SAE 1018
SAE 1018 Bright Bar
Controlled-chemistry low carbon steel — the carburising and cold forming standard.
Also known as AISI 1018 · C15
Overview
What SAE 1018 is, and where it belongs
SAE 1018 is what mild steel becomes when the chemistry is actually specified rather than left to a broad commercial range. Carbon is held between 0.15 and 0.20% and manganese between 0.60 and 0.90% — a narrow window that makes the steel behave the same way in every batch.
That consistency is why 1018 dominates two applications in particular. In cold forming, predictable ductility means a header can be set up once and run without adjusting for incoming material. In carburising, uniform base carbon means uniform case depth across a whole batch of parts — the same reasoning that makes 16MnCr5H valuable at the alloy end of our range.
Compared with commercial MS, 1018 delivers a better machined finish, better response to carburising and tighter dimensional consistency. It costs a little more, and for any part where rework is expensive that difference pays for itself immediately.
Chemistry
Chemical composition
As per SAE J403 / AISI 1018, certified per mill test certificate. Values are percentage by weight.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | 0.150 | 0.200 |
| Silicon | Si | 0.100 | 0.250 |
| Manganese | Mn | 0.600 | 0.900 |
| Phosphorus | P | — | 0.040 |
| Sulphur | S | — | 0.050 |
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
- 440 – 520 MPa
- Yield Strength
- 370 MPa min
- Elongation (A5)
- 15 – 20%
- Hardness
- 126 – 160 HB
- Reduction of Area
- 40% min
Availability
Sizes and tolerances
We draw SAE 1018 across the range below. Exact availability for a given size is confirmed on enquiry.
Round bar
6 – 65 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
- Carburised pins, bushes and shafts
- Cold headed and cold formed parts
- Hydraulic and pneumatic components
- Precision machined assemblies
- Welded structural components
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 |
|---|---|
| AISI / SAE (USA) | 1018 |
| IS (India) | C15 / 15C8 |
| BS (UK) | 080A15 / EN3B |
| DIN (Germany) | C15 / CK15 (1.0401 / 1.1141) |
| JIS (Japan) | S15C / S20C |
Index relative to AISI 1212 = 100. Higher is faster to machine.
Better finish than commercial MS thanks to controlled chemistry, but still a ductile steel that produces a long chip. Sharp tooling and adequate coolant give the best surface. For heavy volume turning, move to a free cutting grade.
Weldability: Excellent
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 SAE 1018?
Send us the size and quantity — Round 6–65 mm · Hex 7–46 mm. We will confirm availability and come back with a price.