ASTM A325 Bolts also referred to as A325 Structural Bolts and A325 Fasteners are high-strength, heat-treated structural fasteners used for steel-to-steel connections in bridges, high-rise buildings, and heavy industrial frameworks. Defined under the ASTM standard for quenched and tempered medium-carbon and alloy steel, A325 hex bolts are produced in two types: Type 1 (carbon or alloy steel) and Type 3 (weathering steel for corrosive environments). Available in diameters from 1/2” to 1-1/2”, they deliver minimum tensile strength of 105–120 ksi. Jade Alloys is an ISO-certified supplier and exporter of ASTM A325 Fasteners with stock held in Mumbai and express dispatch to 50+ countries.
The specification lists two categories of quenched and tempered structural bolting fasteners. Type 1 consists of high-strength plain carbon or alloy steel (including boron variants) that is heat treated, requiring a minimum tensile strength of 120 ksi, a minimum yield of 92 ksi, and a hardness of 25–35 HRC for diameters up to 1”. Type 3 is weathering steel — heat treated with the same strength profile as Type 1 but with significantly enhanced atmospheric corrosion resistance, making it suitable for exposed outdoor and marine environments.
Note: ASTM A325 was officially withdrawn by ASTM International in November 2016 and superseded by ASTM F3125 Grade A325, which carries identical mechanical requirements. Jade Alloys supplies both legacy A325 and current F3125/A325 specifications.
ASTM A325 Bolt Price: Pricing depends on bolt diameter, length, coating type, and quantity. As a direct stockist and exporter, Jade Alloys offers competitive ex-works pricing from Mumbai with shipment to USA, UAE, UK, Saudi Arabia, Singapore, and 50+ countries.
ASTM A325 Structural Bolts Suppliers
Jade Alloys is a Mumbai-based manufacturer and global exporter of ASTM A325 Structural Bolts, holding ISO 9001:2015 certification and maintaining ready stock for immediate dispatch. We supply A325 Type 1 and Type 3 ASTM A325 Fasteners, including hot-dip galvanized, mechanically galvanized, and plain-finish variants, with material test reports (MTRs) and EN 10204 3.1 / 3.2 certifications available on request. Our A325 fasteners have been supplied to infrastructure projects across the USA, UAE, Saudi Arabia, Singapore, and 50+ countries worldwide.
Supplied to structural steel contractors, EPC companies, and fabricators across North America, GCC, and Southeast Asia. Our technical team is available Mon–Sat, 9am–6pm IST for specification queries. Call us or submit an RFQ for a same-day quote.
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Nuts Weight Chart
ASTM A325 Types & Grade Classification
| Type | Material / Description |
|---|---|
| Type 1 | Medium carbon, carbon boron, or medium carbon alloy steel. Heat-treated (quenched and tempered). Most common type for general structural applications. |
| Type 2 | Withdrawn by ASTM in November 1991. For legacy projects specifying Type 2, contact Jade Alloys for engineering consultation. |
| Type 3 | Weathering steel (atmospheric corrosion resistant). Same strength profile as Type 1. Preferred for exposed outdoor, coastal, and industrial environments. |
| T | Fully threaded A325. Restricted to a maximum length of 4 times the nominal diameter. |
| M | Metric A325. Same mechanical properties, metric dimensions. |
Connection Type Codes: SC / N / X
A325 bolts are specified with connection type codes that define installation requirements — the bolt specification itself is identical across all three:
| Code | Type | Description |
|---|---|---|
| SC | Slip-Critical | Full pretension required. Bolt clamping force must resist slip between connected parts under service load. |
| N | Bearing — Threads in Shear Plane | Snug-tight installation acceptable. Threads may be in the shear plane. |
| X | Bearing — Threads Excluded from Shear Plane | Higher shear capacity. Threads must be positioned outside the shear plane. |
- Types of ASTM A325 Fasteners
- ASTM A325 Structural Bolts Specifications
- ASTM A325 vs ASTM F3125 Grade A325 — What Changed?
- ASTM A325 Bolt Chemical Composition
- ASTM A325 Bolts Mechanical Properties
- Comparative Tensile Strength: ASTM A325 vs A490 vs A193 B7
- Equivalent Grade of A325 Fasteners
- A325 Structural Bolts Coating
- ASTM A325 Heavy Hex Bolt Dimensions Chart
- ASTM A325 Heavy Hex Bolt Tolerance Chart
- A325 Galvanized Bolts Torque Chart
- How to Install ASTM A325 Structural Bolts
- ASTM A325 Bolts Inventory
- Compatible Nuts & Washers for A325 Structural Bolts
- Applications of ASTM A325 Bolts
- Related Products
- Frequently Asked Questions About ASTM A325 Bolts
Types of ASTM A325 Fasteners
ASTM A325 Bolts And Nuts
ASTM A325 Carriage Bolt
ASTM A325 Heavy Hex Bolts
ASTM A325 Countersunk Bolts
ASTM A325 Stud Bolts
ASTM A325 Hex Bolt
ASTM A325 Anchor Bolts
ASTM A325 Heavy Hex Structural Bolts
ASTM A325 Bolt Washer
ASTM A325 U Bolt
ASTM A325 Type 1 Bolts
ASTM A325 Type 3 Bolts
ASTM A325 Structural Bolts Specifications
| Property | Details |
|---|---|
| ASTM A325 Fasteners Sizes |
Cold Formed: M2–M24 Hot Forged: M24–M100, 1-1/2” Dia, up to 1100mm length CNC Machining: M100 / 4” Dia, up to 1500mm length Custom metric sizes M2 through M160 available |
| A325 Type 1 Metric Size | Dia: M10 – M110 | Length: 12 – 1200mm |
| ASTM A325 Hex Bolts Size (Inch) | Dia: 1/2” – 4.0” | Length: 1/2” – 52” |
| Standards | ASTM, ANSI B18.2.4 2M, ANSI B18.2.4 1M, ISO, DIN, BS, ASME, JIS, GB/T5783, GB/T5782, IS, SAE, UNI, CSN, EU, IFI, PN |
| Length Range | 3mm to 200mm (standard); custom lengths available |
| Thread Types | UNC, UNF, UNEF, UNJC, UNJF, UNK, UNR, Metric, BSW, BSF, Constant-pitch |
| UTS (Unified Thread Standard) | UNC, UNF, NPT, UNS, UNEF, NPTF |
| Head Drive | Phillips/Slot, Phillips, Slotted, Six-Lobe, Heavy Hex |
ASTM A325 vs ASTM F3125 Grade A325 — What Changed?
| Factor | ASTM A325 (Withdrawn 2016) | ASTM F3125 Grade A325 (Current) |
|---|---|---|
| Status | Withdrawn November 2016 | Active — required for new construction |
| Tensile Strength (≤1”) | 120 ksi minimum | 120 ksi minimum — identical |
| Tensile Strength (>1”) | 105 ksi minimum | Higher requirements for larger diameters |
| Head Marking | A325 | A325 or A325S (alternative heads) |
| USA Building Code | Legacy — many codes still allow | Required for most current projects |
ASTM A325 Bolt Chemical Composition
| Element (Heat Analysis) | 120 ksi (%) | 150 ksi (%) |
|---|---|---|
| Carbon | 0.30 – 0.52 | 0.30 – 0.48* |
| Manganese | 0.60 min | 0.60 min |
| Phosphorus | 0.035 max | 0.035 max |
| Sulfur | 0.040 max | 0.040 max |
| Silicon | 0.15 – 0.30 | — |
| Boron | 0.003 max | 0.003 max |
| Copper | — | — |
| Nickel | — | — |
| Chromium | — | — |
| Molybdenum | — | — |
*Carbon 0.35–0.53% for 1-1/2” A490 / 150 ksi bolts
ASTM A325 Bolts Mechanical Properties
| Size | Tensile (ksi) | Yield (ksi) | Elongation % min | RA % min |
|---|---|---|---|---|
| 1/2” – 1” | 120 min | 92 min | 14 | 35 |
| 1-1/8” – 1-1/2” | 105 min | 81 min | 14 | 35 |
Comparative Tensile Strength: ASTM A325 vs A490 vs A193 B7
Use this table to select the correct specification for your load requirements.
| Grade | Size Range | Tensile ksi (min) | Yield ksi (min) |
|---|---|---|---|
| A325 | 1/2” – 1” | 120 | 92 |
| A325 | 1-1/8” – 1-1/2” | 105 | 81 |
| A490 | 1/2” – 1-1/2” | 150 | 130 |
| A193 B7 | Up to 2-1/2” | 125 | 105 |
| A193 B7 | 2-5/8” – 4” | 115 | 95 |
Equivalent Grade of A325 Fasteners
| Standard | Equivalent Grade |
|---|---|
| ISO | Grade 8.8S |
| DIN | DIN 6914 |
| BS | BS 4395-1 |
| New ASTM | F3125 Grade A325 |
A325 Structural Bolts Coating
| Bolt Specification | F2329 Hot Dip Galvanizing | B695 Mechanical Galvanizing | F1136 Zinc/Aluminum (Geomet) | F2833 Zinc/Aluminum |
|---|---|---|---|---|
| A325 | Approved | Class 55 | Grade 3 | Grade 1 |
| F1852 | N.A. | Class 55 | N.A. | N.A. |
| A490 | N.A. | N.A. | Grade 3 | Grade 1 |
| F2280 | N.A. | N.A. | N.A. | N.A. |
*Other coatings may be used on 120 ksi/A325 fasteners depending on purchaser and user requirements. N.A. = Not Approved
ASTM A325 Heavy Hex Bolt Dimensions Chart
| Bolt Dia. | D — Body Dia. (Max) | F — Width Across Flats | C — Width Across Corners | H — Height | T — Thread Length | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Max | Basic | Max | Min | Max | Min | Basic | Max | Min | Basic | |
| 1/2 | 0.515 | 7/8 | 0.875 | 0.850 | 1.010 | 0.969 | 5/16 | 0.323 | 0.302 | 1.00 |
| 5/8 | 0.642 | 11/16 | 1.062 | 1.031 | 1.227 | 1.175 | 25/64 | 0.403 | 0.378 | 1.25 |
| 3/4 | 0.768 | 1-1/4 | 1.250 | 1.212 | 1.443 | 1.383 | 15/32 | 0.483 | 0.455 | 1.38 |
| 7/8 | 0.895 | 1-7/16 | 1.438 | 1.394 | 1.660 | 1.589 | 35/64 | 0.563 | 0.531 | 1.50 |
| 1 | 1.022 | 1-5/8 | 1.625 | 1.575 | 1.876 | 1.796 | 39/64 | 0.627 | 0.591 | 1.75 |
| 1-1/8 | 1.149 | 1-13/16 | 1.812 | 1.756 | 2.093 | 2.002 | 11/16 | 0.718 | 0.658 | 2.00 |
| 1-1/4 | 1.277 | 2 | 2.000 | 1.938 | 2.309 | 2.209 | 25/32 | 0.813 | 0.749 | 2.00 |
| 1-3/8 | 1.404 | 2-3/16 | 2.188 | 2.119 | 2.526 | 2.416 | 27/32 | 0.878 | 0.810 | 2.25 |
| 1-1/2 | 1.531 | 2-3/8 | 2.375 | 2.300 | 2.742 | 2.622 | 15/16 | 0.974 | 0.902 | 2.25 |
ASTM A325 Heavy Hex Bolt Tolerance Chart
| Bolt Diameter | Bolt Lengths Thru 6” | Bolt Lengths Over 6” |
|---|---|---|
| 1/2” | -0.12 | -0.19 |
| 5/8” | -0.12 | -0.25 |
| 3/4” | -0.19 | -0.25 |
| 7/8” | -0.19 | -0.25 |
| 1” | -0.19 | -0.25 |
| 1-1/8” | -0.25 | -0.25 |
| 1-1/4” | -0.25 | -0.25 |
| 1-3/8” | -0.25 | -0.25 |
| 1-1/2” | -0.25 | -0.25 |
A325 Galvanized Bolts Torque Chart
| Bolt Size | TPI | Tension (lbs) | Tightening Torque Range ft·lbs (Min – Max) | ||
|---|---|---|---|---|---|
| Min | Max | Galv + Waxed | Plain | ||
| 1/2 | 13 | 12,000 | 14,000 | 50 – 58 | 100 – 117 |
| 5/8 | 11 | 19,000 | 23,000 | 99 – 120 | 198 – 240 |
| 3/4 | 10 | 28,000 | 34,000 | 175 – 213 | 350 – 425 |
| 7/8 | 9 | 39,000 | 47,000 | 284 – 343 | 569 – 685 |
| 1 | 8 | 51,000 | 61,000 | 425 – 508 | 850 – 1,017 |
| 1-1/8 | 7 | 64,000 | 77,000 | 600 – 722 | 1,200 – 1,444 |
| 1-1/4 | 7 | 81,000 | 98,000 | 844 – 1,021 | 1,687 – 2,042 |
| 1-3/8 | 6 | 97,000 | 117,000 | 1,111 – 1,341 | 2,223 – 2,681 |
| 1-1/2 | 6 | 118,000 | 143,000 | 1,475 – 1,788 | 2,950 – 3,575 |
How to Install ASTM A325 Structural Bolts
A325 bolts may be installed using three AISC-approved methods. Always consult AISC Specification Section J3 for project-specific requirements.
- Turn-of-Nut Method
Bring assembly to snug-tight condition first, then rotate the nut a specified fraction of a turn (1/3 to 1 full turn, depending on bolt length and grip). This is the most common field installation method. - Calibrated Wrench Method
Use a torque wrench calibrated to achieve the minimum bolt tensions listed in the torque chart above. Torque values differ between plain and galvanized + waxed finishes — use the correct column. - Direct Tension Indicator (DTI) Method
Use ASTM F959 DTI washers, which deform under a specific clamp force, providing visual confirmation of adequate bolt tension. Required for slip-critical (SC) connections where tension verification is mandatory.
Get a Quote for ASTM A325 Structural Bolts
Ready stock available. Dispatch within 3–5 business days. MTR/certifications included.
ASTM A325 Bolts Inventory
ASTM A325 Bolts
ASTM A325 Stud Bolts
ASTM A325 Hex Bolts
Packing & Dispatch: ASTM A325 Bolts are packed in wooden boxes, corrugated cartons, or steel drums per customer requirement. Standard packing: 25 kg per box. Bulk packing available for large orders. Weight per piece varies by diameter and length — use our Bolts Weight Chart Calculator for precise estimates. All packages ship with MTC documentation.
Compatible Nuts & Washers for A325 Structural Bolts
Selecting the correct mating hardware is required for compliant structural bolt assemblies. The following specifications are standard for ASTM A325 bolt assemblies:
🔩 Standard Nuts
ASTM A563 Grade D, DH, or C — standard compatible nuts for A325 Type 1 bolts. View ASTM A563 Nuts →
🔩 Substitute Nuts
ASTM A194 Grade 2H — approved substitute for ASTM A563 in most applications. View A194 2H Nuts →
🔩 Type 3 (Weathering) Nuts
ASTM A563 DH3 or C3 — required for A325 Type 3 bolts to maintain weathering steel system integrity.
🔧 Standard Washers
ASTM F436 Hardened Washer — Type 1 for A325 Type 1 bolts; Type 3 for A325 Type 3 bolts. Required under the turned element during installation.
🔧 DTI Washers
ASTM F959 Direct Tension Indicating Washers — provides visual tension verification. Required for slip-critical connections on many projects.
📦 Complete Assemblies
Contact Jade Alloys to order complete A325 bolt assembly sets with matching nuts and washers — single-source supply with combined MTC documentation.
Applications of ASTM A325 Bolts
- Structural Steel Construction: A325 Structural Bolts are the standard fastener for moment connections and shear connections in multi-story steel frames per AISC specification requirements.
- Bridge Construction: High-strength A325 bolts provide the fatigue resistance required in bridge girder connections subjected to dynamic loading. Both Type 1 and galvanized variants are used.
- Transmission Towers & Lattice Structures: A325 hex bolts with galvanized finish are used in angle-iron tower joints exposed to wind, weather, and vibration over long service lives.
- Heavy Machinery & Industrial Equipment: Used in machine bed bolting and equipment baseplate connections where high preload and slip-critical clamping is required under dynamic loads.
- Mining & Oil & Gas Infrastructure: A325 Type 3 weathering bolts are used in outdoor structural frames and processing plant structures in corrosive environments.
- Industrial & Infrastructure Projects: Used extensively in warehouses, storage facilities, industrial sheds, power plants, and large infrastructure projects requiring compliant high-strength structural fasteners.
Frequently Asked Questions About ASTM A325 Bolts
What is the ASTM A325 bolt standard?
ASTM A325 is an ASTM International standard specification (formally titled Standard Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength) covering high-strength heavy hex structural bolts in diameters from 1/2” to 1-1/2” (approximately 12mm to 38mm). Note: ASTM A325 was withdrawn in November 2016 and replaced by ASTM F3125 Grade A325. Jade Alloys supplies both legacy A325 and current F3125/A325 specifications.
What are A325 bolts used for?
A325 structural bolts are primarily used in structural steel connections requiring high tensile strength and fatigue resistance. They are critical in bridge girder connections, multi-story steel frames, transmission tower joints, and heavy industrial equipment bases — anywhere slip-critical or bearing-type connections are required under significant load.
How do you measure ASTM A325 bolts?
The length of an ASTM A325 Heavy Hex Bolt is measured from directly under the bolt head to the extreme end of the tip. This is standard for all hex-head bolts. Do not include the head height in the measurement.
What is the minimum tensile strength of ASTM A325 bolts?
ASTM A325 bolt tensile strength depends on diameter. For sizes between 1/2” and 1”: minimum tensile strength of 120 ksi with a minimum reduction in area of 35%. For the larger sizes 1-1/8” to 1-1/2”: minimum tensile strength of 105 ksi, with the same minimum area reduction of 35%.
What is the main difference between an A325 and an A490 bolt?
A490 bolts have a higher minimum tensile strength (150 ksi) compared to A325 bolts (120 ksi). A490 bolts are specified when higher strength or higher pretension is required — typically for heavy column splices or moment connections under extreme load. A325 bolts are appropriate for most standard structural steel connections and are the more commonly specified grade.
What nuts and washers are compatible with ASTM A325 bolts?
ASTM A325 structural bolts are used with ASTM A563 Grade D, DH, or C nuts (or ASTM A194 2H as an approved substitute). For Type 3 weathering steel bolts, use ASTM A563 DH3 or C3 nuts. The recommended washer is ASTM F436 hardened washer — Type 1 for A325 Type 1 bolts, Type 3 for A325 Type 3 bolts. ASTM F959 Direct Tension Indicating (DTI) washers are also available. Contact Jade Alloys to order complete bolt assembly sets with matching nuts and washers.
