Grade 1018
Carbon and structural steel · AISI 1018 / SAE 1018, UNS G10180, EN 1.0401
AISI 1018 Mild Cold-Finished Low-Carbon Steel, carbon steel.
Data sheet
| Designations | AISI 1018 / SAE 1018 · UNS G10180 · EN 1.0401 (C15) |
|---|---|
| Standards | ASTM A29, ASTM A108, SAE J403 |
Metallurgy
Reference data for AISI 1018 Mild Cold-Finished Low-Carbon Steel, against ASTM A29, ASTM A108, SAE J403.
Elemental composition
C15 to 1.0401
- Carbon 0,18%0,15–0,20%
- Other additions 1,05%Mn, Si, P, S
- Iron 98,78%Balance
Proportions use the normalised midpoint of each specified range. The midpoint is a derived figure, not something the standard states: read the table for what is actually specified.
Performance profile
Comparative scores out of ten, for weighing one grade against another
These are relative ratings, not measured properties, and they carry no units. Use them to narrow a shortlist, then work from the specified values.
Composition as specified
| Element | Specified | Nominal |
|---|---|---|
| Iron Fe | Balance | 98,78% |
| Carbon C | 0,15–0,20% | 0,18% |
| Manganese Mn | 0,60–0,90% | 0,75% |
| Silicon Si | 0,15–0,35% | 0,25% |
| Phosphorus P | max 0,040%cap | 0,020% |
| Sulphur S | max 0,050%cap | 0,025% |
A cap is a ceiling, not a quantity: a heat may contain far less. The nominal column is the midpoint of each range, used for the chart's proportions only.
Mechanical and physical properties
| Property | Value |
|---|---|
| Tensile strength, ultimate | 440 MPa63,8 ksi |
| Yield strength, 0,2% offset | 370 MPa53,7 ksi |
| Elongation at break | 15% |
| Hardness | 126 HBW / 71 HRB |
| Modulus of elasticity | 205 GPa29,7 Mpsi |
| Density | 7,87 g/cm³0,28 lb/in³ |
| Thermal conductivity | 51,9 W/(m·K)360 BTU·in/(hr·ft²·°F) |
| Thermal expansion | 11,9 µm/(m·K)6,6 µin/(in·°F) |
Test condition not yet confirmed. These figures are typical values for the grade; the condition a bar was supplied in changes them materially, so ask us for the mill certificate before designing to a number.
Pitting resistance
Pitting resistance describes the passive chromium oxide film on a stainless steel. 1018 has no such film, so a PREN score does not apply to it. It relies on a coating, plating or galvanising for corrosion protection instead.
Corrosion and fabrication
Chloride and marine service
No intrinsic corrosion resistance; requires plating (zinc, chrome) or phosphate conversion coating.
Acidic and chemical media
Rapid dissolution in acidic solutions; unsuited for chemical immersion.
Sensitisation and thermal behaviour
Not applicable; ideal substrate for case hardening (carburizing, carbonitriding) to achieve high surface wear resistance while retaining a ductile core.
Welding
Excellent; can be readily welded with all common welding methods without pre-heat.
Machining and cold forming
Machinability index 78% relative to AISI 1212. Very Good; cold drawn bars have high dimensional tolerance and smooth surface.
Where it is used
- Carburized gears, ratchets, and camshaft drive sprockets
- Shafts, pins, studs, bolts, and machine tie-rods
- Drill bushings, dowel pins, and fixture components
- Hydraulic cylinder tie rods and low-stress spindles
Automotive · Industrial Machinery · Tooling & Fixtures · Manufacturing
Performance scores in full
The same six scores the profile plots, as numbers.
| Property | 1018 |
|---|---|
| Corrosion resistance | 2 / 10 |
| Weldability | 9.2 / 10 |
| High-temperature resistance | 4 / 10 |
| Tensile strength | 5.2 / 10 |
| Cold formability | 7.5 / 10 |
| Machinability | 7.8 / 10 |
This page is guidance for selecting a grade, not a specification. Design to the governing standard and the mill certificate for the heat you are supplied.
The specifications and data on this site are provided for general information only. Verify any real-world project with a qualified metallurgist before relying on these figures. We take no responsibility for the use and application of this information.