EN8 (080M40) Forgings
EN8 is the default medium carbon steel of Indian engineering: 0.36–0.44% carbon, unalloyed, forgiving to forge, responsive to normalising and capable of induction hardening on wear surfaces. It handles the vast majority of general-duty forged parts at the lowest cost per kilogram.
- Carbon
- 0.36 – 0.44%
- Manganese
- 0.60 – 1.00%
- Tensile (normalised)
- 620 – 700 MPa
- Hardness
- 200 – 255 BHN
- Forging Temperature
- 1100 – 1200 °C
- Equivalent
- AISI 1040, C40, 080M40
EN8 (080M40) Forgings at a glance
Quotable facts from Avadh Techno Forge, Gundasara, Gondal, Rajkot.
- Carbon: 0.36 – 0.44%
- Manganese: 0.60 – 1.00%
- Tensile (normalised): 620 – 700 MPa
- Hardness: 200 – 255 BHN
- Forging Temperature: 1100 – 1200 °C
- Equivalent: AISI 1040, C40, 080M40
Chemistry and Character
Carbon 0.36–0.44%, manganese 0.60–1.00%, with no deliberate alloying. That simplicity is the point: predictable forging behaviour, wide temperature window, easy machinability and no supply problems anywhere in India.
Heat Treatment Response
Normalising gives 200–255 BHN and a uniform ferrite-pearlite structure. Through hardening is limited by low hardenability on thick sections, so EN8 is usually induction hardened locally where wear resistance is needed rather than hardened throughout.
- Normalised: 200–255 BHN
- Induction hardened: up to 55 HRC surface
- Limited through-hardening depth
- Excellent machinability
Where EN8 Is the Right Call
Shafts, spindles, levers, brackets, studs, sprockets, pins, hydraulic rods and general machinery parts up to moderate load. Above roughly 700 MPa tensile requirement, or on sections above 60 mm needing uniform hardness, move to EN19.
People also ask
Can EN8 be through hardened?
Only in thin sections. Its low hardenability leaves a soft core in anything above roughly 60 mm, which is why induction hardening is used for local wear resistance instead.
What is EN8 equivalent to internationally?
AISI 1040, DIN C40 and BS 080M40 — all medium carbon unalloyed steels of substantially the same composition.
Topics covered on this page
- EN8 forging manufacturer India
- 080M40 forged components
- EN8 steel forging Rajkot
- medium carbon steel forging supplier
Based on work carried out at our own forging plant at Gundasara, Gondal, Rajkot — operating since 2008.
Questions Answered
What is EN8 equivalent to?
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AISI 1040, DIN C40 and BS 080M40 are the common equivalents, all medium carbon unalloyed steels.
Can EN8 be hardened?
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Locally, yes — induction hardening reaches around 55 HRC on the surface. Through-hardening thick sections is limited by its low hardenability.
Is EN8 good for forging?
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Very. It has a wide forging temperature window and forgiving flow behaviour, making it the most economical general-purpose forging grade.
When should I upgrade from EN8?
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When tensile requirement exceeds about 700 MPa, when sections above 60 mm need uniform properties, or when fatigue loading is severe.