Galvanizing Bolts FAQs

Galvanized Bolts with Plain Hardware

Should nuts and washers be galvanized when used with galvanized bolts?  

The short answer is yes. Here is why:  When bolts go through the hot-dip galvanizing process the zinc leaves an extra layer coating the bolt. This extra layer of zinc adds 0.002” – 0.006” of thickness to the bolt. When galvanized nuts are manufactured their threads are tapped oversize to accommodate for the thicker material. ... Read more

Galvanized Anchor Bolt Applications

Do Anchor Bolts Need to be Galvanized?

The short answer is no, they don’t need to be galvanized but they can be. In some cases, they should be. You’ll want to consider galvanized anchor bolts if they are going to be in a corrosive environment or exposed to the weather. Galvanizing anchor bolts provide corrosion resistance to the bolt. Instances where it... Read more

Know Your Marine Fasteners

What Makes Marine Fasteners Different From Other Fasteners?

The purpose of using a marine fastener versus other fasteners is to withstand corrosive saltwater and other harsh marine environments. Marine fasteners are commonly made from stainless steel or carbon steel which has a corrosion-resistant coating applied to it. The reason that these materials would be preferred over other common fasteners is that they offer... Read more

Heat-treatment After Forging

Do headed bolds receive heat treatment before or after the heads are forged?

Not all grades of bolts require heat-treating, but those specifications that do are heat-treated after the heads are forged. Heat-treating is performed in a controlled environment using specific quenching and tempering temperatures and durations. The bolts are then tested to ensure the strength of the heat-treated bolts meet the requirements of the given specification. Since... Read more

Galvanizing A490 Bolts

Can A490 bolts be galvanized?

The ASTM F3125 Grade A490 specification does not allow either hot-dip galvanizing (per ASTM F2329) or mechanical galvanizing (per ASTM B695) due to the risk of hydrogen embrittlement. The only coating currently allowed on A490 bolts is a zinc aluminum coating meeting ASTM F3393, which is itself a combination of three coating standards, F1136, F2833,... Read more

Galvanizing A320 Grade L7M Bolts

Can A320 Grade L7M bolts be hot-dip galvanized?

The A320 Grade L7M is a variation of the A320 Grade L7 specification used in low-temperature, low-pressure applications. Nowhere in the A230 specification does it discuss whether or not A320L7M fasteners can be galvanized. In theory, there is nothing preventing someone from galvanizing the material, however, the L7M designation comes from heat treating being the... Read more

12′ Galvanized All Thread Rod Cut into Studs

Can 12 foot lengths of galvanized all thread rod be cut into studs?

Yes, 12’ sticks of hot-dip galvanized all thread rod can not only be cut to smaller lengths, but it is often preferred. Depending on the application, all thread rod studs vary in length. For this reason, it is most common for all thread rod to be stocked in 12’ sticks, which can then be cut... Read more

Wet Storage Stains

What is a wet storage stain?

A wet storage stain is a white, rust-like surface discoloration that occurs from storing newly hot-dip galvanized materials.  Wet storage stains occur when recently hot-dip galvanized materials are subjected to a moisture-rich environment and/or the materials are packed so closely together that there is not enough air movement and oxygen for the parts to “breathe”.... Read more

Galvanizing A193 Grade B7M

Can A193 Grade B7M bolts be hot-dip galvanized?

A193 Grade B7M is a grade variation of the common A193 Grade B7 used in high-temperature, high-pressure applications. Nowhere in the A193 specification does it discuss whether or not A193B7M fasteners can be galvanized. In theory, there is nothing preventing someone from galvanizing the material, however, the application in which these bolts are intended to... Read more

Partial Galvanizing

Does Portland Bolt partially galvanize anchor bolts?

Yes. Portland Bolt can partially galvanize an anchor bolt. However, it is far more common for anchor bolts to be fully galvanized. If hot-dip galvanizing is required, engineers sometimes specify that only the exposed, projecting end of an anchor bolt should be galvanized, while the rest of the anchor bolt that gets embedded into concrete... Read more