Description
20CrMo Alloy Steel Overview
20CrMo is a high-performance alloy steel known for its excellent combination of strength, toughness, and wear resistance. This steel is primarily used in applications requiring high strength and good resistance to wear and fatigue. Its composition includes chromium and molybdenum, which enhance its mechanical properties and make it suitable for a wide range of demanding applications.
Key Features of 20CrMo:
- High Strength: Provides strong load-bearing capacity and resistance to deformation.
- Good Toughness: Maintains structural integrity under impact and stress.
- Enhanced Wear Resistance: Chromium and molybdenum improve resistance to wear and abrasion.
- Excellent Hardness: Suitable for applications where hardness is a critical factor.
Applications of 20CrMo Alloy Steel
20CrMo alloy steel is used in various industries where high strength, durability, and resistance to wear are crucial. Typical applications include:
- Automotive Industry: Components like gears, crankshafts, and camshafts that require high strength and durability.
- Engineering: Parts subjected to high stress and wear, such as shafts, couplings, and brackets.
- Heavy Machinery: Components used in mining and construction equipment that need to withstand harsh conditions.
- Power Generation: Parts used in turbines and generators that require high strength and resistance to wear.
Equivalent Grades for 20CrMo
20CrMo is recognized under various international standards, ensuring compatibility and interchangeability:
| Standard | Equivalent Grade |
|---|---|
| DIN | 1.7225 |
| BS | 20CrMo |
| AISI/SAE | 4118 |
| UNS | G41180 |
| JIS | SCM420 |
Chemical Composition of 20CrMo
The chemical composition of 20CrMo gives it its unique properties. The typical composition is as follows:
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.17 – 0.22 |
| Silicon (Si) | 0.17 – 0.37 |
| Manganese (Mn) | 0.40 – 0.70 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.035 max |
| Chromium (Cr) | 0.90 – 1.20 |
| Molybdenum (Mo) | 0.15 – 0.25 |
Mechanical Properties of 20CrMo
The mechanical properties of 20CrMo make it suitable for applications requiring high strength and toughness:
| Property | Value (Typical) |
|---|---|
| Tensile Strength (MPa) | 850 – 1100 |
| Yield Strength (MPa) | 600 – 850 |
| Elongation (%) | 12 – 20 |
| Impact Toughness (J) | 30 – 50 (at 20°C) |
| Hardness (HB) | 200 – 270 |
Heat Treatment of 20CrMo
Heat treatment processes are essential for optimizing the properties of 20CrMo:
- Annealing: Heat to 850-880°C, hold until uniform, and cool slowly to improve machinability and relieve internal stresses.
- Hardening: Heat to 830-880°C, followed by quenching in oil or water to increase hardness and strength.
- Tempering: After hardening, temper at 400-650°C to reduce brittleness and enhance toughness.
Hardness of 20CrMo
In its hardened and tempered condition, 20CrMo typically exhibits a hardness range of 200 – 270 HB, providing a balance between hardness and toughness.
Physical Properties of 20CrMo
The physical properties of 20CrMo contribute to its suitability for various applications:
| Property | Value |
|---|---|
| Density (g/cm³) | 7.85 |
| Melting Point (°C) | 1420 – 1460 |
| Thermal Conductivity (W/m·K) | 40 |
| Specific Heat Capacity (J/kg·K) | 460 |
Forging Properties of 20CrMo
20CrMo can be forged at temperatures between 1150 – 850°C. Components should be cooled slowly to avoid internal stresses and potential cracking.
Stress Relieving for 20CrMo
To remove residual stresses from machining or deformation, stress relieving should be performed by heating to 650 – 700°C, holding for a sufficient period, and then cooling slowly.
Normalizing 20CrMo
Normalizing involves heating to 850 – 880°C and air cooling. This process refines the grain structure and improves mechanical properties.
Annealing 20CrMo
Annealing requires heating to 850 – 880°C, holding at this temperature, and then slowly cooling in the furnace. This treatment improves machinability and relieves internal stresses.
Machinability of 20CrMo
20CrMo exhibits good machinability in the normalized or annealed condition. For optimal results, use sharp cutting tools and appropriate machining parameters to enhance tool life and surface finish.
Welding of 20CrMo
Welding of 20CrMo is feasible but requires careful handling. Preheat to 150 – 250°C to prevent cracking, and consider post-weld heat treatment to ensure the integrity of the weld.
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.
