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1018 Mild Steel

1018 is the standard low-carbon mild steel, the baseline against which other steels are compared. With about 370 MPa yield and good ductility, it is inexpensive, readily weldable, and easy to work. It is not hardenable through-thickness by quenching but case-hardens well, making it a versatile general-purpose engineering steel.

How 1018 Mild Steel machines

Machines acceptably (rated 3.5/5) but can be slightly gummy because of its low carbon and lack of free-machining additives, producing stringy chips and a less crisp finish than leaded grades. Cold-drawn 1018 machines better than hot-rolled. Sharp tooling, good feeds, and coolant give clean results; for high-volume turning, 12L14 is far easier.

Manufacturing & processing

Suited to CNC milling and turning and to sheet/plate fabrication. It welds excellently by all common methods with no preheat needed, a key reason it is so widely used. It is readily carburized (case-hardened) for a hard wear surface over a tough core. Common finishes include zinc plating, black oxide, and painting.

Typical applications

Used everywhere general low-cost steel parts are needed: shafts, pins, spacers, brackets, fixtures, jigs, machine bases, studs, and weldments, plus carburized parts like gears and pins. It is the default for prototypes and production parts where moderate strength, weldability, and low cost matter more than hardness or strength.

When to choose it

Choose 1018 when you want a cheap, weldable, easily worked general-purpose steel and high strength is not required. Step up to 1045 for higher strength shafts, 4140 for heat-treatable high-strength parts, or 12L14 for high-volume screw-machine work. Pick 8620 when you specifically need a tough case-hardening steel.

Suitable surface finishes

Common finishes for 1018 Mild Steel: zinc plating, black oxide, powder coating, nickel plating. Use the finish selector →

FAQ

Can 1018 be hardened?
Not by through-hardening; its low carbon content (around 0.18%) means quenching produces little hardness. However, 1018 case-hardens well by carburizing, giving a hard, wear-resistant surface over a tough core. For parts needing through-thickness hardness, use a medium-carbon steel like 1045 or an alloy steel like 4140.
Is 1018 easy to weld?
Yes, very. As a low-carbon steel it welds excellently by MIG, TIG, stick, and other methods with minimal risk of cracking and no preheat required for typical sections. This easy weldability is a primary reason 1018 and similar mild steels are the default for fabricated steel weldments.
Is 1018 stronger than A36?
Slightly, in yield. 1018 yields around 370 MPa versus roughly 250 MPa for A36 structural steel. 1018 is a controlled bar-stock grade for machined parts, while A36 is a structural plate/shape grade specified for buildings and weldments; both are inexpensive low-carbon steels with good weldability.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.