Materials database

Vanadium-microalloyed Mn steel — V 0.08-0.15% for grain refinement and precipitation strengthening. Can be used in as-forged (controlled-cooled) condition without separate Q&T. Lower cost than CrMo grades for moderate-strength applications. Used for hydraulic cylinders, shafts, and structural forgings where UTS 700-850 MPa is sufficient.

Free-cutting variant of 25CrMo4 (1.7218) — sulfur addition (0.020-0.040%) for improved chip formation on CNC automatics. Same mechanical properties after Q&T. THE high-volume CrMo steel for CNC-machined automotive parts where cycle time matters. Used for transmission shafts, steering components, bolts, and any 25CrMo4 application produced on automatic lathes.

CrNiMo quenched & tempered steel — low-C (0.22-0.29%) variant in the NiCrMo QT family. Better weldability than 34CrNiMo6 due to lower C. Good combination of strength (UTS 800-1000 MPa) and toughness for bolts, anchor bolts, studs, and structural fasteners in offshore and bridge construction.

Free-cutting variant of 25Cr4 — S 0.020-0.040%. Low-C Cr QT steel for CNC automatics. Good combination of machinability, moderate strength (UTS 750-900 MPa), and toughness. Used for bolts, studs, shafts, and automotive components where Cr-only hardenability with machinability is needed at lower cost than CrMo grades.

Chromium quenched & tempered steel — 1% Cr, no Mo. The economy QT alloy steel: Cr improves hardenability over plain carbon steels at lower cost than CrMo grades (25CrMo4, 42CrMo4). Adequate for moderately loaded parts up to ~40mm ruling section. Used for bolts, studs, shafts, axles, and general machine parts where better hardenability than C-steel is needed but CrMo cost is not justified.

Boron-alloyed QT steel — between 22MnB5 (press hardening, UTS ~1500 MPa) and 38MnB5 (UTS ~1800 MPa) in the B-steel range. C 0.27-0.33%. Used for high-strength fasteners (class 10.9), chain links, agricultural machinery, and some press-hardened components. Good cold formability before heat treatment.

Ultra-high-strength nickel-chromium-molybdenum steel with outstanding through-hardenability for large cross-sections. Achieves tensile strengths of 1080–1270 MPa (dia ≤40mm) with excellent impact toughness. Very high Jominy hardenability (47–55 HRC). Used for heavy-duty crankshafts, connecting rods, bolts, gear shafts, and critical aerospace structural parts. AFNOR equivalent: 35NCD16.

Heavy-duty NiCrMo quenched & tempered steel with high Ni (3.0-3.5%) — maximum hardenability in the QT range. UTS 1100-1300 MPa. Used for the most heavily loaded shafts, crankshafts, and structural components where 34CrNiMo6 hardenability is insufficient. Large cross-sections up to 250mm. Aerospace landing gear, heavy mining equipment, and large hydraulic press components.

Free-cutting variant of 34CrMo4 (1.7220) — S 0.020-0.040% for improved machinability on CNC automatics. Same Q&T properties. Used for high-volume CNC production of shafts, connecting rods, bolts, and automotive drivetrain components where machining cycle time is critical.

Free-cutting variant of 34Cr4 (1.7033) — sulfur addition (0.020-0.040%) for improved machinability on CNC automatics. Same QT properties as 34Cr4. Used for shafts, spindles, bolts, studs, and automotive components in high volume on automatic lathes.

Nickel-chromium quenched and tempered steel with 1.2–1.6% Ni and 0.9–1.1% Cr for high strength and excellent impact toughness. Good hardenability for uniform properties in medium cross-sections. Used for heavy-duty engine parts, crankshafts, gears, shafts, piston rods, and bolts. Important grade in aerospace (AIR 9160/C as 35NC6) and heavy mechanical engineering.

Boron micro-alloyed QT steel — 0.0008-0.0050% B multiplies hardenability dramatically at minimal cost. Achieves similar through-hardening to 41Cr4 or 42CrMo4 at lower alloy cost. THE cost-optimized approach for automotive fasteners, bolts, and cold-forged QT parts. Used for high-strength bolts (class 10.9/12.9), tie rods, stabilizer bars, and any mass-produced QT part where total alloy cost per ton matters.

Chromium-molybdenum Q&T steel — between 25CrMo4 (lower C) and 42CrMo4 (higher C). Good balance of through-hardenability and toughness for medium-sized parts. Used for shafts, gears, bolts, studs, and structural components in oil/gas and power generation. Better weldability than 42CrMo4 due to lower C.

Free-machining variant of 37Cr4 with controlled sulfur addition (0.020–0.040%) for improved chip-breaking during automated machining. Chromium steel with good hardenability for medium cross-sections. Same mechanical properties as 37Cr4 after quenching and tempering. Used for automotive and mechanical engineering components: shafts, connecting rods, crankshafts, and bolts.

Low-chromium (0.4–0.6% Cr) alloy steel for quenching and tempering with moderate hardenability. Economical alternative to higher-alloyed Cr steels for lighter-duty applications. Cold forging grade suitable for stressed machine and vehicle components, quenched-and-tempered screws, and bolts. Good machinability in annealed condition.

NiCrMo quenched & tempered steel — excellent combination of strength (UTS 1000-1200 MPa) and toughness. Ni 0.9-1.2% gives good low-temperature impact. Between 34CrNiMo6 (higher alloy) and 42CrMo4 (no Ni) in the performance/cost spectrum. Used for heavy-duty axles, crankshafts, large bolts, connecting rods, and hydraulic cylinder rods.

Chromium Q&T steel with higher Cr (1.3-1.6%) than 41Cr4 (0.9-1.2%) — deeper hardenability for larger ruling sections. Used for heavy shafts, large bolts, and machine components up to ~60mm ruling section where 41Cr4 would not through-harden. Also offers slightly better wear resistance and corrosion resistance than lower-Cr grades.

Chromium-molybdenum-vanadium creep-resisting steel for high-temperature fasteners and bolts per EN 10269. Excellent creep resistance up to 540°C with tensile strength 850–1000 MPa after quenching and tempering. Widely used for steam turbine bolts, pressure vessel fasteners, and power generation components. Equivalent to ASTM A193 Grade B16.

High-alloy NiCrMo Q&T steel — Ni ~2%, Cr ~1%, Mo ~0.5%. Very deep hardenability for large cross-sections. UTS 1100-1300 MPa. Used for heavy-duty crankshafts, landing gear, rock drill components, and large forgings requiring uniform through-hardening. Between 34CrNiMo6 and 36NiCrMo16 in hardenability.

Free-cutting variant of 41CrMo4 (1.7225) — S 0.020-0.040% for improved chip formation on CNC automatics. Same Q&T mechanical properties (UTS 1000-1200 MPa). THE most popular free-cutting CrMo QT steel. Used for high-volume CNC production of crankshafts, connecting rods, gears, and shafts in the automotive industry.

Free-cutting variant of 41Cr4 (1.7035) — sulfur addition (0.020-0.040%) for improved chip formation on CNC automatics. Same mechanical properties as 41Cr4 after Q&T. UTS 900-1100 MPa. Used for high-volume automotive shafts, bolts, spindles, and connecting rods on automatic lathes. Most popular Cr-only QT steel for CNC mass production.

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.

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.