While small springs are used in electronic and medical devices, industrial springs are much larger, although their functions are essentially the same.
Thick pieces of round, flat or hollow wire are tightly wound with the application of heat to form a component with good elastic and return properties. When the spring’s shape is changed, it exerts a resisting force and returns back to its original configuration.
Industrial applications require many different types of springs. Compression springs act as a cushion for a downward acting force, extension springs give resistance to outward acting forces and are elongated when pulled from each end, torsion springs store mechanical energy and exert torque and finally, flat springs, which are not coiled wire but rather flat strips of metal that provide shock resistance, are used in simple applications.
Springs are used in the aerospace, railroad, automotive manufacturing, machinery, industrial equipment, nuclear power generation, offshore oil and gas, defense, telecommunications, actuator and valve control applications. They can come in many different shapes, they can be as long as several feet and they can be custom made to fit certain specifications. Industrial springs are also often available in pre-engineered stock sizes.
Depending on the type of spring and the desired strengths and properties, industrial springs are fabricated a couple different ways out of several types of metal. Plastic is only used for light to medium applications and is therefore not strong enough. Spring steel, an industrial grade of steel alloy specifically designed for spring fabrication, is the standard choice of material. It is elastic and exhibits good return properties that last over long periods of time.
Music wire, made of high carbon steel, is also popular for heavy duty applications. It is cold drawn, strong and has a uniform tensile strength. For specialty applications within the food and beverage processing, pharmaceutical and medical industries, stainless steel springs are used for their corrosion resistant, con-contaminating and heat resistant properties. Other metals used for industrial springs include copper, nickel, titanium and tantalum.
The strongest spring design uses braided and wound wire. This type can handle sudden and heavy loads. The largest industrial springs, those over six inches in diameter, must be hot rolled and coiled around special machinery. Because they are thick and hard to form, large springs are hardened post fabrication. Before use, each industrial spring is shot-peened, a process that increases fatigue life. They are also always load tested to ensure compression characteristics.