Materials database

High-Ni case hardening steel — Ni 3.0-3.5%, Cr 0.6-0.9%, no Mo. Ni gives excellent core toughness at low temperature — used for case-hardened parts operating in cold environments. THE classic aerospace/defense case-hardening steel (BS S130/S131). Used for aircraft gears, military vehicle transmission gears, and cryogenic case-hardened components.

High-nickel case-hardening steel for heavily loaded large gears, shafts, and drivetrain components. Excellent core toughness with case hardness up to 62 HRC after carburizing. The high nickel content (3.0–3.5%) provides superior impact resistance even at low temperatures. Standard material for wind turbine gearboxes, heavy-duty industrial gears, and aerospace transmissions. Also known as EN36C (BS) and similar to SAE 9310.

Heavy-duty NiCrMo case hardening steel — Ni 3.0-3.5% for maximum core toughness and deep hardenability. For the largest case-hardened parts: heavy truck ring gears, mill pinions, crane slewing gears, and large marine gearboxes up to 500mm ruling section. Surface HRC 60-63 with extremely tough core. More Ni than 17CrNiMo6 = even deeper hardenability.

Low-carbon case-hardening steel with manganese and chromium. Excellent for carburizing to produce a hard, wear-resistant surface with a tough core. Standard choice for gears, camshafts, piston pins, and transmission components.

Free-cutting variant of 16MnCr5 (1.7131) — sulfur addition (0.020-0.040%) for improved machinability on CNC automatics. Same case-hardening properties: surface 60-62 HRC after carburizing. THE high-volume automotive gear steel where machining cost matters. Used for transmission gears, shafts, pinions, and other carburized parts produced on CNC lathes and multi-spindle automatics.

Nickel-chromium case hardening steel — Ni 0.8-1.1%, Cr 0.6-1.0%, no Mo. Between 16MnCr5 (Mn-Cr) and 14NiCr14 (high-Ni) in hardenability. Better core toughness than 16MnCr5 due to Ni. Used for heavy-duty sprockets, pinions, worms, pins, and shafts requiring case-hardened surface (HRC 58-62) with tough core. EN 10084 standard.

Chrome case-hardening steel — the simplest Cr-alloyed carburizing grade in EN 10084. 0.7-1.0% Cr gives better hardenability and wear resistance than unalloyed C20 but less than 16MnCr5. Used for smaller gears, camshafts, spindles, pins, and bushings with medium wear requirements. ≈ SAE 5117.

Premium CrNiMo case hardening steel for demanding gear applications. Ni 1.2-1.5% + Mo 0.25-0.35% give excellent core toughness and deep hardenability — suitable for large gears up to 400mm ruling section. Surface HRC 60-63 after carburizing. THE wind turbine gearbox steel. Also used for large industrial gearboxes, mining equipment, and heavy truck transmissions.

Premium Cr-Ni-Mo case-hardening steel for the most demanding gear applications. Excellent core toughness and hardenability for large cross-sections. The standard gear steel for wind turbines, heavy-duty gearboxes, and aerospace gearing.

Free-cutting CrMo case hardening steel — S addition to 20CrMo5 base for CNC machining. Higher Cr (1.1-1.4%) and Mo (0.20-0.30%) than 16MnCrS5 = deeper hardenability for medium-large gears. Used for automotive transmission gears, pinions, and differential components on CNC automatics.

Manganese-chromium case-hardening steel with higher core strength than 16MnCr5. Used for heavily loaded gears, shafts, camshafts, and transmission components requiring high surface hardness with tough core. Popular in automotive and heavy machinery.

Free-cutting variant of 20MnCr5 with controlled sulfur (0.020-0.040%). Improved machinability for high-volume gear production without significant loss of mechanical properties. The standard free-cutting case-hardening steel in European automotive gear manufacturing.

Nickel-chromium-molybdenum case-hardening steel — the base grade of the 8620 family. Good weldability, toughness, and machinability. Case hardness up to HRC 60–63 with core strength 700–1100 MPa after carburizing and quenching. Used for gears, shafts, pinions, piston pins, and camshafts in automotive, gearbox, and general mechanical engineering. Equivalent to AISI 8620 and BS 805M20.

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.

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.

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.

Boron-alloyed case hardening steel with higher C (0.30-0.36%) than typical case-hardening grades. B addition for cost-effective hardenability. After carburizing: HRC 58-62 surface with tough core. THE chain link and chain pin steel — also used for agricultural equipment, earth-moving parts, and wear-resistant components requiring surface hardness with impact resistance.

Nickel-chromium-molybdenum case-hardening steel. Good combination of core toughness and case hardness. The most widely used case-hardening steel in the US (AISI 8620). Used for gears, pinions, worm drives, king pins, and cross-shafts.

Lowest practical carbon case-hardening steel — 0.07-0.13% C. After carburizing: hard surface (HRC 55-60) with extremely soft, tough core (HRC 15-20). Maximum impact absorption. Modern designation for Ck10. Used for pins, bushings, small gears, camshaft lobes, and any carburized part where maximum core toughness and ductility are critical. Also used as cold-heading and deep-drawing wire/strip.

Low-carbon unalloyed case-hardening steel. The simplest and most economical case-hardening grade. Used for lightly loaded gears, pins, bushings, rivets, and small machine parts where a hard wear-resistant surface with a soft tough core is needed.

Low-carbon unalloyed case hardening steel — 0.12-0.18% C. Between C10E (softer core) and C22E (harder core) in the case-hardening range. Good balance of surface hardness (HRC 58-62) and core toughness after carburizing. Modern designation for Ck15. Used for small gears, pins, bushings, levers, and carburized parts where moderate core strength is acceptable. Also used for cold forming and deep drawing.

Low-carbon unalloyed steel for case hardening (carburizing). 0.17-0.23% C gives a tough core with a hard, wear-resistant surface after carburizing + quenching. The simplest and cheapest case-hardening steel. Used for pins, bushings, cam followers, light-duty gears, and general machine parts where a hard surface with tough core is needed. ≈ AISI 1020.

Low-carbon unalloyed steel for case hardening and general engineering — 0.17-0.24% C. After carburizing: surface HRC 55-60, soft tough core. Much cheaper than alloy case-hardening steels (16MnCr5, 20MnCr5). Modern designation for Ck22. Used for pins, bolts, levers, lightly loaded gears, and any carburized part where alloy additions are not justified. Also used as cold-heading wire.