Composition & metallurgy

Typically about 0.25–0.60% carbon. Manganese is commonly present, and some grades are modified with chromium, molybdenum or nickel for greater hardenability.

Common grades and standards

SAE/AISI 1030, 1035, 1040, 1045, 1050, 1055; alloyed machine grades such as 4140 are related but classified as alloy steel.

Typical applications

Shafts, axles, crankshafts, couplings, gears, forged components, railway parts, pins, connecting rods and machine components.

Engineering characteristics

Can be normalized, quenched and tempered, or induction hardened. Weldability requires more control than low-carbon steel, especially for thicker sections and higher carbon equivalents.

Known manufacturers and producer regions

India — Tata Steel, JSW, SAIL; Japan — Nippon Steel, JFE, Kobe Steel; South Korea — POSCO, Hyundai Steel; China — Baowu, CITIC Special Steel, Shagang; United States — Nucor, Cleveland-Cliffs; Europe — Ovako, voestalpine, Saarstahl.

Selection checklist

Confirm product form, design code, strength level, toughness/impact requirement, service temperature, corrosion exposure, weldability, forming route, heat-treatment condition, dimensional tolerance, inspection level and mill certification. Do not substitute a “similar” grade solely from a cross-reference table without checking the governing specification.

Element Folio engineering reference. Grade ranges are typical and may vary by standard. Verify the latest ASTM/ASME, EN, JIS, API or other governing specification and the mill’s current product data before procurement.