Light micrograph of steel in thin section. Steel is an alloy of iron and carbon. The carbon content ranges between 0.05% (C5 steel) and 1.5% (C150 steel). The sample seen here is C35 steel, ie 0.35% carbon. The structure of such steels shows fragments of pearlite (fine iron carbide platelets in ferrite), held in a matrix of pure ferrite (body-centred cubic crystalline iron). Steels of this nature are relatively ductile and malleable, but still have significantly more strength than iron. Interference contrast illumination. Magnification x60 at 35mm size.