Spring steels are classified as plain carbon steels, alloy steels and corrosion-resisting steels. Good formability, free of defects, low cost and availability are expected from spring steels for manufacturing of springs.
High mechanical strength, good fatigue resistance, low elastic modulus, good corrosion resistance, good resistance to creep and relaxation are desirable properties after spring manufacturing.
Descriptions of the most commonly used spring steels are given below.
Music Wire: It's also known as piano wire. It is a tempered high-carbon steel (ASTM A228) and widely used of all spring materials for small springs. It has the highest tensile strength and can withstand higher stresses under repeated loading than any other spring material. Maximum service temperature is 120 °C (250°F).
Hard Drawn Wire: Cold drawn steels (ASTM A227) are the most inexpensive spring steels and should be used only where life, accuracy, and deflection are not too important.
Oil-Tempered Wire: A steel wire (ASTM A229) which is used for many types of coil springs where the cost of music wire is prohibitive and in sizes larger than available in music wire. Not for shock or impact loading.
Chrome Vanadium: An alloy steel (ASTM A231) for conditions involving higher stresses than can be used with the high-carbon steels and for use where fatigue resistance and long endurance are needed. Used for shock loads and moderately elevated temperature. Maximum service temperature is 220 °C (425°F).
Chrome Silicon: An alloy spring steel (ASTM A401) for highly stressed springs that require long life and are subjected to shock loading.