What is an A325T bolt?


An A325T bolt is a fully threaded version of an F3125 grade A325 heavy hex structural bolt. The F3125 specification is very specific when it addresses thread lengths. Standard A325 bolts have very short thread lengths due to their application as a bolt intended for use in structural steel connections since often it is undesirable for threads to be included the shear plane.

Fully threaded A325 bolts are marked on the head of the bolt with “A325T” instead of “A325”. Another very important aspect of an A325T bolts is that they are limited to 4 times the diameter in length. For example, 3/4″ A325T bolts cannot exceed 3″ (four times 3/4″) in length and 1″ diameter A325T bolts cannot exceed 4″ (four times 1″) in length.

S1.1 A325 and A325M Bolts with nominal lengths equal to or shorter than 4D may be threaded full length. These bolts need not have a shoulder. 

Modified head geometry or special thread lengths are permitted under Supplementary Requirement S2. When invoked, the bolts are marked “A325S” to designate that something about the bolt varies from a standard A325.

S2.1 Dimensions which differ from the requirements of this specification, such as modified head geometry or special thread lengths that do not the requirements of section S1, are permitted when requested by the customer. 

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    @Majeed- The ‘S’ indicates some sort of non-standard variation, whether that be head dimensions or thread length. The ‘T’ means that the bolts have standard geometry, but are fully threaded.

    @Navid- As far as we are aware, there is no prohibition on pretensioning A325T in the same way as one would a standard A325 bolt.

    Is there such a thing as A325T, 1/2″ x 5-1/2″ (need 1-1/2″ – full threads)
    I see A325 1/2″ bolts all have 1″ of thread and the length usually stops around 4-1/2″
    please advise and equivalent if the A325T is not available.


    @Mona- The ASTM F3125/A325 specification only allows for (A325T) full thread bolts up to 2″ long. However, it does permit special thread lengths, and we can manufacture those per your request.

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