Does ASTM A123 apply to bolts and fasteners as a galvanizing specification?
ASTM A123 does not cover threaded bolts and fasteners. ASTM A153 and F2329 are the ASTM specifications that cover the requirements for hot-dip zinc coating of fasteners.
This specification covers the requirements for hot-dip galvanizing on iron and steel products made from rolled pressed and forged shapes, castings, plates, bars, and strips. It does not cover threaded fasteners that are centrifuged or otherwise handled to remove excess zinc.
This ASTM specification covers zinc coatings applied by the hot-dip process on iron and steel hardware. This specification is intended to be applied to hardware items that are centrifuged or otherwise handled to remove excess zinc. A153 is applicable to steel hardware items of Classes A, B, C, and D.
- Class A – Castings – Malleable Iron, Steel
- Class B – Rolled, pressed, and forged articles
- Class C – Fasteners over 3/8” diameter and washers 3/16” and ¼” thick
- Class D – Fasteners 3/8” diameter and smaller, rivets, nails and washers under 3/16” thick
Since threaded fasteners are spun at high speeds in a centrifuge to remove excess zinc from the threads, they would fall under the A153 class C specification.
The standard specification that covers the requirements for hot-dip zinc coating applied to carbon steel and alloy steel bolts, screws, washers, nuts, and special threaded fasteners applied by the hot-dip coating process. Nails and rivets are not included in F2329. It is intended to be applicable to fasteners that are centrifuged or otherwise handled to remove excess zinc.
ASTM F2329 vs. ASTM A153
A153 covers galvanizing on many products including fasteners, while F2329 is specific to threaded fasteners, nuts and washers. The two specifications have virtually identical coating thickness requirements. Also, A153 and F2329 have different sampling requirements; F2329 requires more samples per lot than A153. Portland Bolt can meet the requirements for both F2329 and A153 Class C. Portland Bolt performs hot dip galvanizing of threaded fasteners within our 94,000 square foot manufacturing facility. Contact us if you have a need for hot-dip galvanized fasteners or with any technical questions regarding hot-dip galvanizing. One of our experienced sales reps will be happy to answer any of your questions.