Structure and Mechanical Properties of Cold-Deformed Galvanized Rolled Sheets for Light Thin-Walled Constructions

Resumo

The influence of the cold plastic deformation that appear in bending zones and subsequent strain aging on the brittle fracture resistance of galvanized low-carbon steel sheets (2.0–3.0 mm thick) intended for light thin-walled constructions is studied. At low temperatures (from –55 to –70°C), cold working followed by strain aging is shown to substantially decrease impact toughness KCU and the fraction of the ductile component in the fracture surface of a steel sheet. The effect of the ferrite grain size on the susceptibility of steel sheets to brittle fracture, in particular, KCU ~ 1/\(\sqrt d \), where d is the ferrite grain size in the rolling plane, is found.