Hot Rolled 18CrNiMo7-6 (1.6587 / 18NCD6) Alloy Steel Round Bar – 105mm Diameter Now in Stock
We are pleased to offer our premium Hot Rolled 18CrNiMo7-6 (DIN 1.6587 / AFNOR 18NCD6) Alloy Steel Round Bar at 105 mm diameter, with customizable sizes available. This nickel-chromium-molybdenum case hardening steel, conforming to EN 10084:2008, is engineered for applications demanding high surface hardness, excellent core toughness, and superior fatigue resistance under extreme loading conditions.
Material Overview & Engineering Significance
18CrNiMo7-6 is a premium case hardening alloy steel that combines a balanced composition of chromium, nickel, and molybdenum to deliver exceptional hardenability and mechanical performance. After carburizing and heat treatment, it achieves a tensile strength of up to 1200 MPa (hardening and tempering at 200°C), with a hardened wear-resistant surface supported by a tough, ductile core — the ideal combination for heavily loaded transmission components.
Extensive metallurgical investigations into 18CrNiMo7-6 components — including optical microscopy, quantitative metallography, and SEM analysis — have demonstrated that the material's failure resistance is governed by geometrical stress concentration factors rather than internal inclusions or grain size inhomogeneity. The carburized layer, transitive layer, and matrix all exhibit tempered martensite microstructures, providing consistent mechanical behavior throughout the cross-section.
Chemical Composition (EN 10084-2008)
| Element | Content (%) |
|---|
| Carbon (C) | 0.15 – 0.21 |
| Silicon (Si) | ≤ 0.40 |
| Manganese (Mn) | 0.50 – 0.90 |
| Nickel (Ni) | 1.40 – 1.70 |
| Chromium (Cr) | 1.50 – 1.80 |
| Molybdenum (Mo) | 0.25 – 0.35 |
| Phosphorus (P) | ≤ 0.025 |
| Sulfur (S) | ≤ 0.035 |
Steels with improved machinability via lead addition or higher sulfur content (up to ~0.1% S) may be supplied on request, with the manganese upper limit increased by 0.15% accordingly.
Mechanical Properties
| Condition | Hardness (HBW) |
|---|
| Shearability Improved (+S) | ≤ 255 |
| Soft Annealed (+A) | ≤ 229 |
| Treated to Hardness Range (+TH) | 179 – 229 |
| Ferrite-Pearlite Structure (+FP) | 159 – 207 |
| Hardening + Tempering at 200°C | Tensile Strength: 1200 MPa |
International Equivalent Grades
| Standard / Country | Equivalent Grade |
|---|
| EN (EU) | 18CrNiMo7-6 |
| DIN / WNr (Germany) | 1.6587 / 17CrNiMo6 |
| AFNOR (France) | 18NCD6 |
| BS (UK) | 820A16 |
| UNI (Italy) | 18NiCrMo7 |
| GB (China) | 17Cr2Ni2Mo |
| SFS (Finland) | 511 |
| ISO | 18CrNiMo7 |
Heat Treatment Designations
| Code | Treatment | Code | Treatment |
|---|
| +A | Soft annealed | +NT | Normalized and tempered |
| +FP | Ferrite-pearlite structure | +QT | Quenched and tempered |
| +TH | Treated to hardness range | +S | Shearability improved |
| +N | Normalized | +SR | Cold drawn, stress relieved |
Key Applications
- Heavy-Duty Gears & Shafts: Transmission components requiring high surface hardness and fatigue resistance
- Drilling & Mining Tools: Drill bits and cutting components subjected to combined twisting and axial impact loads
- Automotive Powertrain: Pinions, crown wheels, and highly stressed powertrain components
- Industrial Machinery: Case-hardened shafts, spindles, and load-bearing structural parts
- Wind Turbine Gearboxes: Critical gearing components for renewable energy applications
Global Supply & Service
As a direct manufacturer and stockist, we supply 18CrNiMo7-6 round bars to markets across the Middle East, South America, South Asia, Africa, Southeast Asia, Northern Europe, and Western Europe. Our minimum order quantity is 15 metric tons, with in-stock material shipping within 7–10 days and production orders delivered within 25–30 days after deposit receipt. Payment is accepted via T/T or 100% L/C at sight. Free samples are available for technical evaluation (customer covers freight).
For technical data sheets, metallurgical reports, pricing inquiries, or to discuss custom diameters and heat treatment conditions, please contact our export team today.
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