Spring material must prepare a high elastic energy, high fatigue limit, high tensile strength and impact resistance and other properties.
Materials can be divided according to the different components
First, carbon steel and alloy steel
Second, the non-ferrous metal alloys
Third, rubber springs, etc.

First, carbon steel and alloy steel
According to the manufacturing process can be divided into two categories:
1. heat-treated spring steel
2. Processing spring steel

1. heat-treated spring steel
After forming the first material is manufactured, and then to the heat treatment method to have flexibility. Types of heat-treated spring steel carbon steel and alloy steel: carbon steel to eutectoid eutectoid steel and steel-based. There silico-manganese steel alloy (Si-Mn steel), chromium-manganese steel (Mn-Cr steel), chrome vanadium steel (Cr-V steel), manganese-chromium boron steels (Mn-Cr-B steel). Table 5-2 shows the AISI (SAE) spring steel types and their ingredients.
The chemical composition of spring steel

2. Processing spring steel
There are types of machining spring steel
(1) Hard steel wire
(2) piano wire
(3) stainless steel wire
(4) between the cold-rolled steel strip
(5) stainless steel band

(1) Hard steel wire
Hard steel wire is made of a hard wire to stretch pumping from normal state of impurity phosphorus, sulfur and other impurities requirements, its content is 0.004% or less. Kind of hard steel wire and its ingredients as shown in Table 5-3.
Table 5-3 hard steel wire (spring) and its species composition (%)
Table 5-3 hard steel wire (spring) and its species composition (%)

(2) piano wire
Piano wire of impurity content of phosphorus, sulfur, copper and other requirements are very strict, decarbonization and other surface defects to be very little, which has been patenting (patenting), the highly stretch performance. In normal pumping into line, (patenting) stretch performance after highly pumped into the line at room temperature good mechanical properties, tensile strength and toughness are large, it is an excellent spring material. Tensile strength of general steel piano wire up to 350kgf / mm2. Kind of piano wire and its ingredients as shown in Table 5-4.
Kind of piano wire and its ingredients

(3) oil return line of fire
Oil return line of fire is the continuous steel cold drawn into a straight line, then oil tempered person. Oil back FireWire carbon steel and alloy steel. As shown in Table 5-5 as an oil return line of fire of the type and use of materials. Steel-based oil back to the firing line in the design stress, fatigue resistance, heat resistance and so superior to steel-based oil back to the firing line.
Oil back FireWire types and use of materials
(4) stainless steel wire and steel
Stainless steel for corrosion resistance and heat resistance place more. Stainless steel spring wire, inter hardened stainless and cold rolled stainless steel strip based. It may also be used 17-7PH (Ni-Cr-Mn steel), steel wire, steel. After the stainless steel spring forming, at the time of low-temperature annealing, the annealing temperature is about 400 ℃ up and down, the best mechanical properties.

Second, non-alloy steel
Spring such material, mostly have good corrosion resistance. Often users are as follows:
1. Phosphor Bronze: mainly composed of copper, tin alloy, has good conductivity and corrosion resistance. Usually cold spring roll into the legal system.
2. beryllium copper (beryllium copper): In addition to copper, beryllium containing about 2%. Has the best conductivity, this material must be cryogenically cooled with a spring roll.
3. Meng Na (monel) alloys: an alloy of copper and nickel, can the temperature to 200 ℃, has the corrosion resistance, often with little magnetic, commonly used in the food industry in the legal system into cold spring.
4.K class Meng Na alloy: the addition of about 3% in Bangladesh sodium aluminum alloys, available in normal or low temperature cold. Room temperature or low temperature cold
5. Inconel (Inconel) Alloy: This material has a temperature resistance, corrosion resistance, there will be no relaxation within 370 ℃. Suitable for spring in the steam valve spring, turbines and jet engines.
6. British high nickel alloys X: British high nickel alloys add a little element titanium and aluminum for precipitation hardening (precipitation-hardened) material. The degree of temperature can be up to 480 ℃ still have slack.
7. Nickel steel: (Ni-span-C) is also a precipitation hardening material. Elasticity of nickel steel at -10 ℃ ~ 66 ℃ between, never deformation.

Third, the rubber spring
Rubber compression spring can be divided into spring, stretching of spring, shear springs and torsion springs. The advantage of having a high energy storage unit and reduce the amplitude effect, and no noise. The disadvantage is cold intolerance, no corrosion fatigue and impatience. Because the elastic coefficient of uncertain value, it can not comply with Hooke's law. Such spring largest utility in preventing vibration and absorb shock as the movement of the buffer.
As the plastic industry continues to progress, there are a lot of resin material can be used as a spring material, resin material of the spring with acid and other features.