Description
30CrNiMo8 Steel Introduction:
30CrNiMo8 is a high-strength alloy steel that combines toughness, high hardenability, and good fatigue resistance. Its primary alloying elements are chromium (Cr), nickel (Ni), and molybdenum (Mo), which provide excellent mechanical properties even under demanding conditions such as high stress, shock, and dynamic loads. This steel is typically used in critical components such as shafts, gears, and parts subjected to high torsional loads in industries like aerospace, automotive, and heavy machinery.
30CrNiMo8 Grade Applications:
30CrNiMo8 is widely used in the manufacturing of components such as:
- Heavy-duty shafts
- Gear shafts
- Crankshafts
- Connecting rods
- Heavy-duty bolts
- Pressure vessels It is often selected for applications that require a high level of toughness, good fatigue strength, and resistance to wear and impact, especially in harsh environments.
Equivalent Grades:
- GB: 30CrNiMo8
- DIN: 1.6580
- AISI/SAE: 4340 (similar, but with slight differences)
- JIS: SNCM439
Chemical Composition:
| Element | Content (%) |
|---|---|
| C | 0.26-0.34 |
| Mn | 0.50-0.80 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
| Cr | 1.80-2.20 |
| Ni | 1.50-1.80 |
| Mo | 0.30-0.50 |
| Si | 0.10-0.40 |
Mechanical Properties:
| Property | Value |
|---|---|
| Tensile strength (MPa) | ≥ 930 |
| Yield strength (MPa) | ≥ 800 |
| Elongation rate (%) | ≥ 12 |
| Reduction of area (%) | ≥ 50 |
| Impact energy (J) | ≥ 40 |
| Hardness (HB) | 230-280 (annealed) |
30CrNiMo8 Hardness:
When annealed, the typical hardness ranges from 230-280 HB, but after hardening and tempering, the hardness can increase significantly to values above 600 HB, depending on the treatment applied.
Heat Treatment:
30CrNiMo8 can undergo various heat treatment processes to achieve different mechanical properties, such as hardening, tempering, and stress-relieving.
Hardening Process:
- 1st Heating: Heat to 820-860°C, then quench in oil or water.
- Tempering: After quenching, tempering is performed at temperatures between 450-650°C to improve toughness without sacrificing too much hardness.
Physical Properties:
| Property | Value |
|---|---|
| Modulus of Elasticity (N/mm²) | 210 × 10³ |
| Density (g/cm³) | 7.85 |
| Thermal Conductivity (W/m.K) | 30.5 |
Thermal Properties:
- Thermal conductivity: 30.5 W/m.K at room temperature.
- Specific heat: 460 J/kg-K.
Forging Properties:
The material is hot forged at temperatures between 1100°C and 850°C. After forging, the material should be allowed to cool slowly to avoid unwanted microstructural changes.
Normalizing:
Normalize the steel by heating it to 850-880°C, followed by air cooling, to refine the grain structure and improve mechanical properties.
Annealing:
Annealing is performed at 650-700°C, followed by slow cooling in the furnace, to soften the material and improve machinability.
Welding:
30CrNiMo8 has good weldability, but preheating and post-weld heat treatment are recommended to minimize the risk of cracking, particularly for thicker sections.
Supply Cities:
Mumbai Ahmedabad, Amaravathi, Ambattur, Bangalore, Belgaum, Chennai, Chittoor, Coimbatore, Dindigul, Mysore, Nellore, Hyderabad, Kochi, Mangalore, Tirupur, Tuticorin, Madurai, Andhra Pradesh, Karnataka, Puducherry, Kerala, Tamil Nadu, Telangana, Visakhapatnam, Kochi, Kerala, Hubli-Dharwad, Karnataka, Ghaziabad Kolkata.
