A449 Bolts

A449 Bolts

A449 is a fastener specification that covers medium-strength steel fasteners ranging from 1/4” through 3” in diameter. A449 is a general-purpose specification made from a medium carbon or alloy round bar which develops its strength properties through a heat-treating process. It is not widely available in the marketplace and typically must be manufactured per order. 

This specification is virtually identical in strength and chemistry to ASTM A325. A449 can reach 1” in diameter and SAE J429 Grade 5. It has more flexibility due to its larger diameter range and not being restricted by any particular configuration.

Grade Marking Specification Material and Treatment Nominal Size (In.) Mechanical Properties Hardness Rockwell
Proof Load Min (ksi) Yield Strength Min (ksi) Tensile Strength Min (ksi) Elong % Min [9] RA % Min [10] Min Max
ASTM A325 Type 1 A325 Type 1 Medium Carbon Steel, Q & T 1⁄2” – 11⁄2“ 85 92 120 14 35 C25 C34
ASTM A325 Type 3 A325 Type 3 Atmospheric Corrosion Resistant Steel, Q & T
ASTM A449 Type 1 A449 Type 1 Medium Carbon Steel, Q & T 1⁄4” – 1″ 85 92 120 14 35 C25 C34
11⁄8” – 11⁄2“ 74 81 105 C19 C30
15⁄8” – 3″ 55 58 90 B91 B100
ASTM A449 Type 3 A449 Type 3 Weathering Steel, Q & T 1⁄4” – 1″ 85 92 120 14 35 C25 C34
11⁄8” – 11⁄2“ 74 81 105 C19 C30
15⁄8” – 3″ 55 58 90 B91 B100

A449 Specification Types

The A449 specification includes two sub-types within it.

  • Type 1 is a medium carbon steel that has undergone a heat-treating process.
  • Type 3 is made from weathering steel that also undergoes a heat-treating process. Type 3 material has natural corrosion-resistant chemical properties preventing the material from rusting in outdoor elements.