EFFECTS OF CARBON CONTENT, ROLLING CONDITION AND COOLING RATE ON THE MECHANICAL-PROPERTIES OF AS-ROLLED HIGH-STRENGTH LOW-ALLOY STEEL

The effects of carbon content, rolling condition and cooling rate on the mechanical properties were examined for non heat-treated steels of 80 to about 100 kgf/mm**2 tensile strength grade. Titanium, boron, and niobium microalloyed 0. 1%C-1. 8%Mn steel was found to provide a good combination of high strength and high ductility after hot rolling. The controlled rolling produces a fine acicular ferrite structure and consequently improves the toughness more effectively than any other rolling conditions.