Carbon Steel 1018
Medium low-carbon steel, has good weldability and slightly better machinability than the lower carbon steels.
Carbon Steel 1045
Medium-carbon steel, can be hammer forged. Can be heat treated, flame or induction hardened, but not recommended for carburizing or cyaniding. AISI cross reference for JIS S45C and KS SM45C.
Carbon Steel 1050
Applies only to structural shapes, plates, strip, and welded tubing. Semifinished products for forging, hot-rolled and cold-finished bars, wire rods, and seamless tubing.
Minimum Cu content when copper steel is specified. Used for guardrails.
Cu enhances the corrosion resistance.