Introduction
The EN8 series represents a family of versatile medium-carbon steels with subtle variations that impact machinability, strength, and heat treatment response. This guide compares:
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Chemical composition differences
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Mechanical properties
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Optimal heat treatment
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Recommended applications
Steelmet Industries supplies all EN8 variants as:
🔹 Round bars (Ø 10mm – 300mm)
🔹 Flat bars and forged blanks
🔹 Turned or ground precision stock
Chemical Composition Comparison
| Grade | C% | Si% | Mn% | P% | S% | Other |
|---|---|---|---|---|---|---|
| EN8 | 0.36-0.44 | 0.10-0.40 | 0.60-1.00 | ≤0.05 | ≤0.05 | – |
| EN8A | 0.36-0.44 | 0.10-0.40 | 0.60-1.00 | ≤0.05 | ≤0.05 | Improved purity |
| EN8B | 0.36-0.44 | 0.10-0.40 | 0.60-1.00 | ≤0.05 | ≤0.05 | Lead added |
| EN8C | 0.36-0.44 | 0.10-0.40 | 0.60-1.00 | ≤0.05 | ≤0.05 | Sulfur increased |
| EN8D | 0.36-0.44 | 0.10-0.40 | 0.60-1.00 | ≤0.05 | ≤0.05 | Controlled Mn |
| EN8M | 0.36-0.44 | 0.10-0.40 | 0.90-1.50 | ≤0.05 | ≤0.05 | Higher Mn |
| EN8DM | 0.36-0.44 | 0.10-0.40 | 0.90-1.50 | ≤0.05 | ≤0.05 | Higher Mn + controlled chemistry |
🔹 Key Variations:
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EN8B: Contains lead (Pb) for improved machinability
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EN8C: Higher sulfur for better chip formation
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EN8M/EN8DM: Increased manganese for better hardenability
Mechanical Properties (Normalized Condition)
| Grade | Tensile (MPa) | Yield (MPa) | Elongation (%) | Hardness (BHN) |
|---|---|---|---|---|
| EN8 | 700-850 | 460 | 14 | 201-255 |
| EN8A | 700-850 | 460 | 14 | 201-255 |
| EN8B | 700-850 | 460 | 14 | 201-255 |
| EN8C | 700-850 | 460 | 14 | 201-255 |
| EN8D | 700-850 | 460 | 14 | 201-255 |
| EN8M | 800-950 | 550 | 12 | 248-302 |
| EN8DM | 800-950 | 550 | 12 | 248-302 |
✅ EN8M/EN8DM offer 15-20% higher strength due to increased manganese
Key Differences & Applications
1. Machinability Comparison
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Best Machinability: EN8B (lead added) > EN8C (sulfur added) > Standard EN8
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EN8M/EN8DM: Require more power but maintain good tool life
2. Heat Treatment Response
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EN8M/EN8DM: Achieve deeper hardening (ideal for large sections)
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Standard EN8: Suitable for smaller components
3. Recommended Uses
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EN8/EN8A: General engineering components, shafts, bolts
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EN8B/EN8C: High-volume machined parts (gears, fittings)
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EN8M/EN8DM: Heavy-duty gears, high-stress components
Equivalents & Alternatives
| Grade | AISI | DIN | ISO |
|---|---|---|---|
| EN8 | 1040 | 1.0511 | C40 |
| EN8M | 1045 | 1.1191 | C45 |
For better machinability: EN1A (free-cutting steel)
Selection Guide
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General purpose: EN8/EN8A
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Mass machining: EN8B/EN8C
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Heavy sections/strength: EN8M/EN8DM
Steelmet Industries provides:
🔹 All EN8 variants in stock
🔹 Custom heat treatment (quenching & tempering)
🔹 Precision ground bars (h9 tolerance)
📞 Contact our technical team for grade recommendations.
Conclusion
While all EN8 grades share similar base composition, subtle variations significantly impact their performance in machining, heat treatment, and final applications.
Steelmet Industries maintains ready stock of all EN8 variants – from standard EN8 to specialty EN8DM. Request a quote for your specific requirements.