A325 Bolt

A325 is an ASTM specification that describes the manufacturing of high-strength structural bolts used in the fabrication and erection of structural steel. There are 2 types of A325 bolts.

Type 1 is a standard unfinished Hex Head bolt (the kind you use in 99 % of your jobs). these bolts may be hot-dip or mechanically galvanized. Type 3 is a plain unfinished Hex Head bolt made of weathering grade steel and is seldom used except on bridges.

Type 3 may be substituted for Type 1 without approval, however Type 1 may not be substituted for Type 3 without approval.

You may wonder why there is no Type 2. That's because they were done away with in the 2000 RCSC Spec. Those of you still using your ASD 9 (the Green Book) might want to scratch that out along with other outdated data.

Bolts which are colloquially referred to as A325-TC are correctly called F1852 and are specially designed assemblies that use a break-off spline to indicate that they are properly tensioned. They are also available as Type 1 and Type 3 and may be galvanized the same as their A325 counterparts. They may be substituted for their respective A325 counterparts without approval.

SC is not a bolt. It is the description of a type of connection (slip-critical) that any of the foregoing bolts may be used in. The other connections that any of the forgoing bolts may be used in are bearing-type connections designated as N or X. the N designation indicates that the threaded portion of the bolt may lie in a shear plane. The X designation indicates that the threaded portion must be excluded from the shear plane.

Complete discussions of this information is available here: http://www.boltcouncil.org/files/2004RCSCSpecification.pdf

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