What is Spring Steel?

The term spring steel refers to a group of medium-to-high carbon, low alloy steel products which exhibit excellent yield strength. The term yield strength refers to a material's ability to endure significant bending or twisting and return to its original shape without deforming. Spring steel stock alloys typically include silicone in their composition and are hardened and cold rolled after casting to improve yield strength. Products made from this type of steel are generally either cold drawn as wire or punched from flat stock. Typical uses include saw blades, tape measures, helical springs, and vehicle suspension elements.

Spring steel alloys feature the unique characteristic of being able to withstand considerable twisting or bending forces without any distortion. Products made from these steel alloys can be bent, compressed, extended, or twisted continuously, and they will return to their original shape without suffering any deformation. This characteristic is defined as a high yield strength and is the result of the specific composition and hardening of the steel alloy. Spring steels are medium-to-high carbon content alloys generally featuring a carbon content of 0.5 to 1.0 percent. The other alloy additives typically include manganese and silicone with silicone being the key component in high yield strengths.

The alloy stock is worked cold after casting to preserve and improve on the yield strength values because heating spring steel after production may negatively affect the resilience of the alloy. This means that the steel components can generally not be conventionally welded unless they are retempered afterward. The alloys are generally cold drawn or rolled into flat sheets or wire stock and hardened to Rockwell C values ranging from 42 to 60. Products are then wound using the wire or punched from the flat plates. Intricate parts are often formed from soft annealed stock and are only hardened once complete.

Spring steels can be used to produce a wide variety of products that supply energy or absorb various forces. These product types include a huge variety of helical, coil, and flat springs, vehicle suspension members, and toy mechanisms. Items such as tape measures and steel rulers are also made from various grades of spring steel. The materials' yield strength is also harnessed in the production of tools such as saw blades and scrapers. Spring steel products may also be found in everyday items such as locks, key rings, door closure mechanism, and even the humble mousetrap.