EN 8 Steel: Composition, Properties, Uses and Equivalent Grades
Navdeesh Kandhari
10 minutes reading
Oct 7, 2026
What is EN 8 steel?
EN 8 is a medium carbon steel with about 0.35 to 0.45 percent carbon. It is stronger than mild steel, machines well and can be heat treated, which makes it one of the most widely used grades in India for shafts, axles, pins, bolts, studs and gears. Its closest equivalents are 080M40 in BS 970, 40C8 in IS 1570, C40 in European standards and, approximately, AISI 1040.
EN 8 is the grade we are asked about most often. This guide covers what it is made of, how it behaves, and when a different grade is the better choice.
Chemical composition
Element | Typical range (percent) |
|---|---|
Carbon | 0.35 to 0.45 |
Manganese | 0.60 to 1.00 |
Silicon | 0.05 to 0.35 |
Sulphur | 0.06 max |
Phosphorus | 0.06 max |
Always check the test certificate against the grade standard on your drawing. The exact limits vary slightly between standards and editions.
Mechanical properties
EN 8's properties depend on its condition. As supplied in the normalised or as rolled condition, it offers moderate strength with good ductility. Cold drawing raises its strength further, which is one reason bright EN 8 bars are so common. Hardening and tempering raises it again for heavily loaded parts. Add SSEW's typical tensile values for bright EN 8 by size.
What is EN 8 used for?
Shafts, axles and spindles.
Pins, bolts, studs and keys.
Gears, couplings and general machine parts.
Automotive and agricultural components.
Machinability, welding and heat treatment
Machinability. EN 8 machines well in the bright drawn condition, though not as freely as a free cutting grade like EN 1A.
Welding. It can be welded, but its carbon content means preheating and controlled cooling are usually needed to avoid cracking. Where a part must be welded often, a lower carbon grade may be simpler.
Heat treatment. EN 8 can be hardened and tempered for higher strength, and its surface can be flame or induction hardened for wear resistance while keeping a tougher core.
EN 8 compared with other common grades
Grade | Carbon level | Strength | Machinability | Choose it when |
|---|---|---|---|---|
EN 1A | Low, free cutting | Lower | Excellent | Volume machining, low load parts |
EN 8 | Medium | Medium | Good | General shafts, pins, bolts |
EN 9 | Higher | Higher, harder | Fair | Wear resistance matters |
EN 19 | Medium, alloyed | High | Fair | Heavily loaded, critical parts |
Frequently asked questions
Is EN 8 mild steel?
No. Mild steel is low carbon. EN 8 is medium carbon, with noticeably higher strength.
What is the Indian equivalent of EN 8?
40C8 under IS 1570.
Can EN 8 be welded?
Yes, with preheating and controlled cooling in most cases.
What is the difference between EN 8 and EN 9?
EN 9 has more carbon, so it is harder and more wear resistant, but less ductile and harder to machine.
Need EN 8 bright bars?
SS Engineering Works draws EN 8 bright bars in Sonipat, in sizes from X to Y mm: confirm. WhatsApp +91 70653 37337 with your size and quantity.