Full annealing is accomplished by heating at a temperature approximately how many degrees Celsius above either A3 line (for compositions less than the eutectoid) or A1 line (for compositions greater than the eutectoid)? 25°C 40°C 50°C 55°C 70°C g

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.