Description
70Cr3 Steel Introduction:
70Cr3 is a high-carbon, chromium-alloyed spring steel known for its high strength, hardness, and excellent fatigue resistance. The addition of chromium enhances the steel’s hardenability and wear resistance, making it suitable for demanding applications where high performance and durability are required. This steel is commonly used in the production of various mechanical components, particularly those subjected to high stresses.
70Cr3 Grade Applications:
70Cr3 is often used in:
- High-performance leaf springs
- Coil springs
- Automotive suspension components
- Industrial machinery parts
- Cutting tools
- High-stress mechanical components
Equivalent Grades:
- DIN: 1.7080
- AISI/SAE: 5160 (similar but may have slight variations)
- JIS: SUP12 (comparable)
Chemical Composition:
| Element | Content (%) |
|---|---|
| C | 0.65-0.75 |
| Mn | 0.60-0.90 |
| P | ≤ 0.025 |
| S | ≤ 0.025 |
| Cr | 1.40-1.70 |
| Si | ≤ 0.35 |
Mechanical Properties:
| Property | Value |
|---|---|
| Tensile strength (MPa) | 1200-1450 |
| Yield strength (MPa) | ≥ 1000 |
| Elongation rate (%) | ≥ 8 |
| Reduction of area (%) | ≥ 30 |
| Hardness (HB) | 300-350 (quenched and tempered) |
70Cr3 Hardness:
In the quenched and tempered condition, 70Cr3 typically has a hardness range of 300 to 350 HB. After appropriate heat treatment, the hardness can achieve 50-55 HRC.
Heat Treatment:
70Cr3 is heat-treated to optimize its mechanical properties, including hardness, strength, and toughness.
Hardening Process:
- Heating for hardening: Heat the steel to 850-900°C, followed by quenching in oil or water.
- Tempering: Tempering is performed at 400-600°C to balance hardness and toughness, reducing internal stresses while maintaining strength.
Physical Properties:
| Property | Value |
|---|---|
| Modulus of Elasticity (N/mm²) | 210 × 10³ |
| Density (g/cm³) | 7.85 |
| Thermal Conductivity (W/m.K) | 45.0 |
Thermal Properties:
- Thermal conductivity: 45.0 W/m.K at room temperature.
- Specific heat: 460 J/kg-K.
Forging Properties:
70Cr3 should be forged at temperatures between 1100°C and 850°C. Post-forging cooling should be controlled to prevent stress and cracking.
Normalizing:
Normalizing is carried out at 850-880°C, followed by air cooling. This process refines the grain structure and improves the steel’s toughness.
Annealing:
Annealing is typically done at 780-820°C, followed by slow cooling. This process softens the steel to facilitate machining and forming before final heat treatment.
Welding:
70Cr3 is generally not recommended for welding due to its high carbon and chromium content, which can make it prone to cracking. If welding is necessary, preheating and post-weld heat treatment are essential to avoid defects and ensure structural integrity.
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.
