Materials database

Silicon spring steel with lower C (0.35-0.42%) than 55Si7 — better toughness and fatigue life at the cost of slightly lower maximum hardness. Si (1.5-1.8%) gives excellent hot sag resistance to ~250°C. THE automotive engine valve spring material in many European OEMs. Also used for clutch springs, suspension springs, and applications requiring fatigue endurance under dynamic loading.

Silicon spring steel with high elastic limit. Standard flat/leaf spring steel in Europe. Si provides high sag resistance. Used for leaf springs, Belleville washers, lock washers, and agricultural machine springs.

Chromium-vanadium spring/tool steel — identical alloy system to 51CrV4 (1.8159) but recognized as a separate grade in some standards. Dual use: heavy-duty springs (EN 10089) AND cold work tools (knives, shear blades). V improves temper resistance and grain refinement. UTS 1200-1500 QT. Used for heavy leaf springs, stabilizer bars, torsion bars, and cold work cutting tools.

CrMoV alloyed spring steel — THE European automotive suspension spring material. CrMo gives deep hardenability for large coil springs, V adds grain refinement and secondary hardening for fatigue resistance. UTS 1350-1600 MPa QT. Used for hot-formed coil springs (cars, trucks), leaf springs, torsion bars, and stabilizer bars. Excellent sag resistance to 200°C.

Chromium-vanadium spring steel. The most important European spring steel grade. Excellent fatigue resistance and high elastic limit after heat treatment. Used for coil springs, leaf springs, torsion bars, anti-roll bars, and high-strength fasteners.

Si-Cr spring steel for high-performance automotive suspension and valve springs. Lower sag tendency than 46Si7 due to Cr addition. The standard European valve spring steel. Used for suspension springs, valve springs, torsion bars, and stabilizer bars where fatigue resistance is critical.

Chromium spring steel — simpler and cheaper than 51CrV4 (no vanadium). 0.75% Cr provides adequate hardenability for flat and small-diameter round springs. Used for leaf springs, agricultural springs, lock springs, and general-purpose springs where the V-premium of 51CrV4 is not justified.

Silicon spring steel — Si (1.5-2.0%) provides high elastic limit and excellent fatigue resistance without expensive Cr/V additions. Better heat resistance than Cr-spring steels — retains spring properties to ~250°C. Used for valve springs, clutch springs, hot-wound coil springs, and applications with moderate elevated temperature exposure. Cheaper than CrV spring steels.

High-carbon chromium-vanadium spring steel — higher C (0.55-0.62%) than 51CrV4 (0.47-0.55%) for maximum hardness and fatigue strength. V refines grain and improves temper resistance. Used for the most demanding spring applications: heavy-duty coil springs, torsion bars, stabilizer bars, and spring tools. Also used as tool steel (1.2242/59CrV4 variant).

Highest-carbon unalloyed spring/tool steel — C 0.95-1.05%. Maximum hardness (HRC 63-66) in the unalloyed range. On the boundary between spring steel and tool steel. Used for flat springs requiring absolute maximum hardness, doctor blades, cutting tools, cold stamping dies, and wood-working saw blades. Also known as Silberstahl (silver steel) in wire form.

Medium-high carbon spring steel — C 0.65-0.72%. The E suffix denotes controlled S+P (<=0.025% each). Used for cold-rolled spring strip (EN 10132-4), spring wire (EN 10270-1), and flat springs. Lower C than C75S/C85S = better toughness and formability. Also used for circular saw blades, scrapers, and clips. Hardened & tempered to HRC 55-60.

Unalloyed cold-rolled spring strip steel — THE standard flat spring material. 0.65% C gives high hardness after hardening (HRC 60+). Very good fatigue properties when properly heat-treated. Much cheaper than alloyed spring steels (51CrV4, 55Cr3). Used for flat springs, circlips/snap rings, saw blades, scrapers, reed valves, and leaf springs in small dimensions.

High-carbon spring strip steel — C 0.70-0.80%. Between C67S (0.65-0.72%) and C85S (0.83-0.90%). Good fatigue strength and edge retention. Used for flat springs, leaf springs, saw blades, snap rings, and reed valves. Available as cold-rolled precision strip in hardened & tempered condition (HRC 58-62).

Highest-carbon unalloyed spring strip steel — C 0.83-0.90%. Maximum achievable hardness (HRC 62-65) and fatigue strength in the cold-rolled spring strip series. Used for the most demanding flat spring applications where maximum hardness is critical: saw blades, scraper blades, precision springs, and high-frequency reed valves. Higher C than C67S (0.65-0.72%) and C75S (0.70-0.80%).