Production of rolled multifunctional weathered steel plates and products thereby

A method of making a weathering grade steel plate includes the steps of establishing a minimum yield strength:plate thickness target from one of 50 KSI:up to 4'', 65 KSI:up to 1.5'', and 70 KSI:up to 1.25''. A modified weathering grade alloy composition is cast into a slab employing effective levels of manganese, carbon, niobium, vanadium, nitrogen, and titanium. The cast slab is heated and rough rolled to an intermediate gauge plate. The intermediate gauge plate is controlled rolled and subjected to one of air cooling or accelerated cooling depending on the minimum yield strength and thickness target. With the controlled alloy chemistry, rolling and cooling, the final gauge plate exhibits discontinuous yielding and can be used for applications requiring a 70 KSI minimum yield strength in plate thicknesses up to 1.25'', a 65 KSI minimum yield strength in plate thickness up to 1.50'' and a 50 KSI minimum yield strength for plates as thick as 4''.