18CrNiMo7-6 is a nickel–chromium–molybdenum alloy case-hardening steel widely used for heavily loaded transmission components requiring a hard, wear-resistant surface and a tough, ductile core.
It offers an excellent balance of surface hardness, core toughness, and fatigue resistance, making it one of the most trusted materials for gears, shafts, and drive components in power transmission systems.
This steel grade is produced in accordance with EN 10084 / DIN 17210, classified as W-Nr. 1.6587, and is often regarded as a European benchmark for carburizing steels.
Chemical Composition (% by weight)
C: 0.15–0.21 | Si: ≤ 0.40 | Mn: 0.50–0.90 | Cr: 1.50–1.80 | Ni: 1.40–1.70 | Mo: 0.25–0.35 | P, S ≤ 0.025
This precise chemical balance ensures excellent hardenability and fine-grained structure after heat treatment.
Mechanical Properties (After Carburizing and Quenching)
| Property | Typical Range |
|---|---|
| Surface Hardness | 58–62 HRC |
| Core Tensile Strength | 900–1200 MPa |
| Yield Strength | ≥ 600 MPa |
| Elongation | ≥ 10% |
| Impact Toughness (KV) | ≥ 35 J (core) |
18CrNiMo7-6 maintains stable mechanical properties across large cross-sections, suitable for large forged gears and shafts where uniformity and fatigue strength are critical.
Key Features and Benefits
Excellent carburizing response, achieving high surface hardness and core strength balance
Outstanding fatigue strength, ideal for cyclic or impact loads
Good dimensional stability during heat treatment
Reliable toughness and ductility even in thick sections
High wear and contact stress resistance, ensuring long service life
Typical Applications
18CrNiMo7-6 is used in high-performance mechanical and power transmission systems, including:
Industrial and wind turbine gears
Heavy machinery shafts and couplings
Automotive gearbox and differential components
Aerospace transmission elements
Pressure and mining equipment gears
Equivalent Grades:
W.Nr. 1.6587
DIN 18CrNiMo7-6
GB 18Cr2Ni4WA (approx.)
AISI 4320 / 8620 (similar performance range)
Precision Supply from ChinaSpecSteel
ChinaSpecSteel supplies 18CrNiMo7-6 alloy steel produced by Jiyuan Iron & Steel Group, a leading Chinese manufacturer specializing in special quality bar and forged steels.
Jiyuan operates a long-process integrated production system combining ironmaking, steelmaking, rolling, and heat treatment — ensuring uniform composition, stable quality, and excellent machinability across all batches.
Available Forms:
Forged and rolled bars, discs, and rings
Normalized, quenched & tempered, or annealed delivery conditions
Machined blanks for OEM or gear manufacturing
Certified material with EN 10204/3.1 test reports and third-party inspection (SGS, BV, TÜV)
Manufacturing Excellence — Jiyuan Iron & Steel
Jiyuan Iron & Steel is one of China’s largest and most advanced production bases for special and high-quality steels, equipped with state-of-the-art refining, continuous casting, and rolling equipment.
Its production covers a broad range of steels, including bearing steel, spring steel, gear steel, cold heading steel, alloy structural steel, carbon structural steel, wear-resistant steel, and anchor chain steel.
Deep-processed materials such as heat-treated bars, precision wires, and bright bars are widely used in automotive, machinery, shipbuilding, and energy industries.
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