Metal compression spring
Metal compression spring is a general term for different spring material types. When making metal compression springs, there are three more common material types, and because each type of material has different characteristics, this needs to be taken into account when choosing a metal compression spring. The more common spring materials are: piano wire, stainless steel and chromium silicon. Different material characteristics are different, according to the use and application of the spring, consider each property in order to choose a normal material.
Piano wire:
Piano wire is the most common type of material used in spring manufacturing, and this type of spring wire can withstand high temperatures of 250°F(121 ° C) and Rockwell hardness of C41-60. This material has the advantage of being both strong and economical. However, it is not recommended to expose the spring to a wet environment, because it is easier to rust in a wet environment.
Stainless steel:
Stainless steel is commonly used to make metal compression springs, there are three different types of stainless steel wire, the more commonly used and recommended is 302 stainless steel, it can resist temperatures of up to 550°F(288ºC), and piano wire is actually stronger than stainless steel. However, unlike piano wire, stainless steel can withstand higher temperatures and does not rust under wet or corrosive conditions, which makes stainless steel wire ideal for use in medical and high-temperature conditions.
Chrome silicon alloy:
This kind of material is also relatively common, it is an alloy steel wire, better than piano wire in high temperature resistance, but also stronger than stainless steel. However, it is not recommended to use in wet conditions, because exposure to wet environments will rust. The maximum temperature it can withstand is 475ºF(246ºC). High tensile strength chromium-silicon is the ideal spring because its special properties enable it to provide greater force and higher elasticity.
The energy stored by a metal compression spring is determined by the material characteristics, wire diameter and coil number of the spring. The speed or stiffness of the spring is determined by the wire diameter and the number of coils. It is measured in pounds per inch or Newtons per millimeter. The speed of the spring can be adjusted by changing the wire diameter or the number of coils.
When we buy a metal compression spring, we need to know the parameters:
Stress
Size as well as load and deflection requirements determine the stress in the spring. When the metal compression spring is loaded, the coil is stressed when it is twisted. The stress on the surface of the steel wire is the greatest. When the spring deflects, the load changes, causing a series of working stresses. The stress and stress range determine the life of the spring. The wider the range of working stresses, the lower the maximum stress required to achieve a comparable lifetime. Relatively high stresses can be used when the working stress range is narrow or when the spring is only subjected to static loads.
Outer diameter
The diameter of the cylindrical shell formed by the outer surface of the metal compression spring coil.
Hole diameter
This is the measurement of a space when the compression spring is inserted. It is the diameter of the part that fits with the compression spring and is often mistaken for the size of the spring itself. Taking into account tolerances and the expansion of the spring under load, the hole diameter should be designed to be greater than the outside diameter of your compression spring.
Rod diameter
By compressing a measuring rod inside the metal compression spring, essentially a mating component, the rod can be used as a guide shaft to minimize the buckling of the spring under load. Considering the tolerance factor, the rod diameter design should be less than the inner diameter of the compression spring; However, it cannot be too small, otherwise it will lose the ability to minimize spring buckling.
Free length
The length when the spring is not loaded. Note: For retractable springs, this may include the anchor end.
Wire diameter
This is the measurement of the size of the raw material used to form the spring. Traditional springs are made of round wire, which has a certain diameter.
Solid height
This is the length size of the compression spring in its maximum load state. In fact, this is the height of the compression spring when all the coils are pressed together.
Spring set
This happens when the load of the spring exceeds the elastic strength of its material. It is a permanent deformation that is evident when the spring does not return to its original length after releasing the deflection load. Depending on the application, the spring set can be ideal or not.
Solid height load
This is a measure of the force required to fully deflect the compression spring until the coil is fully pressed together. For product designers who want to avoid bottoming the compression spring, loading at solid height is a quick reference property to find a spring that can handle the maximum workload of the component.