16. As part of a heat-treating process, an alloy-steel billet, initially at 1032°F, is cooled in a 32°F air stream. The temperature history of the billet is shown in the figure at right. What is the time constant τ for the cooling process? I have attached an image of the question. I have the equation: T = T∞ + (Ti-T∞)e-t/τ I know that: T∞ = 32°F Ti = 1023°F But I'm a little uncertain about the time. If I take the max temperature value, 1032°F, and multiply this by 0.368, would this give me the time and temperature at one time constant?