EN8 is a plain medium-carbon steel with 0.36–0.44% carbon and 0.60–1.00% manganese, and no deliberate alloying. It machines well, responds to heat treatment and costs less than alloy steels, which is why it is the default bar grade in Indian engineering. In the R condition it delivers 700–850 MPa tensile strength at 201–255 HB, enough for most shafts, spindles, gears, studs and hydraulic components.
OneKaizen sources EN8 from India's leading mills and international partner mills and supplies it as rolled round bars in Ø 16–500 mm, bright bars in Ø 8–160 mm, bright hex bars in 18–50 mm AF and square bars in 20–480 mm, plus forged bars in Ø 250–1,030 mm and shafts in Ø 25–500 mm. Delivery condition is your choice: hot rolled, normalised, cold drawn, bright turned or quenched and tempered. Every consignment ships with a mill test certificate.
EQUIVALENT GRADES
EN8 Equivalents
Direct means the same grade under another name. Close means the same alloy concept with slightly different limits, commonly substituted. Approximate means similar use with real differences: check with us before substituting.
| Standard | Designation | Match |
|---|---|---|
| Old BS EN | EN8 | Direct |
| Old BS EN | EN8D | Close |
| BS 970 | 080M40 | Direct |
| IS | 40C8 | Close |
| EN | C40E (1.1186) | Close |
| EN | C45E (1.1191) | Close |
| DIN W.Nr. | 1.1191 | Close |
| AISI/SAE | 1040 | Close |
| AISI/SAE | 1045 | Close |
| JIS | S45C | Close |
| JIS | S40C | Close |
| KS | SM45C | Close |
| GB | 45 | Close |
EN8 Chemical Composition
Per BS 970-1:1983 (080M40, EN8)
| Element | Range, wt % | Range chart |
|---|---|---|
| C | 0.36 – 0.44 | |
| Si | 0.1 – 0.4 | |
| Mn | 0.6 – 1 | |
| P | ≤ 0.05 | |
| S | ≤ 0.05 |
EN8 and Its Equivalents: Chemical Composition
Equivalent grades are written to different standards, so their limits differ slightly. Use the column for the standard on your drawing or purchase order.
| Element | 080M40 (EN8) BS 970-1:1983 | C40E EN 10083-2 | 1040 SAE J403 | S40C JIS G4051 |
|---|---|---|---|---|
| C % | 0.36–0.44 | 0.37–0.44 | 0.37–0.44 | 0.37–0.43 |
| Si % | 0.10–0.40 | ≤ 0.40 | – | 0.15–0.35 |
| Mn % | 0.60–1.00 | 0.50–0.80 | 0.60–0.90 | 0.60–0.90 |
| P % | ≤ 0.05 | ≤ 0.025 | ≤ 0.04 | ≤ 0.03 |
| S % | ≤ 0.05 | ≤ 0.035 | ≤ 0.05 | ≤ 0.035 |
EN8 Mechanical Properties
| Condition | Tensile, MPa | Yield min, MPa | Elongation min, % | Hardness |
|---|---|---|---|---|
| Condition R (BS 970 080M40) | 700 – 850 | – | – | 201-255 HB |
Delivery Condition and Heat Treatment
Typical practice is to normalise at about 830–860 °C and air cool for a uniform structure, or to harden from a similar temperature, quench and temper to the strength you need. EN8 is a shallow-hardening steel, so it hardens fully only in small sections and the core of a large bar stays softer than the surface. If you need uniform strength through a larger section, EN19 is the grade to move up to.
EN8 machines easily in the normalised condition and can be induction or flame hardened where only the surface needs to be hard, for example on journals and gear teeth.
Weldability is limited. Carbon at 0.36–0.44% makes the weld zone hard, so welding needs preheat and ideally a stress relief afterwards. For welded construction, a low-carbon grade is the better choice.
What We Supply EN8 In
Round BarsRolled Ø 16–500 mm · Forged to order↗
Bright BarsRound Ø 8–160 mm · Hex 18–50 mm AF↗
Forged BarsRound Ø 250–1,030 mm · Square 280–800 mm↗
ShaftsDiameter Ø 25–500 mm · Length 300–6,000 mm↗
Hex BarsHot rolled 18–60 mm AF · Bright 18–50 mm AF↗
Square BarsSquare 20–480 mm↗
RCSRound-corner square 20–75 mm↗
Where EN8 Is Used
Industries: General engineering, Automotive, Fasteners, Agricultural equipment, Machine tools, Hydraulics, Material handling
Compare EN8 with Similar Grades
EN8 Questions
What is the difference between EN8 and EN9?
EN9 (070M55) has a higher carbon content than EN8, so it is stronger and harder but machines less easily and is less ductile. EN8 is the general-purpose choice; EN9 is used for parts needing more strength or wear resistance without alloying.
What is the difference between EN8 and EN19?
EN19 is a chromium-molybdenum alloy steel; EN8 is unalloyed. EN19 hardens deeper into the section and reaches much higher strength after quenching and tempering, 900–1,300 MPa against 700–850 MPa for EN8 in the R condition. EN8 costs less and machines more easily, so use it when your section is small or your strength requirement is moderate.
Is EN8 the same as C45?
No, it is close but not identical. EN8 (080M40) has carbon at 0.36–0.44%, while C45 and SAE 1045 sit in a higher carbon band, and C45E specifies tighter phosphorus and sulphur limits than the 0.05% maximum in EN8. In most applications they are used interchangeably; tell us if your drawing specifies C45E.
What hardness does EN8 have?
In the R condition (BS 970 080M40) it is 201–255 HB with 700–850 MPa tensile strength. After hardening and tempering the hardness depends on the tempering temperature and the section size. Tell us the hardness you need and we supply it in that condition.
Can EN8 be welded?
It can, with preheat and stress relief, but it is not a weld-friendly grade. The medium carbon content makes the heat-affected zone brittle if cooled quickly.
What is the minimum order for EN8 bright bars?
3 tonnes, flexible depending on grade, size and your situation. Round bars, hex bars, square bars, forged bars and shafts are supplied on request; send us your size, condition and quantity.
What is EN8 equivalent to?
EN8 is the same grade as Old BS EN EN8, BS 970 080M40. Close equivalents are Old BS EN EN8D, AISI/SAE 1040, AISI/SAE 1045, EN C40E, EN C45E, DIN W.Nr. 1.1191.
In which forms do you supply EN8?
OneKaizen supplies EN8 as Round Bars, Bright Bars, Forged Bars, Shafts, Hex Bars, Square Bars, RCS, delivered across India and exported to buyers abroad.
Do you supply EN8 with a mill test certificate?
Yes. Every lot ships with an EN 10204 3.1 mill test certificate showing chemistry and mechanical properties, traceable to the heat number.
Data compiled by the OneKaizen metallurgy team from the standards named above. Updated 26 October 2026. Equivalents are nearest matches; confirm critical substitutions against the governing standard and mill certificate.