Stainless steel screws, bolts, nuts and other fasteners are very popular fastening tools because of their qualities of strength and corrosion resistance.
Stainless steel fasteners are particularly popular in the automotive industry, which involves stainless steel screws in the construction of structural automotive components.
Because automobiles are subject to variable weather conditions and hazardous contaminants like salt in some cases, stainless steel is an excellent fastener composition; it resists weather and salt-induced oxidation. For these and other reasons, stainless steel screws are also used in the electronics manufacturing, medical products, watercraft building and construction industries.
Stainless steel alloys are iron-based metals containing at least 10% chromium and other metals, which provide added corrosion and heat resistance. They do not require a protective coating, and they are able to perform well in a wide range of conditions and temperatures.
Stainless steel fastener materials are identified as the B8 class of stainless steel alloys. These fasteners come in a wide range of head styles, shoulder forms, thread forms and point styles.
Stainless steel fasteners are manufactured by two different processes: machining and cold heading. Machining is the preferred method for larger fasteners in smaller production runs. This procedure is older and creates a weaker product with less fatigue resistance.
Cold heading forms stainless steel wire into different shapes by forcing it through die and punch cavities. This method is fast and takes fewer steps in the process. After the fasteners have been machined or cold worked, they are threaded if necessary. This is done by cold forming as well. Stainless steel fasteners are often precipitation-hardened, a form of aging that combines low temperature aging treatments and cold working.
Stainless steel is not without its limitations, and it can be inappropriate for use in some contexts. Aerospace fasteners, for example, are often made of titanium instead of steel.
Titanium is lighter than steel, which contributes to flight performance, and it is stronger, which is especially important in aircraft construction. That said, stainless steel performs very well when installed in automobiles and other vehicles.
It is important to carefully pair fasteners with their applications. Especially in the context of automotive manufacturing, improperly chosen or installed screws can end up causing damage to the vehicle and injury to its user. Properly chosen stainless steel fasteners will contribute to the extended lifespan of the products and systems in which they are installed.