1/4-7 | 0.024 | 1.0756 | 1.1217 |
| 1-1/2-6 | 0.027 | 1.2727 | 1.3271 |
Oversize-tapped nuts for galvanizing are not interchangeable with standard-tapped nuts on non-galvanized bolts. Always confirm galvanizing specification before ordering.
ASTM A563 Nut Coatings & Surface Finishes
| Coating | Standard | Thickness | Best For | Notes |
|---|---|---|---|---|
| Plain (Uncoated) | ASTM A563 | N/A | Interior, dry environments | Most economical; not for outdoor use |
| Hot-Dip Galvanized | ASTM F2329 | 86 µm avg | Outdoor structural, bridges, marine | Requires oversize tapping |
| Mechanical Galvanized | ASTM B695 Cl. 50 | 50 µm | Outdoor with better thread fit | Thinner than HDG; no oversize tap needed |
| Zinc Plated (Electroplated) | ASTM B633 | 5–13 µm | General indoor/outdoor | Not for structural joints per RCSC |
| Black Oxide | MIL-DTL-13924 | 1–5 µm | Indoor, oiled assemblies | Minimal corrosion protection |
| Xylan (PTFE-based) | Whitford Spec | 15–25 µm | Chemical plants, torque control | Low-friction, chemical resistant |
| Teflon Coated | Manufacturer Spec | Variable | Chemical and food-grade applications | Excellent chemical resistance |
| Cadmium Plated | ASTM B766 | 8–13 µm | Aerospace, military | RoHS restricted; declining use |
| Zinc-Nickel | ASTM B841 | 8–15 µm | Automotive, marine | Superior corrosion vs. zinc plate |
Types of ASTM A563 Fasteners
Jade Alloys supplies ASTM A563 nuts in all standard head configurations. Each type serves specific assembly requirements:
ASTM A563 Heavy Hex Nuts
ASTM A563 Hex Nuts
ASTM A563 Jam Nuts
ASTM A563 Square Nuts
ASTM A563 Coupling Nuts
ASTM A563 Cap Nuts
ASTM A563 Lock Nuts
ASTM A593 Wing Nuts
Applications of ASTM A563 Nuts by Industry
ASTM A563 nuts are specified across virtually every sector that uses structural or mechanical bolted connections. Here is how each industry uses them:
| Industry | Application | Typical Grade Used |
|---|---|---|
| Structural Steel Construction | Beam-to-column connections, moment frames, braced frames | DH, C (with A325/A490 bolts) |
| Bridge Engineering | Girder splices, bearing connections, expansion joints | DH3, C3 (weathering steel required) |
| Oil & Gas | Flanged piping, wellhead equipment, offshore platforms | DH, D (with A193 B7 studs) |
| Petrochemical Plants | Process piping, heat exchangers, reactor flanges | C, DH |
| Power Generation | Boiler flanges, turbine foundations, transformer bases | DH, D |
| Mining & Heavy Machinery | Crusher frames, conveyor structures, excavator pins | D, DH |
| Shipbuilding & Marine | Deck fittings, hull structures, engine mounts | DH (galvanized) |
| Water & Wastewater | Pump stations, pipe flanges, treatment plant structures | A, C (galvanized) |
| Pharmaceutical / Chemical | Pressure equipment, stainless or coated assemblies | C, DH (Xylan or Teflon coated) |
| Construction & Infrastructure | Foundation anchor bolts, guardrails, sign structures | A, B (galvanized) |
ASTM A563 Nuts Price List
| Product Description | Grade | Price Range (USD) | Unit |
|---|---|---|---|
| ASTM A563 Grade A Hex Nut | A | $0.02 – $0.80 | Per Piece |
| ASTM A563 Grade C Heavy Hex Nut | C | $900 – $1,400 | Per Ton |
| Hot Dip Galvanized A563 Grade C Heavy Hex Nut | C | $0.05 – $2.00 | Per Piece |
| ASTM A563 Carbon Steel Hex Socket Nut with Groove | A/B | $0.97 – $1.44 | Per kg |
| Alloy Steel Black Heavy ASTM A563 Hex Nut | D/DH | $0.02 – $3.00 | Per Piece |
| Grade DH Heavy Hex Teflon-Coated Nut | DH | $0.01 – $0.50 | Per Piece |
| Black A563 Grade DH Heavy Hex Nut M64 | DH | $0.08 – $1.00 | Per Piece |
| ASTM A563 Grade C3 Heavy Hex Nut | C3 | $0.005 – $2.00 | Per Piece |
| ASTM A563 Grade DH Heavy Hex Nut (standard) | DH | $0.39 | Per Piece |
| A563 Grade DH3 Weathering Steel Heavy Hex Nut | DH3 | POA | Per Piece / Ton |
Prices vary based on grade, size, finish, quantity, and delivery location. Contact us for volume discounts and export pricing for USA, UAE, Saudi Arabia, and European destinations. MOQ: 1 piece for standard stock items.
Get competitive pricing for ASTM A563 Nuts — Grade A, B, C, D, DH, C3, DH3 in stock.
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Testing, Certifications & Quality Assurance
Every lot of ASTM A563 nuts supplied by Jade Alloys undergoes rigorous quality control before dispatch. Our QA programme covers:
- Proof Load Testing per ASTM F606 — mandatory for all structural grades
- Hardness Testing (Brinell HBN) — verified against grade limits
- Chemical Composition Analysis — Optical Emission Spectrometry (OES)
- Dimensional Inspection per ASME B18.2.2 — 100% visual, sampling-based dimensional
- Thread Gauging — go/no-go gauge verification for all thread sizes
- Hot-Dip Galvanizing Inspection per ASTM A153 / ASTM F2329
- Mill Test Reports (MTR / MTC) available for all lots
- Dual Certification: ASME & ASTM codes
- Third-party inspection available: SGS, Bureau Veritas, TUV, RINA
