The term "steel springs" broadly references any type of spring made from any type of steel. In turn, the term "springs" references elastic members of machinery, devices and systems that exert a resisting force when their shape is changed. Though there are innumerable variations on the steel spring, there are, in fact, just four main types of steel springs. These types are: compression springs, extension springs (also known as tension springs), flat springs and torsion springs. Between the four of them, these steel springs cover a wide range of industries and applications. Among the many industries they serve are aerospace, agriculture, automotive manufacturing, electronics, hardware, manufacturing, medicine, military and defense, oil and gas, sports and recreation, telecommunications and textiles. Some examples of the many applications they serve within these industries include: outdoor power equipment, gardening equipment, measuring tape, retractable safety devices, toys, fitness equipment and timing devices.
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Types of Steel Springs
In short, the difference between the four major types of steel springs is as follows: First, compression springs serve as a cushion against downward acting force. Second, extension springs work by providing resistance to outward acting forces by elongating, or extending, when pulled by hooks that are attached at either side. In essence, extension springs are the opposites of compression springs. Third, the function of flat springs is to provide resistance and shock absorption in straightforward and uncomplicated applications. They work only with such applications because they are constructed very simply, consisting of flat strips of steel that have been tempered with a specific curvature. Fourth and finally, torsion springs work by exerting a twisting force, or torque, in order to store mechanical energy within a twisted coil.
Materials in Steel Springs
To make these and other steel springs, manufacturers rely on just a few primary types of steel, including blue steel, also sometimes known as spring steel, and stainless steel. Of the two, blue steel is the more traditionally used metal in spring creation. A high carbon spring steel, before springs made from it are finished, blue steel is tempered, hardened and polished to meet the specific requirements of the application it will serve. Blue steel springs are best served aiding applications that do not face harsh elements. That is because, while blue steel is aesthetically pleasing, it is inclined to rust. For more heavy duty or harsh environment applications, stainless steel springs are a better match. Stainless steel, while is similarly aesthetically pleasing to blue steel, but is not inclined to rust. Rather, it is highly resistant to corrosion and other element effects.
Cold Rolling Process
To make steel springs, manufacturers most often engage in the cold rolling process, which is a type of roll forming. Cold rolling works by putting a metal coil through a roll forming machine, which consists of a series of roller die parts called calendars. The calendars are positioned above and below the metal coil to be formed. As the metal goes through the machine, these rollers bend it linearly, and thus the metal takes on a more uniform grain flow and shapes into flat coil strips. During this process, the raw steel material is heated only to temperatures below its point of recrystallization, thus increasing its tensile strength. After a steel spring has been initially formed, manufacturers put it through secondary processing in order to wind it or coil it. Depending on the type of steel with which the spring has been made, manufacturers will approach this differently. First, for example, a tempered blue steel spring can be annealed, or made softer through heating and worked on while it is more malleable. This is possible because tempered blue steel responds very well to heat treatment. Stainless steel, on the other hand, cannot tolerate heat treatment, and thus a stainless steel spring cannot be annealed. A common alternative method manufacturers use in this case is lathe forming. During lathe forming, a lathe machine winds coils using rapid rotation. After the coils have been wound, a steel spring, if the material allows it, is heat treated in such a way that its stresses and fractures are reduced and the spring as a whole is strengthened.
Things to Consider When Purchasing Steel Springs
Steel springs can make or break an application, so it is important that a customer select the right ones for his or her needs. For the best advice, such a customer should reach out to an experienced spring manufacturer who can offer sound advice. To find such sage wisdom or to get started with a quote, reach out to one of the excellent manufacturers listed on this page.