EN353
EN353 Alloy Steel as Surface-Hardened Steel for Wear-Resistant Applications.It is a low-carbon, nickel–chromium–molybdenum alloy steel known for its excellent case hardening properties. It is specially designed for carburizing, a heat treatment that creates a hard, wear-resistant surface while keeping a tough, ductile core.
This combination of a hard outer layer and a tough interior makes EN353 ideal for components that experience high surface stress, such as gears, shafts, bearings, and automotive transmission parts. After carburizing and quenching, the surface hardness can reach up to 58–62 HRC, providing excellent wear resistance without sacrificing the toughness of the core.
EN353 also offers good machinability in its untreated condition, allowing complex shapes to be formed before heat treatment. Its core toughness and fatigue strength make it reliable in demanding mechanical and engineering environments.
Applications
EN353 is widely used in applications where high surface hardness and core toughness are essential. Its excellent case-hardening ability makes it ideal for components subjected to continuous friction, wear, and load. Common applications include:
Automotive Gears – Ideal for transmission and differential gears due to high wear resistance.
Pinions and Shafts – Used where a tough core and hardened surface are needed for durability.
Clutch Components – Withstands repeated engagement and disengagement.
Bearing Races – Provides a hard surface to resist rolling contact fatigue.
Camshafts and Crankshafts – Offers strength and surface durability under high loads.
Bushes and Couplings – Handles torsional stress while resisting surface wear.
Industrial Gearboxes – Suitable for heavy-duty mechanical systems with continuous operation.
Machine Tool Parts – Precision components requiring a hard surface and stable core.
Chemical Composition
| Element | Carbon (C) | Manganese (Mn) | Silicon (Si) | Nickel (Ni) | Chromium (Cr) | Molybdenum (Mo) | Sulphur (S) | Phosphorus (P) |
|---|---|---|---|---|---|---|---|---|
| Percentage (%) | 0.15 – 0.25 | 0.50 – 1.00 | 0.10 – 0.35 | 1.00 – 1.50 | 0.80 – 1.20 | 0.08 – 0.15 | ≤ 0.05 | ≤ 0.05 |
Hardness
EN353 is designed for case hardening, meaning it develops a very hard surface while retaining a tough and ductile core. The hardness of EN353 varies based on its heat treatment condition:
Core Hardness (Before Case Hardening):
Typically around 28–32 HRC
This allows for good toughness and shock resistance in the core.
Surface Hardness (After Carburizing & Quenching):
Can reach up to 58–62 HRC
Ideal for resisting wear, friction, and surface fatigue.
Equivalent Grades
- AISI / SAE (USA) 5120 or 8620 (closest match)
- DIN (Germany) 20NiCrMo2-2 or 17CrNiMo6
- BS (UK) 655M13 (old British spec)
- JIS (Japan) SNCM220 or SNCM420
- ISO 20NiCrMo2
Heat Treatment
1. Carburizing
Heat the steel to 880–920°C in a carbon-rich atmosphere.
Purpose: Adds carbon to the surface to prepare for hardening.
2. Hardening (Quenching)
After carburizing, reheat to 780–800°C, then quench in oil.
Purpose: Hardens the carburized surface while the core remains tough.
3. Tempering
Reheat to 150–200°C, then cool in air.
Purpose: Reduces brittleness in the hardened surface while preserving hardness.
Hardening
1. Carburizing:
Heat the steel to 880–920°C in a carbon-rich atmosphere. This process adds carbon to the surface, preparing it for high surface hardness.
2. Reheating:
After carburizing, the component is reheated to 780–800°C to prepare it for quenching.
3. Quenching:
The steel is then quenched in oil, rapidly cooling the surface. This hardens the outer layer while maintaining a tough and ductile core.
4. Tempering (Optional):
To reduce brittleness and relieve internal stress, the part is tempered at 150–200°C, then allowed to air cool.
5. Final Hardness Achieved:
Surface Hardness: Up to 58–62 HRC
Core Hardness: Around 28–32 HRC
Welding
1. Preheating:
Preheat the steel to 200–300°C before welding. This helps reduce the risk of thermal cracking during the process.
2. Use of Low-Hydrogen Electrodes:
Use low-hydrogen electrodes or filler rods to minimize the risk of hydrogen-induced cracking (e.g., E7018 or equivalent).
3. Controlled Welding:
Perform welding with low heat input and controlled interpass temperatures. Avoid overheating the material.
4. Post-Weld Heat Treatment (PWHT):
After welding, apply stress relieving or tempering at 600–650°C, followed by slow cooling. This reduces residual stresses and improves toughness.
5. Surface Re-Treatment (if needed):
If the component was previously case-hardened, re-carburizing and re-hardening the weld area may be necessary to restore surface properties.
Machinability
1. Best Machining Condition:
Machine EN353 in the annealed state for smoother cutting, better tool life, and less wear.
2. Tool Selection:
Use high-speed steel (HSS) or carbide tools for general machining. For hardened or surface-treated parts, coated carbide inserts or ceramic tools are recommended.
3. Coolant Use:
Always use an appropriate cutting fluid or coolant to avoid overheating and to improve surface finish.
4. After Case Hardening:
Machining hardened EN353 (surface hardness ~58–62 HRC) is difficult and should be limited to light finishing operations or grinding.
5. Final Machining Tip:
For precise components, it’s ideal to machine first, then carburize and harden, followed by grinding or finishing.
Physical Properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Melting Point | 1420–1460°C |
| Modulus of Elasticity | 200–210 GPa |
| Thermal Conductivity | ~45 W/m·K (at 100°C) |
| Specific Heat Capacity | ~460 J/kg·K |
| Electrical Resistivity | ~0.45 µΩ·m |
| Coefficient of Thermal Expansion | ~12 × 10⁻⁶ /°C (20–100°C) |
Chemical Properties
| Property | Value |
|---|---|
| Corrosion Resistance | Moderate; improves with heat treatment and alloying elements |
| Hardness | 250–280 HB (annealed); 55–60 HRC (case hardened) |
| Tensile Strength | High; typically 850–1100 MPa |
| Toughness | Excellent with proper heat treatment |
Dealer
We are a leading dealer, supplier, stockist, and distributor of high-quality EN353 alloy steel, catering to the needs of engineering, automotive, and industrial sectors across India.