CS · carbon steel
Carbon Steel 1018
The baseline mild steel: soft, predictable, cheap. Published machinability index around 78% against B1112 = 100%. It machines well and then rusts if you leave it overnight.
Quoting this material
- Typical lead time
- 5–10 working days
- Condition
- As-rolled, normalised, or cold drawn (cold drawn is roughly 15% stronger)
- Achievable finish
- Ra 1.6 µm typical · Ra 0.4 µm best
Machined in-house to your drawing: see the precision CNC machining service and the machine and inspection capability it runs on.
Machinability
Our own 1–10 shop ranking, not a published index: 10 is free-cutting brass C360, 1 is Inconel 718. It ranks how a material behaves on the floor - cycle time, chip control and tool life together. Where a published index exists it is quoted in the note.
The baseline mild steel: soft, predictable, cheap. Published machinability index around 78% against B1112 = 100%. It machines well and then rusts if you leave it overnight.
Properties as supplied
| Parameter | Value | Unit |
|---|---|---|
| Tensile strength | 440 | MPa |
| Yield strength | 370 | MPa |
| Elongation | 15 | % |
| Hardness | 126 | HB |
| Thermal conductivity | 51.9 | W/m·K |
| Modulus of elasticity | 205 | GPa |
Hardness, tensile and thermal figures are typical published values for the condition stated. Actual mill certificates govern; send the specification with the drawing and we confirm against the certificate before the material is cut.
Condition
As-rolled, normalised, or cold drawn (cold drawn is roughly 15% stronger)
Heat treatment
Too little carbon to through-harden meaningfully - 0.18% carbon will not respond to a quench. It can be case carburised to give a hard wear surface over a tough core, which is the usual reason to specify it for a wear part.
Achievable surface finish
Ra 1.6 µm
Ra 0.4 µm
Takes fine finishes and threads cleanly. Any finish other than a plating needs to be decided early: bare 1018 in a damp shop will show surface rust within days.
Tooling and cutting parameters
Cutting speed
- 150–300 m/min (carbide)
Feed
- 0.15–0.35 mm/rev turning · 0.10–0.25 mm/tooth milling
Tooling
- Coated or uncoated carbide; geometry is forgiving
Coolant
- Flood for turning and tapping, mist is often enough for milling
Starting points for carbide on a rigid setup, not a guarantee. The right numbers depend on the machine, the toolholder and the fixturing - ask and we will say what we would actually run.
Typical applications
- Shafts and spindles
- Weldments and frames
- Mounting plates and brackets
- Fixture components
- General purpose turned parts
DFM notes for this grade
- Not strong and not hard: if the part carries load or wears, it should be 1045 or 4140, or designed for carburising
- Cold-drawn bar is stiffer, machines better and holds a tolerance closer - worth specifying if the part is turned from bar stock
- Rust protection is part of the design: black oxide, zinc plating or paint, decided before the part is drawn
Questions buyers ask
- Can 1018 be hardened?
- Not through-hardened - there is not enough carbon. It can be case carburised to roughly 0.5–1 mm of hard surface at 58–62 HRC with a soft core, which is ideal for a wear surface on a part that must not become brittle throughout.
- Why is 12L14 sometimes suggested instead of 1018?
- Because on a high-volume turned part it can halve the cycle time. The trade is that leaded steel is not welded and is restricted in some specifications - if the part is a simple turned fitting, the saving is real.