When looking at aerospace compression springs, the calculation method, the material used will depend on how much stress will be applied to that specific area and part.
Many preferred types are merely not in stock in the quantities need while others call for heat treatment after being wound. Nearly all springs are cold hard wire when wound.
The continual drawing by dies, and each drawing process gains strength from both the shear and tensile work hardened. Therefore, the shear stress that can be used will hinge on the wire size. Basically the smaller the diameter the more stress it can absorb.
The "regular" spring wire from this process is known patented carbon steel spring wire, the process of applying the steel to make it simpler to for smaller gauges. It typically has no alloying content and is available metric diameters as well as the usual Standard Wire Gauge size.
Because carbon steel wire is not suitable for temperatures over 125c and they may have the risk of corrosion or the temperatures can get high, the more useful material is the hard-drawn stainless steel springs. Where steam/water are a concern, the hard drawn phosphor-bronze is non-corrosive and is usually recommended for uninterrupted use below about 110 deg. C. It is comparatively easy to take in a broad range of gauges or to metric dimensions.
A corrosion resistant material is the nickel alloy spring. They offer heat resistance and superior strength in a grade of wire that has high elastic qualities akin to music wire. Yet it maintains the corrosion resistance quality of standard stainless. An excellent material for all types of springs, the nickel alloy spring, offers long life when required for severe service conditions while giving excellent fatigue properties.
Chrome is a higher prime spring material, such as vanadium steel, that must be heat treated after winding. The spring is wound while soft and then hardened. The shear elastic limit is approximately the same as carbon phosphor-bronze. Hard-drawn brass is an inexpensive spring material and perfect for mild conditions. It is more common used for flat springs that can provide sharp bends as needed.