In a metal manufacturing plant and its heat treatment process, a long, hexagonal copper extrusion (or rod) comes out of a heat-treatment furnace at 400°C and is then quenched by immersing it in a 50°C airstream
flowing perpendicular to its axis at 10 m/s as depicted in the figure. The surface of the copper has an emissivity of 0.9 due to oxidation in this process. The rod is 3 cm across opposing flat sides, and it has
a cross-sectional area of 7.79 cm² with a hexagonal perimeter of 10.4 cm. Determine the time required for the center of the copper to cool to 100°C.

Transcribed Image Text:

Air U = 10 m/s T = 50°C 3 cm Copper extrusion