Patriot Bolt machines ASTM A307 stud bolts from low-carbon steel bar. A307 is the economical carbon steel bolting grade, with 60 ksi minimum tensile strength, in diameters from 1/4 to 4 in.
Grade A is for general applications. Grade B is the grade written for flanged joints in piping systems with cast-iron flanges. We make A307 studs to your purchase order or drawing, and every order ships with mill test reports traceable to the heat.
A307 Grade A / B Stud Bolts at a Glance
- Specification
- ASTM A307 Grade A or Grade B
- Material
- Low-carbon steel, 0.29% C max
- Strength
- 60 ksi min tensile; Grade B 60–100 ksi
- Size range
- 1/4 to 4 in
- Matching nut
- A563 Grade A
- Configurations
- Fully threaded, double-end and tap-end
Why Engineers Specify A307 Studs
- Economical. Low-carbon steel with no heat treatment keeps cost down where high strength is not needed.
- Grade B for cast iron. Grade B adds a maximum tensile strength of 100 ksi, which protects cast-iron flanges from being overloaded.
- Wide size range. 1/4 to 4 in.
A307 is not a pressure-flange grade for steel piping in high-pressure or high-temperature service. Use A193 B7 there. For anchor bolts, F1554 Grade 36 replaced A307 Grade C in 2007.
A307 Stud Bolt Specifications
ASTM A307 sets properties by grade.
| Grade | Tensile | Yield, min | Elongation, min | Intended use |
|---|---|---|---|---|
| A | 60 ksi min | — | 18% | General applications |
| B | 60–100 ksi | — | 18% | Flanged joints with cast-iron flanges |
A307 Chemical Composition
| Element | Grade A | Grade B |
|---|---|---|
| Carbon | 0.29 max | 0.29 max |
| Manganese | 1.20 max | 1.20 max |
| Phosphorus | 0.04 max | 0.04 max |
| Sulfur | 0.15 max | 0.05 max |
Limits per the current edition of the specification. The mill test report for your heat is the controlling document.
Stud Configurations
- Fully threaded studs, threaded end to end, for flange bolting where grip length varies.
- Double-end studs, threaded on both ends with an unthreaded center.
- Tap-end studs, with one end made to thread into a tapped hole.
Applications and Industries
- Low-pressure piping: Cast-iron flanged joints with Grade B studs.
- General fabrication: Equipment, frames and non-critical connections. See Industrial Manufacturing.
- Utility and water systems: Low-pressure flanged valves and fittings.
Certification and Traceability
Patriot Bolt is ISO 9001:2015 certified. Each A307 order includes mill test reports traceable to the heat, along with a certificate of conformance to the specification on your purchase order.
Fasteners are marked as the specification requires, along with our identification.
Compare A307 with other bolting grades in our Fastener Materials Matrix.
A307 Grade A / B Stud Bolts FAQ
What is the difference between A307 Grade A and Grade B?
Both have 60 ksi minimum tensile. Grade B also has a 100 ksi maximum and is intended for cast-iron flanged joints. Grade A is for general use.
Which nut goes with A307?
A563 Grade A. Use heavy hex nuts on Grade B studs.
Can A307 replace B7 on steel flanges?
No. A307 is far weaker than B7 and is not intended for high-pressure or high-temperature steel flanges.
What replaced A307 Grade C?
ASTM F1554 Grade 36 replaced A307 Grade C for anchor bolts in 2007.
Request a Quote
Send us the stud configuration, diameter, length, thread, specification and quantity, or upload your drawing. Our team will confirm the material and lead time. Call (281) 581-0176 or request a quote.
Also in A307: A307 fasteners hub · A563 heavy hex nuts · F1554 anchor bolts · All stud bolts