Beginning Galvanized Bolts 101

Galvanized bolts are special types of hardware used to outdo screws and nails in different applications. They are heavy duty construction materials that allow support of heavier than usual loads, with special coatings to help prevent damage, rust and corrosion. Galvanized coatings are typically used to join wood and steel and can be found mostly in bridges and residential decks. Like most types of fasteners, these bolts are made of steel which make them susceptible to corrosion and rust. This is why a special zinc coating is applied to them to extend their life and durability.

Galvanization is the process that allows for this reinforcement coating, making a bolt more useful for a wide variety of applications through its increased performance. This process is made up of a series of chemical reactions - first, the bolt is coated with hot zinc. This coating serves as a barrier between the bolt and outside corrosive elements. When the zinc coating reacts with the atmosphere, the oxygen forms zinc oxide. On the other hand, when carbon dioxide reacts with zinc oxide, then zinc carbonate is formed; this is what makes galvanized bolts stronger. The zinc carbonate layer in the bolts are what protects them from rust and corrosion.

Galvanized bolts can be differentiated by their spangled crystallized surface. These bolts are great for outdoor applications as they are more resistant to rain and moisture than standard steel fasteners. Galvanized coatings are also great for marine settings or coastal areas where exposure to salt water quickly corrode untreated steel. Most industrial establishments use these bolts because of their strong resistance to chemical exposure as compared to regular bolts. Because of this reinforced quality, a galvanized bolt is typically more expensive than regular varieties, but will give you greater savings on future maintenance and repair costs.

Bolts with a galvanized coating should always be used along with galvanized washers, doing otherwise will compromise their quality. Installers should be careful in welding and cutting bolts and nuts with galvanized coating due to their possible toxic fumes which are harmful to people and the environment. Also, there is no such thing as a double or triple coated galvanized fastener or bolt even for the most corrosive of environments. Doing such would lead to an excessive build up of zinc which will make it impossible to allow the nuts to screw unto the bolt. A galvanized bolt can never be chased as excess zinc during the hot dip galvanizing process builds up in the threaded part of a fastener.

Chasing is a term used for re-cutting a thread after the hot dip process on galvanized bolts, as the weight of bolts tends to significantly increase by 3.5% after galvanization. Hot zinc is not the only coating used for these special bolts but there are other alternatives like aluminum and dacroment. It is also important to note that not all high strength bolts can be galvanized. High strength bolts are bolts which have been tempered, quenched, and heat treated to develop stronger specification requirements. It is important to note that zinc plated nuts cannot be used on a galvanized bolt and vice versa.