Spring steel is an elastic and fatigue-resistant structural steel with high tensile strength, which is mainly used for winding springs. Spring steel must have a high elastic and sufficient plastic deformation capacity (spring coiling). In addition, a high alternating and fatigue strength is required for occasional or frequent overloading. The yield strength, formability and suitability for welding are the most important factors for use. Spring steel is generally used in the machine and vehicle sector. Examples are compression or tension springs, disc springs, helical disc springs or ring springs.