ASTM A307 Bolts
ASTM A307 carbon steel bolts — low/medium carbon, 60,000 psi minimum tensile, Grades A and B, hardness B69–B100. The standard general-purpose low-strength inch-series grade for non-structural joints.
Last updated: 2026-11
Specifications
A307 is the general-purpose low-carbon steel bolt specification of the inch series: 60,000 psi minimum tensile, no quenching and tempering, and the lowest cost per fastener in the structural catalog. Grade A covers general use — cast iron to steel connections, light framing, equipment anchoring; Grade B covers flanged joints in piping systems with its tight tensile window (60 ksi min, 100 ksi max) to control bolt load on gaskets. It is not a substitute for A325/F3125 in engineered structural connections.
| Standard | ASTM A307, Grade A (general) or Grade B (piping flanged joints); size range 1/4"–4" |
|---|---|
| Material | Low or medium carbon steel, no quench and temper |
| Tensile strength, min | 60,000 psi (Grade B: 60,000 psi min / 100,000 psi max) |
| Hardness | B69–B100 (Grade A); B69–B95 (Grade B) |
| Joint type | Low-pressure, static-load, non-structural connections |
| Typical applications | Light structural framing, equipment anchoring, support brackets, pipe flanges (Grade B), general construction |
| Finishes | Plain, zinc plate, hot-dip galvanized |
Where this grade fits
A307 is the low-strength, non-structural grade: 60,000 psi minimum tensile, no quench and temper, and correspondingly low torque values — a static-load joint grade, not a substitute for F3125 A325 in engineered connections. Because it is not hardened, neither hydrogen embrittlement nor fatigue govern its use; the joint type does.
Deep read: How to Determine Tightening Torque and Choose a Tightening Method for a Bolted Joint
Materials
- Low carbon steel
- Medium carbon steel
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ASTM A307 Bolts) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 1,000–10,000 pieces depending on size. Stock items run 3–7 days. High-strength and custom parts run 15–25 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Can A307 bolts be used instead of A325 structural bolts?
No — not where the connection is engineered. A307 carries roughly half the tensile strength of F3125 Grade A325 (60,000 vs 120,000 psi) and is not produced to the structural-bolt heavy-hex, thread-length and rotation-capacity requirements that structural codes such as AISC and DOT specifications reference. A307 is the correct, economical choice for static, low-load and anchoring work; the moment a connection is designed to a structural code, the specification will require A325 or equivalent.
What is the MOQ and lead time for this bolt grade?
The minimum order quantity is 1,000–10,000 pieces depending on size. Stock items ship in 3–7 days; high-strength and custom parts in 15–25 days. Common diameters in this grade are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
What should an RFQ for this bolt grade state?
State the standard and grade (for example ISO 4017 Class 8.8 or ASTM F3125 Grade A325 Type 1), diameter and length, thread type (metric coarse or UNC/UNF), finish (plain, zinc, or hot-dip galvanized where the grade permits), required certificates such as a mill test report per EN 10204 3.1, and quantity per size — plus destination country.
Related knowledge
- What Bolt Property Classes 8.8, 10.9 and 12.9 Encode — and When High Strength Stops Being the Right Choice
- Bolt Grade Selection: ISO 898-1 8.8/10.9/12.9 vs ASTM A307 and A325
- 8.8 vs 10.9 vs 12.9 Bolts: Strength, Hardness and Cost — What the Evidence Settles
- Calculating Bolt Preload and Clamp Force: Torque, Friction and Tightening Method
- How to Determine Tightening Torque and Choose a Tightening Method for a Bolted Joint
- Fastener Failure Modes: Which Fatigue, Creep and SCC Controls the Evidence Supports
- Hydrogen Embrittlement in High-Strength Bolts: Which Grades Need Controls, Which Coatings and Baking Schedules Are Acceptable, and What to Require Before the RFQ
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support