SAE 1018 steel

What 1018 identifies

Encore's 1 in diameter cold-drawn 1018 tables show 55 ksi expected minimum yield and 73 ksi typical yield. Preserve the table qualifier and bar diameter. A purchase guarantee needs the applicable order and verification. Encore cold-drawn property tables

SAE 1018 is a low-carbon steel grade. Eaton's published 1018 chemistry lists carbon 0.15–0.20% and manganese 0.60–0.90%. Those ranges identify chemistry, not a universal finished-product strength or dimensional tolerance. Eaton, 1018 hot-rolled bar

SAE's J403_202402, Chemical Compositions of SAE Carbon Steels, is marked stabilized February 23, 2024, with its prior technical revision in June 2014. Its public scope distinguishes cast/heat analysis from product-analysis allowances under SAE J409. It also states that the listed grades are SAE grades because AISI no longer issues steel grade designations. Historical “AISI 1018” terminology is therefore not a separate mechanical-property specification. SAE J403_202402 publisher record

Product specification and manufacturing route

ASTM's active A108-24 covers cold-finished carbon and alloy steel bars, in straight lengths and coils. Its scope identifies grades by numbers or chemistry; supplementary requirements apply when individually ordered. It is a product specification that adds context beyond a chemistry grade name. ASTM A108-24, public scope

Eaton identifies ASTM A576 among its hot-rolled 1018 capabilities and ASTM A108 for its cold-finished offering. Confirm the exact ordered specification and condition rather than inferring either from a catalogue title. Eaton hot-rolled 1018; Eaton cold-drawn 1018

Nucor distinguishes cold-rolled sheet/coil from cold-finished bar. Cold finishing includes drawing or turning, with dimensional tolerances depending on shape, carbon content and finishing method. “Cold rolled” is consequently too vague to define a precision bar purchase. Nucor cold-finished bar guidance

Encore explains an important distinction: cold drawing reduces oversize hot-rolled bar and changes mechanical properties, while larger turned-and-polished bars can retain the original hot-rolled properties. A bright machined surface does not prove that a bar has the strengthening associated with cold reduction. Encore, 1018 cold-finished characteristics

Mechanical-property examples are condition-specific

Eaton labels the following as estimated mechanical-property ranges, rather than guaranteed minima:

These are that supplier's estimates, without a size-specific qualification in the displayed property table. They are useful for seeing why processing condition matters, not for assigning every 1018 bar the cold-drawn column. Eaton hot-rolled estimates; Eaton cold-drawn estimates

Encore separately publishes both “expected minimum” and “typical” cold-drawn tables by diameter. For its 1 in. diameter example, the former gives 55 ksi yield, while the typical table gives 73 ksi yield. A supplier's expected-minimum reference table is not automatically a contractual guarantee for untested stock. Preserve the qualifier, diameter and route when carrying a value into a comparison. Encore property tables

If strength governs, require the applicable mechanical tests on the order.

Machining, welding and case hardening

Nucor describes 1018 round stock as weldable and associates its cold-finished products with machining and forming applications. This is a material-selection statement, not a complete procedure for every joint, section or service condition. Nucor product guidance

For welding, establish the actual joint design, stock condition, section thickness, restraint, consumable and acceptance criteria. Where properties depend on cold work, assess the final welded assembly rather than assuming the unwelded bar's catalogue values apply throughout it. A general “good weldability” description does not establish fatigue performance or finished-part dimensional accuracy.

Encore identifies 1018 as suitable for carburizing and lists gears, pinions and king pins among carburized applications. That describes a case-hardening route; it does not mean an as-supplied 1018 component already has a hard wear-resistant surface. Encore applications and processing

If a hardened case is needed, specify surface hardness, effective case depth, core requirements, allowable distortion and final inspection. Select and qualify the thermal route with the heat treater. Do not substitute one universal time/temperature cycle for differing geometries, case depths and equipment. Separate the surface requirement from bulk tensile strength and reserve finishing allowance where final dimensions matter.

For machining, establish the needed diameter, straightness, surface finish and stock allowance before selecting a finish. A nominal bar size is not a fit tolerance. For an outdoor or wet-service component, define corrosion protection independently of the chemistry designation.

Bounded strength interpretation example

Assume an ideal 1.000 in. diameter solid bar under 10 kip uniform axial tension. Gross area is π/4 × 1² = 0.7854 in²; nominal stress is 10 / 0.7854 = 12.73 ksi.

Using Encore's two cited 1 in. reference yield values would give simple gross-section yield-force products of 55 × 0.7854 = 43.20 kip and 73 × 0.7854 = 57.33 kip. The difference is 14.13 kip, despite the same grade and diameter. Neither is an allowable load: this example omits factors, connections, holes, eccentricity, fatigue and certification. Its purpose is to demonstrate why a typical value and an expected minimum must remain distinct.

Versions and release information

The cited standards are SAE J403_202402 and ASTM A108-24. Eaton, Nucor and Encore are live product pages without a specific issue date used here; their website copyright dates are not treated as datasheet revisions. Retain the ordered standards, heat/lot, condition, supplier certification and any subsequent processing record with the drawing and final inspection evidence.

See also grades, tempers and conditions.