Steel grades

Medium-carbon martensitic stainless steel. Higher hardness than 410 but lower than 420C (1.4034). Good balance of strength, corrosion resistance and machinability. Used for turbine blades, pump shafts, valves, bolts, surgical instruments, and cutlery.

High-carbon martensitic stainless steel. Higher hardness than 410 (up to 56 HRC). The standard knife steel for European cutlery. Used for kitchen knives, pocket knives, surgical scalpels, machine blades, roller bearings, and valve components. Not weldable.

High-strength quenched and tempered chromium-molybdenum steel. Widely used for shafts, gears, crankshafts, connecting rods, and high-strength bolts. Excellent hardenability and good fatigue resistance.

Free-cutting variant of 42CrMo4 with controlled sulfur content (0.020-0.040%). Improved machinability while maintaining essentially the same mechanical properties. Used for high-volume CNC machined components: gears, shafts, bolts, and automotive parts.

Chromium-vanadium quenched & tempered steel — higher Cr (1.3-1.6%) than 41Cr4 plus V (0.10-0.20%) for grain refinement and secondary hardening. Good fatigue life and wear resistance. Used for heavily loaded shafts, gears, piston rods, and mining equipment where higher hardenability and finer grain than 41Cr4/42CrMo4 are needed.

Vanadium-microalloyed medium-carbon steel for controlled-cooling after forging — achieves target properties without separate Q&T heat treatment ("as-forged" concept). V precipitates (VN, VC) give precipitation strengthening during air cooling. THE modern automotive crankshaft steel — replaces 42CrMo4 Q&T at lower total cost (no heat treatment furnace needed). Also used for connecting rods and large forged parts.

Ferritic chromium stainless steel with good corrosion resistance and formability. Lower cost than austenitic grades. Used for automotive trim, kitchen sinks, architectural panels, and appliance components.

Nickel-bearing martensitic stainless steel with higher corrosion resistance than 410/420. Highest strength of the standard martensitic grades (up to 1100 MPa). Used for marine shafts, propeller shafts, high-strength fasteners, valves, and pump components.

17% Cr Ti-stabilized ferritic stainless. Cost-effective alternative to 304 for many applications — no Ni means ~30-40% lower cost. Immune to chloride SCC. Used for automotive exhaust systems (downstream), kitchen sinks, washing machine drums, heat exchangers, and architectural trim.

High-carbon martensitic stainless steel with molybdenum and vanadium. Hardenable to 58+ HRC while maintaining moderate corrosion resistance. Used for cutlery, surgical instruments, valve components, bearings, and pump parts where hardness and corrosion resistance are both needed.

Highest-hardness standard martensitic stainless steel. Achieves 57-60 HRC — the hardest commonly available stainless grade. Excellent wear resistance from chromium carbides. Used for bearings, races, valve components, surgical instruments, high-end cutlery, and precision molds.

Stabilized ferritic stainless steel with Mo addition. A cost-effective alternative to 316L for applications where austenitic properties are not needed. Excellent resistance to chloride stress corrosion cracking. Used for hot water tanks, solar collectors, automotive exhaust, and catering equipment.

Ultra-high-strength NiCrMo Q&T steel — Ni 3.5-4.5%, the highest-Ni standard QT grade. UTS 1250-1450 MPa. Maximum through-hardenability for the largest cross-sections (300mm+). Used for the heaviest crankshafts, large forged rotors, press columns, and critical structural forgings in energy and defense. Comparable to AISI 4340 but with higher Ni.

Medium-carbon chromium steel for quenching and tempering. Good hardenability for medium cross-sections. Used for crankshafts, connecting rods, spindles, bolts, and other moderately stressed machine parts requiring through-hardening.

Higher-carbon CrMo Q&T steel — 0.42-0.50% C vs 0.38-0.45% for 42CrMo4. Higher maximum hardness (HRC 52-56 surface after induction) and tensile strength (UTS 1000-1200 MPa QT) at the expense of slightly reduced toughness and weldability. Used where 42CrMo4 is not quite hard/strong enough: heavy-duty gear shafts, large bolts (12.9 class), crankshafts, and torsion bars.

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.

High-carbon Cr-Mo steel for springs and high-strength applications. Higher carbon than 42CrMo4 for greater hardness and spring properties. Used for coil springs, leaf springs, torsion bars, highly stressed bolts, and heavy-duty shafts.

Free-cutting variant of 50CrMo4 — S 0.020-0.040% for machinability. Higher C (0.46-0.54%) than 42CrMoS4 = higher hardness after Q&T (UTS 1100-1300 MPa). Used for high-strength shafts, torsion bars, and heavy-duty bolts produced on CNC automatics where maximum CrMo strength with machinability is needed.

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.