Materials database

Free-cutting variant of 20NiCrMo2-2 (1.6523/AISI 8620) — S addition for improved machinability on CNC automatics. Same case-hardening properties as 8620. THE free-cutting automotive gear and pinion steel for high-volume CNC production. Surface HRC 58-62 after carburizing with good core toughness.

Free-cutting variant of 20NiCrMo6-4 — S addition for improved machinability. NiCrMo case hardening steel with excellent core toughness and deep hardenability. Used for high-volume CNC production of automotive transmission gears, pinions, and shafts.

Cr-Mo-V high-temperature alloy steel for bolting at elevated temperatures up to ~550°C. Higher Cr and Mo than 15CrMoV5-9 for improved creep resistance. Used for turbine casing bolts, main flange bolts in steam power plants, and high-pressure/high-temperature petrochemical fasteners.

THE press hardening (hot stamping) boron steel — used in virtually every modern car for B-pillars, bumper beams, and side impact reinforcements. As-delivered: ferritic-pearlitic, UTS 450-750 MPa, formable. After hot stamping + die quenching: fully martensitic, UTS 1300-1650 MPa. Boron (0.002-0.005%) provides critical hardenability at low cost. Usually AlSi or Zn coated to prevent oxidation during austenitizing at 880-950°C.

Manganese-chromium case hardening steel with Mn+Cr for good hardenability. Part of the 20MnCr5 family (EN 10084). Surface hardness 60-62 HRC after carburizing + hardening. Good core toughness. Used for transmission gears, pinions, camshafts, piston pins, and small-to-medium sized carburized components.

Cold-heading boron steel — optimized for cold forming of high-strength fasteners. Boron gives hardenability equivalent to much more expensive Cr-Mo alloys. Supplied spheroidized for cold heading, then quenched+tempered after forming. Property class 10.9 bolts are commonly made from this grade. Used for high-strength bolts (M8-M24), screws, studs, and threaded fasteners for automotive and construction.

CrMoV nitriding and warm-work steel — Cr 1.2-1.5%, Mo 0.45-0.65%, V 0.25-0.35%. Lower Cr than 30CrMoV9 (2.3-2.7%) but higher Mo — better creep resistance at elevated temperature. Used for warm-work tools (forging dies to 400°C), nitrided piston rings, and power generation components. Also specified in EN 10269 for fasteners at elevated temperature.

Medium-carbon chromium-molybdenum steel with good toughness and weldability. Used for seamless tubes, pressure vessels, aircraft structural parts, and automotive components. Better weldability than 42CrMo4 due to lower carbon.

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.

Cr-Mo-V high-temperature bolt steel for service up to ~540°C. Used alongside 21CrMoV5-7 in power plant bolting — slightly higher Cr+Mo for improved creep resistance at the cost of toughness. Used for turbine casing bolts, high-pressure steam valve studs, and boiler fasteners.

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.

Low-carbon Cr-Mo QT steel — between 25CrMo4 and 30CrMo4. Excellent weldability for a QT grade (low C). Good hardenability for medium sections. Primary use: high-pressure gas cylinders (EN ISO 9809-1). Also used for pressure vessels, boiler parts, and automotive components where weldability + moderate strength are needed.

Manganese-chromium-boron steel for direct hardening and hot stamping. Boron addition (0.0008-0.005%) dramatically improves hardenability at low cost. The standard grade for automotive press-hardened body-in-white components (B-pillar, side impact beams, bumper reinforcements).

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.

Manganese case-hardening steel for large components requiring deep case depth. Higher Mn than 16MnCr5 for better hardenability in thick sections. Used for large gears, heavy-duty pinions, and mining/construction equipment.

Low-to-medium carbon Cr-Mo QT steel — lower C than 34CrMo4/42CrMo4 giving better weldability and toughness. THE gas cylinder and pressure vessel grade in Europe (EN ISO 9809). Good hardenability for medium sections. Also used for automotive crankshafts, gears, and high-pressure hydraulic components. AISI 4130 equivalent.

THE Cr-Mo-V nitriding steel — Cr 2.3-2.7% forms hard CrN nitrided case (800 HV surface). V addition for secondary hardening. Core QT to UTS 1080-1270 MPa before nitriding at 570-580°C. Used for piston rods, valve stems, cylinder liners, turbine parts, and any component needing extreme surface hardness + fatigue resistance without distortion (low nitriding temp).

High-strength quenched and tempered Cr-Ni-Mo steel for very large cross-sections. Even better hardenability than 34CrNiMo6 due to higher Cr and Ni content. Used for large shafts (>200mm diameter), heavy-duty gears, turbine rotors, and critical aerospace components.

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.

Deep nitriding steel with 3% Cr — the highest Cr content in the EN 10085 nitriding series. Produces the deepest and hardest nitrided case (surface hardness >900 HV, case depth >0.5mm). Core strength 800-1000 MPa QT. Used where maximum surface hardness and wear resistance with a tough core is needed: large gears, cylinder liners, spindles, precision measuring tools, and heavy-duty sliding components.

THE standard nitriding steel — Cr-Mo-V combination optimized for gas nitriding. Vanadium refines grain and forms hard VN nitrides (surface >750 HV). Better core toughness than 31CrMo12 at similar strength. THE default choice when "nitriding steel" is specified without further detail. Used for crankshafts, gears, spindles, extrusion screws, and precision machine components.

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.