A solid mild steel $5$ cm diameter by $6\mathrm{.}25$ cm long cylinder initially at $650C$ is

quenched during heat treatment in a fluid at $90C$ with $850\frac{W}{m^2}-C.$

Determine the centerline temperature at the midpoint of length at $t=2\mathrm{.}7$ minutes

after immersion. Use $=1\mathrm{.}2{10}^{-5}\frac{m^2}{s}$ and $k=43\mathrm{.}2\frac{W}{m}-K.$ANSWER: $108$ DEG C