These bolts are intended for use in structural connections. ASTM A325 specifications are manufactured in the diameters ranging from ½” – 1-1/2” Ø. A325 structural bolts have two different types, Type 1 and Type 3 (there was type 2 but it was withdrawn in November 1991). Similar ASTM Specifications are: A449 and A490.

Type 1: Medium carbon, carbon boron or medium carbon alloy steel 
Type 3: Weathering steel 

Recommended Nuts: 
Type 1 Plain: A563-C, C3, D, DH, DH3 
Type 1 Zinc Coated (Galvanized): A563-DH
Type 1 Coated to F1136 Grade 3: A563-DH, F1136 Grade 5
Type 3 Plain: A563-C3 
* Please note that a subsitute nut for A325 Type 1 is a A194 Grade 2H 

Recommended Washers: 
Type 1 Plain: F436 
Type 1 Zinc Coated (Galvanized): F436 
Type 1 Coated to F1136 Grade 3: F436 
Type 3 Plain: F436