Federstähle

Federstähle are a family of steels optimized for high elasticity, yield strength and fatigue resistance, intended primarily for the manufacture of springs and other elastic components. They are usually carbon steels with alloying elements such as chromium, vanadium, silicon and sometimes molybdenum that improve hardenability and promote stable microstructures after heat treatment.

Typical grades include 50CrV4 and 51CrV4 (used for medium to high-strength springs) and higher-alloy variants such as 60Si2CrV6 or 55CrV7, chosen according to required stiffness, hardness and fatigue life. The exact composition varies by standards and producer.

Federstähle are formed into wires, bars or sheets, then hardened and tempered to achieve a martensitic structure with high yield strength and toughness. Austenitizing temperatures commonly range around 800–900°C, followed by quenching and tempering to set the target hardness, usually in the range of roughly 45–60 HRC depending on grade and design.

They provide high resilience, good fatigue strength and stable properties under repetitive loading. They generally offer limited corrosion resistance and may require protective coatings or corrosion-resistant grades for aggressive environments.

Applications include coil springs, leaf springs, torsion springs, valve springs, clock and watch springs, and other fatigue-critical components in automotive, machinery and consumer products.

Federstähle are produced to strict mechanical property and chemical composition requirements by steelmakers, and are tested for hardness, tensile strength, impact resistance and fatigue life according to applicable national or international standards.