EN1A
EN1A Free Cutting Bright Bar
The highest-volume free cutting grade — built to be turned fast.
Also known as 230M07 · AISI 1213 · 9SMn28
Overview
What EN1A is, and where it belongs
EN1A is the steel that keeps automatic lathes running. Sulphur is raised to 0.20–0.30% and combined with manganese, forming manganese sulphide inclusions distributed through the bar. Those inclusions are deliberate weak points that fracture the chip as it forms.
The consequence on a shop floor is immediate. Instead of a continuous ribbon of swarf wrapping around the tool and the workpiece, the chip breaks into short curls that fall clear. Spindle speeds rise, tool life extends, surface finish improves, and — critically for a multi-spindle automatic running a night shift — the machine does not jam.
EN1A is not a strength grade. Carbon is below 0.15%, so it cannot be hardened usefully and its tensile strength is modest. It exists for parts defined by their shape and finish rather than their load: nuts, studs, couplings, adaptors, spacers, bushes and the enormous variety of small turned components that any engineering cluster consumes.
Where the part will be plated or case hardened afterwards, EN1A carburises acceptably to give a hard skin — a common route for low-cost wear parts.
Chemistry
Chemical composition
As per BS 970 Part 3 : 230M07, certified per mill test certificate. Values are percentage by weight.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | 0.070 | 0.150 |
| Silicon | Si | — | 0.100 |
| Manganese | Mn | 0.800 | 1.200 |
| Phosphorus | P | — | 0.070 |
| Sulphur | S | 0.200 | 0.300 |
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
- 480 – 600 MPa
- Yield Strength
- 380 – 450 MPa
- Elongation (A5)
- 7 – 12%
- Hardness
- 140 – 190 HB
Availability
Sizes and tolerances
We draw EN1A across the range below. Exact availability for a given size is confirmed on enquiry.
Round bar
5.5 – 65 mm
Nominal diameter
Hex bar
6 – 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
- Nuts, bolts and fasteners
- Screw machine and automatic lathe components
- Couplings, adaptors and fittings
- Spacers, bushes and washers
- Hex bar turned parts in volume
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) | 230M07 / EN1A |
| AISI / SAE (USA) | 1213 / 1215 |
| DIN (Germany) | 9SMn28 / 1.0715 |
| JIS (Japan) | SUM22 |
| IS (India) | 9S20 / 11S22 |
Index relative to AISI 1212 = 100. Higher is faster to machine.
The benchmark free cutting grade. Short broken chips, high permissible cutting speeds and long tool life. For the very highest speed automatic work — or wherever surface finish off the tool must be exceptional — EN1A PB is a further step up.
Weldability: Not recommended
Related grades
Further reading
- Bright Bar vs Black Bar: What Cold Drawing Actually Changes7 min read
- EN1A vs EN1A PB: What the Lead Actually Does6 min read
- How to Calculate Bright Bar Weight (Round, Hex and Square)5 min read
- Understanding h9, h10 and h11 Tolerance on Bright Bar6 min read
- Free Cutting Steel Explained: Why Adding Sulphur Makes Steel Better6 min read
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 EN1A?
Send us the size and quantity — Round 5.5–65 mm · Hex 6–46 mm. We will confirm availability and come back with a price.