FOCUS ON FASTENERS construction and medical applications as they offer high rust-resistance and durable bonds . Aerospace grade fasteners are increasingly being used in aircraft engines ; baggage racks ; cabin doors ; cargo containers ; floor panels bulkheads and cabin structures . These products provide longevity and structural integrity to aircraft structures .
Industrial fastener segmentation
Industrial fasteners include a wide variety of mechanical fastening devices , ranging from mass-produced simple items with little opportunity for product differentiation , to complex and ad-hoc products designed for specialist applications .
The most common form of product segmentation identifies threaded and non-threaded fasteners . The major types of threaded fasteners are bolts , nuts and screws . Bolts are usually used in conjunction with nuts . A variety of materials are used for their production , depending upon the required tensile strength of each application . Standard bolts are made of iron or steel , with brass and copper bolts widely used in electrical assemblies . Aluminium bolts are frequently , but not exclusively , used in the aerospace sector , and those made of nickel are used where high-temperature tolerances are required .
Standard nuts utilise hexagonal heads , although square-headed nuts are commonly used for woodworking applications . Different shape variations are also used to ensure the satisfactory locking of bolts . In safety-critical applications and where frequent vibration occurs , self-locking nuts are most commonly used . Applications for self-locking nuts have increased strongly over the past few years and a wide range of these mechanisms are now available . Screws differ from bolts as they have the capability to be used in a threaded hole without a nut .
The most commonly identified non-threaded fasteners are nails , tacks , studs , staples , rivets and washers . Nails and tacks are some of the simplest mass-produced fasteners , with little opportunity for product differentiation . Even so , a wide variety of materials are used in their production depending upon the required tensile strength and corrosive resistance of the finished item . Studs and staples also tend to have similar characteristics .
Rivets are one of the oldest forms of fastener and , like most fasteners , can be manufactured using a wide variety of materials , depending upon the application for which the product is required . Washers are also classified as non-threaded fasteners , although strictly they are not fasteners but components within a fastening system .
Increased levels of automation in enduser industries , particularly the automotive sector , have fundamentally changed the requirements of fasteners in recent years . In the past , the emphasis of production centred around time , handling and effort , but now the key characteristics are repeatability and tight performance tolerance .
The increased life expectancy of many end-use products , such as the two-sided galvanization of automotive bodies , better finishes , increased use of plastics and new designs in engines and transmissions , have required that fasteners adapt to greater longevity . This has resulted in old practices , such as electroplating and phosphate and oil finishing , being replaced by sophisticated organic coatings . In turn , this has led to adjustments in tightening strategies and torque / tension testing .
Organic coatings include dry paint films or the subsequent oil treatment of products . Pigmented oil films have proved both versatile and capable of self-healing . Zinc-rich coatings have proved useful where a sacrificial layer is required for use against other metals , such as aluminium or magnesium , to protect against galvanic corrosion . n