ASTM A307 Bolts

307A		Headed bolts, threaded rods and bent bolts intended for general applications.
307B		Heavy hex bolts and studs intended for flanged joints in piping systems with cast iron flanges.
307C		Non-headed anchor bolts, either bent or straight, intended for structural anchorage purposes. The end of a grade C anchor bolt intended to project from the concrete will be painted green for identification purposes. Permanent marking is a supplemental requirement.

* Grade C was officially replaced by ASTM F1554 Grade 36 as of August 2007. Jade Alloys can still supply Grade C anchor bolts when specifically required by project specifications — confirm with your engineer. We also stock ASTM F1554 Grade 36 anchors.

ASTM A307 bolts are manufactured from low-carbon steel. The specification sets maximum limits for carbon, manganese, phosphorus, and sulfur. Both heat analysis (ladle) and product analysis (check) limits are defined to ensure consistency across production batches:

 The low carbon content (max 0.29%) makes ASTM A307 bolts readily weldable and machinable, while the manganese addition provides the baseline strength required to meet the 60 ksi tensile minimum.

Important: ASTM A307 does not specify a minimum yield strength. The 60 ksi requirement applies to tensile strength only. For yield-controlled applications, consider upgrading to ASTM A325 or ASTM A490.

 For tensile strength comparison across all bolt grades, see our Bolt Tensile Strength Chart.

ASTM A307 hex bolts conform to ASME B18.2.1 dimensional standards. The table below provides standard nominal sizes, across-flat (wrench) dimensions, head heights, and thread pitch for commonly ordered A307 hex bolts:

 Custom lengths are available. Contact our team for non-standard diameters beyond 4″ or lengths beyond standard stock.

The lower sulfur limit for Grade B (0.05% vs. 0.15% for Grade A) reflects the more demanding service conditions of flanged piping joints. Base material is typically equivalent to ASTM A36 carbon steel round bar.

 Note: Equivalents are approximate. Always verify specific project requirements with the applicable design engineer before substituting international standards for ASTM A307.

A563 nuts of higher grades (e.g., Grade C, D, DH) may also be used where specified. All nuts and washers are available from Jade Alloys as a complete fastening kit.

Jade Alloys manufactures ASTM A307 / ASME SA307 bolts in the following product forms:

Surface finish selection affects corrosion resistance, installation torque, and compatibility with structural coatings. Jade Alloys supplies A307 bolts in the following finishes:

 Hot-dip galvanized A307 bolts require oversized nuts per ASME B18.2.2 to allow for the additional zinc coating thickness on the threads.

Engineers frequently need to select between A307 and higher-strength bolt standards. The comparison below helps clarify which specification is appropriate for your application:

Choose ASTM A307 Grade A when you need a proven, economical carbon steel bolt for general structural and construction applications. Upgrade to A325 only when AISC/RCSC requires pretensioned high-strength connections. For anchor rod applications, use F1554 Grade 36 (the official A307 Grade C replacement).

ASTM A307 requires manufacturer identification marks on the bolt head. The following markings are mandated:

• Manufacturer’s identification symbol — a unique marking registered with ASTM and IFI
• Grade designation — ‘A307’ or ‘A’ or ‘B’ marking as appropriate to the grade
• No grade marking is required for Grade A bolts intended for general use — absence of other grade markings indicates A307 Grade A
• Grade B bolts must be marked with the manufacturer’s symbol but do not require ‘B’ on the head per standard

Jade Alloys supplies A307 bolts with complete manufacturer identification on the head and provides EN 10204/3.1 Mill Test Certificates (MTC) with every shipment confirming chemical composition and mechanical property compliance.

Grade A Applications — General Structural

• Building construction — steel frame to concrete slab base plate connections
• Bridge construction — timber deck boards, guardrail systems, sign support structures
• Highway infrastructure — guardrail splicing, barrier bolts, highway sign supports
• Timber framing — post-and-beam connections, wood-to-wood and wood-to-steel joints
• Industrial facilities — machinery anchorage, equipment bases, structural mezzanine connections
• Prefabricated structures — modular building frames, steel building kits

Grade B Applications — Cast Iron Flange Piping

• Water and wastewater treatment — cast iron flange connections per AWWA standards
• HVAC systems — cast iron heat exchanger flanges, chiller connections
• Low-pressure piping — Class 125 and Class 250 cast iron flange systems per ASME B16.1
• Municipal infrastructure — water mains, pump connections, valve assemblies