5. Stress Relieving a Copper Alloy Rod by Radiant Heating When Temperature Gradients Within The Rod are Negligible

In an electrical motors factory, after machining, copper alloy rods are stress relieved at a temperature of 260 C for 1 hour. Stress relieving is done in a vacuum oven to avoid surface oxidation and the vacuum oven’s inner surfaces have radiant heating elements. A copper alloy cylindrical rod which has a characteristic length, $Lcu=VcuAcu=0.5Rcu$⁠, or 0.005 m, has to be stress relieved by placing it in the middle of a vacuum oven with radiation heaters at its inner surfaces as shown in Figure 5-1.