Introduction
EN8 and EN9 are medium-carbon steels widely used in engineering, but their subtle differences impact strength, machinability, and heat treatment response. This guide compares:
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Chemical composition
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Mechanical properties
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Heat treatment effects
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Best-use cases
SteelMet Industries stocks EN8 and EN9 in round bars, flats, and forged blanks—tailored to your project needs.
Chemical Composition Comparison
| Element (%) | EN8 Steel | EN9 Steel |
|---|---|---|
| Carbon (C) | 0.36 – 0.44 | 0.50 – 0.60 |
| Silicon (Si) | 0.10 – 0.40 | 0.10 – 0.40 |
| Manganese (Mn) | 0.60 – 1.00 | 0.50 – 0.90 |
| Phosphorus (P) | ≤ 0.05 | ≤ 0.05 |
| Sulfur (S) | ≤ 0.05 | ≤ 0.05 |
🔹 Key Difference: EN9 has higher carbon (0.50-0.60%) vs. EN8 (0.36-0.44%), making it harder but less ductile.
Mechanical Properties
| Property | EN8 | EN9 |
|---|---|---|
| Tensile Strength | 700 – 850 MPa | 800 – 950 MPa |
| Hardness (BHN) | 201 – 255 | 248 – 302 |
| Elongation (%) | ~14% | ~10% |
✅ EN9 offers higher hardness and strength but lower ductility than EN8.
Key Differences & Applications
1. Machinability & Weldability
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EN8: Better weldability and moderate machinability (lower carbon).
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EN9: Superior hardness post-heat treatment but harder to machine.
2. Heat Treatment Response
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EN8: Typically used in normalized or tempered conditions.
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EN9: Excellent for quenching and tempering (achieves HRC 50+ hardness).
3. Common Uses
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EN8: Gears, axles, bolts, and general machinery parts.
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EN9: High-stress components like pins, shafts, and cutting tools.
Equivalents & Alternatives
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EN8 ≈ AISI 1040 (USA) | EN9 ≈ AISI 1060 (USA).
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For better machinability: EN1A (free-cutting steel).
Which Grade Should You Choose?
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Need strength + weldability? → EN8
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Require extreme hardness? → EN9 (heat-treated)
SteelMet Industries provides:
🔹 EN8/EN9 round bars, flats, and custom forgings
🔹 Pre-cut sizes, turned, drawn or ground finishes
🔹 Heat-treated options (annealed or normalised or quenched & tempered)
📞 Contact us for technical specs or bulk orders!
Conclusion
EN8 and EN9 serve different needs—EN8 for balanced properties, EN9 for high hardness. Understanding their differences ensures optimal material selection.
SteelMet Industries supplies both grades in ready-to-machine or heat-treated conditions—get a quote today!