Corrosion Failure of Fasteners

If you thought corrosion was merely about unsightly patches of red oxide – rust –
which plague steel and iron products in coastal areas and offshore applications, think again. Corrosion is present everywhere and can occur in even the most arid land-locked countries. It’s also a case of prevention being better than cure as corrosion can be delayed but never prevented.

Fasteners may be a small component in the construction process but must also be designed with care. If the bolt corrodes, the danger is that the larger structure or product will fall apart.

“Fasteners, as an integral part of modern life, must be dependable,” states Coronado. “Corrosion of fasteners not only results in metal loss and possible failure, but in the case of high-strength fasteners, cracking and sudden failure.

Engineers and designers alike can greatly reduce this type of corrosion by specifying fasteners made of the proper materials or with the right coatings.

Stainless Steel is one of the preferred materials when it comes to combating corrosion. In extreme conditions, Titanium is also used. 

Some glaring examples of failure:

San Francisco Bay Bridge Bolt Failure: In March 2013, 32 steel bolts that were intended to stabilize the bridge during an earthquake cracked.For a bridge built between two major earthquake faults, the failure of the bolts placed the entire seismic safety system of the new span into question. While investigations continue on the primary causes of bolt failures, corrosion was recognized as the foremost contributor.

Corrosion-related failure of bolts used to secure lifeboat winches: The incident concerned the failure of a number of bolts used to secure lifeboat winches to the deck. The use of the associated lifeboats either during trial launch or emergency use could well have resulted in a very serious incident.

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