Description
40Cr Steel Introduction:
40Cr is a versatile medium carbon alloy steel with good wear resistance, high strength, and toughness. It is one of the most commonly used alloy steels in mechanical engineering due to its excellent balance between hardness and machinability. 40Cr can be hardened and tempered to improve its mechanical properties and is often used in manufacturing high-stress components in industries such as automotive, machinery, and power generation.
40Cr Grade Applications:
40Cr steel is widely used for producing components that require good mechanical properties and wear resistance, such as:
- Gears
- Shafts
- Axles
- Connecting rods
- High-strength fasteners
- Machinery parts It is typically chosen for applications requiring moderate to high tensile strength and toughness, and where parts are subject to medium-to-heavy loads.
Equivalent Grades:
- GB: 40Cr
- DIN: 1.7035 (41Cr4)
- AISI/SAE: 5140
- JIS: SCr440
Chemical Composition:
| Element | Content (%) |
|---|---|
| C | 0.37-0.44 |
| Mn | 0.50-0.80 |
| P | ≤ 0.035 |
| S | ≤ 0.035 |
| Cr | 0.80-1.10 |
| Si | 0.17-0.37 |
Mechanical Properties:
| Property | Value |
|---|---|
| Tensile strength (MPa) | 835-1080 |
| Yield strength (MPa) | ≥ 540 |
| Elongation rate (%) | ≥ 9 |
| Reduction of area (%) | ≥ 45 |
| Impact energy (J) | ≥ 47 |
| Hardness (HB) | ≤ 229 (annealed) |
40Cr Hardness:
In its annealed state, 40Cr typically has a hardness of ≤ 229 HB. After quenching and tempering, the hardness can reach 28-34 HRC, depending on the heat treatment process and cooling method.
Heat Treatment:
40Cr can undergo various heat treatments, such as quenching and tempering, to enhance its mechanical properties.
Hardening Process:
- Heating for hardening: Heat the material to 850-880°C, followed by quenching in oil.
- Tempering: Tempering is typically performed at 500-600°C, which enhances toughness and maintains a good balance between strength and ductility.
Physical Properties:
| Property | Value |
|---|---|
| Modulus of Elasticity (N/mm²) | 206 × 10³ |
| Density (g/cm³) | 7.85 |
| Thermal Conductivity (W/m.K) | 44.5 |
Thermal Properties:
- Thermal conductivity: 44.5 W/m.K at room temperature.
- Specific heat: 460 J/kg-K.
Forging Properties:
40Cr can be forged at temperatures between 1100°C and 850°C. After forging, slow cooling is recommended to reduce internal stresses and prevent unwanted hardness.
Normalizing:
Normalizing is performed at 880-920°C, followed by air cooling. This process improves the grain structure and enhances the overall mechanical properties of the steel.
Annealing:
Annealing is typically carried out at 850°C, followed by slow furnace cooling. This softens the material, making it easier to machine and enhancing ductility.
Welding:
40Cr steel has moderate weldability. Preheating is recommended before welding to reduce the risk of cracking, especially for thicker sections. Post-weld heat treatment, such as stress relieving, is also advisable to ensure stability.
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.
