EN8M
EN8M Free Cutting Bright Bar
Medium carbon strength with free cutting machinability — the best of both families.
Also known as 212M44 · AISI 1144
Overview
What EN8M is, and where it belongs
EN8M answers a common shop floor problem: the part needs medium carbon strength, but it also needs a lot of turning, and plain EN8 is slow to machine.
The solution is sulphur — raised to 0.12–0.20% instead of the 0.050% maximum in EN8 — together with higher manganese to bind it as manganese sulphide. Those sulphide inclusions break the chip and lubricate the cutting zone, lifting machinability by roughly a third over standard EN8 while the carbon content keeps the mechanical properties in the medium carbon class.
The trade-off is real and must be understood. Those same inclusions reduce transverse ductility and impact toughness, and they make the steel harder to weld soundly. EN8M belongs in machined parts, not in welded structures or in components taking heavy shock loading across the bar axis.
Chemistry
Chemical composition
As per BS 970 Part 3 : 212M44, certified per mill test certificate. Values are percentage by weight.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | 0.350 | 0.450 |
| Silicon | Si | — | 0.250 |
| Manganese | Mn | 0.900 | 1.300 |
| Phosphorus | P | — | 0.060 |
| Sulphur | S | 0.120 | 0.200 |
A dash in the minimum column means only an upper limit applies to that element.
Properties
Mechanical properties
Typical values in the Cold Drawn condition. Certified values for your consignment appear on the test certificate.
- Tensile Strength
- 620 – 780 MPa
- Yield Strength
- 470 – 560 MPa
- Elongation (A5)
- 8 – 14%
- Hardness
- 190 – 240 HB
- Impact toughness
- Lower than EN8Sulphide inclusions reduce transverse ductility — avoid heavy shock loading
Availability
Sizes and tolerances
We draw EN8M across the range below. Exact availability for a given size is confirmed on enquiry.
Round bar
6 – 60 mm
Nominal diameter
Hex bar
7 – 46 mm
Across flats (AF)
Tolerance bands
All bands are ISO 286 ‘h’ — the bar is never above nominal size. See exact values for your size.
Where it is used
Typical applications
- High-volume turned shafts and studs
- Machined pins, bushes and adaptors
- Automatic lathe components needing strength
- Hydraulic fittings and valve bodies
- Induction hardened wear surfaces
Application guides
Cross reference
International equivalents
Nearest designations under other standards. Equivalents are close but rarely identical — check the specific requirement that matters for your part.
Full equivalents chart| Standard | Designation |
|---|---|
| BS (UK) | 212M44 / EN8M |
| AISI / SAE (USA) | 1144 |
| DIN (Germany) | 44SMn28 / 1.0762 |
| JIS (Japan) | SUM43 |
| IS (India) | 40C15S12 |
Processing
Heat treatment guidelines
Indicative parameters. Actual cycles depend on section size, furnace and the properties your drawing calls for.
- 01Hardening820 – 860 °C, quench in oil
- 02Tempering550 – 660 °C, air cool
- 03Induction hardeningSuitable for localised surface hardening to 50 – 55 HRC
Index relative to AISI 1212 = 100. Higher is faster to machine.
Roughly 30–35% faster than EN8 at equivalent tool life. Chips break short and clear themselves, which matters most on unattended automatic machines. Surface finish off the tool is noticeably better than plain EN8.
Weldability: Limited
Related grades
Chemical composition and mechanical properties shown are as per the applicable standard and are indicative. Actual values for your consignment are certified in the Mill Test Certificate supplied with each dispatch. Available sizes and tolerances are confirmed at the time of enquiry.
Need EN8M?
Send us the size and quantity — Round 6–60 mm · Hex 7–46 mm. We will confirm availability and come back with a price.