EN36 Steel: Properties and Key Applications Overview
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Table Of Content
Table Of Content
EN36 steel is a medium-carbon alloy steel primarily used in the manufacturing of gears, shafts, and other high-strength components. Classified as a case-hardening steel, it contains significant amounts of carbon, manganese, and chromium, which enhance its hardness and strength after heat treatment. The primary alloying elements in EN36 steel include:
- Carbon (C): Increases hardness and strength.
- Manganese (Mn): Improves hardenability and tensile strength.
- Chromium (Cr): Enhances corrosion resistance and hardenability.
Characteristics and Properties
EN36 steel is known for its excellent wear resistance, toughness, and ability to withstand high stress. Its properties make it suitable for applications requiring high strength and durability.
Advantages:
- High tensile strength and fatigue resistance.
- Good machinability and weldability.
- Excellent case hardening properties.
Limitations:
- Limited corrosion resistance compared to stainless steels.
- Requires careful heat treatment to achieve desired properties.
Historically, EN36 has been significant in the automotive and aerospace industries, where high-performance components are essential. Its market position is robust, with widespread use in various engineering applications.
Alternative Names, Standards, and Equivalents
| Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
|---|---|---|---|
| UNS | G86200 | USA | Closest equivalent to EN36 |
| AISI/SAE | 8620 | USA | Minor compositional differences |
| ASTM | A29/A29M | USA | General specification for alloy steels |
| EN | EN36 | Europe | Primary designation |
| DIN | 20MnCr5 | Germany | Similar properties but different composition |
| JIS | SCr440 | Japan | Equivalent with slight variations |
The differences between these grades can affect performance in specific applications. For instance, while AISI 8620 and EN36 are similar, the latter may offer better hardenability due to its chromium content.
Key Properties
Chemical Composition
| Element (Symbol and Name) | Percentage Range (%) |
|---|---|
| Carbon (C) | 0.18 - 0.22 |
| Manganese (Mn) | 0.60 - 0.90 |
| Chromium (Cr) | 0.90 - 1.20 |
| Nickel (Ni) | 0.40 - 0.70 |
| Silicon (Si) | 0.15 - 0.40 |
| Phosphorus (P) | ≤ 0.025 |
| Sulfur (S) | ≤ 0.025 |
The primary role of carbon in EN36 is to enhance hardness and strength, while manganese improves hardenability and tensile strength. Chromium contributes to corrosion resistance and hardenability, making it suitable for high-stress applications.
Mechanical Properties
| Property | Condition/Temper | Test Temperature | Typical Value/Range (Metric) | Typical Value/Range (Imperial) | Reference Standard for Test Method |
|---|---|---|---|---|---|
| Tensile Strength | Quenched & Tempered | Room Temp | 800 - 1000 MPa | 116,000 - 145,000 psi | ASTM E8 |
| Yield Strength (0.2% offset) | Quenched & Tempered | Room Temp | 600 - 800 MPa | 87,000 - 116,000 psi | ASTM E8 |
| Elongation | Quenched & Tempered | Room Temp | 10 - 15% | 10 - 15% | ASTM E8 |
| Hardness (HRC) | Quenched & Tempered | Room Temp | 30 - 40 HRC | 30 - 40 HRC | ASTM E18 |
| Impact Strength | Quenched & Tempered | -20 °C | 30 - 50 J | 22 - 37 ft-lbf | ASTM E23 |
The combination of high tensile and yield strength, along with good elongation, makes EN36 steel suitable for applications that experience dynamic loading and require structural integrity.
Physical Properties
| Property | Condition/Temperature | Value (Metric) | Value (Imperial) |
|---|---|---|---|
| Density | Room Temp | 7.85 g/cm³ | 0.284 lb/in³ |
| Melting Point | - | 1425 - 1540 °C | 2600 - 2800 °F |
| Thermal Conductivity | Room Temp | 45 W/m·K | 31 BTU·in/h·ft²·°F |
| Specific Heat Capacity | Room Temp | 460 J/kg·K | 0.11 BTU/lb·°F |
| Coefficient of Thermal Expansion | Room Temp | 11.5 x 10⁻⁶/K | 6.36 x 10⁻⁶/°F |
The density of EN36 steel contributes to its weight and strength, while its thermal conductivity and specific heat capacity are important for applications involving heat treatment processes.
Corrosion Resistance
| Corrosive Agent | Concentration (%) | Temperature (°C) | Resistance Rating | Notes |
|---|---|---|---|---|
| Chlorides | 3-5% | 25 °C | Fair | Risk of pitting corrosion |
| Sulfuric Acid | 10% | 20 °C | Poor | Not recommended |
| Sea Water | - | 25 °C | Fair | Moderate resistance |
EN36 steel exhibits moderate corrosion resistance, particularly in chloride environments, where it may be susceptible to pitting. Compared to stainless steels like AISI 304, which offer excellent corrosion resistance, EN36 is less suitable for highly corrosive environments. However, its wear resistance makes it favorable in applications where mechanical stress is a concern.
Heat Resistance
| Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
|---|---|---|---|
| Max Continuous Service Temp | 300 °C | 572 °F | Suitable for prolonged exposure |
| Max Intermittent Service Temp | 400 °C | 752 °F | Short-term exposure |
| Scaling Temperature | 600 °C | 1112 °F | Risk of oxidation beyond this temp |
At elevated temperatures, EN36 steel maintains its strength but may experience oxidation. Proper heat treatment can enhance its performance in high-temperature applications.
Fabrication Properties
Weldability
| Welding Process | Recommended Filler Metal (AWS Classification) | Typical Shielding Gas/Flux | Notes |
|---|---|---|---|
| MIG | ER70S-6 | Argon + CO₂ | Preheat recommended |
| TIG | ER80S-Ni | Argon | Post-weld heat treatment |
| Stick | E7018 | - | Requires careful control |
EN36 steel is generally weldable, but preheating is recommended to avoid cracking. Post-weld heat treatment can help relieve stresses and improve toughness.
Machinability
| Machining Parameter | EN36 Steel | AISI 1212 | Notes/Tips |
|---|---|---|---|
| Relative Machinability Index | 60 | 100 | Moderate machinability |
| Typical Cutting Speed (Turning) | 30 m/min | 50 m/min | Adjust for tool wear |
Machining EN36 requires careful selection of cutting tools and parameters to achieve optimal results. It is less machinable than free-cutting steels like AISI 1212.
Formability
EN36 steel exhibits moderate formability. Cold forming is feasible, but hot forming is preferred for complex shapes. The material's work hardening can affect bend radii, necessitating careful design considerations.
Heat Treatment
| Treatment Process | Temperature Range (°C) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
|---|---|---|---|---|
| Annealing | 600 - 700 | 1 - 2 hours | Air | Softening, improved machinability |
| Quenching | 850 - 900 | 30 minutes | Oil or Water | Hardening, increased strength |
| Tempering | 150 - 300 | 1 hour | Air | Reducing brittleness, improving toughness |
The heat treatment processes significantly alter the microstructure of EN36 steel, enhancing its mechanical properties. Quenching increases hardness, while tempering reduces brittleness, making it suitable for high-stress applications.
Typical Applications and End Uses
| Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection |
|---|---|---|---|
| Automotive | Gear manufacturing | High tensile strength, wear resistance | Durability under load |
| Aerospace | Shaft components | Fatigue resistance, toughness | Safety and reliability |
| Machinery | Crankshafts | High strength, machinability | Precision engineering |
Other applications include:
- - Heavy machinery components
- - Tooling and dies
- - Structural components in high-stress environments
EN36 steel is chosen for these applications due to its combination of strength, toughness, and wear resistance, making it ideal for components subjected to dynamic loads.
Important Considerations, Selection Criteria, and Further Insights
| Feature/Property | EN36 Steel | AISI 4140 | AISI 8620 | Brief Pro/Con or Trade-off Note |
|---|---|---|---|---|
| Key Mechanical Property | High tensile strength | Good toughness | Excellent hardenability | EN36 offers a balance of properties |
| Key Corrosion Aspect | Fair | Poor | Fair | EN36 is more corrosion-resistant than 4140 |
| Weldability | Good | Moderate | Good | Preheating recommended for EN36 |
| Machinability | Moderate | Moderate | Good | EN36 is less machinable than 8620 |
| Approx. Relative Cost | Moderate | Moderate | Low | Cost varies by market conditions |
| Typical Availability | Common | Common | Common | Widely available in various forms |
When selecting EN36 steel, consider factors such as cost-effectiveness, availability, and specific application requirements. Its balance of properties makes it suitable for a wide range of engineering applications, particularly where high strength and durability are critical.
In summary, EN36 steel is a versatile material that excels in high-performance applications, offering a unique combination of strength, toughness, and wear resistance. Its properties can be tailored through heat treatment, making it a preferred choice in demanding environments.