1.6587 - 18CrNiMo7-6 - 16 326
Delivery condition
🔩 Delivery condition
| Condition designation | Description | Hardness / Strength | Application |
|---|---|---|---|
| +A, annealed | Soft annealed – intended for machining and subsequent heat treatment | approx. 200 HB | Semi-finished products for further processing |
| +QT, quenched and tempered | Final delivery condition | approx. 850–1100 MPa, Rm / approx. 30–38 HRC | Finished parts, shafts, gears |
| +N, normalized | Fine-grained structure, suitable for subsequent hardening | approx. 220 HB | Formed and case-hardened components |
| +SR, stress relieved | Stress relieved after forming | — | Before final machining |
Steel number
⚙️ Basic designation
| Parameter | Value |
|---|---|
| Material number | 1.6587 |
| EN designation | 34CrNiMo6 |
| ČSN designation | 15 340 |
| Steel type | High-strength alloyed quenching and tempering steel |
| Standard | EN 10083-3 – Quenching and tempering steels |
Applications and properties
🔩 Properties
| Property | Value / Description |
|---|---|
| Surface hardness after case hardening | Up to 58–62 HRC |
| Heat treatment | Case hardening, hardening, tempering |
| Machinability | Good in annealed condition, reduced after hardening |
| Weldability | Limited, preheating and subsequent annealing recommended |
| Wear resistance | High after case hardening |
Mechanical properties
| Property | Value |
|---|---|
| Hardness (HB) | 295–384 HB, after heat treatment (case hardening + hardening + tempering) |
| Yield strength Rp0.2 (MPa) | 685–835 MPa |
| Tensile strength Rm (MPa) | 980–1420 MPa |
| Elongation A5 (%) | 5–10 % |
🧰 Applications
| Industry / Area | Typical applications | Required properties |
|---|---|---|
| Mechanical engineering and heavy machinery | highly stressed shafts, spindles, pins, tie rods, gears, cams | high strength, toughness, resistance to dynamic loading |
| Automotive industry | crankshafts, camshafts, axles, transmission shafts, gear segments | high fatigue strength, core and surface hardness |
| Energy and industrial equipment | pistons, connecting rods, turbine shafts, couplings | resistance to thermal changes and material fatigue |
| Aerospace and defence industry | load-bearing and rotating components under high stress | stability, toughness even at elevated temperatures |
| Tool holders and moulds | holders, pins, precision mould components | tough core, surface hardness after nitriding or hardening |
⚙️ Summary of application properties
Tensile strength after +QT: 850–1100 MPa
Core hardness: 30–38 HRC
Surface hardness after nitriding: up to 60 HRC
Excellent toughness and dimensional stability
High hardenability, uniform properties even in large cross-sections
Chemical composition
⚗️ Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.15–0.21 |
| Si | ≤ 0.40 |
| Mn | 0.50–0.90 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
| Cr | 1.50–1.80 |
| Ni | 1.40–1.70 |
| Mo | 0.25–0.35 |
Heat treatment
🔥 Typical heat treatment
| Process | Temperature (°C) | Medium / Procedure | Result / Purpose |
|---|---|---|---|
| Soft annealing | 650–700 | Slow cooling in furnace | Removal of internal stresses, improved machinability, hardness approx. 200 HB |
| Normalizing | 850–880 | Air cooling | Grain refinement before quenching and tempering |
| Quenching | 830–870 | Oil or water | Martensitic structure, hardness after quenching approx. 50–55 HRC |
| Tempering | 540–680 | Air, holding time 2–4 h depending on thickness | Reduction of internal stresses, required strength 850–1100 MPa |
| Quenched and tempered condition, +QT | Combination of quenching and tempering | — | Final delivery condition with tough core and hardness 30–38 HRC |
| Nitriding, optional | 480–530 | Gas or plasma | Surface hardness up to 58–60 HRC, increased wear resistance |
| Stress relieving | 550–600 | Air | After machining or welding, reduction of deformation |
Delivery condition
Steel number
Applications and properties
Chemical composition
Heat treatment
