🔹 When to Use ASTM A307
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Low-strength, general-purpose applications
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Tensile strength: 60 ksi (414 MPa) minimum
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Typical yield: ~36 ksi (250 MPa)
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Common Uses:
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Light construction (non-structural)
- Anchor bolts (for light duty, often replaced by F1554 Grade 36 in modern specs)
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Not allowed for structural steel joints governed by AISC/RCSC specs.
👉 Use A307 when cost efficiency matters more than strength, and loads are low.
🔹 When to Use ASTM A325
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High-strength structural applications
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Tensile strength: 120 ksi (827 MPa) for ≤ 1 in. dia.
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Yield strength: 92 ksi (635 MPa) minimum
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Common Uses:
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Structural steel connections (beam-to-column, trusses, bridges, towers)
- Joints covered by AISC / RCSC (Specification for Structural Joints Using High-Strength Bolts)
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Preferred over A307 when safety-critical, high-load, or code-regulated.
👉 Use A325 when structural integrity and code compliance are required.
🔹 Quick Comparison
| Property | A307 Grade A | A325 |
|---|---|---|
| Min. Tensile Strength | 60 ksi (414 MPa) | 120 ksi (827 MPa) |
| Yield Strength | ~36 ksi (250 MPa, typical) | 92 ksi (635 MPa) |
| Elongation | 18% | 14% |
| Typical Use | General-purpose, light-duty, non-structural | Structural steel connections, bridges, buildings |
| Code Compliance | Not accepted for AISC/RCSC structural joints | Required for structural steel joints |
✅ In short:
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Use A307 → for non-structural, light-duty fastening where high strength is not required.
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Use A325 → for structural steel and high-load connections, where safety and code compliance demand high strength.
ASTM A307 vs A325 — Usage Comparison
| Application / Industry | Typical Use of A307 (60 ksi) | Typical Use of A325 (120 ksi) |
|---|---|---|
| Building Construction | Light framing, handrails, ladders, equipment supports, non-structural bracing | Structural steel connections (beams, columns, girders), moment connections |
| Bridges & Towers | Small utility brackets, sign supports | Main structural joints, trusses, tower legs, splice plates |
| Anchor Bolts | Light-duty anchor bolts for machinery bases, fences, HVAC supports (often replaced today by F1554 Gr.36) | Heavy anchor bolts for columns, crane rails, bridge bearings |
| Machinery & Equipment | Attaching guards, covers, light equipment frames | Heavy machinery frames, lifting points, hoisting equipment |
| Plumbing / Piping | Pipe hangers, brackets, light flanges | Pressure vessel supports, structural pipe racks |
| Agriculture / Light Industry | Farm equipment repairs, light-duty fastening | Structural steel sheds, silos, conveyor supports |
| Infrastructure | Road sign supports, traffic light bases | Highway overpasses, structural joints, heavy gantry supports |
| Code Compliance | General-purpose only, not allowed for AISC structural steel | Required by AISC/RCSC for structural joints |