High-strength steel is required for use in building structures and equipment (e.g., cranes). It is produced by heat treating quench-hardened steel in a process called tempering that reduces brittleness and imparts toughness. In a production facility, alloy steel plates (k = 50 W/m K, c = 460 J/kg K, and p = 7865 kg/m³) of thickness 3.0 cm have to be tempered in a convective oven by heating them to 550°C. If the plates are initially at 40°C and the air inside the heat treating oven is at 700°C with a convective heat transfer coefficient of 45 W/m²•K, determine how long the plate has to remain in the oven.